toro455

I'm just now checking all the vacuum lines for the OAI and intake manifold on a 1970 442 W-30 I purchased in 2008. It seems to function correctly but I would like to double check the routing if anyone has a nice readable diagram they can post or email me. The main concern is the vacuum lines that are part of the OAI set up and if there is a "T" fitting for the two lines on the top part of the OAI that connect with each other.

bwichman

Do you have a shop manual ? It's in there.

toro455

I do have a shop manual but I cannot see the diagram as the printing on the page is faded. It looks like there is a "T" fitting somewhere between the two vacuum lines and then one goes into the back of the carburetor...does that sound right ? Again, Does anyone have a good readable diagram...I wouldn't waste anyones time if I already did.

Allan R

You mean this?

toro455

Thank you Allan R ! This is what I was looking for...I was interested in the vacuum "T" I see in the diagram now that connects with the air cleaner snorkel and the flapper door on the OAI. Different diameter hoses...then the "T" goes to "manifold source" but I don't see exactly where that would be on the back side of the intake manifold. Anyone know or have photos of their routing or OAI set up they can share with me ?

I can take photos of what mine looks like now if that would help...it is not routed like this at all.

Thanks, Mike

wmachine

Mike, for future reference, this page is out of the 1970 Assembly Manual, and the whole manual is available on Wild About Cars, downloadable and free of charge.
http://wildaboutcarsonline.com/cgi-b...aldisplayed=50

The Engine Assembly Manual is likewise there.
http://wildaboutcarsonline.com/cgi-b...aldisplayed=50

Wild About Cars. http://wildaboutcars.com. An information supersource, especially Oldsmobile. More Olds content than anywhere else on the internet and continuing to grow.
You'll find Chassis Service Manuals, Product Information Manuals (AKA Assembly Manuals), Inspector's Manuals, and other documents that will contain this and much much more.
Dealer Brochures, magazine ads and articles, and a home page for you online with your own garage where you can show off what you have.
Free to join, free to learn.

Allan R

Mike, do you have OEM intake manifold or an aftermarket? The intake manifold source should have a vacuum fitting behind the carb. You can hook it to the same source as the vacuum for the TCS, or I think the vent on the rear of the carb.

My car is NOT a 70 - it's 72. And it's not an OAI but I think the back of the manifold is going to be similar to this and so should the back of the carb. I'm pretty sure the line you're looking for is the one on the left side of this picture because it goes to the air cleaner thermal vacuum motor. That would be the same need for the OAI, right?

All of those lines run vacuum.

jrzybob442

The proper routing for all 1970 V8 cars can be found in the Chassis service manual Section 6 C-17. Here is the link at Wild About Cars. You can download this section and print it out full size. http://wildaboutcarsonline.com/membe...Section_6D.pdf
There is a difference between the auto and standard trans W-30s

Vacuum rounting is in every service manual under tune up.

Allan R

Hey Mike, Yeah I looked at that section of the CSM that jrzybob442 posted before I decided to post that pic. Only reason I did my pic is the ones on the CSM at WAC weren't as clear about where the vacuum lines at the back were routed. Hard to tell the details when all you see is a black line...Anyway use whatever references you need; hope you get it hooked up ok.

BTW, I didn't ask if you had a AT or MT. Hopefully that web page I posted for you (which came from Thornton's web site BTW) gave you the needed info.

jrzybob442

It is clear in the 1970 Engine Assembly Manual where the hoses go pages 35-36.

http://wildaboutcarsonline.com/membe...bly_Manual.pdf

Allan R

Yeah, well that's a whole lot different than The CSM isn't very clear at all. Why didn't you just post that second engine building link in the first place?

BTW its not pages 35/36, it's Sec 6 pages 30-34

jrzybob442

Not what I'm looking at - the PDF page numbers are 35-36 in the engine assembly manual. The reason why I didn't say it earlier was because Kurt cited it in his earlier post, he just didn't cite the page numbers.

It's nice to yank a page and then show to people, but to my mind it is better to send people to the source so they can make a decision what part of the source to use.

Allan R

Whatever. Not everyone thinks like you and Kurt though. Sometimes it's way more practical to give the OP exactly what they were asking for so they can just get on with their repair.

I find it easier to specify the section and page. That way there's no guesswork. Google Chrome doesn't have the page x of y format you may be using.

toro455

Allan R - thank you for posting that photograph of the back of your carburetor and intake manifold. When I saw that, I knew that the routing of the vacuum lines on my car was messed up. Here's the short story...I took my car in to get the carburetor tweeked a few weeks ago. I think the carburetor on it was 7040253 which is not correct for my car. Anyway the shop determined that the carburetor was "plugged up" and they put a 1977 Olds ? carburetor on my car to get it running. It seems to run about the same as it did before and they tried to keep my old carburetor. One of the guys at the shop made a comment that the vacuum lines didn't look right which is what prompted me to look into this...and sure enough it was all messed up. I took some photos of what it looked like earlier this evening. Based on the photographs and the much better diagrams everyone shared with me it looks like I got it back together correctly. The only problem is the port on the back of the carburetor should have a "T" fitting instead of just a straight fitting. I think I saw that somewhere in another photograph of the correct carburetor for the OAI. If anyone has such a carburetor could you post a photo. I'm in the process of getting my old carburetor rebuilt by Sparky as suggested in another one of my posts.

Allan R

Toro, glad it was of some help. Hopefully when you get your carb back from sparky it will be just what you need. NEVER let a shop take your carb away - they know what it is and prolly wanted it for themselves!

I looked up that number you posted and the reference said it falls in the range of carb numbers from 7016937 - 17055024 (pretty wide) 1970-1974 Cadillac Rochester 4MV carburetors, 1967-1974 Oldsmobile as well as marine and industrial Oldsmobile engines.

You might want to get in touch with sicky olds (https://classicoldsmobile.com/forums...icky+olds.html )
or jensenracing77 ( https://classicoldsmobile.com/forums...nracing77.html ), they both have 70's with OAI and are very helpful and knowledgeable guys. They could prolly shoot some pics of what you want.

BTW, in one of your pics you answered a question (without me asking) I've been curious about for a long time. It was about how the springs for the flapper were attached to the engine. I see now there's a special tab used on the valve cover!

toro455

Allan R and WMachine, Thank you both for the detailed information and resources I was not aware of. I guess that's why these forums are so helpful. I appreciate your help a great deal as some of this is overwhelming to me. I am still trying to hunt down a 7040258 and have another post going in the "Parts Wanted" section. As of today I may have a possible lead on the right carburetor but may have Sparky take a look anyway. Also, I did ask Sparky about the carburetor that is currently on my car ( 17057258 ) which he said is from a 1977 Olds low compression with smog stuff.

On another note, and getting back to the actual problem...I test drove the car today and it seems to idle lower and of course the exhaust leak is now gone since I put new gaskets in. The old ones were mismatched and falling apart. I don't think I'm getting what I would like from the current carburetor so I am going to continue to hunt for the right one. I'm also going to send Sparky the carburetor that was taken out of my car and according to the carb shop was "plugged up". I might be able to sell that to someone who needs a 7040253. I found the paperwork for that carburetor...It was purchased from Carbs Unlimited in 2006 by Matt Woods who did some restoration work on this car back then before I owned it.

Also, Allan R. I may have some extra tabs if you want them. I would just give them to you if interested and I can find them. I think the ones I have are powder coated silver if that matters. Let me know.

Allan R

toro - thanks for the offer, but I don't have OAI. If I ever get one though I'll let you know.
re: 7040253. I don't know how hard they are to find, but I do have a 7043251 if all else fails. It's from a 73 455 Complete with anti diesel solenoid. Needs rebuild but in decent shape. LMK if you want pics and I can send them to you. Use PM - private messaging if you want pricing and pictures.