Crankshaft thrust washer clearance

[Ian Vincent]

Whilst I have the sump off and am waiting for new bearings to turn up, I checked the end clearance on the crank this afternoon.  It was .007" which is outside the allowable range of .004" to .006".

So how does one go about adjusting this?  I have a pair (i.e. two halves that would fit one side of the crankshaft - the other two halves are already in place), of 0.005" oversize thrust washers (bearings) but if I use them the clearance will be reduced to 0.002".  What happens if there isn't enough end float on the crank?  Or do I have to gently rub down the oversize thrust washers to bring them down to 0.003" oversize?

Rgds Ian

PS I have checked the thickness of the oversize ones and they are the full 5 thou over, it's not split 2.5 thou each side.

[Z320]

I had 0.17 mm for years, now 0.19 mm.

I do nothing and check next year or in 2 years again.

Ciao, Marco

[jerrytr5]

You can usually get the right clearance with a combination of std & oversize.

Jerry

[BlueTR3A-5EKT]

5 hours ago, Ian Vincent said:

Whilst I have the sump off and am waiting for new bearings to turn up, I checked the end clearance on the crank this afternoon.  It was .007" which is outside the allowable range of .004" to .006".

So how does one go about adjusting this?  I have a pair (i.e. two halves that would fit one side of the crankshaft - the other two halves are already in place), of 0.005" oversize thrust washers (bearings) but if I use them the clearance will be reduced to 0.002".  What happens if there isn't enough end float on the crank?  Or do I have to gently rub down the oversize thrust washers to bring them down to 0.003" oversize?

Rgds Ian

PS I have checked the thickness of the oversize ones and they are the full 5 thou over, it's not split 2.5 thou each side.

What thickness were the old ones?

Can you mix the thickest old ones with a new pair to get the required end float?   Ie two new one side two used the other.

Rubbing down the steel backing as you mention is the next step.

Do not forget if you move the whole crank forward or backwards excessively, 0.005” or more, you will be upsetting the cam to crank sprocket alignment and may cause wear, affecting the cam thrust end float setting.   This being set with shim washers behind the crank sprocket so the two timing sprockets are level at full thrust position.

Edited November 25, 2023 by BlueTR3A-5EKT

[Lebro]

I ended up using half the new set with half of the originals to get within tolerance as Pete suggested.

Bob

[Andy Moltu]

I would get a set of standards (or whatever you have fitted at present) and see what the end float is with those.

It may be simply wear on the thrusts so it might be all that's required is replacement. If it's still out of tolerance get a set a size up from those you removed. You can mix and match to get it in clearance. 

Don't go too tight as there is a risk of the clearance being too little when the engine is hot and damaging the thrusts.

[Ian Vincent]

I currently have STD on one side of the crank and +5 thou on the other and the end float is 7 thou.  Moss list an 8 thou oversize thrust washer set but they are NCA.  I also have in my spares box another full set plus a half set of +5 thou along with one and a half sets of STD.  I have mic'd up all of these and there is minimal variation from the quoted thicknesses of .0925" and .0975".  So it looks like I will need to gently rub down a pair of 5 thou oversize to 3 thou unless there is something I have missed.

Rgds Ian