Seating the Rings

[Bob Harvey]

To all you experts and 'pros', please explain 'Seating the Rings'. It makes NO sense to me, in that, a new cyl. sleave (cross hatched) and a newly bored cyl. (cross hatched) with new pistons or just new rings, are at their optimum NEW. Any 'seating' is the first stages of wear. The drag guys that get 8,000 HP from their engines certainly don't 'seat'. The F1 guys that make 18,000 R.P.M and 900HP don't also. Thoughts please.

 

[souNdguy]

IMHO.. slight wear in from the rings to the cyl bore will result in better compression.. ie matching ID and OD

soundguy

 

[Tom N MS]

Run it like you stole it--seat them right..

 

[fireater]

also means run it up to operating temp and put a mall load on it...rings like that when new... gets them hot so they can conform to the cylinder walls better so it wont burn oil

 

[fireater]

err small load i mean

 

[Fuddy Duddy]

If put under a microscope you would see though new it not perfect. Seating just takes off the rough edges to make a better fit.

 

[JMOR]

(quoted from post at 18:51:48 04/30/11) To all you experts and 'pros', please explain 'Seating the Rings'. It makes NO sense to me, in that, a new cyl. sleave (cross hatched) and a newly bored cyl. (cross hatched) with new pistons or just new rings, are at their optimum NEW. Any 'seating' is the first stages of wear. The drag guys that get 8,000 HP from their engines certainly don't 'seat'. The F1 guys that make 18,000 R.P.M and 900HP don't also. Thoughts please.

"Any 'seating' is the first stages of wear. The drag guys that get 8,000 HP from their engines certainly don't 'seat'. The F1 guys that make 18,000 R.P.M and 900HP don't also."

You answered your own question with the 1st sentence above and if you don't think 1st stages of wear do not occur in those engines, well, I am at a loss for words.

Many cylinders actually change shape slightly just in the process of bolting on the cylinder head. Rings & cylinder have to wear to fit this new shape.

 

[Bob Harvey]

Not trying to be a PITA, but. Are you saying a cast iron block (normal type engine or 1 with sleaves) deforms enough that the rings make up the difference ?

 

[504]

High performance engine builders always bore and hone the blocks with thick steel plates torqued to the block, so the cylinders are round when the engine is finally bolted together.

 

[JMOR]

(quoted from post at 21:25:22 04/30/11) High performance engine builders always bore and hone the blocks with thick steel plates torqued to the block, so the cylinders are round when the engine is finally bolted together.

xactly! And the reason it paines me to see so many on these boards pull the head off "to take a look see". I would never remove a head unless I had already reached a degree of certainty, thru careful diagnostics, that it absolutely had to be removed. Even with a torque wrench & proper sequencing, you just know that the cylinder will NOT be returned to its exact former shape. At that point, the designed wear face on the rings & the hone of the cylinder have already seen their one-time use.
Yes, it will run again, but it won't ever be like it was.

 

[36 Coupe]

Back in the hot rod days chrome rings took a long time to seat.Some new rebuilds burned oil for a while.

 

[G6 at Snook, TX]

[/quote]

JMOR,

I have watched and read your posts for some time now and I think you are one of the eight or ten who know their stuff. I have come to that conclusion while working on my tractors and using your advice while discarding other's advice.

Would you write up and post a brief diagnostic procedure we can use to test whether or not a head gasket is blown without pulling the head? I would like to read it and file it away for the time, inevitably, the head gasket does blow.

Thanks,
G6

 

[JMOR]

G6, I'm not sure that is complex enough to warrant a 'procedure', but I'll ramble a bit on it. Look at the block to head interface on the flat head N engine and you see 4 combustion chambers that you want to seal. What is around them that you want to seal from? Lots of water holes/passages, adjacent combustion chambers, and the outside world found around the outer edge of head/block. Three areas. Easy first. Eyeball, feel, listen around the outer edge of head/block for any leak of gases or coolant. Run a compression check as it might point you to a gross leak & while you are at it look for coolant on spark plugs or plugs that look steam-cleaned. Two adjacent cylinders with 50# versus two others at 125# out to light a bulb. Small leaks are more difficult. To find those and to isolate them, you can pressurize the radiator moderately and watch gauge to see if it leaks down and if it does, search for source of leak visually, by ear, loss of coolant & where it is going. One of the best methods is to apply compressed air to each cylinder, one at a time via spark plug holes, when cylinder id fixed at TDC-compression stroke. Now observe bubbles in near full radiator, sound of escaping air at adjacent spark plug holes, radiator filler, periphery of head/block. A bonus here, that isn't head gasket related, is that you can listen at intake to carb, at exhaust, at oil filler tube, etc. and maybe find a leaking intake valve, exhaust valve, rings/sleeve/piston breaks. Maybe others can think of something else?

 

[Ultradog MN]

Well said Jmor.
It has always baffled me to hear of another new N owner who has some trouble with his engine and the next thing you know he's ripped the head off of it to see what is wrong. Next thing you know he's doing a $1500 "rebuild" on an engine that would have run for years yet with a little TLC.

 

[JMOR]

(quoted from post at 11:31:39 05/01/11) Well said Jmor.
It has always baffled me to hear of another new N owner who has some trouble with his engine and the next thing you know he's ripped the head off of it to see what is wrong. Next thing you know he's doing a $1500 "rebuild" on an engine that would have run for years yet with a little TLC.

Yes, Sir.

 

[rnorum]

JMOR is right on.Race builders are looking for blowby on a dyno. With torque plates, they hone to almost size, then hone to platua finish, maybe use low tension rings, rings then will seat good enough for no blowby, ready to race.
Engine rebuilders expect to use 1 to 1 1/2 quarts the first 500 mi. then rings should be seated.