seating chrome rings

[jsgarage]

As Statsystems & others said, chrome needs special care 'cause they are HARD- meant for dirt track racing or long-haul trucks. I once had a Pinto 4 cylinder bored & honed and didn't tell the shop what rings I was using. Assembled with chrome rings, the engine would not start on the starter- it had so little compression it needed a bump-start. I could get about 1200 rpms from the engine with the starter & no fire. My partner and I took turns driving the thing 100 miles a night for almost a month until we accumulated around 1000 miles before the poor engine would start with the starter. It just kept slowly improving. Note- once the rings DID seat, the engine lasted for over 20 yrs of daily city driving with no further problems.

[Geoff2]

Yes, that is why Chrome rings need lots of miles to fully bed in. Chrome rings are hard chrome, not decorative Chrome, a hard material as the name implies. It is amazing that people think that 30 min on a dyno & rings have fully bedded-in & sealed....

From A.G. Bell, 'Modern Engine Tuning'.
'Chrome plated rings are harder to bed in than any other type of ring, but they offer long service life...

From the ACL engine Reconditioning book, ACL manufacturers of pistons, rings, engine brgs & other engine components.
' Chromium is very hard & has excellent wear resistance. As a consequence it can take a long time to bed in to give a good seal. It is essential that the bore surface finish is correct or bedding-in will be delayed with resultant oil consumption problems'.

[mag2555]

You folks who have issues with Moly face rings need to do what the car manufacturers do and plateau hone the cylinders.
I never have issues when doing that especially seeing that the rings themselves are laped by the manufacturer.

[HDBD]

no idea, the pistons came with the rings already installed. 1967 Mercedes Benz i-6 gas job.

they wanted piston to wall clearance set at .0009" on a 3.248" piston.

sounded ridiculous. I put it at .002" P to W.



what does the ring base material have to do with the price of tea in china?

I worked on those in the day as a line mechanic. There were either Kolbenschmidt or Mahle pistons available. You set them to the factory spec IE 80mm the bore, period, no variation. They were tight! The ring end gaps end up perfect and with the proper hone pattern they break in in short order with a load unload break-in drive. Used valvoline non-detergent oil for the first 100 miles then blue top 10w/30 or red top 30w.
I had a machine shop talk me into larger clearance only one time and it was an oil burner. Had to take it apart and bore it to the next OS to cure the issue.

[statsystems]

You folks who have issues with Moly face rings need to do what the car manufacturers do and plateau hone the cylinders.
I never have issues when doing that especially seeing that the rings themselves are laped by the manufacturer.

My dislike of moly rings has nothing to do with how to finish the bore. Moly was used on rings so the sorry assed Dealerships could slam a set of rings in with ZERO bore prep and have them seal.


I don't care what the ring face is, but if it takes hundreds of miles to seat the rings you did something wrong. I've NEVER had a chrome faced ring take any longer than any other ring face materiel to break in and seat.

That's just crazy to think rings take that long to seal.

[HDBD]

Those 220 230 250 and 280 motors had hard nickel blocks. When rebuilt with the stock rings and pistons properly fit, the right tight rod and main clearance, again not relying on Billy Bob machine to put the crank on the high limit they would last in excess of 180k miles.
One more hint, replacement pumps back in the day were fit too loose, cover to gears. Close that up to .001 and they will have full oil pressure right off idle. Today we have better choices for valve seals but all oem parts and tolerances in the heads too will reward you for the effort too. Replace the water jets too, cc the chambers.

[pdq67]

He, He!!

A good shake of either Bon Ami Powder Cleanser or Comet down the carb and go!!

This is chrome ring flathead day stuff.

I just had to mention this...

pdq67

[Truckedup]

Looks like guys saying chrome rings seat quickly and others who say they need many miles to seat properly....

Bon Ami Powder Cleanser or Comet

.. There's a huge difference between Comet and Bon Ami...I do know true stories of a teaspoon of Bon Ami, a fine polishing compound used in some situations... But Comet? That a very coarse grit..

[groberts101]

Looks like guys saying chrome rings seat quickly and others who say they need many miles to seat properly....

Bon Ami Powder Cleanser or Comet

.. There's a huge difference between Comet and Bon Ami...I do know true stories of a teaspoon of Bon Ami, a fine polishing compound used in some situations... But Comet? That a very coarse grit..

Remember though. There are many guys who matt the pedal on cold engines to "clear the carb" too. Have to admit of being guilty myself of getting on it while the manifold is still cold to enjoy all that extra mixture density and torque. lol

I think some of it has to do with the honing procedures too. Some machinists are like doctors.. talk with 5 different machine shops and you'll get 6 different honing and finish recommendations.