MEP-802A Connecting Rod small end bushing

[skwishst]

I have been working on a MEP-802A rebuild and I have an issue with the connecting rod small end bushing. The one I pulled out is marked 751-10150. From the TM 9-2815-252-24 table 3-6 section 3-70, the pin diameter should be 24.9925-24.9975 mm (mine is) and the connecting rod end bushing ID should be 25.005-25.017 mm (mine is pretty scored but does roughly have this dimension) (these are also the same numbers in the Lister Petter alpha series shop manual). When I order a 751-10150 from the auction sites (listed as the right part for this engine and matches what I pulled), the ID is 24.6995 which is way too small.

Has anyone seen this with auction parts? Do I have something wrong or did the part change somehow with rebuilds? Is there a better source for this part that will be the 25.005-25.017 from the TM?

Any help would be appreciated!

 

[skwishst]

I have been working on a MEP-802A rebuild and I have an issue with the connecting rod small end bushing. The one I pulled out is marked 751-10150. From the TM 9-2815-252-24 table 3-6 section 3-70, the pin diameter should be 24.9925-24.9975 mm (mine is) and the connecting rod end bushing ID should be 25.005-25.017 mm (mine is pretty scored but does roughly have this dimension) (these are also the same numbers in the Lister Petter alpha series shop manual). When I order a 751-10150 from the auction sites (listed as the right part for this engine and matches what I pulled), the ID is 24.6995 which is way too small.

Has anyone seen this with auction parts? Do I have something wrong or did the part change somehow with rebuilds? Is there a better source for this part that will be the 25.005-25.017 from the TM?

Any help would be appreciated!

I missed the fact that the small end bushing needs to be reamed to size. Back to the machine shop is all that is needed!

 

[Ray70]

Strange.... I have bought both piston / pins and connecting rods from Mayi Diesel on the big auction site and didn't have to ream the rod bushing.
Everything went right together easily.
Where did you end up getting the rod from?
If by chance you end up having any kind of issue getting your rod sized, I have several spare used piston / rod combo's if you need one.

 

[skwishst]

I bought them from Mayi. The rods, pins and pistons were in good shape but the bushings were worn on the bottom half. I got them as part of a full bearing kit (3 main, 2 piston and rod bushing) so because of the wear, I replaced them.

 

[Ray70]

Oh, I see... you bought new bushings to put in your existing rods.
I had purchased a new piston and a new rod. I had an 803 that probably got hydrolocked at some point and 1 of the rods was tweaked a little bit.
It ran fine but smoked at start up for 30 seconds. Just the little bend it had was enough to change the deck height enough to lower the compression enough to smoke until warm.

 

[skwishst]

This one had water in the cylinders due to a bent exhaust cover. I think it was run very little after the last reset since all the bearings look pretty good but since I pulled the crank to do a good honing job, I am putting in all new bearings and rings. This is the last missing piece before reassembly.

 

[skwishst]

I had emailed Lister Petter and the responded

"The connecting rod bush internal diameter needs to be machined once its pressed into the connecting rod to ensure correct roundness, size and squareness of the final bore relative to the connecting rod."

and supplied a drawing (attached). The rods and pins are currently at the machine shop and hopefully will be done soon. It is going to cost $20 for both. I already have the crank reinstalled.

 

[skwishst]

Just some before and after pictures. Sorry I left the plastic on the head, but I want to leave it clean before I install

 

[Ray70]

looking good! There's nothing quite like engine parts, fresh from the machine shop!
A quick word of caution, if you haven't already done so.... I would suggest taking that oil pressure relief tube apart and cleaning it and make sure it is working correctly. If that thing is stuck closed you will quickly be in need of new pushrods!

 

[skwishst]

Thanks Ray, I pulled it apart and clean it well. The other thing that I found that surprised me was the tappets. I pulled the clip off the top and pulled them apart and the were full of black burnt oil with quite a bit of particulates. Now they are clean and well oiled.

 

[skwishst]

Just as an update, I have it reassembled on the base