Technical Re ringing an engine

With the price of rebuilding an engine these days I am considering re ringing the pistons . What kind of wear should I expect before I should consider a reborn and new pistons ?? Engine has a bit of blow by now ,but I can't get my head around rebuilding an engine that I will only put 5-6 thousand miles maybe in my lifetime
Engine is a 425 buick nailhead.

 

Personally, I'm a bit persnickety about the bores. I just went through an inline 6 that had .005" out of round on one cylinder. The rest were only .002" at worst.
Like you, I probably won't put a bunch of miles on this, but I wanted it to be as good as it could be so I wouldn't ever have to think about it again. I wanted it last as long as I do.
I ended up boring to the next oversize. Yep, it cost for the machine shop and the pistons. But I'm not gonna worry about that, or be dissatisfied because I took a shortcut, and then the thing uses oil, makes noise or loses power.
Ultimately, it's your call as to what you can live with.

 

Until you get it apart and know cylinder out-of-round, cylinder taper, and piston ring land wear there is no way to know if you can get away a potential re-ring. But if it has blow by now, it's telling you that the rings can't provide the seal needed. You just don't know the reason why. Any idea how many miles are on the engine currently?

 

I freshened up a Chevy 6 cylinder. Honed bores, new rings, bearings, etc. Before this, I didn't even know that they make rings just 1,000 of an inch oversize. But they do. So I got me a set of them there. Figured it would take up just a little bit of the wear in the bore. Seemed to work fine. Not actually recommending it, and even I might not do that again. Just saying, I had no problems.

 

http://buick.oldcarmanualproject.co...vice Manual/09-Engine Mechanical/image65.html

http://buick.oldcarmanualproject.co...Chassis Service Manual/02-Engine/image26.html

 

I'm mostly used to working on small twostrokes, so usually relatively easy to just replace a worn cylinder rather than reboring the old one, but in my experience from there compression issues are very rarely caused by the rings alone - at the very least the piston is usually quite worn and often the cylinder worn or damaged too. Only replacing rings mostly gives you a warm fuzzy feeling of having done something, instead of actually improving anything about how the engine works.

Yes, doing it properly will cost more... but if you count the money you spend anyway, the time you spend pulling, disassembling, reassembling and installing the engine, does the rebore add a huge amount to what you'll be spending anyway?

 

I will be the contrarian here. WE DID THAT ALL THE TIME back in the 50s and 60s. Bust the glaze and go.

 

If the cylinder has a ridge it most likely should be bored to seal properly...

 

Every engine I have ever torn down started out with the high hopes of being able to get away with a Re-Ring and Gasket Job. Every engine ended up with a full rebuild.....

Remember, there is a good reason you are tearing it down in the first place.

 

We did not. Use a ridge reamer and go.

Ben

 

You guy must all have lived in a richer country than I.

Ben

 

I have no idea of how many engines I have done re-ring jobs on in the past 60 years but it is a bunch.

I've cut the ridges out of every engine I ever did a re-ring job on. True the taper on a few was too much and they had to be bored but you have to cut the ridges out to get the pistons out anyhow.

I have to go with what Ben said, I don't know what a lot of these guys budget is but I've used a lot of those 80 buck ring, bearing and gasket kits to freshen up a small block Chevy and get 60/70K out of it in my lifetime. One of those engines was the one that I left Toppenish for Waco with 36 miles on the speedometer after the re-ring, valve and bearing job in 1981. That engine got 5 K put on it in three weeks. I ran it about 60K, pulled it because I was going to put a 396 in and sold it to a buddy who I helped do a fresh ring and bearing job on it an we stuck it in his 60 something square GMC and he ran it until he sold it. The 292 will get rings and bearings and a valve job simply because it has unknow miles and has been sitting for too many years since I got it.

 

For me .005 taper is the limit. With taper the ring has to go in and out every stroke which equals short ring life. I would hone it straighter and knurl the pistons.

 

On a 235" Chevy 6, I put in new rings and rod bearings on the same motor twice. Like you said, in my
younger years, that was just what you did, and you did it yourself. Also did the same for a couple of sbc's.
Now, later in life and a little more $$, I try to do a job just once, and will spend the extra amount up front
to do that. Fun to hear the different opinions depending on how and where you grew up, and when.
That's what hot rodding is all about. Something for everyone....

 

What kind of shape are the ring lands?

 

You told all the necessary information in the 1st post .
You’re only going to put 5-6 thousand miles on it ,,,,,,tear it down,,,,,clean the pistons good,,,,,,new rings will last it all your gonna do to it .
Do a decent valve job on it,,,,that Nailhead will go a long ways yet .

Tommy

 

I’ve cut ridges, cleaned ring lands and tossed new rings in. Polished cranks, lapped the valves and drove the crap out of em. But these were within tolerances. Some pushed it.
I just sold a truck that had an engine we did a re-ring in 1989. Put that engine in 3 different rides. Drove the crap out of it. Seen it Monday cruising, guy drives it everywhere.
Got over 30k on a 350 re-ring we did 5 years ago.
If it’s in spec or close let it ride
One thing that kills some of these re-rings is cam bearings. I’ve had a couple that bores were in spec but the cam bearings were gone. Usually needed cranks turned with these.

 

My Dad was born in 1921 in a dirt floor shack. His Dad died when he was 6. He liked to say they didn't have two nickels to rub together (an exaggeration.)
When my first car smoked like a freight train he said re-ring it. I was 16 and had purchased it in '76 for
$250, so you know it was a peach. He showed me how to cut the ridge and hone it, got a proper valve job on the original heads. Cleaned it all up and reassembled it. It ran great for the 2 years or so I had it. I sold that engine in another car and it was running well.
About 6 years ago my not very valuable OT car had 180,000 miles on it needed refreshing, but oversized pistons were $900 so I couldn't really justify bore and pistons. The bore was very close to max with some 6-7 thousands of clearance. Even though I had some concern of cold start rattling, I honed it and re-ringed it and it now has over 250,000 miles on the clock.

 

Done at least a dozen. May not last as long a proper rebuild but I never had one fail to my knowledge . I just replaced a single Piston ring in a 289, in chassis. Cut the ridge honed it and put it together, it runs fine. I did have an issue, where my rings butted and did not allow the piston to go in. 200 miles from home without all my tools I gapped the rings with what I found in the shed. I called Hastings, and spoke to one of these engineers before I buttoned it up,, and is used all potential issues, from wrong ring in box to taper and out of round, and he even said run it. So I did . This is the same stuff my grandfather's, and the old timers I grew up with thought me. Rings, bearings lapping compound and go. I have yet to use bacon. Feeler gauges or sawdust, but I have even honed cylinders with pistons in. While not Ideal, the engines will take a lot of mistakes and shortcuts and still run.

 

I totally agree with this.....did it often in the '60s when money was scarce......never had a bit of issues, even with a 315 HP 283 SBC.....ran like a champ for a long time....

 

Well once it's apart, you will be able to tell if the bore is too far out, or you have some cracked piston skirts, what the rod and main bearings look like. Some things that just rings will not fix. But, I have re-ringed lots of engines, and ran them for-almost-ever.

 

I am with the re ring camp, or just leave it alone, runs good ,quiet ,just a little blow by !!!

 

The engine in my Model A came out of a 65 Electra. I drove the Buick and it ran very well with the exception of a lifter tick at startup. I pulled it down expecting to hone the cylinders, replace the rings and bearings and put it back together. I had used a telescoping gauge to check the cylinders and they appeared to be okay. However, when I got to the machine shop, the machinist checked with and inside mike and showed a lot of wear right at the end of piston travel. I ended up with a 0.030 over bore new pistons, cam, lifters, rockers, valves, etc,, etc. I was amazed at how worn the lifters were. On many the bottoms were concave rather than convex.

Can you just pull it down and re-ring it and have it run okay? Probably, mine actually ran quite well before I tore into it. However, you run the risk of having to do it again a bit down the road. Face it, your engine is at least 56 years old and probably has a good bit of wear. I performed pretty well at 56, but not like when I was 25!

 

As the others have said it can be done and has been done many times. On a couple occasions I put a used piston or two with the used rings and bearings in a motor so a guy could get to work the next day. I think most of those engines drove the cars to the junk yard when the guys were done with the cars.

 

Related question: Will honing reduce eccentricity and/or taper, or does the hone just follow the shape of the bore?

 

Nailhead Buick blocks have a high nickle content, so the wear may be not too bad. 425 blocks are limited to .040 over, and sonic testing (especially at the bottom) is preferred. Just the gasket set and adding the steel head gaskets are over $400.00. For no more planned miles than stated, I'd run it as is.....

 

Most of us at home use a brush hone, or a stone hone. The stone hones are adjustable for tension, but still spring loaded. The brush hones, are pretty much the same but not adjustable.
So in effect you’re following the contour of the cylinder.
A stone hone makes a better finish, but since stone are flat, when you get up to the top of the bore (even after cutting the ridge) you get less “hone”.
But to directly answer your question, neither will make a taper or out of round bore straight.
I suppose you could find a fixed stone hone that was adjustable, but you’d have arms the size of the Incredible Hulk before you trued up a cylinder

 

Lisle makes a hone P/N 15000 that will correct taper and out of round if you go at it long enough. This is NOT a spring loaded hone. My O/T Ranger work truck blew a head gasket and my FIL let it sit with water in it for several years. I was given the truck and the engine was ruined. I found an old wagon with the same engine and 235,000 miles on it. We pulled it apart, honed it, rings, bearings, cam bearings, oil pump and had the heads done. It runs great and uses literally no oil between 5,000 mile oil changes. I even reused the cam and lifters. I’ve done quite a few engines like this with excellent results.

 

I’ve done several ring and bearing jobs in the past, never had any problems other than a 4 cyl that had a hairline crack in one cylinder that you couldn’t see until it got warm and opened up and let coolant in that cylinder. Pulled the head off while it was hot was the only way I caught that one.

 

I've done some fairly scroungy ring / bearing "rebuilds"

They work. I've been surprised by how well some of the questionable ones sealed up and ran. Don't expect 100K. Measure everything and make a judgment call on how far you want to push the limit of "within tolerance"