UPDATE A question on Les Andrews's ring specs
 

Les specifies ring gaps as .012-.015 for top; .010-.012 for middle. .008-.010 for bottom.
Tbirdtbird specifies .022 top; .-016-.018 for middle.

I used Les's when I put my engine together. I didn't have Tbird's specs at that time. The engine seems pretty tight when it's warmed up. Now I'm wondering if I should tear it down and reset the gap.

These are significantly different. Can anyone explain that?

See 5/21/15 followup below.

Re: A question on Les Andrews's ring specs
 

Briggs & Stratton air cooled engines (warmer cylinder) specify 0.007 to 0.017 range for all sizes.

Been like this for a long time.

You may be fine where you are.

Here's the B&S Service Bulletin from the 1950s. http://www.oldengine.org/members/murphy/Briggs%20&%20Stratton%20Repairman's%20Handbook.pdf Page 50 of the book.

There are other numbers given for feeler gauges/piston clearance.

Joe K

Re: A question on Les Andrews's ring specs
 

I would go with Les's specs , General rule is .004 per inch of bore for top ring and less for the others.
4 in. bore =.016, model a is 3 7/8.
.022 is kind of excessive.
Bill

Re: A question on Les Andrews's ring specs
 

I don't know the specifics on B&S engines, but the end gap is dependent on many factors, including bore diameter. All else being equal, the larger the diameter the larger the ring gap needed for expansion.

Re: A question on Les Andrews's ring specs
 

A Briggs is not a Model A, especially considering the bore size. I'd recommend .004/1" of bore for first and second rings. If you were to tear it down, if only for a look-see, check the ends of the rings to see if they are shiny. That would be a sure sign they do not have enough end gap. An end gap too large is always much less of a problem than one too tight.
That Briggs manual also said .005 ring groove to ring clearance max. which is way over any reasonable amount.

Re: A question on Les Andrews's ring specs
 

Not sure if this is an apples to apples comparison that will work for something like the Model A engine, but what a book!
Thanks for sharing that with us.
When asked I have always told folks the engine is like an old Briggs and Stratton, but I was just trying to give them a sense of how different the modern engine is compared to the one in my Model A.

I liked these engines but had no idea how well you could rebuild them.

Re: A question on Les Andrews's ring specs
 

How about following the ring manufacturers specs??? They should know.

Re: A question on Les Andrews's ring specs
 

Listen to Flathead. What did the instructions recommend that came with the rings? You probably used either Grant or Hastings rings, I imagine, and they come with instructions. Certainly before yanking and ripping the engine apart.........check it out. And by the way, I use Hastings rings using the Les Andrews recommended gaps and works fine. Of course that is with lowly Snyder's pistons, mind you....

Re: A question on Les Andrews's ring specs
 

Flathead and Greg are correct gaps and clearance are manufacturer specific
follow the instructions from the manufacture and it is hard to go wrong
I see guys here quoting clearances for 1 single part that they may use and applying it to everything model A
Wrong if I used those clearance say with my Ross forged pistons that engine would never have gotten pass the 1st 5 minutes
Happily I followed the manufactures instructions and all is well

Re: A question on Les Andrews's ring specs
 

Good idea from Greg, Flathead, and Colin. I checked the Hastings specs, which were the rings I used. Top ring and middle rings: .012-.022; oil ring: .010-.050. So using Les's recommendations, I'm pretty good, except the middle ring might be a little tight.

I went on an 80-mile tour today with no adverse affects. I'm going to let it settle in a little more and see what happens. I might try a scope on Monday if I can find one and it isn't too cold to get out to the garage.

An added note: the engine was sleeved back to standard at the same time the new pistons and rings were installed.

Re: A question on Les Andrews's ring specs
 

Ray, you are prolly OK, if it did not lock up by now

"My" specs do not come from me but as I have mentioned a close friend who builds motors including racing motors.

As for the gentleman who thinks .022 is "excessive" consider that is not even the width of a spark plug gap. He needs to explain what he thinks the consequences are gonna be. Remember, the top ring sees much hotter temps than the other rings. Be nice to it.

Re-read what Fordors said.

Re: A question on Les Andrews's ring specs
 

Tbird, it would lock up in the first 500-600 miles, but would be OK after a few minutes of cooldown. But I also had a weak battery, and that made it difficult to turn over. But after about 1000 miles and a new battery, it seemed be OK. Now, at 1500 miles or so, there is no lockup, but when I shut it off it stops immediately. So it's still pretty tight.

Like I said, I'll scope it, and if it looks alright inside I'll drive it for another 500 miles and see what happens.

Re: A question on Les Andrews's ring specs
 

5/21/15 Update: With now 1875 miles on the new engine, it still locks up when it gets driven up to operating temps. I pulled the head and dropped the pan. There is no scoring or scuffing or discoloration on the cylinder walls. I conclude from this that my original ring gaps were too tight, and am going to regap them. There is minor carbon buildup on about 2/3s of each piston on the valve side, and a carbon ring at the top of each cylinder. I would like to hear from you experts what you think a better gap might be, and also your opinions on the carbon buildup.

Thank you.

Re: A question on Les Andrews's ring specs
 

I think you will find that the gaps have increased by now. If the engine actually locks up when hot there should be some visual clues in there.

Re: A question on Les Andrews's ring specs
 

Re: A question on Les Andrews's ring specs
 

Marco, it seizes up, and cannot be turned with starter or hand cranking. After about a 15 minute cool down, it will turn over with the starter. It has been like this since I put it back together last year. I haven't tried it without plugs, but I've got it torn down now and can't do that. When cold it turns fine. Bill Barlow set the crank, and I installed the rods with .001-.0015 clearance. The piston specs were .003 and that is what my engine shop honed the cylinders to. Why not rings, and what else is a possible?

Re: A question on Les Andrews's ring specs
 

Can you post a picture of the cylinder walls and piston skirts?

Sure seems like there should be some scuff marks if the pistons were seizing.

Re: A question on Les Andrews's ring specs
 

The Andrews book does have some problems that have been noted here over time. The ring gap spec does not seem to be one of them. Even with your original listing last year no one else chined in with "I had the same problem". Could it be that everyone else that has installed rings followed the ring manufacturers recommendation, I don't know.

I'm glad you updated your post and be sure that the members here will work to see that the problem is found and solved.

Would pistons placed 180 out cause them to seize?

Re: A question on Les Andrews's ring specs
 

Re: A question on Les Andrews's ring specs
 

Re: A question on Les Andrews's ring specs
 

How do you conclude that it is locking up from too tight of ring gaps when there is no sign of scuffing or scoring on the cylinder walls? If you do some research you will find that Les Andrews, The Motors Manuals The ring manufacturers and most of the experienced engine builders on this site agree on approximately .004 per inch of bore! A Model A has a 3 7/8 bore which would be just under .016 for the top ring and less for the rest of them.
At .022 you would have increased the recommended gap by 50%, gaining nothing but a little more leakage through the ring gap.
Bill

Re: A question on Les Andrews's ring specs>>FOLLOWUP
 

A fresh rebuild will seem tight. The engine will come to a stop quicker than a worn engine, and it likely won't rock back and forth on the final compression stroke when the key is turned off.

I'm wondering what you meant by "seems pretty tight"?

Re: A question on Les Andrews's ring specs
 

Curious if minimum piston clearance has been exceeded since it is sleeved.

Re: A question on Les Andrews's ring specs
 

How might that happen?

Re: A question on Les Andrews's ring specs>>FOLLOWUP
 

Yes, Tom. That is what I expected and experienced. My trouble is that when it is stopped and turned off after a drive of, say, 30 minutes at 35 mph, if I try to start it immediately after shutoff, it frequently will just grunt, not turn over, and I can't turn it by hand. When cold it can be cranked by hand or starter like normal for a new rebuild with 1800 miles on it. Stiff, but not unduly so. I had hoped that since my initial breakin at 500 miles that it would hace loosened up and this problem would have gone away. It hasn't, so here I am. I will take some photos later and post them.

Re: A question on Les Andrews's ring specs
 

Screw up in boring diameter (geometry) prior to sleeve insertion or improper final hone?

Re: A question on Les Andrews's ring specs
 

Unlikely. The shop that sleeved and honed the block has a high and long-established reputation.

Re: A question on Les Andrews's ring specs
 

Were the pistons installed of a brand and alloy that they were used to working with? Keep in mind I know nothing of the shop, but have seen folks trip on the proper piston clearance. Some folks are paranoid of piston slap so they keep them tight - sometimes too tight for a given piston. Tends to not "wear in" like piston rings will. And has similar issues as to what you are experiencing. Piston, depending on alloy, will expand more than cylinder wall with heat. I believe the cast iron pistons are the worst for this - requiring a significant gap and creating some slap till up to temp. Gap them too tight and they will bind.

I am in no way a model A engine expert, so all of this might be for moot.

Re: A question on Les Andrews's ring specs
 

Good thoughts. Anything is possible, and I'm open to suggestions. Thanks!

Re: A question on Les Andrews's ring specs
 

700,
Once bought a '26 Chev, that had been re-ringed, if run OVER 50 MPH, for only 1/2 mile, it would SEIZE & engine would STOP. I would coast in neutral, down to 10 MPH, kick it in gear to start it & it ran perfect if held to 50MPH!
I just drove it "easy" & in time, as the rings settled/wore in, and it became normal.
With any new engine/overhauled engine, just drive it EASY & with CARE, until everything settles in/laps in & you'll be set to go! AND, don't do some "WEIRD" procedure to "seat" in the rings, the rings WILL do what they are designed to DO!
As for ring gaps, do what the instructions say, for THAT PARTICULAR SET OF RINGS!----------Is READING a LOST ART?
Just like when your wallpaper hanging goes to CRAP, you probably DIDN'T read the instructions, for THAT PARTICULAR WALLPAPER!
Bill W.

Re: A question on Les Andrews's ring specs
 

Here are some photos of my condition. The vertical lines may be scoring, but they are so slight I am not able to feel them with a fingernail. The cylinder walls are shiny, and what appears to be discoloration is merely the reflection of carbon on the piston heads.

Re: A question on Les Andrews's ring specs
 

With only 1500 miles I would have expected to see a nice crosshatch pattern yet.

The crosshatch was still visible on my dad's 1970 Pontiac 400 engine with over 100,000 miles, and the engine was spotless inside.

I would remove the pistons and fit the rings to the cylinders to check the gaps. Also measure the piston clearance.

Also make sure the water jacket is spotless clean. Rust and junk likes to build up in the rear by #3 and #4.

Re: A question on Les Andrews's ring specs
 

A couple more photos.

Re: A question on Les Andrews's ring specs
 

Bill, I didn't get any instructions about gaps with those rings. Or if I did, I didn't see them, and I'm pretty careful about stuff like that. That's why I relied on Les's book, which I have come to believe was/is incorrect, at least in my case.

Re: A question on Les Andrews's ring specs
 

Could be the piston clearance is just a tad bit on the tight side so when up to running temperature, the pistons have expanded just enough to be at or near zero clearance. Let's assume we still have an oil film on the cylinder walls for just enough lubrication to prevent scoring but at shut down, the pistons squeeze the oil off the cylinder walls. Now the pistons are tight against the cylinder walls without that oil film, so the engine won't turn until the pistons cool down and contract.
For this to happen, you must be right on the ragged edge of seizing the pistons in the bores!

Re: A question on Les Andrews's ring specs
 

As long as you're this far into it have you re-checked brg clearances?? I can't see how ring clrncs could cause your problem.
Paul in CT

Re: A question on Les Andrews's ring specs
 

Paul, that is on the agenda. Thanks.

Re: A question on Les Andrews's ring specs
 

You say you can't feel them with your fingernails. From what I see, if they're IRON rings, this may be "normal" until the ring surfaces polish over & those marks "may" go away.
IF, the marks were from pistons too tight, you should see, almost like ALUJIMUM like deposits in the marks. I'd just drive it & DON'T WURRY! BUT, WHUT DO I KNOW--------------?????????????????????--(The Dorg's SMILIN')
Bill W.

Re: A question on Les Andrews's ring specs
 

looks like it is passing some oil the way the carbon is washed away in some areas of the piston

can you rock the pistons any in the bore---left to right

Re: A question on Les Andrews's ring specs
 

Kurt, excellent suggestion, and I'll check that this weekend and let you know.

Even though I may have missed it on the packaging, I see that Snyders specifies that Hastings suggests that their top and middle rings be gapped at .012-.022. Since I gapped mine at .012-.014, I'm at the low end. More and more, with Barner suggestions and other data gathered, I'm settling on just increasing the ring gaps.