[71 Ventura II]

Is it possible to chuck a piston pin in a lathe and open up the inside diameter? I notice the pins in my L2262F 0.040 pistons has very thick walls. I have access to the mahinery, is it OK to machine the pins? If so what is a safe wall thickness?

Also, should I try to weight match them or just match the piston/pin as an assembly? JD

[RAIV55]

I definately wouldn't machine the TRW type pins ID. My opinion,.... they would be tough to machine, the gain small and risk high.

I called TRW tech one time asking about shortening their pins and they even advised against that. Was told that any cutting would be detramental for pin life since it would remove the case and cause fractures.

However have to admit I didn't follow their advice, I did shorten the pins and did not have a problem doing so.

[Mr. P-Body]

Pins are harder than "Chiinese arithmetic" (that's HARD!). Grinding is the method of choice for removing material from a hardened part. .125", absolute minimum for a street engine, and only then if they're "floating" pins. .150" for press-fit.

The pins provided with the L2359F (455 Speed Pro) is significantly lighter and will fit perfectly. You may be able to order a set through your Federal Mogul dealer.

Ross and JE, among others, offer a selection of pins for the .980" diameter. Some are VERY light, but again, for floaters. They do have a nice "tool steel" pin for about $10 each, suitable for a press-fit.

Jim

[71 Ventura II]

Originally Posted by Mr. P-Body

Pins are harder than "Chiinese arithmetic" (that's HARD!). Grinding is the method of choice for removing material from a hardened part. .125", absolute minimum for a street engine, and only then if they're "floating" pins. .150" for press-fit.

The pins provided with the L2359F (455 Speed Pro) is significantly lighter and will fit perfectly. You may be able to order a set through your Federal Mogul dealer.

Ross and JE, among others, offer a selection of pins for the .980" diameter. Some are VERY light, but again, for floaters. They do have a nice "tool steel" pin for about $10 each, suitable for a press-fit.

Jim

I'm torn, it looks like a lot of work for a tiny gain working with these pins. A local shop wants to hone out the small end of the rods and the pistons to run the .990 BBC pins. I was looking for a "cheaper" way of doing it as the "pins" they were suggesting were more than I paid for the pistons!

Jim, the "tool" pins you mentioned for $10.00, are they lighter than the stock TRW L2262F pins? I suppose I'm asking, is it worth the money to bother?

Keep in mind these pistons have already been weight matched by the previous owner. I'm no longer using the reconditioned factory rods they came with; instead going with the Scat 6.625 H-beams which are also weight matched already, but will need checking with the new cap-screw bolts. The engine could see 6500+ rpm's depending how the heads flow, so I need this to be strong enough to handle some RPM. JD

[screamingchief]

Any time tool steel pins were mentioned here in the past there was always a torrent of people raving that they are not to be used in street applications,or applications seeing very high pin loads (IE:nitrous),so dont be surprised if you get some of that sorta thing here.

Remeber,your using a fairly heavy piston,and going too light on the pins is'nt the best idea,like Jim said .150" wall pins are common and safe to use,and most offer an easy 50 gram weight savings per pin (150 grams appx.).

And a .125" wall pin commonly saves around 75 grams per pin (125 grams appx.).

There are lots of lighter .980" pins out there,just gotta hit the catalogs and pick up the phone.

Most all are also just slightly shorter than the TRW pins are,but that is not a major concern,there is still more than enough pin in the piston to support everything properly.

The thin wall/tool steel jobs are usually down just under 100 grams per pin,and wall thickness is like .090",run at your own risk.

HTH.

[cgeise]

I have run the 138 gr Ferra pin for a long time - .990 chev size with no prob - I do think the effort to cut a pin down is just not worth it

[Skip Fix]

Yea my RAIV 400 has those darn TRW pins that barely have a hole too. I think they weigh in around 250 gms! They are definitely going to get swapped out when it gets freshened. teh ones for the 455 Jim mentioned are around 200gms.

[mechanic17]

FYI, if your Scat H-beams are press fit, have the machinist double check the small ends for the proper interference. They are known for being a couple thousands off, and will not press on correctly until finish-honed.

[racegto65]

Originally Posted by 71 Ventura II

I'm torn, it looks like a lot of work for a tiny gain working with these pins. A local shop wants to hone out the small end of the rods and the pistons to run the .990 BBC pins. I was looking for a "cheaper" way of doing it as the "pins" they were suggesting were more than I paid for the pistons!

Jim, the "tool" pins you mentioned for $10.00, are they lighter than the stock TRW L2262F pins? I suppose I'm asking, is it worth the money to bother?

Keep in mind these pistons have already been weight matched by the previous owner. I'm no longer using the reconditioned factory rods they came with; instead going with the Scat 6.625 H-beams which are also weight matched already, but will need checking with the new cap-screw bolts. The engine could see 6500+ rpm's depending how the heads flow, so I need this to be strong enough to handle some RPM. JD

Another option is to use .984 Chrysler small block pins and have the pistons and pins honed to fit.I used to do this years ago as a lighter alternative on a budget.

[Polar-Pontiac]

I run a .927 steel tool pins not a problem.

[71 Ventura II]

Originally Posted by mechanic17

FYI, if your Scat H-beams are press fit, have the machinist double check the small ends for the proper interference. They are known for being a couple thousands off, and will not press on correctly until finish-honed.

Thanks for the heads up, everything will be checked for sure. I might mention these rods were run before by a fellow PY member, so the small ends have probably been worked already. Since I'm unsure how many "stretchings" the cap screws have I'm upgrading them to be safe and checking all the measurements. Thanks again.

I like the idea of the .984 pins, they may be a better deal? Idunno But thanks all the same for the idea! JD

[Skip Fix]

I used a set of the Mopar pins from Ross in some TRWs and a 400 build where the rods were a little loose.