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Hello
Speedmaster H beam connecting rods and Sealed Power bearing (83345P).
Road bearing is misaligned on the cap side (all rods). One edge is parallel with cap and other has many mm left.
- Is it normal?
- Is some other bearing better?
- If normal, where should the shifted side look if two rods are assembled to crank: each other or crank?
Speedmaster tech support answer is: bearing tang should always go to the outside. the big flat side of the rod goes to the inside. hope this is of some help.
How to understand that?
Are the bearings labeled "upper" and "lower"? Usually the "upper" goes in the cap, and the "lower" goes in the rod, even though that seems crazy. I hit the same problem when putting them in the wrong place. Also be careful to keep each cap with its matching rod as they are machined pairs and you'll get all kinds of problems if they get mixed up.
You might need narrowed bearings but it's hard to tell. If the rods seem to lock up when a pair get tightened down then the bearings are either clamping down on the crank filet or rubbing against the neighbor.
Are the pistons pressed onto the rods? Usually there's marks on the pistons showing which way they need to be installed. That should match the rods. What they were saying with the tangs is that when installed correctly, the tang will be "outboard" - closest to the oil pan rail. For example, the bearing tangs on the #1 rod will swing close to the left side oil pan rail when the rod spins around. This is called the outside. Many (most?) other engines do the opposite where the tang goes "inboard" and swings closest to the cam. The big chamfer on the side of the cap and rod should also face the shoulder of the crank throw while the smaller chamfered side faces the neighbor rod.
^^^^^.
But a couple of questions as well, did you check the big end of those rods for proper size AFTER you took them apart once and reassembled them?
And why that bearing? Where Clevites not available?
My experience with those rods is that they’re crap, I won’t use them. Hope the ones you got are better.
There is nothing wrong with the Sealed Power / Federal Mogul bearings. They are every bit as good as Clevite.
It appears that the rods are made incorrectly. Do you have a stock connecting rod that you can try the bearings in just to be sure ? If not maybe your machine shop does.
See reply #5 below
The bearing tangs go in towards the camshaft on Oldsmobile engines. That might give you a clue as to Speedmasters tech support. They are wrong in this case.
Depending on exactly what you are building you might be better off with a good set of factory rods that have been reconditioned.
Last edited by BillK; February 20th, 2024 at 05:58 AM.
Where the tangs go is irrelevant. The large chamfer on the big end of the rod always goes against the crank cheek, period.
And use the CB542HN as instructed. That’s a better bearing anyway.
Last edited by cutlassefi; February 20th, 2024 at 09:50 AM.
It's quite embarrassing that I didn't notice the manufacturer's note about the bearings type.
Even more odd that the manufacturer's technical support didn't point that out...
I probably go with recommendation:The bearing tangs go in towards the camshaft on Oldsmobile engines.
Have now CB-542HN Clevite bearings and situation seems similar (picture below).
Originally Posted by oddball
Are the bearings labeled "upper" and "lower"? Usually the "upper" goes in the cap, and the "lower" goes in the rod, even though that seems crazy.
I have not found any support material about that statement, but it seems to be right. Most of schemes in internet show it other way around.
Mahle site is only stating: always install the thickest wall shell in the upper position if installing a rod bearing or the lower position if installing a main bearing , but thickness of shells is same (measured with calibre). Didn't find anything about upper/lower position on their instruction.
CN-542HN have upper and lower marking in the bearing. I have assembled two pairs to rod and measurements are as following (bearing is 4mm narrower than rod).
1) Upper/rod + lower/cup -> cup side edge 4,0mm/0,0mm -> rod side edge 2,6mm/1,4mm (so in cup side, bearing is flat with one rod side)
2) Upper/cap + lower/rod -> cup side edge 2,9mm/1,1mm -> rod side edge 1,4mm/2,6mm (rod side is same, but bigger gap has changed side)
cutlassefi: Where the tangs go is irrelevant. The large chamfer on the big end of the rod always goes against the crank cheek, period.
Just to be 100% sure:
1) Follow that cup side bigger clearance (2,9mm) is always facing crank (or still this 4,0mm?)
2) Follow that cup side smaller clearance (1,1mm) is always facing crank (or still this 0,0mm?)
In both cases tang is by turns inside and outside (and yes, is irrelevant).
Picture is not showing exactly, but the right side cup bearing is flat with rod:
Ok, let me try this again. The bearing number is CB542HN correct ? The bearing marked "upper" goes in the connecting rod. The bearing marked "lower" goes in the cap.
The part about putting the thickest bearing in one position only applies when you are mixing sizes on a journal. Has nothing to do with your situation.
Yes, correct, bearing number is CB542HN. The bearing marked "upper" goes in the connecting rod. The bearing marked "lower" goes in the cap.
Try to assemble both ways (because second post by oddball claim other way around).
If assembled as "upper" goes in the connecting rod and "lower" goes in the cap. Bearing are still misaligned (see picture). Ones side of cap bearing is parallel with rod edge and other side have 4,0mm clearance. In rod side situation is better but not ideal, bearing is not in the middle of the rod.
If assembled vice versa, situation is little better, both side have some clearances, but bearing is still not in the middle (2,9mm and 1,1mm).
Wow. That tells me that the rods are made wrong. The slots must not be in the correct position ? I think I have a set of stock rods here. Let me try to measure something later on. MIght be in the morning
Speedmasters. Like I’ve said a half dozen times on here, they’re junk. Purchased multiple sets over the years. I sent every set back for various issues. I’ll bet they’re not in size either.
Buy Molnar’s, Scats, or Eagles instead.
As I'm located in Estonia, its almost impossible to make any returns to US. I pay usually twice what You (taxes + transportation) and get my parts with minimum 2 weeks.
I got one extra rod already, as one thread was bad, it took my over 4 weeks of time...
So now I'm just in situation, that I need to used them and any advice would help.
From many places I can read that tangs do not play any role in locking bearings in place (only during assembly).
Does it sound good plan to modify one or other?
1) modify bearing tang, its 3mm wide, I could take some material off
2) modify bearing tang slot in rod side
I could then line bearings to centre of cap and with each other. Or is there any particular reason they are not in the centre. Below is pictures of stock and Speedmaster rods with different bearings. Also stock rod and bearing is not aligned to centre. Or is it just not that important and I should not worry too much.
Looking original rods I can finally see what is rod chamfer, Speedmaster rod sides look the same.
I dont see why you cannot modify them like you said. I finally got a stock rod a little while ago and measured the distance between the grooves as shown in my picture below. Looking at your pictures of the caps it looks like the bearing needs to move just slightly to the left to move it away from the edge of the cap a little. Then you could modify the slot in the rod to move the bearing to match the one in the cap ?
February 19th, 2024, 11:52 PM
