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As spring has sprung, I thought i'd get back to were I left off on my 53, over the winter I bought a Ridge Reamer and new bearings including mains to get to grips with my low oil pressure. The reaming tool worked a treat and took the ridge off real easy and clean, popped out #5 (the worst piston) rings are good wrist pin good but the top is pitted very badly, most of them are in much better shape like #1.
Others have recommended replacing all of them, I was hoping due to financial constraints just to replace the two worst...is this a no no?
Replacing one or a few pistons used to be done in the 1940s and 1950s if the bore wear was within tolerances. You need to measure diameter and taper of your bore and compare to whatever acceptable wear tolerances are to determine if its feasible.
The preference is always to overbore to the next size for which pistons are available and replace all pistons and rings.
If more than a honing is required to restore cylinder walls and you have to overbore, say .030 and replace pistons and rings that is a whole different and more expensive route as you indicated.
There have been some threads recently about getting 303 internal parts. You might do a search here on CO to see who is recommended.
Jerry
Replacing one or a few pistons used to be done in the 1940s and 1950s if the bore wear was within tolerances. You need to measure diameter and taper of your bore and compare to whatever acceptable wear tolerances are to determine if its feasible.
The preference is always to overbore to the next size for which pistons are available and replace all pistons and rings.
If more than a honing is required to restore cylinder walls and you have to overbore, say .030 and replace pistons and rings that is a whole different and more expensive route as you indicated.
There have been some threads recently about getting 303 internal parts. You might do a search here on CO to see who is recommended.
Jerry
Thanks Jerry, the engine is still in the car and I had been driving it for a little last summer until a valve spring broke which prompted another tear down, but im definitely not in a position financially to go the route of removing the engine and having it re bored..excellent as that would be.
Last edited by Eightbanger; March 26th, 2017 at 11:31 AM.
Stock bore is 3.750 inches. Looking at Internet most seem to think you can get by with .005 to .007 wear on the cylinder walls and just re-ring. I couldn't find std. piston diameter with just a quick look maybe you can. It may not be all that important as most of the wear occurs on the rings and cyl. walls. As long as your cylinders are not visibly scratched the authors I read seem to think they would be OK. An obvious clue to cylinder wear is the size of the ridge at the top. Yours is gone in the cylinder in question but the other cylinders may provide a clue about the amount of wear. Good luck with the repair and finding replacement piston.
Jerry
Nigel, there's a Listing named vintagetruckscars.com that list a complete set of new pistons and matching rings for a 1953 Olds 303! Their price is under $400. Only had two sets available. They say stock, not oversize. Good luck ,Larry
I'm just curious what caused that pitting? Was the head gasket blown on that cylinder?
Just a thought if it ran well before I can't think of a reason you couldn't run it again. It's doubtful the piston would break(though it is pitted worse than most I've seen) and if the cylinder walls aren't pitted and the skirt is in tolerable shape it should run till your better healed. Back in the day we did some pretty marginal repairs, some worked some not so much. Your call... Tedd
Stock bore is 3.750 inches. Looking at Internet most seem to think you can get by with .005 to .007 wear on the cylinder walls and just re-ring. I couldn't find std. piston diameter with just a quick look maybe you can. It may not be all that important as most of the wear occurs on the rings and cyl. walls. As long as your cylinders are not visibly scratched the authors I read seem to think they would be OK. An obvious clue to cylinder wear is the size of the ridge at the top. Yours is gone in the cylinder in question but the other cylinders may provide a clue about the amount of wear. Good luck with the repair and finding replacement piston.
Jerry
My maintenance manual lists the pistons as 4" overall.
Many thanks again Jerry for your help.
Originally Posted by Rocketowner
Nigel, there's a Listing named vintagetruckscars.com that list a complete set of new pistons and matching rings for a 1953 Olds 303! Their price is under $400. Only had two sets available. They say stock, not oversize. Good luck ,Larry
Thanks Larry, I will check them out, I was told of another company called Egge.com that lists a full set of std for $362.00.
Edit; not had any luck finding that link.
Originally Posted by Tedd Thompson
I'm just curious what caused that pitting? Was the head gasket blown on that cylinder?
Just a thought if it ran well before I can't think of a reason you couldn't run it again. It's doubtful the piston would break(though it is pitted worse than most I've seen) and if the cylinder walls aren't pitted and the skirt is in tolerable shape it should run till your better healed. Back in the day we did some pretty marginal repairs, some worked some not so much. Your call... Tedd
Well this is the thing Tedd, if you remember when I first got the car it had been poorly stored and maintained, had sat unattended for 3 yrs, I got it running for the first time in many years initially with new leads plugs etc, but once I pulled the pan and rockers I discovered the mess within, the head gaskets had gone along with just about every other on the entire engine. There had been a great deal of moisture in the engine for quite sometime, which must account for the pitting, the cylinder walls all seem to be in reasonable shape but could do with a little honing.
But I had it running and driving for a few weeks after I had repaired and replaced everything that needed doing, that is until one of the valve springs broke which took her off the road again.
Remember this mess?
Last edited by Eightbanger; March 26th, 2017 at 03:48 PM.
I tell ya, Nigel, I, too, have never seen a piston pitted that badly, and it's bad enough that I wouldn't want to run it. I'd be afraid of hot spots leading to detonation leading to further destruction of the crown.
The other one looks fine, and, this being a low-tech, lo-po, slow-revving tractor engine, I'd be inclined to just replace that one, hone and install new rings, and call it a day.
Egge is a very reputable firm that's been around forever, and makes all sorts of obscure stock pistons for restorers. I'd check with them and see whether they'd be willing to sell you just one.
X2 Tedd. I am not sure that the pitting on top of the Pistons would hurt the running. You might try replacing the broken valve spring, rings and head gaskets and try running it this summer. Be sure to check for cracks on the Pistons up each side of the wrist pins, they sometimes would crack there and would cause an annoying peck when the car was in a hard pull. Good luck ,Larry
X2 on MDchanic's advice...just change the pitted pistons. The only thing I would add is make sure the weight of the replacement pistons are the same as the ones being replaced so nothing gets too out of balance.
Good used ones would be fine if you can find that needle in the haystack.
Great to see you are back on the project, please keep us posted and good luck!!!
My source for quoting a 3.75 in. bore: http://secondchancegarage.com/public/546.cfm
I know yours is a 53 but think all 303 cubic inch Olds engines would be same bore and stroke.
My source for quoting a 3.75 in. bore: http://secondchancegarage.com/public/546.cfm
I know yours is a 53 but think all 303 cubic inch Olds engines would be same bore and stroke.
Jerry
X2 on the piston size being 3.75. Oldsmobile didn't get to a 4 inch bore till the 371.Even the 324 only has a 3.875 bore.... Tedd
My source for quoting a 3.75 in. bore: http://secondchancegarage.com/public/546.cfm
I know yours is a 53 but think all 303 cubic inch Olds engines would be same bore and stroke.
Jerry
Originally Posted by Tedd Thompson
X2 on the piston size being 3.75. Oldsmobile didn't get to a 4 inch bore till the 371.Even the 324 only has a 3.875 bore.... Tedd
Simple enough to check, you are holding the piston in the first post, can't you just measure it?
I tell ya, Nigel, I, too, have never seen a piston pitted that badly, and it's bad enough that I wouldn't want to run it. I'd be afraid of hot spots leading to detonation leading to further destruction of the crown.
The other one looks fine, and, this being a low-tech, lo-po, slow-revving tractor engine, I'd be inclined to just replace that one, hone and install new rings, and call it a day.
Egge is a very reputable firm that's been around forever, and makes all sorts of obscure stock pistons for restorers. I'd check with them and see whether they'd be willing to sell you just one.
Good luck, you're doing great!
- Eric
Something similar to what I was thinking and hoping Eric. Thank you mate
Originally Posted by Rocketowner
X2 Tedd. I am not sure that the pitting on top of the Pistons would hurt the running. You might try replacing the broken valve spring, rings and head gaskets and try running it this summer. Be sure to check for cracks on the Pistons up each side of the wrist pins, they sometimes would crack there and would cause an annoying peck when the car was in a hard pull. Good luck ,Larry
Cheers Larry.
Springs have all been replaced, valves and seats have been refaced, and when the pistons issue is done it will all go back together with yet another new set of head gaskets.
Originally Posted by Sugar Bear
X2 on MDchanic's advice...just change the pitted pistons. The only thing I would add is make sure the weight of the replacement pistons are the same as the ones being replaced so nothing gets too out of balance.
Good used ones would be fine if you can find that needle in the haystack.
Great to see you are back on the project, please keep us posted and good luck!!!
I had heard about about the possible risk of differing weights between old and new S.B, i'll have to careful there. Cheers buddy.
Originally Posted by 47 Convertible
My source for quoting a 3.75 in. bore: http://secondchancegarage.com/public/546.cfm
I know yours is a 53 but think all 303 cubic inch Olds engines would be same bore and stroke.
Jerry
I messed up Jerry, it's the overall length that's 4".
Originally Posted by Sporty45
Simple enough to check, you are holding the piston in the first post, can't you just measure it?
Cheers Dennis....Why didn't I think of that...
Last edited by Eightbanger; March 27th, 2017 at 12:34 PM.
Hurray Nigel,I found you a NOS Piston /Pin for your 1953 Olds "303" engine. It's listed at oldsobsolete.com for $65. The # shows 561577 ,still in box. We must be living right! At least I hope so. Good luck ,keep me posted. Larry
Last edited by Rocketowner; March 27th, 2017 at 07:01 PM.
Reason: Correct
Hurray Nigel,I found you a NOS Piston /Pin for your 1953 Olds "303" engine. It's listed at oldsobsolete.com for $65. The # shows 561577 ,still in box. We must be living right! At least I hope so. Good luck ,keep me posted. Larry
My parts book shows 561577 to fit 52 & 53 Olds with standard size piston.
What a stroke of luck .
$65 seems fair compared to buying a whole set of pistons .
You can be sure the weight is proper .
It was made in USA.
My books show the same part number as Larry & Charlie show. Something must have changed with the 303 piston in 1952, as the older 303 has a different part number. As Tedd, I'm also curious what caused the pitting on just those two pistons. Perhaps those two had valves that were open, allowing corrosive gas to enter. It's definitely a cosmetic issue which most would prefer not to have, however I've seen many cosmetic unfortunates operate quite well. (It's like severe acne in a beauty contest.) Look at those two cylinders in particular, very closely. Check if anything else is diminished additionally than in the other 6 (cylinder wall wear, piston wear & scuffing, ring grooves, and especially piston to bore clearance). It would be nice to be able to replace those two with original equipment pistons and have all dimensions within specifications. The shop manual should provide some guidance. Let us know how it goes.
That's for the oil control ring. You don't have that on any of the pistons? I'm not familiar with early 50's motors, but know that modern engines have those. There should be 2 solid rings that go with it, one on top and one on the bottom of it, like a sandwich.
Look at this picture. The bottom set of rings are the oil control set with the spring.
Last edited by Sporty45; March 28th, 2017 at 02:45 PM.
That's for the oil control ring. You don't have that on any of the pistons? I'm not familiar with early 50's motors, but know that modern engines have those. There should be 2 solid rings that go with it, one on top and one on the bottom of it, like a sandwich.
Look at this picture. The bottom set of rings are the oil control set with the spring.
That is different. I suspect the new style can replace the old style without trouble, but like I said before, I'm no expert on early engines. I'm guessing there will be someone here that knows for sure and will be along soon to educate the both of us!
That is different. I suspect the new style can replace the old style without trouble, but like I said before, I'm no expert on early engines. I'm guessing there will be someone here that knows for sure and will be along soon to educate the both of us!
Those are the standard-type one-piece oil rings used on all Olds engines through at least the late seventies.
The multi-piece design is a good design, and also works well, and is often used as a replacement, as it is better able to follow worn cylinder walls and still control oil use. Its disadvantage is that the two thin scraper rings are made of steel instead of iron, and so can cause more cylinder wear than the iron rings.
This can be important under some circumstances, but in a worn engine, which will be bored sooner or later anyway, it can buy time.
In your case, I would recommend the original-style rings, which should work fine.
Are you sure that the original piston you bought doesn't come with rings? They often did.
Charlie & Ozzie thank you both...and special thanks to Larry, I bought that Piston & Pin.
Ozzie, once I have them all out I'll have a real close inspection of the cylinders.
Also, can anyone tell me if this ring set from Egge are correct, they seem to have a strange spring like ring which isnt on my pistons.
Yes , they are correct .They are a different DESIGN than your original rings . But they will work just fine if they are specified for your car . (which they are) .
I see that these are Grant rings . Their design of their oil rings is different than the original rings , which may have been Burd , Muskegon , or one of a dozen piston ring manufactures that Olds may have bought rings from .
Not an area of concern .
However , do be careful to make sure that the replacement rings are the same width as your originals within a thousandth of an inch or so .
Absolutely never even THINK about re-using old piston rings once you have taken the pistons out of the cylinder .
It's impossible to get the rings back in the places that they are seated and "worn in" to .
Make sure to hone the cylinders in a "cross hatch" pattern . Even if it's only with a "berrybush " hone .
Break one of the old rings in half and use it to scrape the carbon buildup out of the ring grooves .
As indicated, either design should work correctly. Just be sure that it fits in the piston's groove correctly, that the groove is clean on a used piston, that there is no "bell mouth" to the groove, and that the ring's end gap measures correctly in the cylinder. (Also assemble with a lubricant.) Often the ring manufacturer will provide some instructions with their product.
Are you sure that the original piston you bought doesn't come with rings? They often did.
- Eric
Thanks Eric, Just listed as NOS Piston & Pin.
Originally Posted by Charlie Jones
However , do be careful to make sure that the replacement rings are the same width as your originals within a thousandth of an inch or so .
Absolutely never even THINK about re-using old piston rings once you have taken the pistons out of the cylinder .
Make sure to hone the cylinders in a "cross hatch" pattern . Even if it's only with a "berrybush " hone .
With that you should be good to go .
Thanks Charlie, I certainly wont be using the old rings now, to be honest I had contemplated it, and I planed to buy a Honing tool which fits on a cordless drill.
Originally Posted by Ozzie
As indicated, either design should work correctly. Just be sure that it fits in the piston's groove correctly, that the groove is clean on a used piston, that there is no "bell mouth" to the groove, and that the ring's end gap measures correctly in the cylinder. (Also assemble with a lubricant.) Often the ring manufacturer will provide some instructions with their product.
Nigel,when rebuilding these type Olds Engines back in the sixties,we used Hasting Rings that had those same type "sandwich style rings"on the lower groove. We also had a ring grove cleaning tool made by Lisle, that made cleaning the ring grooves much easier. It looked something like the one below,and had three different "wheel sizes to fit different groove size groove widths. Best of luck,Larry
When cleaning the ring grooves be careful not to clean excessively and remove any metal from the ring grooves, it happens easily.
When replacing the rings read, understand and follow the ring manufacturers precisely. The top two compression rings will have marks on them to indicate which groove they go in and which is the top of each ring. The directions should also indicate the ring gap orientation/clock positions. Deglaze/hone the cylinders and clean, clean, clean the bores.
Break-in/seat the rings...we did it by warming up the engine then full throttle from 20 - 50MPH (KPH ? ) and no throttle/coast from 50 - 20 MPH ten times.
... warming up the engine then full throttle from 20 - 50MPH (KPH ? ) and no throttle/coast from 50 - 20 MPH ten times.
Good point. Rings need some hard acceleration and deceleration to seat properly.
If you go too easy on them when breaking in, they may never seat properly.
My father's got a BMW that happened to - he bought it new and, being an "old guy," drove it very, very carefully for the first thousand miles.
At 50,000 miles, thing runs great, but burns a quart of oil every 800 miles.
Well reading this warning about being sure on all the various sizes has spooked me, I am at best a weekend mechanic and learn as I go, and I dont have all the required tools,,,I have to keep buying them along with the parts but this is serious stuff were if I get it wrong i'm going to do some serious damage to the engine.
Can anyone in the know tell by looking at these sizes from Egge ring set and my maintenance manual if they are correct for my application?
March 26th, 2017, 10:36 AM
It's definitely a cosmetic issue which most would prefer not to have, however I've seen many cosmetic unfortunates operate quite well. (It's like severe acne in a beauty contest.) Look at those two cylinders in particular, very closely. Check if anything else is diminished additionally than in the other 6 (cylinder wall wear, piston wear & scuffing, ring grooves, and especially piston to bore clearance). It would be nice to be able to replace those two with original equipment pistons and have all dimensions within specifications. The shop manual should provide some guidance. Let us know how it goes.
Piston Rings
