Thrust bearing clearance

[2cams70]

The usual cause of the thrust surfaces requiring a regrind is someone installing one or both washers back to front. The thrust faces on the crank in an engine used normally usually have negligible wear.

[rgh0]

Other possible causes of the need to regrind the crank thrust faces can be an engine failure putting metal through the oil system, a filter failure putting griot through the engine, or a head gasket failure putting water into the oil or just not changing the oil for extended periods so it degrades. Probably other I cant think of immediately also.

cheers
Rohan

[2cams70]

It’s not part of a normal crank re grind to grind the thrust faces. Unless you take some further measurements you can’t establish which part is out of tolerance.

[rgh0]

Yes I think thats exactly what I said

cheers
Rohan

[cadwell]

Rohan
Yes I will do that to check it out, the journals are -0.010 so the thrust faces have probably been ground as as well, as you suggest.
We are on a Mediterranean cruise until the 8th July but I will post the results on my return.

Thanks for your interest

Peter

[2cams70]

Yes I think thats exactly what I said

cheers
Rohan

You originally went along with replacing the thrust washers until I made the suggestion to further investigate the cause. Then rather than acknowledging the suggestion you just repeated what I already had said. After that you went on about spurious stuff such as contamination in the oil when I suggested that the usual cause of thrust faces requiring a regrind is washers fitted the wrong way around.

[Quart Meg Miles]

Back in 2007 I discovered why my clutch was misbehaving, sometimes not disengaging until fully engaged which often needed the engine to be switched off. Then I had a piston break and on dismantling the engine found one crank thrust face scoured beyond belief and one of the thrust washers was in the sump!

It was suggested (on this forum) that the washers were fitted in reverse but they weren't, the thrust faces were scoured like the crank and the backs were still pretty flat.

I have always changed oil and filter annually despite just a few thousand miles running and always warm up the oil, as a result of which the crank journals are worn less than 0.001 inches despite my high total mileage.

I had the thrust faces remetalled and ground to give standard clearance with standard thrust washers and have had no problems since; it cost almost £400 (UKP). I don't know of anyone else who has had this problem but odd things seem to happen.

[rgh0]

Another thought is to see if you can make a suitable thicker thrust bearing from the Pinto block thrusts bearings which may be avaiable in the needed oversize and are very similar in dinensions except designed for the full circle using 4 bearings.

These bearings are used on the new Ford Motorsport 1600 and 1500 blocks

cheers
Rohan

[cadwell]

Thanks Rohan, that one seems worth investigating. I will post the results of my search!

Peter

[Elan45]

I may have a pair of .015 thick, but all my thrusts are in Florida and I'm in Ohio for at least 3 months. I'd hate to sell them because I just bought them last year. I bought 4 or 5 pairs from the same vendor off ebay and I'm building the engine for my coupe, so don't know which size I will need.

Roger

[cadwell]

Roger
Very interesting, would it be possible to let me have the name of the eBay seller please

Thanks

Peter

[StressCraxx]

If the sources below are not able to supply you with what you need, recommend contacting Ivey Engines in Portland OR. They are Twincam and Kent gurus.
http://www.iveyengines.com

Another alternative is Tony Ingram, Tony Ingram Racing. http://www.lotus7.com/Home.html

Both companies provide excellent service.

[Elan45]

And Tony seems to get another brand of bearing shells, ACL, I believe made in Australia. and that may benefit you.
I've bought several sets of bearings from Tony, but I found it unusual that they were making cam bearings for twin-cams.

Peter,
I don;t remember the ebay seller and I bought his entire 4 or 5 sets of oversize thrusts. I'll double check what I have in my garage here but pretty sure I left all my bearing thrust stuff in Florida with the short block.

Roger

[rgh0]

ACL only currently make 5 and 10 thou oversize thrust bearings as far as i am aware.

cheers
Rohan

[cadwell]

Rohan and Roger
Any luck with your search for 0.015” oversize thrusts Roger!
Rohan
I have found a white metaller, Chase Engines, Newcastle under Lyme. Been to see them today and they seem to be very competent. My 0.010” oversize thrusts are Vandervell and bronze faced. Chase Engines suggested that white metal does not adhere too well to bronze so they usually remove the bronze down to the steel backing and white metal from there. They also agreed that it was only necessary to do the non thrust side, 0.012” offset being not material.
Cost will be circa £120.
Still thinking of making a pair from sae660 bronze/lead, but would value your input Rohan.

Peter