Looks like there is different bearings, oilholes differs.
But that dont explain why all is ruined. Did you assemble the crank and rods? On the nearest bearing in the picture you can see the surface been drawn in to the oilhole, is the tab on the bearing ok or has it been mounted the wrong way around?
nothing yet has explained the situation, you defiantly should check the core plugs behind the aux shaft seal housing
not so sure, mains dont get the same hammer action and dont forget its still being run in, but that said right now i suspect issue is the ends have been ground but std shells used, as i said earlier its rare for a crank to be undersize on the mains but not the ends
Thanks everyone I checked the two front core plugs today as I fitted new ones but no there perfect. Engine is completely stripped now only damaged is big ends and pump rings bores mains all good and the cams
Funny you should say that graham bloke at the machine shop said it’s strange how the big ends wasn’t machined with the mains.
Shells were fitted correctly all tabs still in place hadn’t spun. All I can think off now is I fu#$ed up big time I should of plastigaged it. Even though the engine shop I was using back then wrote the sizes of the mains and big ends on the crank with a marker lol
There going to measure up at the machine shop to see if it’s standard size or not
Last edited by Graham; 15-10-2020 at 16:56.
When I put the wrong shells on my Xflow the bearing damage looked similar to these but not as bad since I didn't drive it before discovering the problem.
It sounded perfect on idle, you'd never tell.
I was suspicious about the low oil pressure though before discovering it knocked when revved above 4000 rpm when cold, and above maybe 2500 rpm when hot.
Stripped it down to discover similar results to the OP.
Had bought the engine second hand in bits and didn't know it needed oversize bearings.
Produced good power though once up and running.
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I have known Engine Machine shops get their tolerances wrong on more than one occasion so be aware of that one. Who reground the crank, them or another source?
When you are satisfied and have rebuild the engine make sure you use a new oil pump of good repute and have the correct gasket fitted between the pickup pipe and pump. You'll have to pay North of £200 for a decent 4x4 oil pump. The best of luck.
And of course prime the oil galleries by using a drill to spin the oil pump drive with the distributor removed, you should see full oil pressure on the gauge by using this method.
Hi thanks everyone
It was S.E.P kegworth who did all the original work to the crank. Old school place I would if took it back but they had my crank and block for nearly a year lol.
It’s at a different place now as soon as they ring me I’ll go fetch it and see what they have to say about it
Been in the "Motorcycle engine work" business since 1987, S.E.P used to have a very good Rep, a few years ago they had a management / owner change and have since gone very downhill with some appalling work, some i have personally had to put right.
Please do keep us posted on what the new place finds.
A low comp engine with thick oil and easy breaking in does
Not nessetivetly knock. I had a 11 litre diesel with one sice ground crank and standard bearings and we opened it just because low oil pressure. And a diesel has higher comp. Some others had overhauld it. So I agree with both of you.
Hi everyone sorry I haven’t been on for a while
I picked the crank up yesterday it’s been repaired but unfortunately it’s now on 50 mains and 25 big ends. After speaking to the machine shop they insisted I took the rods in so he can measure them up.
Glad it's right now then.
I take it this was a different machine shop as to who had it the 1st time round? It was good idea for them
to have asked for the rods aswell just to double check all the associated parts.
The main bearing shells and journals looked ok on 0.25 but needed to be reground to 0.50? Why was that then?
As an engine post-mortemist it bothers me not to know!
Last edited by HonkyWhiteTrash; 05-11-2020 at 17:27.
Apparently out of balance 5 thousands so had to be done to straighten it back up.
Right got the rods back from the engine shop they checked the roundness and said there fine but he didn’t really answer my question when I asked if there the correct size. So I have them with me at work and just measured them
but were your first set of bearings the right size?
He said the crank big end was on its standard size and the shell fitted was standard size but he said it’s to badly damaged to measure. That’s all he told me apart from check oil galleries and oil pump a bit disappointing really I was hoping he’ll find the problem
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