Need a piston(s)

[Bassman/NZ]

My C59A is in need of one 3 3/16 +45thou 3 ring piston. I have scoured the usual suppliers, and +40 or +60 is no problem, but +45 is like unobtanium. So.... I'm looking for suggestions. The rest of the engine is great, so I do not want to bore to +60. Any one have any ideas? Marty.

[bobH]

How about a 40, and let it slap? Or, how about a 60 and a lathe? If Burt Munro can whip out pistons in his home garage shop (Fastest Indian), ought to be able to conquer this situation. Just opinion.
How about contacting the piston manufacturers and have made what you want. Previous posts on this forum suggest this is possible. Again, just opinion.

[Alaska Jim]

you might try egge pistons, they can probably come up with one.

[Lawrie]

I spoke to EGGE to see if they would make a set of .050 pistons.no deal,
but the did make me a set of .065 ones .
I don't know what the difference was.
But talk to them on the phone,not via e/mail and plead your case.I just got One 3-3/16 +.040 X 4 inch stroke piston from them.
they are good to deal with.
Lawrie

[flatheadmurre]

If they make a .040 and are willing to do a custom set .045 shouldnt be impossible.
The cost for setting up the tooling is same for one piston as for a set so might be a very expensive piston.
Or start hunting for a shop that has a pistongrinder....

[kiwitony]

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I have some used ones call me on 094240594 if any help. Cheers Tony.

[Mart]

They are about. +.045 is a common size in the French motors. I have some used French +.045 pistons with Rings. I don't know how much it would cost to get a couple to you, but I suspect it wouldn't be cheap.

Edit: Sounds like Tony's would be cheaper!

Mart.

[Bassman/NZ]

Originally Posted by kiwitony

I have some used ones call me on 094240594 if any help. Cheers Tony.

Cheers Tony. It's getting a bit late now, I'll give you a bell tomorrow night, about 7ish if that suits.

[leakers]

Originally Posted by Mart

They are about. +.045 is a common size in the French motors. I have some used French +.045 pistons with Rings. I don't know how much it would cost to get a couple to you, but I suspect it wouldn't be cheap.

Edit: Sounds like Tony's would be cheaper!

Mart.

There's plenty of Kiwis in Jolly old England at the moment all coming home in a couple of weeks with the Thugby world cup. If Tony's pistons don't pan out, you could slip a couple in with the silverware . Some Rugby fans luggage is a better idea though, Someone will know Marty, he is famous in NZ....or he will know someone who is over there.

[Walt Dupont--Me.]

Back in the 60-early 70s I turned and ground many many pistons on a piston grinding machine, we had different cams for the machine A-B-C-D-E-and special E cams, we use to have semi pistons that would clean .060 I turned a lot of used pistons like .060 to .040 ect. For some people that don't know, pistons are not round, they are cam ground and tapered, the ring lands are about .025 smaller than skirts. I'm sure it's hard to find a shop with a piston grinder now days. If you could they could grind a .060 to .045 easy. Walt btw, pistons in a Briggs - Stratton are round.

[JSeery]

With almost any of these approaches I would think you would need to have the whole set balanced. It is hard to believe you would find a piston that matched (weight) with the ones you have.

[deuce_roadster]

I see Walt cleared that up, I was going to mention that car engine pistons aren't round.

[tubman]

Originally Posted by JSeery

With almost any of these approaches I would think you would need to have the whole set balanced. It is hard to believe you would find a piston that matched (weight) with the ones you have.

This was bothering me too, but then I thought, if he has the old piston and rings, the new ones could be brought to the weight of the old ones, which would probably be close enough for a street engine, If there is no original piston, or if it has significant damage, it might be worthwhile to remove a second piston and use that to provide the original weight. If the engine wasn't balanced on the previous rebuild, this could probably be an exercise in futility.

[JSeery]

Originally Posted by tubman

This was bothering me too, but then I thought, if he has the old piston and rings, the new ones could be brought to the weight of the old ones, which would probably be close enough for a street engine, If there is no original piston, or if it has significant damage, it might be worthwhile to remove a second piston and use that to provide the original weight. If the engine wasn't balanced on the previous rebuild, this could probably be an exercise in futility.

As tubman stated, the whole assembly may not need to be balanced (I balance all of my engines regardless) but at the least you would want the replacement piston in the same weight range as the one it replaced. That should be simple enough with a decent scale.

[Shu47]

Walt and Deuce, I have always know pistons are tapered with the top being smaller diameter than then skirt but are you also saying they are not round? That the piston is oval shaped?

[bobH]

Originally Posted by Walt Dupont--Me.

Back in the 60-early 70s I turned and ground many many pistons on a piston grinding machine, we had different cams for the machine A-B-C-D-E-and special E cams, we use to have semi pistons that would clean .060 I turned a lot of used pistons like .060 to .040 ect. For some people that don't know, pistons are not round, they are cam ground and tapered, the ring lands are about .025 smaller than skirts. I'm sure it's hard to find a shop with a piston grinder now days. If you could they could grind a .060 to .045 easy. Walt btw, pistons in a Briggs - Stratton are round.

At the risk of 'being on my soapbox'....
Walt almost addressed his own comment, or rule, automotive "pistons are not round", and "btw, BS pistons ARE round." There are other examples around, for example, I keep a forged TRW piston sitting here that IS round.
Yes, the ring land area is smaller.
I interpret the original OP to be inquiring about a 'repair' or possibly a 'patch-job', since it is being asked about ONE piston. That means to me that the repair is 'compromised'. Taking a used .060, and making a .045, is, in my opinion, fair game. As for balancing, yes, I would make sure that the single 'replacement' piston matches the other ones in weight.
As for turning one on a lathe, in my opinion, fair game. Especially for a 'compromised' repair. I've done it, many of us have done it, it can work.
Also, using a .040 piston in a .045 bore, would be fair game to at least look at. That's only .005 off, and there are a whole bunch of engines running with at least .005 or more wear. I'd be looking at skirt design, and clearance, and would think to myself, 'in my experience, would this work?'
I also mention, that for my own personal engines, I'm of the school-of-thought that 'runs them loose'. For me personally, my preference is to match piston-to-bore, at the loose end of the spec. So, carefully picking a .040 piston out of the junk barrel would be something to look at, and see if I think the skirt clearance (and style) is acceptable. I'm ok with a little 'cold-slap'.
I'm going to partially credit this thinking to rumbleseat (Paul). You can look up all of this in his notes. He built his own, 'loose'.
Also, I reference numerous magazine articles that deal with 'compromises' and running them 'loose'.
And, finally, the set of volumes by Smokey Yunick, where he references racing one night, having a burned piston, welding it up and hand-shaping it, overnight, and racing it the next day. (and sometimes winning, or at least placing.) IMO, if it's good enough for Smokey to race it, then it ought to be good enough for me, to get an old flathead down the road.
Now, caveat... I would never do any of this for someone else. Only when I'm messing with, and responsible for, my own stuff.
Only opinion, and Off soapbox...
I recognize there are numerous opposing opinions here. I came from an era when the norm was to patch them up, used-car-style. At the time, that is generally what the customers wanted.

[Walt Dupont--Me.]

One more thing, we used to knurl a lot of pistons, if you can find a .040 piston and maybe an old shop that still has a knurl rig, it not very big, it's easy to knurl the skirt .005 or more. Walt

[Bassman/NZ]

I took my old 45 to the top machine shop in my area to get it micropeined. They said they haven't done that for 20 years!
bobH is correct... my repair IS compromised. My engine runs nice and quiet (using a stethoscope) except on #5. I did a dirty measure on the skirt with a digital caliper, and it read 7 thou under. I tried another 45 piston in the bore and it was much better fit. Unfortunately I cannot use it as the ring lands are badly damaged. BTW, that piston was not out of this engine, it was just a junker I had laying around. I am trying to make this engine last a while without spending too much on it. Flathead parts and engine machine shop work is horrendously expensive in this part of the world, hence my compromise.

[bobH]

Originally Posted by Bassman/NZ

I took my old 45 to the top machine shop in my area to get it micropeined. They said they haven't done that for 20 years!
bobH is correct... my repair IS compromised. My engine runs nice and quiet (using a stethoscope) except on #5. I did a dirty measure on the skirt with a digital caliper, and it read 7 thou under. I tried another 45 piston in the bore and it was much better fit. Unfortunately I cannot use it as the ring lands are badly damaged. BTW, that piston was not out of this engine, it was just a junker I had laying around. I am trying to make this engine last a while without spending too much on it. Flathead parts and engine machine shop work is horrendously expensive in this part of the world, hence my compromise.

On the subject of 'one more thing',,, Walt mentioned knurling, which is what we did 'all the time' (so-called overhauls).
Another 'one more thing'... regarding ring lands... it used to be a common practice to 'shim' the lands. Used to be that you could buy a ring, that looks like a modern oil scraper ring, and put it in place to tighten up the lands. The lands were machined (could be on a lathe) to accomodate the 'shim', plus the normal compression ring. I don't see any reason for not using a oil scraper ring for this purpose today. Maybe could save that piston you are talking about.

[Bassman/NZ]

Originally Posted by bobH

On the subject of 'one more thing',,, Walt mentioned knurling, which is what we did 'all the time' (so-called overhauls).
Another 'one more thing'... regarding ring lands... it used to be a common practice to 'shim' the lands. Used to be that you could buy a ring, that looks like a modern oil scraper ring, and put it in place to tighten up the lands. The lands were machined (could be on a lathe) to accomodate the 'shim', plus the normal compression ring. I don't see any reason for not using a oil scraper ring for this purpose today. Maybe could save that piston you are talking about.

Thanks BobH, that would probably work, but this piston has chunks out of it from migrating pieces of broken ring. My hope is to find a good used, or ideally new, piston that specs well. I'll even buy a whole set if I have to, although I'd rather not. It seems that 45 thou pistons were a common overbore size here in New Zealand back in the 60s and 70s, and as my pistons all have Made In Canada on them, I would think it was commonplace in Canada too.