Piston Ring End Gap

B

Bruce/Texas

Member
I am re-ringing my '49 8BA. The pistons are .040" oversize. What should the ring end gap be and do the compression rings and oil rings all have the same gap?

Also, I plan on using a flex hone to deglaze the cylinders. Any tips or a better idea as I have not done this before. Thanks
 
Bruce, you should have about .004 per inch of cyl. clearance on a new bore job. That should be about .014 on your engine. BUT, if this is just a rering job with quite a few miles on the engine, I'm sure you have more that that. If you have .020 or better on an old engine, don't worry about it. Walt
 
A couple of questions for Walt. Do you compensate for cylinder taper if you don't clean up the bore and only brake the glaze? How much taper would you consider acceptable?
 
Their home page http://www.brushresearch.com/

Your flex hone is a very good tool choice for the application.I have done 100's of cylinders.Use a variable speed drill at about 1/2 speed and stroke at 45 deg angles without stopping and remove the hone while it is still turning.It is very forgiving and won't get away from you and remove excessive material.The tool has many indorsements from some prominent engine manufactures.
Use some 10w30 oil for a flex hone oil and you will get a excellent result.The critical item to overcome is to get the bores clean.After honing wipe the bores clean with shop rags.You are now ready to wash the cylinders out with hot soap "tide" and water using a good sponge or a flex hone cylinder cleaning brush.Wash the bores at least twice and check for cleanliness using a clean white tissue pressed down the side of the bore.The tissue must come out clean with "no" smudges of dirt.If you have smudges clean some more.Now wipe the bores with wd40 to prevent flash rust and you will have no worries.
Do not attempt to clean the bores with diesel fuel,brake clean,lacquer thinner or some other home brew they WON'T give you the desired results a clean honing residue free bore. Your question about taper with a flex hone you won't any correction. How much do you have? Check taper by putting a single compression ring in the bore at the top below ridge that has been removed and record the end gap.Now put the same ring in the bottom where the rings don't run and record the gap this will determine you change in end gap which gets larger "About 3 to 1" with taper.There are numerous other ways to check taper dial gauges mic's but this way doesn't require any outlay of money for expensive tools just feeler gauges.
hope this info helps

Ronnie
 
Have the finished hone lines intersect at 45 deg cross over each other (cross hatch) you will get this effect by the stroke being slow or fast. You will see when the hone is removed. If it was too flat just re hone for about 5 to 6 strokes at a quicker stroke time and you will get the desired pattern.The is very forgiving and you will get great results.Read on their web site about cross hatch pattern.This also gives a pattern that reduces excess ring rotation which is always present and is of no harm as most ring designs are suposed to rotate.

Ronnie
 
41 ford 1--They usually say that rings will take up to .010 tapper. If you have a .040 bore you'll have to use .040 rings. Check it down to bottom of the hole, you''ll probably have about .015 or so. If you have .020 or so just under the ridge it will run fine for quite a while. If you have a big ridge it should be bored to the next oversize. Walt
 
Even if you don't have a BIG ridge, consider using a ridge reamer... The new ring will otherwise run into a bit of the bottom of it and knock the top edge off of the ring... Karl
 
The ridge MUST always be removed My statement about below ridge was to insure you were getting a measurement "below" where ridge was not "where" ridge was as you would get an erroneous reading.Sorry for not being more clear for the statement.

Ronnie
 
Will the flex hone remove the ridge? Or is a separate ridge reamer required?

What grit Flex Hone is good for a 37 flathead...120, 180, 240?

Also, will an "Ultra Finish" brush clean out the junk left by the Flex Hone? Or will adequate soap,towels, etc do the job just as well?

Thanks for the help!
 
Ridge reaming is a separate operation a flex hone will not remove ridge.You will have success cleaning the bores by wiping all the honing residue out with a shop rag before you commence with the bore cleaning operation.The cleaning must be done with hot water and laundry soap sponge rag or an equivalent such as dish washing detergent.You can also use non grit hand cleaner as a pre wash before the final wash.Do not use brake clean,lacquer thinner,gasoline,solvent diesel fuel or any other home concoction.Read on the ring package they tell you warm water and detergent.Don't try to re invent the wheel just keep it simple it works.When final wash is done wipe the cly clean with wd40. Take a final smudge test with clean white tissue paper and wd40 press hard all the way down cylinder.The paper must come out with no smudge on paper if there is residue clean again with soap.A 180 grit flex hone will do well with engine oil as a lubricant while honing.Remember to clean around the bottoms of the cly's as well as residue accumulates here also. This will work for you.

R
 
Now that's the best way to do it, Ol' Ronnie has it. I picked up a new ridge reamer several years ago at a flea market and it's thee best one I've ever used, Unfortunately I don't get a chance to use it very often, because I bore the block. It's important to remove the ridge BEFORE you remove the pistons if you want to reuse them, other wise you could break a ring land. Hay Ron, keep up the good work.
 
Some other ideas for using the three-legged hones: If you want a coarser finish without buying new stones, use brake clean instead of oil for the lube. Spray liberally as you hone to flush the grit away. Also, most hones have a knob ro adjust tension on the stones, so you have a choice of using oil and light pressure to barely break the glaze or more tension and brake clean to take out minor scratches (you will take a little material off the walls, but, as they say, 'loose is fast').
It's amazing what you can get by with when you need to do an overhaul on the cheap! .025" taper, out of round rod journals, loose wrist pins, 'most everything on the wrong side of the wear limits, yet these old engines would run and run, and run good! Of course, if you tried to get away with too much, it would let you know quick! Ah, the good ol' days.
 
Ol' Ron said:
Now that's the best way to do it, Ol' Ronnie has it. I picked up a new ridge reamer several years ago at a flea market and it's thee best one I've ever used, Unfortunately I don't get a chance to use it very often, because I bore the block. It's important to remove the ridge BEFORE you remove the pistons if you want to reuse them, other wise you could break a ring land. Hay Ron, keep up the good work.
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Thanks OL'Ron I've been in the engine parts game for 30 years have seen many disasters due to lack of knowledge and poor workmanship,and poor advise from some dudes that say it worked for him or his friend uncle grandfather or whatever.Ask questions to qualified people and get a straight answer.

My 2¢

R
 
Not a problem, been there done that. I try to help, not many guys like Walt, JWL, myself and a few others I can't think of right now that have made as many mistakes as we have. I like to try different things, experiment with the norm. That's why we're getting better mileage with a very long cam. I am really surprised and can't offer an explanation. At present I;m building an ECono engine, built specifically to give better mileage, but still have enough power to drive in today's traffic. We'll see, I hope.
 
40Pickup said:
You guys that have a ridge Reamer, can you show us some photos.
Thanks, Jorgen
Click to expand...

Here is a link that will get you started with the set up.This style of ridge reamer does a good job.I have used this type many times.You cut cast iron dry no lube.The fellow in the vid follows the instructions ok.A reamer comes with detailed instructions.The set up is the important part.I am not a fan of using rental tools as it is usually beat up from abuse and misuse.See if a friend has a serviceable reamer to use.
Hope this helps.

Hastings,KD tools and Lisle are suppliers of a ridge reamer
http://www.youtube.com/watch?v=h6t4bBd4ppk
2¢more.

Ronnie
 
Ronnie, thanks for your replies.
Here an old one, I found!
 

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