Re: Lapping piston rings
 

I had this tool made up about 25 years ago. It is for a 4.060 bore. On one side there is a dish cut in it that allows you to hold a ring inside of it. The ridge is about .025 tall so that the ring is exposed. I can then use this fixture to sand down the ring on a piece of fine paper taped to a piece of glass. The other side of this ring fixture is used for squaring rings in bores when checking / setting the ring end gaps.

Re: Lapping piston rings
 

There is now a new guy at JE running the Stock and Super Stock program, his name is Allen. I have not dealt with him as of yet, but plan to talk to him in the next 2-3 weeks.

Re: Lapping piston rings
 

George when you put a taper face ring into the fixture does it want to cup the ring up, away from the land when in compression?


Thanks Larry

Re: Lapping piston rings
 

This is how a friend of mine back cuts rings to decrease tension.

Re: Lapping piston rings
 

Mine look just like that, but a little deeper. .035" for the old .043" rings I was using.
And, no the rings stayed in place just fine.
Lap one side flat, flip them over and lap the other side flat. Mic the ring, and if needed, touch up the thickness.

Re: Lapping piston rings
 

I was not using tapered rings.

Re: Lapping piston rings
 

Larry, the top rings I have used were all barrel faced. Had tapered second rings. Never lapped those.

Re: Lapping piston rings
 

Finally figured out a way to post the article...

http://i.imgur.com/APjuKKdm.jpg
http://i.imgur.com/u09rh7ym.jpg

Re: Lapping piston rings
 

Thanks Jerry!

Rick Thomason
GTOMayhem

Re: Lapping piston rings
 

Ok fellas ,I'm a dummy ,I just read a lot trying to understand. If you actually increase the thickness of the rings doesn't that allow compression to leak behind them.? Thanks

Re: Lapping piston rings
 

GM's Top Engine Cleaner was used primarily to decarbon pistons and combustion chambers. Have you ever used it or seen someone else use it. Oh my!!!! I used it many times when I worked at Chevrolet Dealers in the 1970's, mostly to eliminate "carbon knock" when carbon build up was great enough to create contact between the piston and the head.

Here's the process: Bring engine up to operating temp. Open throttle to 3000 to 4000 rpms. Pour the TEC down the carb to reduce rpms to around 2000. By now the smoke is rolling like the building is on fire. Pour the last 1/3 to 1/4 of the can in quickly in order to stall the engine. Let the engine cool 30 to 60 minutes. Fire it up and take it out for a very aggressive test drive.

Most of the time it fixed the carbon knock issue. However, I did see one tech pour the last part in too fast and it bent a rod. Not surprising. I'd be very surprised if it is still in use today. The EPA would have a hay day with the emissions, not to mention damaging the cats.

Re: Lapping piston rings
 

I made the mistake of using that stuff ONE time inside my shop. And, the tail pipes turned down. Black spots on the floor, and could hardly see. That is an outside operation, imho. :-)

Re: Lapping piston rings
 

We always had the rear end just outside the bay door when we used it. Some guys claimed that ATF worked just well but I never used it.

Re: Lapping piston rings
 

In my early days of turning wrenches I worked with an old(er) drag racer who used ATF down the carb to eliminate carbon knock. It always seemed to do the trick, but it had the same characteristics as you related about TEC. We had the local fire department show up once . . .

Re: Lapping piston rings
 

Onan made a product to carbon clean engines. 4C cleaner, and you sprayed it in the carb of a running engine. Similar smell as the GM cleaner and some other products you could buy. Bluish white smoke poured out the engine. It did help but definitely not as effective as removing the heads and carbon cleaning the engine.

An Older Onan flathead engine can literally stop turning over from the carbon buidup. Took a machine out of a support vehicle at the World Trade Center site after 9/11 that did.
We put in a new generator but the old one was just locked up from carbon on top of the pistons.....No time to waste there....

The stuff was easily the best carb cleaner as it dissolved pretty much anything in carb passages.

None of these products are still available and I tried to hunt down a case of 4C a while ago.....None available and no longer made.

Tried a lot of other chemicals....Mopar made a carbon cleaner too but I don't think they sell it anymore either....

SeaFoam works but nowhere near as well.....

Re: Lapping piston rings
 

Hi,

I worked at a Cadillac Dealership and had to work on the HT4100 engines. The tune up guys would send the cars to heavy duty to have the trans diagnosed for no full throttle upshift. We would run a can of TEC through the engine to remove the varnish from the valve stems to prevent them from sticking. Re-road test and the trans was fixed.

The varnish caused the engine RPM to flatten out and not reach the RPM needed by the governor to do a full throttle upshift.

We pulled out a lot hair on that one.

Bob

Re: Lapping piston rings
 

Interesting!

Re: Lapping piston rings
 

I can definitely identify with the difficult diagnosis issues from my days as a dealer mechanic.......Mid 1970's Pontiac-Jeep-Subaru line mechanic....flat rater

GM was producing some really poor stuff and the Jeeps and Subarus new to this country had more than their share of problems....

Re: Lapping piston rings
 

You got it right...............

440-T-4, 700-R-4, 200-4-R, 200C some them so bad that the factory said when you get it figured out call us and we will put out TSB's....

They built them and early in the production runs we had to figure out how to fix all of the drivability problems......

As time went on the factory got a handle on them and had updates for the problems...

I worked at several dealerships Chevy, Pontiac, Olds, GMC & Cadillac but no Buick dealerships and we raced one of those also............

Bob

Re: Lapping piston rings
 

The Bon Ami deal was only something I heard about but did not remember how it was actually used. My apology for giving bad info there. 50 years ago is hard to remember. Makes more sense in the top of the engine and not in the oil. The stuff is abrasive and Pontiacs don't need any help with spinning bearings ....lol Total Seal sells a powder to use on your cylinder walls to help seat rings. I have used it. Maybe they heard about Bon Ami....!

Re: Lapping piston rings
 

we use to dribble bon ami, down carb on radial aircraft engines to help rings seat . it was bit smokey, lol. it was used as a last resort before engine was torn down. it would deglaze the bores?

Re: Lapping piston rings
 

For the guys who used top engine cleaner. Have you ever tried Ice Water? Basically do everything the same as top engine cleaner. Except use ice water.

Re: Lapping piston rings
 

I idon't know about ice water but I have seen guys crack the throttle open and shoot a garden hose down the carb. A little pre-teardown steam cleaning I guess.