Lapping piston rings

[Dwight Southerland]

Originally Posted by Eman

I remember reading that Chevrolet used cleanser as a field fix for seating rings on the early V-8's.

Bon-Ami was the choice. I got to experience stopping on the way to Amarillo to a point race, unloading the car and running it up and down the highway applying the Bon-Ami to get stainless steel rings to seat.

[older racer]

lol, I remember aircraft radial engines, had chrome cylinders and cast rings, bon ami was used to get them to quit pumping oil. they could use a lot of oil too . it was a last resort.

[Ed Wright]

Originally Posted by Dwight Southerland

Bon-Ami was the choice. I got to experience stopping on the way to Amarillo to a point race, unloading the car and running it up and down the highway applying the Bon-Ami to get stainless steel rings to seat.

Been there. Used Bon-Ami as well. Stainless Dykes rings in my old '56 Jr Stocker.

[Rich Biebel]

The BonAmi trick was a Pontiac approved fix attempt for oil burning engines. I recall hearing of it and to this day if I hear the name BonAmi that's exactly what I think of. Add some to your oil to get your rings to seat.

[Bob Mulry]

Originally Posted by Rich Biebel

The BonAmi trick was a Pontiac approved fix attempt for oil burning engines. I recall hearing of it and to this day if I hear the name BonAmi that's exactly what I think of. Add some to your oil to get your rings to seat.

Just a quickee................

It doesn't go in the oil!!!!!!!!!!!!!!!!!!!!!

Remove the spark plugs and put the BonAmi directly into the cylinders and crank her over....Use air to blow out whatever you can from the cylinders.....Start it up....Let it run for a bit....Change oil and filter...See what you got....Sometimes better...Sometimes not...It's just a bandaid..

GM also had TSB's about helping ring seal and oil consumption by using GM Top Engine Cleaner in Gas & Diesels.....Gas it went down the carb and diesels it went in thru the glow plug holes...

Just a crutch...

Bob

[goinbroke2]

We called this "flinting" an engine when we did it to 6v53detroits. They would idle so long they would gum up and when you stepped on it there was a cloud you could see for a mile plus it had no power for a while. Once it got real bad we'd pull the air filter and at a fast idle throw a handful of scouring powder in. Couple rev's and see how much it smoked, maybe do it again.

Worse case scenario, we sent the engine to second line for rebuild.

[Larry Hill]

The NHRA approved rod list for the Pontiac 350, 389, 400,421,428, 455, it looks like all the OEM rods were the same size. 13 rods are listed on the approved list with only two rods as super stock only. Of the remaining 11 rods, nine are listed as the OEM size. Crower makes two, Oliver has three, Eagle has one, Childs and Albert has one, and Carrillo makes two.


It looks to me a lot of venders make a rod for that engine. It ok to grind the crank .049'' under (NHRA allows -.070'') to 2.200'' crank pin size but nobody makes a rod bearing -.049'' under that fits into a 2.375'' housing bore. If I read the rules correctly spacers are not allowed in stock.


So if good bearings are not available just ask NHRA for a new rod, AKA the FE ford rule.

[nolongerracing]

Mopar ask for the same thing for the dragpaks. At least the Pontiac uses a corporate bearing size.

So if good bearings are not available just ask NHRA for a new rod, AKA the FE ford rule.[/QUOTE]

[Pvt Parts]

Originally Posted by Bob Mulry

Just a quickee................

It doesn't go in the oil!!!!!!!!!!!!!!!!!!!!!

Remove the spark plugs and put the BonAmi directly into the cylinders and crank her over....Use air to blow out whatever you can from the cylinders.....Start it up....Let it run for a bit....Change oil and filter...See what you got....Sometimes better...Sometimes not...It's just a bandaid..

GM also had TSB's about helping ring seal and oil consumption by using GM Top Engine Cleaner in Gas & Diesels.....Gas it went down the carb and diesels it went in thru the glow plug holes...

Just a crutch...

Bob

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.

[Ed Wright]

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. :-)