Technical Re-Ring it and send it?

I just use an old 3 stone hone lubricated with light spray can oil, and run plain cast rings, and they usually work fine. I expect there are a lot of ways to do this, and have it work.

 

I like your approach. I did a very similar re-ring and gaskets on a Ford 302 25 years ago and it ran great for many thousands of miles afterwards, with little oil use.

 

Also if you have more than a couple thousandths of taper you should probably spend a bit of time checking the ring end-gaps at the top and bottom of their travel in the bore. To be safe you might have to hand fit and file the end gaps for the proper clearances. You might even want to run them a few thousandths loose just to be safe.

 

Northern looks pretty good. (I used to use Speed-o-motive thru the '70s, but Al Teague sold the shop (?)
Formerly had Automotive Industrial Supply (San Jose, CA)
Rich Fox was a steady customer also...1963 and previous

@ClayMart is spot on, with end gaps. I repeat the method of using a ring at the top and bottom of a cyl, (all 8!) and subtracting the end gap values. Circumferential method is quite accurate, everything clean, of course.
Save that $150 for the tool, use it toward some rings and bearings!

 

I do this fairly often at work higher hour engines , tired , burning oil , but still run decent .

I have a 3 stone hone , a dingle ball hone , ridge cutter , piston ring groove cleaner and a valve lapping tool . Along with installers valve removers etc . A bunch of old tool I bought for next to nothing at swap meets or garage sales .

anyways , cut the ridge , hone , lap the valves , new bearings , rings , all seals , take the oil pump apart and inspect , and put it all back together nice and clean with new parts .I just install factory sized bearings and rings , whatever my supplier stocks is what I use . Usually “ white box” stuff

no machine work , no inspecting for taper or fancy tools and has always done me and customers well on those lonely nights at sea

now this is on low compression propane engines in forklifts , I’ve also done this on road worthy engines .

a few that had rod knock , emery cloth , then crocus cloth on the crank to remove the bad stuff and****emble .


If it’s a simple driver , you’ll be fine . Not everything is spinning at 12,000 rpm and getting beaten like a government mule .

I truly think we over think stuff now-a-days.

this was common place when our cars where new , and look at some videos what they do in “ developing countries “ I’m surprised anything runs without proper and full machine work and all new factory parts !!

 

There’s that phrase again, beaten like a government mule!!! I love it!!

Call Northern Auto Parts and get the ring and bearings kit with a timing chain and cam bearings and you will be good to go!! Or, if you’re a cheap***** (like me most of the time) go to The Rock and get the Engine Tech stuff.

 

A Rangers fan! I so badly want to say something about Potvin...

Instead I will second the notion that the exact thing you're contemplating was the norm for many years of regular old driver vehicles

 

Lundqvist goes into the HHOF today on the first ballot. It's a good day. Might have to take a ride up to Toronto in Mid-November.

 

So in discussing this general issue, ie the rings are sealing poorly, what is it that usually wears first? The cylinder walls or the rings? Or some combination of the two?

The reason I ask is that I want to understand this conceptually. Let's use the 383 here as an example. 4.250" bore. If the cylinder walls wear an additional .005", now effectively my bore is 4.255". If I put a standard size ring in, isn't that going to allow the end gap to open and cause blowby? Seems like it renders the exercise moot. Or is the new ring slightly oversized and you file it to fit?

 

My understanding of what happens.....

The rings seal combustion pressure, and as the piston travels downward, the pressure drops off because it has more space to fill. So, the maximum pressure is near the top of the bore. Rings work by the pressure pushing the "back" side of the ring out towards the cylinder wall. This pressure seals the rings to the bore, but it also causes more wear where the pressure is highest, at the top of the bore. So....as the engine wears, the top of the bore wears more than the bottom. This results in taper.

The taper makes the rings have to change size (and end gap) as the piston travels up and down in the bore. The other part of the ring seal is the bottom of the ring against the ring land. You'll note that this part of the ring, and the ring land on the piston, get wear on them also. Now....as the ring is changing size as it goes up and down in the bore, there is movement of the ring against the land, causing more wear here.

So, as the engine wears, and the bores get taper, the rings wear faster.

Put fresh rings in the engine with the taper in the bores, and they'll keep wearing faster than they would in a straight bore.

Bottom line, if you want the engine to last a long time, rebore it. If you don't envision it getting more than a few tens of thousands of miles over the rest of the life of the car, or as long as you own it, then you can get away with a ring job, without a rebore, and it will last sufficiently long.

Most old cars that get nice fresh rebuilt engines, will never get driven enough to wear out. And most cars that just get a ring job these days, will never get driven enough to wear out.

Make an informed decision.

....normal (not racing) rings are set up to fit the bore size stated onthe package, you don't need to file them to fit a worn bore, you'll have plenty of end gap. But measure it at the very bottom of the bore where the bore is smallest.

 

I didn’t read all the posts, but if you have an engine that runs good, but needs help, a set of rings, bearings and valve seals will drastically improve it’s performance. I have done it many, many times! Not every situation calls for a perfect rebuild!





Bones said that!

 

He deserves it

 

...
I have done a 45 degree hone with sandpaper by hand and water to give the rings on a worn bore to seat to

In the 60s, many could not afford a fully machined engine, just needed to put put back and forth to work

A guy back in the 70s owned a machine shop and raced a car all over the country would hammer the valves out of the heads without filing the top ridge off of them, hand lap them and hammer them back in

He was competitive, at 8,000 rpm air/fuel is moving so fast that it not that much HP lost

Like super thin rings, dyno tests some have posted show around 5 HP ...


Ricky.

 

Make sure the top ring land isn't worn out. And if the cylinder has more than.010" taper get ,020" oversized rings and file the ends to get the proper end gap.

 

Your overhaul with machine work is a ---rebuild. An overhaul is a quickie with no machine work. I disassembled the yblock in my 59, honed the cylinders, new bearings, gaskets, rings and reassembled it in the year 2000. It runs good, no smoking, no oil usage. new rings can take up .019 wear.

 

There's a range between an overhaul and a rebuild....I've done a few that got some machine work, but not enough that I would consider it a rebuild. And years ago, when machine shop rates were a bit more affordable, I'd send a few blocks in for hot tank, hone, and cam bearings. Now I do that stuff myself, most of the time.

 

Looking back over this thread I don't believe I've seen any mention of the engine's actual mechanical condition, other than it seems to still run smoothly, quietly and has good oil pressure. Before you get into it too deeply, I think I'd be checking cranking compression with the engine at operating temperature and see if anything looks suspicious. Does it pull good, steady manifold vacuum at idle?

It may in fact need a rear main seal but I'd make sure that there wasn't an oil leak somewhere else at the back of the engine. As far as blow-by (which only exists in the crankcase, not in the exhaust), how are you set up for c/case ventilation? If you have a working PCV system, is it routed like the stock PCV for that engine, or has it been "modified"?

If you have access to a bore-scope you might sneak it down thru the spark plug holes and turn the engine by hand to lower the pistons in the bore. Then look around for any obvious signs of piston damage or cylinder wall scoring.

As far as smoke out of the exhaust goes, that can be caused by excessive cylinder wear or scoring, broken rings or badly carboned or varnished rings that are sticking in the piston grooves. Driving the car infrequently and for only short distances may contribute to the problem.

As for valve guides and seals you'll usually only see exhaust smoke under high manifold vacuum conditions, like at idle or when de-accellerating. If the guides aren't sealing properly the high vacuum will pull oil past the intake valve stem and into the combustion chamber. It will not only smoke but it will also foul the plugs in the affected cylinder(s). Also suspect valve guides and seals if you see a quick puff of smoke on a cold start-up. It might not do it with every start-up though. It kind of depends on which valves are left in an open position when the engine is shut off.

 

@squirrel Thanks Jim, really appreciate the explanation re the taper in particular. Always a good day when I learn something new.

 

All really good points.

Admittedly, I have never checked the compression of the engine. When I put this engine together many years ago, I didn't even have a compression gauge. One thing I did find out is that the balancer had spun on it. When I got this engine put together, I couldn't get the damn thing to run right for the life of me. Finally a buddy posed the question, "what if TDC on the balancer isn't actually TDC?" I set TDC with a screwdriver in the spark plug hole and found the timing mark to be 30 degree retarded. I reset the mark, advanced the distributor until it broke up, back it off a couple degrees, and locked it down. That was 16 years ago. I'll have to go fire it up at some point here and put a vacuum gauge on it.

I've always worked under the premise that if your valve seals are bad, you'll get smoke out of the exhaust at start up. But if you get smoke out of the exhaust under acceleration, it's likely rings. That's exactly the scenario I have here. Couple that with the blow by and it seemed like a pretty fair approximation of what the diagnosis is. And we had put new umbrella seals on the heads I reused. I blew the bottom end out of my first 383, that engine never smoked or had blowby, so I would surmise the heads wouldn't be an issue on the next engine. But I agree it would be a good idea to just replace the seals and lap the valves with the heads off. Might as well while it's all apart.

My engine does have a PCV system. That consists of a PCV valve in the one valve cover and a breather in the other. Carb is a 600 cfm Holley (single inlet, vacuum secondary, manual choke) on a Weiand dual plane intake, and the PCV is plumbed to manifold vacuum. The system is totally overtaxed by the amount of blowby the engine makes. I had considered putting a crankcase evacuation system on it so the crankcase would just vent into the exhaust, which would at least make the car more tolerable to drive, but would probably speed oil consumption and really just masks the issue.

 

Excellent explanation, Jim. Thank you for sharing that

 

It sounds like you're working under all the right****umptions. I mainly made my previous post because I see too many replies here where I'm not sure that somebody understands exactly what blow-by is. They often seem to use the term to describe excessive exhaust smoke caused by oil getting past the rings, coolant finding its way into the combustion chamber or an extremely rich fuel mixture.

Is your PCV system laid out like the OE system was? If you've got aftermarket valve covers are they properly baffled where the PCV valve is fitted? Is the breather filter free and clear?

 

I have used ridge cutters, ball hones, piston groove cleaners, valve lappers. Cam bearing tool. As long as it's not "dusted" which can open up ring grooves, low buck can work. Machine shop service costs... ridiculous. Buy new.

I showed friend how to build the cheapest low dollar sbc rebuild you can do. All above tools, kerosene, wash at car wash.. build it. Add summit cam Ran in a demo car all year....

 

I've done it a few times over the years. It depends on the condition of the cylinder walls when you take it apart. Being that it runs now, and you know that it needs rings I would go for it.

 

I’ve have patched up tractors/trucks in the field/ laying in my back in dust dirt mud etc. No it’s not ideal but when you have to it’s pretty simple.
I will not count the number of RACE engines that I have built where the only thing in them new was the bearings and the timing chain.
I have knurled pistons / with a pattern on a piece of paper /a hammer and a punch. I am actually looking for the hand held version made by snap on now. ( the machinist that I used for most of my life had one and more than one set of race pistons got knurled. ( when they sold off his stuff I got out bid. )
For what you are doing check gaps. Check crank clearances and go from there.
I have seen race pistons that were run at .010 out of the box. I have no issue with a good machinist honing square and running a 10 over ring or file fit and knurling piston. I was always more concerned with the crank clearances etc. And from what you have said that’s fine.
You have been at this a good while.Don’t over think it. You got this.

 

I've got to ask for an explanation of the term "dusted". I don't think I've heard that used before to describe used engine parts.

 

maybe using cleanser powder to "seat" the rings?

 

It's a pretty common term used mostly by heavy machinery / diesel engine guys to describe an engine that's been ingesting dirt. Almost always caused by neglected air cleaners or a hole in an intake hose or pipe. We see it a lot at the diesel engine rebuild shop where I've been for the last 30 years.

Terry

 

Yep, this term is used regularly in my business of equipment manufacturing. Although I had never heard it before in all the years I had messed with engines.

 

Well now we're gettin' somewhere! A new word to add to my glossary of "legitimate but infrequently heard" terminology. Thanks for the update!

 

I had the right idea, just off on "intentional"