Supernaut72

Hey there, new to the forums but I've learned a lot from this place in the past. I'd appreciate a little bit of help trying to figure out what's wrong with this 88 Custom I just picked up. Sorry for the length of the post, but there's quite a bit to cover!

Here are the symptoms I'm working with:

-Knocking sound at fast-idle (sounds like marbles in a coffee can, and it sounds like it's coming from the top end, but I'm really not 100% sure on that as I've only briefly run the motor for fear of truly screwing something up.) I've pulled the valve covers and the pushrods all seem to be oiling fine, so I'm pretty sure it's not that. Don't know if the sound subsides at lower idle speed, because I've been hesitant to try running it any more before I gather some opinions.
-Dry carbon fouling on all eight spark plugs.
-Water pump leaks like a sieve, have a replacement on hand and plan to replace that today or tomorrow.
-Engine runs for a couple of minutes before growing weak, then shaking and stopping with hot coolant spraying from the bad pump. Found this out the hard way while trying to diagnose the ticking sound. Engine still cranks and starts, thankfully.

The engine is the original 425 2-barrel with about 120,000 miles on it. Besides this issue, it seems great-- it starts up the first time, every time, with the slightest twist of the key. Not sure if this is the 9:1 or 10.25:1 compression ratio version of the 2v 425. It does have an unmodified black air cleaner, complete with service instructions painted on the side and a "Super Rocket" emblem on top. Not sure if that's any indicator.
I am running straight 91 octane pump gas (the best I can acquire here, short of racing fuel or octane boosters.)


My theory is that the engine is having issues with the 91 octane fuel, which is causing it to pre-ignite and get very hot, very fast (carbon fouling on spark plugs can't be helping). The bad water pump and lack of cooling system pressure cause a total overheat within 2 to 3 minutes. Does this sound plausible?

I'm thinking about getting an octane booster and replacing the plugs to see if that does anything to stop the knocking. Any suggestions for octane booster brand? Or does it sound like I'm looking in the wrong place for the issue? I'd rather not waste my money testing stuff like octane boosters if the issue is more likely to lie elsewhere. I can't imagine even a bottom-end-only rebuild would exactly be budget-friendly, if it comes to that, so every cent counts.


Thank you in advance!

jaunty75

I have a '67 Delta 88 with a 425. Currently has about 130,000 miles on it.

I don't know about the knocking sound.

If your car has the original air cleaner, and it's black, then you have the low compression version of the 425, and you should not be running premium fuel in it. High compression 425's came with a red air cleaner and a decal on the top that says "Ultra High Compression" and "Use Premium Fuel" on the right side.

Here's a photo of one:



Does the car have the original gas tank cap? That would say "premium fuel only" on it if the car takes that kind of fuel.

Some of your problems might be caused by fact that you're running premium fuel when you should be running regular. I would think that you should definitely not be putting an octane booster in your fuel tank.

Have you checked the engine timing? I would do a complete tune up with points, rotor, condenser, plugs, set the dwell and timing correctly, etc.


As far as overheating, yes, of course a bad water pump might be the cause. It caused also be due to an engine badly mis-timed. That's why it's so important to do a proper tune-up first along with replacing the water pump and making sure the rest of the cooling system is in good shape.


Let's see some photos of this beast! Here's one of mine:

droldsmorland

Back up a minute here. Lets start with some basics. Spark and Fuel. The can of marbles sound; is it happening when you hit the throttle or while its just sitting there fast idling? If its happening while its just sitting at high idle then it could be lean and or one of the ignition settings is off. The fact that it "goes weak" and makes a pre-ignition sound suggest a lean condition, IE: vacuum leak.

Fix the coolant system issue first. Do a complete coolant system flush including separately flushing the heater core. Use new 50/50 mixed coolant. Inspect the rad cap all the hoses & replace them while the systems empty etc. Replace the T-Stat with a HD high quality Stant. 180* or a 195* should do it.

Do you have any vacuum leaks? Look at the carb base gasket and all hoses running to and from the carb and intake. Look at the brake booster line and check valve. Wiggle the carb and see if its 3 parts are tight and its tight to the intake. Hows the fuel? Hows the fuel filter?

Then look at the ignition system. Sounds like the point gap/dwell and timing are in question too. Have you inspected the rest of the ignition system...cap, rotor,wires, plugs, coil etc...
Also test the vacuum advance canister on the distributor.
Pull the distributor rotor and look at the advance springs and weights. They could be frozen open or not working smoothly.

Take all this one step at a time until you find the problem. Dont just buy a boat load of parts and throw it at the engine. You will gain greater satisfaction fixing the problem by finding the root cause.

Follow up when you have found the problem. Purchase the highest quality parts you can find, especially for the ignition system.

Oldsmaniac

The dry black carboned plugs tell me the carb is feeding a rich mixture to the cylinders. Maybe choke is not coming off completely or the carb needs attention. As said one thing at a time....

jaunty75

Here are relevant pages out of the '67 Olds brochure. Your engine is apparently the one on the second (lower) page, top row, second from left with the black air cleaner. That was the base engine for the Delta 88 and the Delta 88 Custom, and it was an optional upgrade on the Delmont 88. In base form, the engine was low-compression, rated at 300 hp, came with a 2-bbl carb, and used regular fuel. Optional were a high-compression with 2-bbl carb putting out 310 hp (my car has this), a high-compression with 4-bbl carb putting out 365 hp, and a high-compression with 4-bbl carb putting out 375 hp. All of these options used premium fuel, and I think the last one came with dual exhaust.

Supernaut72

That's a very nice Olds you have there! I'll be sure to share some pics of mine as soon as I have them! We moved the car from the PO's crowded yard in the late evening, and parked it in my friend's cluttered carport, so I haven't been able to get any decent pictures yet. Hopefully soon!


I did try timing the engine with a timing light, but with the engine overheating and stalling out within a couple of minutes, I didn't have much time to tinker with the timing. I think I'm going to manually check where the dizzy rotor is with cyl #1 at TDC, just so I can see exactly what's going on with the spark before I risk running the engine any more.

Thanks for the tips on what engine I probably have. As far as the PO is aware, the air cleaner is original to the engine, so now I'm inclined to believe that it's a low-compression 425. I can check the numbers to verify once I've got a little less on my plate, of course. According to Oldsmobility, low-comp 425s come in around 9:1 advertised compression, just like my Ford's 289. Never had problems with that one when it's had premium pump gas, then again the premium in this city is weak by most places' standards. I'll have another look at the gas cap, it sure looked old but I don't recall seeing any mention of premium fuel on it. It's only a couple of gallons, so worst case, I'll dilute it with some regular.

I dropped the tank and emptied it out, and inspected the inside of it after taking out the sending unit. It was surprisingly clean and the fuel that's in there now is all fresh stuff.

Right before calling it a day yesterday, I had considered the mechanical advance sticking open being a cause of excessive ignition timing, as I once had a weight spring in my Chevy's HEI come loose somehow and that caused one heck of a detonation problem even though the distributor hadn't budged. I'll look into that next time I pop the hood, for sure.
I'll be sure to test out the rest of the ignition components too.

I've only found time to work on the car over the last couple of days, so I really haven't messed with very much of it yet. I did check for vacuum leaks, however, and everything seems in order there.

As for the carbon on the plugs, I'm left to wonder how old these plugs really are. If they're old enough to not be "self-cleaning" plugs, I suppose the carbon could be residual, from before the PO cleaned and attempted to re-tune the carb. They're all stamped with "AC Lansing, Mich", and interestingly enough this car was rolled out of the Lansing assembly plant.

Thanks for all of the replies, hopefully I'll get to the bottom of this soon enough.

jaunty75

How's the sending unit itself? Those canister-style units are notorious for getting stuck. The one on my car was stuck when I got it, so the gas gauge didn't work, and I couldn't get it to work reliably when I took it out of the car and cleaned it up. These are not made new, but I found that a sending unit that fits a '72 Delta 88 is a drop-in replacement if you ever have this issue.

Supernaut72

Yep, the fuel gauge doesn't work in this car either. I just figured I would take the sender back out and try to rebuild it later, but switching to a more conventional style sending unit will probably save me a lot of hassle down the road. I'll probably go ahead and replace it as soon as I figure out what's going on with the engine. Good to know that there's a later part that's directly compatible, thanks for letting me know about that.

jaunty75

The part number you want is FG106A at rockauto.com, but you can certainly find it through other vendors. Be aware that it's 100% compatible as far as fit and electrical connection, but it's not an exact match in that it is not a canister style. The canister style uses the canister to dampen the fluid movement as the car goes over bumps and around corners, but cars that use this other style have baffles in their gas tanks to dampen the fluid motion. These baffles are not present in our cars' gas tanks.

The result is that the gauge tends to move around a bit as the car moves because of the gasoline sloshing around, but it steadies out when you're at a steady speed or stopped, and it is far better than having no gas gauge at all. I've seen NOS sending units for our cars on ebay for more than $300. This unit at rockauto.com is $54 plus shipping, and it's not 47 years old. I've had mine in the car for about 4 years now.

Here's what it looks like:

ent72olds

You know, I was having the same issue as far as the "marbles in a can" sound with my '67 delta. At the same time, it had an issue charging and would run rough and stall. I truly was convinced it was a bad lifter. I used a long ratchet extension as a stethoscope , and was able to narrow the sound coming from....the alternator, believe it or not. I pulled it, had it rebuilt, and solved both of my issues. Sounds crazy, doesn't it?

Octania

Removal of belts will determine if the noise is coming from a belt driven item
Like, oh I dunno, your WATER PUMP?

:-)

I would love to see pics of these spark plugs that say Lansing MI on them.

Since timing affects detonation and the springs in the distributor mech. adv. system control timing.... it's not surprising that detonation might result from a lost spring. Simple detective work there.

Keep plugging away, update us.

Supernaut72

No worries about the needle moving a bunch, another old GM car of mine has always done that so I'm quite used to it. I'd gladly accept that instead of hunting down a vintage sending unit in the triple-digit price range.


Hmm, hadn't thought about the possibility of a belt-driven item making all that racket. I'll try popping off the belts to check that out. I have to change them anyways, as the AC belt is missing and the other two are on their last legs.


I'll take some pictures of them when I go to change the spark plugs. Not sure why I didn't do that the first time I had them out. I wonder what the story behind them is.

MDchanic

What makes you say this?


Don't worry about your fuel. Your car is not detonating at idle.
And if it was, it sure wouldn't be because you were using premium gas.

You can confirm your engine's compression by checking the engine number stamped into the front surface of the right-side head (or back of the left head if they've been swapped). This, of course, ASSumes that that head is original to the car.

There is a good chance you will need 91 octane fuel in a high-mileage 45 year old 9:1 engine, even though you might have gotten away with 89 octane when it was newer, as carbon deposits and extra oil in the cylinders from normal wear can lower the detonation threshold.


Check all of your accessories for the source of your noise, as stated above, and don't forget other possibilities, like a loose water pump pulley or a loose flexplate.

Of course, it could also be a spun rod bearing...

Good luck!

- Eric

Supernaut72

Thanks for chiming in! I hadn't considered a loose flexplate as a possible source of noise, but I probably should have, since I've dealt with that problem before-- Once had a car that a PO had done an engine swap in a few years prior to selling, which made a loud metallic rattling sound on acceleration for the longest time. One day I got the idea to pull the transmission's inspection cover. Inside the cover I found two bolts, caked in old oil that had leaked down from the engine, and one bolt holding the flexplate to the torque converter. Don't recall it making a noise like this, and it was dead quiet except under load, accelerating up to exactly 35 MPH, but still worth a look.

A spun bearing or something of that sort is what I'm really worried about, but then again this engine doesn't sound quite the same as the engines I've heard run with spun bearings, and we found no glitter in the oil at all when we changed it out (just very dark). Additionally, the oil pressure seems healthy. I'm only going off of the dummy light until I can borrow a friend's pressure gauge, but considering the dummy light is on when the engine is off, ignition in "on" position, and goes out almost immediately once the engine begins spinning, that sure looks like a good sign to me.
Of course, I've only ever listened to a couple of engines with spun bearings, so I certainly can't rule it out. With any luck, something in the giant checklist I've put together will solve the problem before I have to go tearing into the engine's internals.

jaunty75

Sorry. Take it away, Mr. Know-It-All.

MDchanic

Premium gas may not be quite as easy to ignite, or the flame front may propagate more slowly, and this may lead to a very slight, and probably not measurable, reduction in efficiency when it is used in low-compression engines, when compared to Regular, but it will not in any way make the engine run any worse, or any differently.

Regular gas in high compression engines, of course, will cause detonation and engine destruction, or will reduce efficiency and power if the timing is retarded to compensate for it.

- Eric

Supernaut72

Update: Got the water pump and thermostat replaced. Both appear to be original to the car or close to it, had to spend a good hour attempting to remove the fossilized gasket from the t-stat housing by hand in order to re-seal it. The engine sounded pretty healthy with no belt-driven accessories going, and was considerably less troublesome than before once I had the cooling system back together.

I did notice that the cylinders have quite a bit of carbon in them, so I've left some seafoam to soak in the cylinders overnight. Planning to test ignition components tonight and while I have the distributor cap pulled I'll check on timing, though given that this car doesn't have any of the starter kick-back issues that my over-advanced Chevy had, a severe timing problem is looking unlikely.

From idle, the engine hesitates noticeably when I open the throttle, and sometimes cranks a bunch without starting, so my next target is the fuel filter.


On another note, I changed the differential oil a few days back, but I noticed that the fill plug is below the level of the axle tubes. Near as I can tell this is the original 10-bolt anti-spin Olds axle. How are the wheel bearings lubricated in this type of rear axle? What would I have to do in order to service them? Sorry for the ignorance, up until now my department has mainly been C-clip style Chevy axles.

jaunty75

While you have the cap pulled, put one of these in:



http://www.jegs.com/i/Mallory/650/61001M/10002/-1


You can get it or something like it from many different places. I actually got mine from Amazon for less than the Jegs price. Anyway, just about a week ago I put this kit in my '67 along with a new coil, spark plugs, and plug wires, adjusted the timing after the installation as the instructions said would likely have to be done, and the engine runs like a top. Seems to start more quickly, too, at barely a touch of the key. I did the conversion without removing the distributor from the car.

An excellent thought. It's only a couple of dollars, and I found that, when I had been messing around with my fuel tank/sending unit/etc., enough crud had gotten kicked up and drawn through the fuel system that my car was hesitating and bucking when accelerating. Changing the fuel filter cured the problem.


I don't know about the rear wheel bearing lubrication. I've yet to touch anything on the rear of my car except for the brakes. Haven't yet needed to.

Supernaut72

Great suggestion, I'll definitely have a look around and try to pick one of those kits up. I'm planning to order a bulk batch of just-in-case parts that I can't find locally, so maybe I could pick one up reasonably cheap along the way online.

That's good, that you haven't found a need to mess with the rear wheel bearings. With any luck, this car will be the same. Guess I'll just leave it be for now and listen for howling rear bearings when I get the car out on the road.

jaunty75

I found that this kit was not available at any of the local auto parts stores (O'Reilly, Autozone, NAPA) without having to order it. No one had it in stock. The price varied by as much as $10 depending on the vendor.

Supernaut72

That sounds about par for the course, especially for a non-stock component. I expect the same result at the outlets here. So far I've found that even basic items like radiator hoses are hit-or-miss when you go to the parts counter and ask for them here. Guess that's the price to be paid for driving an Oldsmobile these days.

jaunty75

I wouldn't be so negative. We're talking about cars that are pushing 50 years old here. It's not like people walk in every day asking for parts for one, and it doesn't surprise me that the auto parts stores don't keep them regularly in stock. Inventory that takes up shelf space and that you sell maybe one every six months costs money.

Chevys are a different story, of course, but I doubt it's any more difficult to get parts for 50 year old Oldsmobiles than it is to get them for similar-age Pontiacs or Buicks or Cadillacs. I'm just glad we can get them at all.

Supernaut72

Oh, I'm not being negative about it. Just an observation. I'm used to being able to go in and get a water pump for an old Chevy for $40, as opposed to having to special order an Olds pump for $100 and go back for it a couple days later. Just a bit different, is all. I agree that it's good that the parts are even available, many of them brand-new and not just reconditioned.

jaunty75

$100! Wow. Where did you buy it? Does your car have air-conditioning?

Autozone has new pumps for this car (non-A/C) for $56. With A/C they're $88. Plus sales tax.

rockauto.com has them for $42 for non-A/C, $54 with A/C. Of course there's shipping added on, but, still, that's well less than $100.

These are all new pumps, too, not remanufactured.

Supernaut72

It's got AC, yeah. I bought it at a chain called Merle's, which can usually acquire parts a bit quicker than other chains. Didn't think to look on RockAuto for the water pump, but even with shipping factored in, that's a pretty dramatic price difference! Lesson learned.

The one I bought was a new water pump as well, by GMB, though I have to admit I'm a little disappointed with it. The lower bolt near the pump's inlet can't be tightened down all the way because the dunderheads didn't leave space for any tool to reach it! There isn't as much iron milled out around that bolt head as on the original pump, but it's such a small difference that I didn't notice it visually. All my sockets are too thick, and no wrench can fit around the bolt head where it is. Had to go finger-tight and then a little bit more with the prongs of a wrench held perpendicular to the bolt. Fortunately all the other bolts are torqued down and the gasket's sealed properly, so we'll see if that holds in the long-term.

Jaybird

Hi Supernaut72: Welcome to the Classic Oldsmobile Forum. There's a lot of great people and good help here for you.
I happen to own a '67 Delta Custom as well. Post some pictures of your car, when you have a chance.

Supernaut72

Thank you kindly for the welcome! I've had a very pleasant experience here so far.

Planning to have the car ready for the road in about a week or so, I'll make sure to get some pics for you guys once it's free from the cavern of tools and fluid bottles.

droldsmorland

The fill line should be at that location. You dont want your axle tubes full of oil. If this is an O style axle, as Im not familiar with the early big cars, then the outer bearings are sealed non service units. The axle is retained at the brake plate with a 4 bolt housing/flange. If true then you would not see C clips in the pumpkin.

Supernaut72

Sealed bearings in a car from the '60s! Well, that possibility sounds pretty likely, given that there's no way that gear oil is getting up into the axle tubes. I guess I'll leave the rear bearings alone unless I'm given a reason to look at them. If Jaunty hasn't had any problems with his rear bearings at 130k, then with any luck mine will be about the same at 120k.

---------------

Went out to get a fuel filter and go to work on the car, but rain started coming down pretty heavy so I headed home after getting the filter. I'm now looking through my Olds manual to try and find out where the filter is at. The only mention of a "filter" in the manual appears to be the sock filter that fits over the end of the sending unit, and that's not what I'm looking for. I'm not at the car right now, so I can't see for myself if there's an inline filter anywhere in the system, but it would save a lot of hassle later if I know that I have the right fuel filter for an entirely stock fuel system.

This is the one I bought, it's surprisingly tiny compared to what I expected.
http://www.fleetfilter.com/mm5/graph...0001/33044.jpg
It's the only filter any store lists for this car, so I'm pretty sure that it has some kind of housing that it fits into.

droldsmorland

Check the fuel inlet line on the carb. If in fact thats where it is be careful un-wrenching the fuel line and filter housing nut attached to the carb. Get a quality flare wrench set...not harbor junk. Use only flare wrenches on the fuel line nut. Soak it down with PB Blaster or Castles "Thrust" penetrant over night.
The fuel line nuts are soft and easily strip (round off). Use a large open end wrench on the housing nut which screws into the carb top (air horn). Use the two wrenches against (opposed) each other. Do not attempt to torque on the carb or it will break. Also be very careful to not cross thread the housing nut or the fuel line nut on the way back in. It helps to loosen the other end of the fuel line at the pump (or strainer if you have that) upon reassembly. The fuel line will line up easier and lessen the chance of cross threading.

There is likely a thin metal or nylon gasket on the fuel housing nut. Replace that if its questionable. A little anti-seize on the threads will help it go in smoothly.

What carb do you have? Whats the PN on the filter you bought?

Pay attention to the direction the fuel filter is inserted into the housing and which way the bypass spring goes in. Try youtubeing this as there may be one there. Visuals are worth their weight in gold...most of the time.

On the rearend, yes sealed bearings. They are just a large "common looking" sealed roller bearing if in fact you do have an O style rear with this design. Like I said Im not too familiar with the early 60s big rides...They are pressed on the axle. You'll know when they go bad. They will grumble and make noise. Dont let them go for even 10 miles. They are known to friction weld to the axle if driven long enough. Which means you will need to source a new axle. I cant imagine that would be an easy find?

jaunty75

OK, just as a counterpoint from someone who actually has changed the fuel filter on a car exactly like this.

1. Yes, the fuel filter IS in the line coming from the fuel pump located right where the line enters the carburetor.

Here is a photo of my car's engine with the location of the fuel filter circled.



2. Line wrenches are great, and if you have them you should certainly use them, but I changed my fuel filter using standard open-end wrenches with no problems.

3. I didn't spray PB Blaster on the fitting the night before. I did it about 10 minutes before. I figured if it didn't loosen, plan B was to let it soak for a longer period. I had no problem loosening it after the 10 minute soak.

4. I did not loosen the other end of the fuel line at the fuel pump. I had no problems reinserting the fitting into the threads on the carb and tightening without stripping or cross-threading the threads. The fuel line is flexible enough that there is plenty of play if you need to wiggle it around to get the fitting to properly align with the threaded opening on the carb.

5. I didn't put any anti-seize on the threads, although, in retrospect, that probably wouldn't have been a bad idea.

6. Yes, do pay attention to the orientation of the filter in the holder. The open end of the filter faces away from the carb towards the front of the car. The little spring, which can pop out when you first remove the old filter, goes in first, then the filter itself as the spring pushes the filter against the end of the fuel line. Fuel enters the filter through the open end and exits around the edges through the filter material itself. You'd find out very quickly if you inserted it wrong as the car wouldn't start.


Yes, changing the fuel filter is something you want to be careful doing, and droldsmorland's suggestions are of course good, but the process is not as life-and-death as he makes it sound. Try to actually have fun doing it.

Supernaut72

Thanks for the instructions, guys. Very much appreciated. The filter that I bought was Wix #33044, which looks about the right size to fit into the fuel inlet on the carb. I had hoped that the filter might be housed in the carb, that makes things nice and accessible. No crawling around under the car tracing fuel lines for this job.
PB Blaster hasn't let me down yet, even with this car's more stubborn bolts. I've kept a can of it handy from square one, because I had a feeling I'd be needing it.

As for those bearings, I'll make sure to pack it in right away if I do hear the drone of death when I take the car out on the street. Here's hoping that doesn't happen!

Supernaut72

Well, got the fuel filter changed. The old one was in there all wrong, so now I know someone has been monkeying around with the carb who probably shouldn't have been. Now that it runs better, the problem is that I can't seem to control the idle. The idle screw at the side of the carb doesn't actually touch down on anything, and yet every time I blip the throttle the idle raises more and more each time without coming down. As far as I can tell, the screw for the fast idle is the same way, not actually touching the fast idle cam (and even then it shouldn't raise the idle more with each blip of the throttle). The choke works perfectly as the engine warms up and cools down, so I don't suspect anything on that side of the carb at the moment.

Shutting off the engine with the idle running fairly high, it ran-on briefly and then backfired through the carb. Either a result of the high idle/lack of a throttle cut-off solenoid, or the heavy carbon in the cylinders, which I'm working to remove by soaking the cylinders in Seafoam after each time I run the engine. Sure spooked my friend when it happened.

On the bright side, we found all-new distributor components in the trunk, unopened, except for the coil pack. Plan to install those next time I'm at the car, once I'm done installing some new door glass.

Here's a couple of photos of the carb, from the images alone is there anything discernibly missing or installed wrong in the linkage setup? Given that the fuel filter was installed all wrong, I wouldn't put it past the previous owner to have taken some guesses while putting the throttle linkage back together as well...

http://imgur.com/a/olcOv

I'll take a look at my Chevy's carb as well, it's also a Rochester 2bbl, but then again I don't know if there are any Olds carb linkage oddities that I'm unaware of.
If it's not in the carb then I'll suspect things like timing and vacuum of course, but given that the idle screw isn't even touching against anything I'm getting the feeling that something is amiss there.


Besides the crazy idling, things are looking promising, there's no smoke from the exhaust except for the white cloud caused by the Seafoam and no discernible banging sounds from within the crankcase. Knock on wood. Still really really holding out hope that this engine doesn't turn out to need a total tear-down.

MDchanic

Sounds like you're making progress.

Nothing looks out of place in the pictures, but the dashpot does seem to be extended, and have the throttle tab resting on it - have you tried backing it off?
Also, have you tried disconnecting the throttle linkage?

Here are your pictures in case others want to see them:

vterord.jpg

IWJjt0N.jpg

- Eric

jaunty75

As you can see in the photo of my carb up above, there is no dashpot in my car. Do I need one? There's never been one during my ownership of the car, and the engine has always run fine. As I understand it, it just dampens the slowing of the engine when you let off on the gas when the car has been traveling at highway speed to help prevent stalling. I've also read that, in cars with automatic transmissions, the dashpot is an emissions control device, and its absence doesn't affect performance.

Note what it says under "Exceptions" on this page:

http://www.ehow.com/facts_6918312_ca...-dashpot_.html


Comments? Maybe a prior owner removed it thinking doing so would improve gas mileage? If I need one, anyone have a spare?

jaunty75

Here's a used one that just came up for sale on ebay. He claims the float moves up and down freely, which I think is the primary failure mode in these things. He also notes that the sock filter on the bottom is missing. If you look at the photos, you can see that it has torn or worn away.

This filter was damaged on mine as well when I had it out of the car back in 2009, and no one I tried (local auto parts stores, local GM dealer--even though the parts counter guy was really good and spent several weeks trying to track one down for me) could find a suitable replacement. It was another reason I decided to just go with the replacement that I did.

http://www.ebay.com/itm/Original-Can...974f54&vxp=mtr

Supernaut72

Thanks for re-posting the pictures, MD. Not too familiar with posting pictures to forums (when I tried using "insert image", it tried posting them full-size, which would have been obnoxious).
I'll try backing off or removing the dashpot and disconnecting the throttle linkage to see what the engine does. Very possible that that could be my problem, thanks for pointing that out.

Jaunty - Thanks for showing me that listing. Might try going for it, as I could probably transfer the sock filter from my sender to it (it's mostly intact, though as you might expect, mine is also very brittle). If that falls through though, the '72 Delta 88 float-type sender still seems a very good alternative.

As for the dashpot, I'll keep a look out for you if you decide you want to get one. I've never had stalling problems with cars that haven't had dashpots though, even after prolonged high-RPM travel, for what it's worth. In fact, I think the only car that I have actually stalled out by accelerating then coming to quick stop was a car equipped with a dashpot.

jaunty75

When you use the "insert image" feature, it's supposed to insert them full size. To my mind, that's a feature, not a flaw. I don't find this obnoxious. I find it the exact opposite. A blessing. I don't like thumbnails because you're constantly clicking back and forth between seeing the image and wanting to read the text that goes with it. I always use the insert image feature and post the image as it was meant to be seen, as you can tell from the photo of my car earlier in this thread and the photos of the sending unit a few messages above.

Supernaut72

Fair point. When the page first loads, I notice the gigantic images, but it looks like it automatically downsizes them a little bit anyways so as not to be too huge; the original resolution of the pictures is kind of outrageous. I was just worried about that, but I guess it's no big deal.


Anyways, I checked the carb out a little more, and I was able to get the throttle blades to close a bit more by backing off the dashpot nearly all the way and fiddling with the fast idle cam screw. Guess we'll see how that works out next time I run the engine.

Overall I took the day off from engine work to install some door glass. Sure was a bear to get in, though most of the trouble was cleaning out the shards of glass and years of amassed dust inside the door. Poor car was once a target for kids with some rocks and nothing better to do, but then again that's probably part of the reason the car was stored away and later sold. Next on the list is to apply some rustproofing paint inside the car's doors and get the vent window regulators out, as both vents are either totally shot or need some major adjustment.

Getting closer to moving her out of my friend's carport!

Supernaut72

Been a long time, got real busy with other matters and have been working on the Olds on and off. I gave in and bought a rebuilt Rochester to throw on it, which is working decently. The engine sounds a lot less like a tractor's engine since I replaced the ancient plug wires, as well. Not sure why it sounded so odd, but it's starting to run and sound like a proper Olds big-block now.

Got a repro '72 model fuel sender, but I'm gonna have to empty the tank before I can drop it again, at which point I'll probably take care of cleaning up and rust-proofing the rearmost portion of the frame.

Currently investigating an issue whereby the car tends to stall out unless the throttle is held open by the highest step of the fast idle cam. Any less than that just won't do. This was with a makeshift plastic fitting wrapped in electrical tape threaded into the back of the carb acting as a PCV port, since the reman carb didn't include one. The one in my original carb seems to be in there too good for me to get it loose, so there's not much I can do until the new fitting arrives in the mail. The plastic fitting seemed airtight enough for temporary use, but the engine not holding idle unless you're giving it a fair bit of throttle reminds me exactly of my Ford when it ballooned a PCV hose end and blew it off of the valve.

While I was running the car, I noticed a little bit of noise every now and then that's hard to describe. It isn't quite a "banging" sound but it's definitely different from the clacking of the engine's noisy lifters. Doesn't sound as rhythmic as a shot rod/crank bearing and nowhere near as loud, and doesn't make the same noise as one when I blip the throttle. Had my dad on-site to have a listen. He says it sounds to him like the bearing in a belt-driven component getting sloppy, so I'm holding out hope that it's just one of the belt-driven components or, somehow, the fuel pump starting to make noise. The power steering pump is an old, old remanufactured unit, and the fuel pump looks quite old as well. The power steering belt that's still on there is old, cracked, and missing large chunks, so maybe that's contributing to the noise. We'll see once I swap it.

Pics are soon to come, just need to find two more usable tires for my ET mags and get those on the car before I'd consider it even remotely "presentable".