Club 80-90 Forums

Hi Folks, I'm probably worrying about nothing but. These main bearings that aren't split seem to have some play on the journals. the engineers insist that the journals are well within limits for standard bearings. So when the case is bolted down do they close up a little? ie: is it normal for the clearance to feel a little large before tightening down. I was sort of expecting negligible feelable play on the shaft. Urgent help and advice required.

Surely someone must have built a bottom end on one of these? Well I tried putting the old bearing in on the large journal at flywheel end and tightening the case down, measuring the clearance between the crank and the top of the bearing with thin feelers yielded 0.15mm. So I tried the new bearing and did the same this time the clearance was 0.065mm. The case was not torqued up just cracked up with a wrench. This gives a gap of 0.033mm for oil clearance when running? Possibly slightly less when torqued down. I reckon that sounds ok but any comments?

Bit impatient here aren't we - 2.5 hrs and griping that there is no reply. People have other lives you know!

Perhaps you are all too fast usually, I was merely saying that I think I have solved the problem, they obviously do tighten up with the case.

Hello,

123-jn wrote:Surely someone must have built a bottom end on one of these? Well I tried putting the old bearing in on the large journal at flywheel end and tightening the case down, measuring the clearance between the crank and the top of the bearing with thin feelers yielded 0.15mm. So I tried the new bearing and did the same this time the clearance was 0.065mm. The case was not torqued up just cracked up with a wrench. This gives a gap of 0.033mm for oil clearance when running? Possibly slightly less when torqued down. I reckon that sounds ok but any comments?

That is not a good way to 'mike' your crank..

Look at the 'Ooops' thread, where I show the crank testing..

Measure the journal with a good quality.. preferably referenced.. digital micrometer..

4 times at 90 degrees.. take the lowest as the oval point..

Then make up the big ends.. and mike the internal dia..

All the specs are in Haynes..

Is this a 1600 or a 2 litre

Cordialement..

Thanks saran, unfortunately I don't possess a mic big enough for this job. Instead I gave the crank to an engine shop who apparently measured it and reckon it is within spec for std bearings. They could not however supply the bearings but told me to order standard and that my crank was the larger of the two grades. I was thus surprised that when trying the new bearings from brikwerks there was play in them. The method described was my only available option to give me an idea whether they close up when torqued down.(which they seem to do to some degree). I suppose I was trying to persuade myself that the machine shop were right?

Plastigauge:

http://www.ebay.co.uk/itm/Plastigauge-p ... _542wt_722" onclick="window.open(this.href);return false;

Or if you can get hold of a suitable size micrometer:

http://www.ebay.co.uk/itm/Telescopic-Bo ... 1440wt_722" onclick="window.open(this.href);return false;

They take a bit of experience/feel to use though.

Those look great I might invest in a set! The trouble with plastigauge is that I cant use it on the full ring bearings on my crank only on the split one in the middle!!!
Thanks.
I suppose I could try trusting the machine shop and put it together and hope? nnaaahhh!!!