Ok, I realize I’ve asked before but I’m gonna ask again. I’m trying to find big end rod bearing for my 2.5L engine with alloy connecting rods. Not sure why the rod material matters but apparently it does. I’ve tried Worcester Classic Spares and they have a set of NOS +.020 for $220 but they have rust on them. Mostly on the back but a few have rust on the needed surface. Cordel Newby thought he had a set but can’t find them. I’ve tried every one else suggested but I think I’m going to have to start at the top of the list again.
If any one here has even the slightest memory of a possible supplier, please pass it along. I’ve done everything else on this engine and would hate to have to throw it out and start looking for another engine!
Id find some old guy, at a NAPA, or an old machinist, and scour catalogs to find possible bearing sets.
You might have to resize the rods and/or crank.
Have you contacted Ed Nantes?
I have the crank out and ready to go to the machine shop for a journal hair cut but the +.020 bearings turned out to have rust on them. Not a good way to start a $225 relationship!
Don’t know of Ed Nantes.
I too want to know this as I will face it eventually.
According to the Mark V Manual pg B35, the shell bore diameter is 1.896" to 1.895"; presumably this is for new parts.
Vertical clearance called for is .001" to .0025"
The ID of the rod big end is 2" +.0000" -.0005"
The width is 1-3/16"
Can you confirm these are the correct measurements?
Crank pin 1.895"
Rod big end bore 2"
Rod width 1.187"
I suspect the alloy rods may have the anti-rotation notch on the opposite side from the steel rods. But that is a minor detail that can be modified.
Vandervell is now part of Mahle. They say they cater to the classic and vintage market, but their online listings only go back to E-Type. So the task is to look through Mahle Clevite catalogues for some other engine with the same size bore and ID.
I found a pdf catalogue here:
763 pages of bearings. There’s bound to be something close in ID and OD, and even if width didn’t match it might be ok to use.
All dimensions are in inches even for metric cars.
I sent a private note to Ed Nantes to see if he has any words of wisdom about the 2-1/2 L engines.
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It certainly would not hurt to use slightly narrower bearings.
That was the case, when Dad modified the Auburn’s rods and journals to use Jaguar bearings. They worked fine.
Hi Rob,
That bore spec is correct for the MkIV and V but there was also an earlier bore size 1.824". Depending on what crank you have you may not be able to use the MkIV shells. I think the only long term solution for the 2½ litre is that proposed by Ed Nantes namely, convert to a 3½ litre crankshaft and XK rods and convert to Chevy 350 main bearings.
Peter
I heard back from Ed Nantes, and he said the same thing, convert to a 3-1/2 crank out of a Mark V with steel XK rods and Chevy 350 main bearings. The stroke increases by 4mm to 110 so you now have a 2.8 litre engine.
Did Ed inform you of the need for different pistons Rob, due, of course, to the increase in stroke.
Nope. Maybe that’s why he said 3 litres. I thought he just didn’t calculate it right.
What’s the problem; rods hit the sides of the bore, or pistons hit the head?
You really need different pistons anyway because of the larger gudgeon pin unless you wanted to use a thicker small end bearing but even after doing that you still need to reduce the crown height or they would pop out the top by 2mm. In a word, you need special pistons. You also need some machining of the block to take the Chevy mains.
Peter
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This is what I received back from Ed.
The issues to consider
The 2 1/2 litres had alloy rod, which frequently break$$$$$$
You can buy a St Christopher charm and hope for the best
Or… change the crank to one from a 3 1/2 MK5 and use steel rods z series engines in MK5 used steel rods T series didn’t
Then you probably need to get a set of pistons made or other makes modified
Or if one was buying a MK5 3 1/2 crank , one could just buy a 3 1/2 Z Series engine and swap it over
That would also help with your keeping up with traffic, and while doing that buy the back axle. Your 2 1/2 has a 4.55:1 dif, the 3 1/2 has a 4.27:1. Longer legs. Easier than a 5 Speed modification. Remember though Mkvs had either. A Salisbury back end or an ENV and they aren’t interchangable but the same type from a 3 1/2 would drop into a 3 1/2. One might even get a 3,77 CW&P from a man OD XK 120 i did that in one of my cars.
In any case to check the journals on you existing engine have you tested by putting some Plastigauge in the journals and bolting the caps up, to correct tension?
That might be the first step if you keep the 2 1/2 engine
Regards
Ed
So Wayne, can you confirm these measurements?
Rob,
I’m getting
Crank pin. 1.875
Big Rod End Bore 1.985
Rod Width 1.1835
Ok thanks, that’s great.
I’ll start delving through that Mahle Clevite catalogue.
Can you post a picture of one of the rods?
I’ll post a pix once I get out to my shop.
I called Mahle Clevite and got an old Jag mechanic now selling bearings. He spent about a half hour with me going through his computer files with no luck. I had great hopes after finding someone willing to actually search for me.
So I took my crank to my local engine machinist and we found that the journals are now at 20 over and are showing .005 wear already so now I’m in search of +.030 rod bearings. The mains are 10 over but are at spec, so I’ll keep those as they are.
I have found that Tom Zwakman in the Netherlands has standard bearings but is now looking to see if he has a set that’s 30 over.
Very interesting. I see you have the offset oil tube up the side of the rod. Can you see a part number on it, like C1050?
Looking in the parts books, I see the '36-'38 used a Standard numbered rod 43038 which has an oil tube; then about '39-'46 used a rod 45738 or C805 where no oil tube is mentioned; then about '46-'51 a third rod C1050 which has an oil tube.
You want to be careful that your shells have an oil hole that is aligned with the passage up the rod. If they don’t, open them up with a round file.
It is my theory, unfortunately un-researchable at this late date, that the use of shells with wrongly placed holes would lead to oil starvation at the wrist pins at high speed, and may be the root cause of rod failures, as mentioned by Ed.
I bought something from Zwakman once, first time I ever saw guilders on my credit card bill.
Seems the Vandervell bearings have the oil holes in the correct place but the Glacier bearings, which most catalogues show as correct, have oil holes in the center which is 1/2 hole out.
I had the set from the car coated by Calico Coatings which filled in the scoring grooves but when I was installing the piston cap on the first rod, it needed taping to get it on and I didn’t realize that the upper half rotated down and overlapped the lower shell. Screwed up the coating. That’s when I decided to take the crank out.
In the US, bearings are marked if oversized not so on these. That’s why I was chasing standard bearings for so long. Glad I didn’t pay the $220 for a set of standard ones!
Mean while I’m experimenting with swapping the tranny for a Volvo M41 with type J Laycock overdrive. Looks like it’ll work with out touching the frame. I’ll have to make a different rear mount but that’s a small thing. The whole unit with adapter plate is 3/4” longer then the original and there’s room between the tranny and X frame for it. The tranny shaft is about 1/2” shorter then original and adding the 1/4” adapter plate makes the shaft 3/4” shorter. I’m going to remove the crank bushing and machine one that will fit the Volvo shaft (1/16” larger diameter) and extend it past the end of the crank so the tranny shaft will have full support.
This all may not work in the end but it gives me something to do instead of sanding fenders!
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Greetings All,
Jaguar had a compact OD on the later 70’s? Sedans. Possibly the smaller size might be of use?