I’ve been emailing with Anna at Worcester Classic Spares trying to find +30 rod bearings for my 2.5L MK V. She say that she can order two sets of bearings for a 1.5L engine and I can use 6 of the 8 sets. They are for steel rods but I can have the tang slots machined into my aluminum rods to allow them to fit. Does this all sound correct? Are 1.5L bearings the same as 2.5L bearings? Any knowledge from the group would be appreciated.
Wayne
Cutting slots for the different tang position is fine. You should arrange the slots such that the dead ends of the tangs prevent the shells from rotating in the rods with the normal direction of crank rotation. Also check the position of the oil feed to the small end. The dural rods have the feed pipe offset but the steel rods of the 1.7 litre are central so you may need to file the holes in your new shells.
Peter
Peter,
Thanks for the response. I did file out the oil holes on the previous set before I had them coated but there’s still too much wear slip which is why I’m now looking for +30 bearings. I’m just wondering if the 1.5L engines from the SS model are actually going to fit properly.
Wayne
The shells are B4026 or GS1849S. The 1.5 litre shells should be the same as yours except for the tangs.
Peter
Peter,
Are the B4026 ones Vandervell bearings? The others are Glacier I’m thinking.
Ok, so I did find out from Peter here and Cordell Newby that the 1.5L rod bearings are the same as the 2.5L engine.
I called MAHLE Bearings and they found bearings the correct size (for a Wisconsin engine) but instead of 1 3/16” wide, these are .864 wide.
Any thoughts???
Are these 2" outside diameter and 1.866" (1.896" -30 thou) inside diameter? What’s the Mahle part number?
Peter
MAHLE #CB979M20. (20 undersized) I’m having the crank ground anyway, so he said these were close enough to grind to get the .030 under.
That’s very interesting!
So they are suggesting 1.855/6" i.e -41/40 thou or 1.865/6" -31/30 thou.
Peter
I guess…it’s not in my circle of knowledge. I call a tech at a known and suggested supplier who turns out to have had several MK 2’s and this is what he told me. His thought that these bearings would fit other then being almost 1/2” narrower, would work. He figured that I wasn’t going to race the car so the engine wouldn’t be running in the red line very often so the width shouldn’t matter so much.
It’s not the optimaL solution but it’s in the proper direction.
Hi,
Are you reusing old aluminium rods? Is that safe, or should they be replaced with something? IIRC brother Nantes used to suggest switching got steel or some modern rods as the Duraluminium rods are prone to aging and mechanical stress may cause them to stretch or break.
Sorry if this causes any confusion, I just thought that might not always be a good idea to reuse old alu rods.
Cheers!
Pekka T. - 647194 -
Fin.
There certainly is a risk in running with dural rods. I ran on them for many years but was always careful never to labour the engine and never exceed 3500 rpm. There was a progression of dural rods starting with some very elegant skinny ones then progressively beefing them up until the MkV that has the least elegant but probably stronger type.
Peter
