wrist pin size

Bent-8

Bent-8

Junior Member
In process of gathering parts for a stroker build. So far I have a 4 1/8 crank, 21A rods, and a set of forged 3 5/16 pistons. These pistons were custom made by Wiseco for this application several years back, but have never been used. I picked them up second hand. I called Wiseco today and got the specs for the pistons. I was told they require .750" x 2.70" wrist pins. I know .750" is the stock diameter, but I'm not sure about the length. I checked a set of stock Ford wrist pins I have on hand and found they measure 2.77" long. These pins are from an 8BA engine. Did Ford make different length pins? Any place I've found them listed for sale doesn't list the length. Anybody know where I can get a set of 2.70" pins?

Any help is appreciated.
 
I recently built a stroker. The pins supplied by Ross for the pistons they made were 5 mm shorter than the equivalent Ford pistons, but were considerably heavier [thicker wall section]. I like keeping everything as light as possible, so shortened up the genuine tapered bore, thin wall nos Ford pins to the shorter length.
Suggest you simply shorten up what you've got to suit your Wiseco pistons.
 
Bent-8 said:
In process of gathering parts for a stroker build. So far I have a 4 1/8 crank, 21A rods, and a set of forged 3 5/16 pistons. These pistons were custom made by Wiseco for this application several years back, but have never been used. I picked them up second hand. I called Wiseco today and got the specs for the pistons. I was told they require .750" x 2.70" wrist pins. I know .750" is the stock diameter, but I'm not sure about the length. I checked a set of stock Ford wrist pins I have on hand and found they measure 2.77" long. These pins are from an 8BA engine. Did Ford make different length pins? Any place I've found them listed for sale doesn't list the length. Anybody know where I can get a set of 2.70" pins?

Any help is appreciated.
Click to expand...
Have you in fact tried to assemble the stock pins with the cir-clips?
If too long then, as stated, shorten them giving consideration to any balance issues.
 
Thanks for the replies

Have you in fact tried to assemble the stock pins with the cir-clips?
If too long then, as stated, shorten them giving consideration to any balance issues.
Click to expand...

No, I have'nt tried them. But, I was assured by Wiseco that the stock pins would not work. I measured the stock pins before calling them, so I asked. The stock clips won't work either. The grooves are too narrow for them to fully seat, but that's no big deal. I've found some regular internal c-clips that work. Wiseco confirmed the clips will work.

I recently built a stroker. The pins supplied by Ross for the pistons they made were 5 mm shorter than the equivalent Ford pistons, but were considerably heavier [thicker wall section]. I like keeping everything as light as possible, so shortened up the genuine tapered bore, thin wall nos Ford pins to the shorter length.
Suggest you simply shorten up what you've got to suit your Wiseco pistons.
Click to expand...

Yeah, I've read that Ross's pins are heavier. Interesting that they are shorter as well. I didn't know that. Sounds like they "may" fit my application. But, I agree with you on the weight issue. I'd rather use stock, thin wall pins. I could turn down the set I have, but I'd buy a set if I can find them.

Anybody know a source?
 
Bent-8 said:
Thanks for the replies



No, I have'nt tried them. But, I was assured by Wiseco that the stock pins would not work. I measured the stock pins before calling them, so I asked. The stock clips won't work either. The grooves are too narrow for them to fully seat, but that's no big deal. I've found some regular internal c-clips that work. Wiseco confirmed the clips will work.



Yeah, I've read that Ross's pins are heavier. Interesting that they are shorter as well. I didn't know that. Sounds like they "may" fit my application. But, I agree with you on the weight issue. I'd rather use stock, thin wall pins. I could turn down the set I have, but I'd buy a set if I can find them.

Anybody know a source?
Click to expand...

Hi "Bent", the Ross pins are identical, weight-wise, to most aftermarket Flathead piston pins.

I keep both piston brands here, Nylen's and Ross', either pin weighs 120 grms. The Ross pins are 2.770" long x .195" wall, the Nylen pins are 2.835" but with a 190" wall. This minor wall difference is why the weight is still the same with the different lengths.

The Nylen pistons and the OEM's both use very thin "wire" clips, Ross use the "flat" "Spirolox's", we use these on many aftermarket race pistons. Some of these Chevy's are even changing over to "wire" locks also, but much heavier!

Thanks, Gary in N.Y.

P.S. On these Flatheads would much rather see a lighter pin, in the 80 gram area! They would definitely survive with a .125" wall (nominal). We use Chevy pins with .110" walls. 2.500" long, that weigh 85 grams. These are also much higher HP builds.
 
A few years ago I had custom pins made by a company called Western Wrist Pin. I think I had to buy 100 pieces but got .090 wall bullet proof parts. I do not know if that company still exists but somebody, somewhere, can give you anything you want.
 
Ross lists two different weight pins on their site:

a set of thin wall H13 series pins at 81 grams
http://www.rosspistons.com/h13-wrist-pins/
0.750 2.770 C .125 TW 81 H13 750-07-27C Taper Wall Pin w/ Ends Camfered for Wire Lock Pin Retainers


and the heavier 5115 series at 120 grams
http://www.rosspistons.com/5115-wrist-pins/
0.750 2.770 0.195 120 5115 750-01-27

But both of these are shown at the longer 2.77" length, so they won't work for me. Interesting that they would supply the heavier pins with their piston sets for the flathead.

JWL,
I'll check into Western Wrist Pins, but I only need one set. Thanks for the lead though.
 
Well, I've been able to at least partially answer my own question. I finally found one of my old service manuals that lists the specs for wrist pins, or piston pins as they are referred to in the manual. Ford made several different pin sizes over the years. Here's what the manual lists

Pin Diameter .7501-.7504" (all applications)
Pin Length
Lincoln Zephyr ('36-'39) 2.482"
Lincoln Zephyr ('40) 2.607"
Ford 85HP (steel piston) 2.850"
Ford 85 HP (aluminum piston) 2.780"
Ford and Merc 95 HP 2.975"

This manual only covers up to 1950 and does not make a distinction between the 59 series engines and the 8BA series. It also does not mention the 255" Mercury engines, so I don't know if the specs are any different. Maybe someone else can provide that info.
 
Bent-8 said:
Well, I've been able to at least partially answer my own question. I finally found one of my old service manuals that lists the specs for wrist pins, or piston pins as they are referred to in the manual. Ford made several different pin sizes over the years. Here's what the manual lists

Pin Diameter .7501-.7504" (all applications)
Pin Length
Lincoln Zephyr ('36-'39) 2.482"
Lincoln Zephyr ('40) 2.607"
Ford 85HP (steel piston) 2.850"
Ford 85 HP (aluminum piston) 2.780"
Ford and Merc 95 HP 2.975"

This manual only covers up to 1950 and does not make a distinction between the 59 series engines and the 8BA series. It also does not mention the 255" Mercury engines, so I don't know if the specs are any different. Maybe someone else can provide that info.
Click to expand...

8BA and Mercury is the same bore only compression height of the piston is different so piston pin is the same.
 
I'd run these:

a set of thin wall H13 series pins at 81 grams
http://www.rosspistons.com/h13-wrist-pins/
0.750 2.770 C .125 TW 81 H13 750-07-27C Taper Wall Pin w/ Ends Camfered for Wire Lock Pin Retainers

It would not be terribly difficult to shorten them - though they are very hard. My guess, it would need to be done via grinding. Heck, if I was in this situation I'd probably chuck them in my lathe and use my toolpost grinder. :)
 
why not just buy them from Wiseco? Is there a cost or availability issue?
Click to expand...

Wiseco says they can't supply them (don't carry anything near the size). These were custom pistons, so I guess that's why.

I'd run these:

a set of thin wall H13 series pins at 81 grams
http://www.rosspistons.com/h13-wrist-pins/
0.750 2.770 C .125 TW 81 H13 750-07-27C Taper Wall Pin w/ Ends Camfered for Wire Lock Pin Retainers

It would not be terribly difficult to shorten them - though they are very hard. My guess, it would need to be done via grinding. Heck, if I was in this situation I'd probably chuck them in my lathe and use my toolpost grinder.
Click to expand...

Might try those if my current plan doesn't work out. I've got a set of NOS pins on the way now. I've got a tool post grinder. That's what I plan to use to shorten them up. Just would have been nice to find some that would drop in without modification. I'm lazy:)
 
Just for shits and grins I contacted Ross to get a price on these pins

a set of thin wall H13 series pins at 81 grams
http://www.rosspistons.com/h13-wrist-pins/
0.750 2.770 C .125 TW 81 H13 750-07-27C Taper Wall Pin w/ Ends Camfered for Wire Lock Pin Retainers
Click to expand...

Was told those pins have been discontinued. They offered to order me a set of "comparable" pins and quoted me $221.76 for a set of 8!

Oh well, I guess I'll be grinding down a set of Henry's pins on the lathe soon.
 
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