inlet/exhaust roller rebuild

[Martin Pettingell]

I am working my way through the engineof my 27 J.
Its not in bad condition but after 90 years of use most of the moving parts are worn out and need replacing.

I acquired a roller rebuild kit from CD and sat down this morning to set about replacing the rollers.
First thing i did was measure the circumference of the old and new rollers - they were the same to within 0.001.

There is play in the rollers, both laterelly and vertically but this does not seem excessive and i imagine then need to spin freely. Even on the new parts it seems as though there may be play between the roller and the pins they spin on - so i am beginning to wonder whether they actually need replacing at all.

Can anybody help on what to look for and/or how to measure the wear on rollers so i can determine whether i need to replace them?

If they do need replacing how do you remove the old pins. Is it necessary to grind the ends of off the old pins from the back of the roller arm in order to knock them out?

And what is the technique for fitting the news pins and rollers?

I was hoping that somebody might have posted information about this previously but cant find anything so far. If there is something out there i'd be grateful for a point in the right direction.

Thanks

Martin
in the UK

[jellywrestler]

maybe allowing for heat expansion?

[DanM]

Martin,
I don't know any factory specs for clearance, but I do know that the one's I have done were quite loose, maybe .005 or more, the outer wheel wobbled, and showed wear in the form of grooves. One wheel was not running fully on the cam and had worn offset, leaving part of the OD untouched.

My first set came from Comp Dist so loose I thought if they were correct I was wasting my time. I sent them back and the new set was matched quite a bit better. A "just loose" clearance fit. I don't recall or have my notes of size, but those inners just fit the outers perfectly. The kit comes with the tool for removal. Its really a punch. The axle has been pressed into the arm and peened right flush, or ground flush. You need to spot drill right on center, then use slightly larger drills until you can get to the axle diamter and punch it out. To find the peened center, I recall cleaning the arms well, then apply some ink or bluing to the area and rub it with a cloth. You should produce a faint ring where the ink or paint gets into the joint around the peened/riverted head of the axle. Center punch best you can. Support the arm while drilling on a socket, or piece of tubing, or make up something. Obviously, you want to leave as much of the arm intact as possible, while removing as much of the axle as possible . Too much axle and you can't punch it through.

Take note of the positions and axles and match up the various rollers and axles to match. If you have a caliper or micrometer, you should find the inner roller is slightly wider than the outer roller. If not, sand or stone the roller so it is approximately .005" narrower. When the axle is peened over it will capture the inner roller, and that clearance will allow the outer roller go turn. You don't want to end up capturing the outer roller!

I peened the end of the axle into the countersunk hole as deeply and thoroughly as possible, then filed anything off that could interfere during operation.

When you put the arms back on, check the rollers ride on the cam face fully. You may need to use a combination of shims on the cam or arms to get them all lined up.

Hope this helps!

Dan

[Martin Pettingell]

Dan,

That's great - thanks very much. My original rollers were riding on the cam ok but I imagine they are worn to some extent - the rest of the motor was well worn and there is no evidence that the rollers have been tampered with or changed in the past.

I will follow your guide and maybe post some pictures for future reference

thanks again

Martin