Main Bearings

[stuart 31 3 Cars]

Received them today and want to crack on getting the engine built up but not sure if I can use this combination or not?

 

There's a couple of combinations of grooved / plain bearings in the Haynes but not 6 grooved and 4 plain...hmm confused...

 

Cheers

 

Stu

 

P.S. Engine is from a 1991 XU5

[Tom Fenton 1,542]

From memory I think there should be 5 of each? You could look in my XU5T build thread and see if there is a picture there, there should be as I took lots.

[stuart 31 3 Cars]

From memory I think there should be 5 of each? You could look in my XU5T build thread and see if there is a picture there, there should be as I took lots.

 

That's the concensus up to now from another thread I've found asking similar questions and also on puma racing's website.

 

I had a look through your thread last night actually and just checked again now but can only see that the grooved shells go in the block but not what goes in the caps.

 

Would there be any reason not to use the 'spare' grooved shell in the centre bearing cap instead of a plain one?

 

It's just this is the 2nd set I've received from the company so can't imagine them sending the wrong ones twice...

 

EDIT:

 

Managed to get hold of Matt at QEP where I got them and as I suspected, the centre cap has the grooved bearing top and bottom. Let the building commence!

Edited November 3, 2009 by stuart

[craig_007 1]

Yep that was the same for me when I built my bottom end,From what I recall the locating lug on the main bearing didn't match the one of the main bearing cap though !!

[stuart 31 3 Cars]

I'll have to check if mine is the same or not then...how did you get around that if you don't mind me asking?

[Miles 331 1 Cars]

Top row Groved and caps plain on all XU's, Yes there's been loads of different options listed in the joke book but 99% of the time the engine's are like that without any problems at all.

[craig_007 1]

Rightly or wrongly I made a small notch in the main bearing cap to suit the shell,I've run the engine in etc and have had no problems at all.

[stuart 31 3 Cars]

Well I fitted the crank today but I'm not 100% sure that one of the mains is right...

 

I fitted the grooved shells in the block and they all seem ok apart from on no. 1 bearing (cam belt end), which, due to the position of the locating lug sits slightly inboard of the block and overhangs the bearing housing by about 1mm.

I can also see from oil marks on the cap that the original bearing was sat in the centre, the same as the others, so this doesn't seem right.

I have also used the 'spare' grooved bearing in no. 1 cap, as I tried one of the plain ones in there but it sat even further inboard and so didn't line up with the bearing in the block. A grooved shell in the centre cap would not line up with the centre bearing either so used a plain one there too.

 

The crank does however seem to run ok on the bearings, although I haven't torqued them up yet.

 

If the current configuration isn't correct though, it looks like I need 2 shells with a different offset to the rest for no. 1 bearing, which doesn't seem right.

 

I probably need to take a picture to illustrate this better but hopefully it'll sound familiat to someone in the know

 

 

Cheers

 

Stu

[sub205 5]

I have also used the 'spare' grooved bearing in no. 1 cap, as I tried one of the plain ones in there but it sat even further inboard and so didn't line up with the bearing in the block. A grooved shell in the centre cap would not line up with the centre bearing either so used a plain one there too.

 

you can also use a dremel and fine-tune the notch :-)

the forces on a mounted bearing are high enough so the bearing wont start to move itself.

i had similar issues with my xu10 bigend-bearings, the notch was far to wide in the rods, so i centered the bearings and mounted them that way. no problems, because the bearings are slightly bigger than their circle, so they build up some pressure. in theory, you dont need notches at all, they are just helpful for quickly building an engine.

[Tom Fenton 1,542]

Something sounds amiss to me. The bearings should go back where the old ones were. I would definitely get hold of some plastigauge and check running clearances when torqued down before doing anything else.

[stuart 31 3 Cars]

I too thought that they should go back where the old ones came from but bearing no. 1 seems to have the notches for the locating lugs further inboard.

 

This is how it looks at the moment:

 

 

 

P.S. the thrust washers aren't fitted yet.

Edited November 10, 2009 by stuart

[stuart 31 3 Cars]

Right, I've had the crank out again today to see if I can make any sense of it.

All the shells in the block line up with the oil ways perfectly so I'm 99% sure they are ok. The 'overhang' I spoke about in previous posts isn't as bad as I first thought either, maybe 1/2mm max. I also found a pic of another engine on here with the caps off and looks the same as mine with the shell in no. 1 (or is it 4 going by hanyes?) offset inboard slightly, so I'm happy with that.

 

The only thing that concerns me a little is that the grooved bearing in the cap in the pic above doesn't fit where the old one did, although it does line up with the bearing in the block...

The crank spins beautifully with hardly any resistance, no horrible noises, etc.

 

So best bet now is to check it out with plastigauge just to be sure then? Can anyone tell me which tolerance band I need?

[welshpug 1,657]

1 is flywheel end, 4 timing belt end