Melted 1 piston, replacement advice requested

[tttype]

Melted 1 piston in a fresh engine I did not build, so dont know brand of piston.
Was hoping a brand name would be on underside of piston , but no luck there.





Anyone recognise these ?

4" diameter, 6.5" rod, 3.625 stroke

Engine Originally assembled around 2000.

With custom pistons is it usual to replace 1 or must order a whole set ?

Thanks

 

[forcefed3.8's]

Are you sure it has a 6.5 rod? The pin looks low for 3.625 and 6.5.

 

[BlownV6]

Are you sure it has a 6.5 rod? The pin looks low for 3.625 and 6.5.

X2 - That looks like it would be more like for a 6.200 rod. A 6.500 rod with 3.625 crank would have the pin right at the bottom of the oil rings. Mike

 

[750H.P.V6]

Looks like a 6.2" Crower rod to me. Replacement pistons will be custom order. I was wondering if it's an old Diamond piston. Unfortunately you'll probably have to order a whole set.

Neal

 

[tttype]

Thats why I posted here, where all the smart guys are !

Did a quick measuring of a rod & am getting just under 6" center to center . I would guess they are measured off center of pin & rod bores ?
Rough measurement is more like 5.95

Dug up sellers ad listing engine specs . It states Crower billet 6.5" rods & wiseco pistons.


This look like a crower rod ?

 

[BlownV6]

Looks like a Crower rod to me. Mike

 

[750H.P.V6]

Look on the head of the rod bolt for the manufacturers name, they should say Crower.

Neal

 

[forcefed3.8's]

I don't like the top ring placement.

 

[Mike Licht]

For sure not a Diamond piston, the dish is wrong. Wiseco is likely the one since they don't mark a lot of pistons and they use that style of forging

 

[BlownV6]

I agree with Mike. More than likely it Weisco's Mike

 

[BlownV6]

Jim Rock says it looks like a TRW. I think thats a real good chance also!!! Mike

 

[tttype]

I don't like the top ring placement.

Can you further this statement ? As I am probably in the market for new pistons now .

While talking about rings, The 2nd ring is actually 2 thin rings. Are these low tension rings ?
Good idea for street car ? Is this a ring option or must be decided on when building pistons ( required different land width ? )

Thanks for all the replies

 

[750H.P.V6]

For sure not a Diamond piston, the dish is wrong. Wiseco is likely the one since they don't mark a lot of pistons and they use that style of forging

The reason I was thinking it could be an old Diamond piston goes back to some Stage II stuff my buddy bought from Ray Baker years ago. There were some Diamond pistons in that lot and my recollection was they were machining them from TRW forgings at the time.

As far as the placement of the ring pack on the piston goes you would like to see the top ring down at least .250" from the top of the piston. A 1/16th, 1/16th, 3/16th ring package is most durable. The 2nd ring on your piston appears to be some type of zero gap ring most likely Total Seal.

Neal

 

[norbs]

Were you using alky on the run? boost ? Wheres the pic of the melted piston?

 

[tttype]

OK finally getting around to this project, thing happen slowly around here !

Con rods are 5.960 not 6.5 as advertised .

Measured all bores,
Some are around 4.002ish largest is 4,004
max out of round is .0015 on one cyl.

Whats the usual procedure for ordering custom pistons ?

Hone to size then order pistons ?

Whats the latest trend in styles, coatings , manufacturers etc ?

 

[Nick Micale]

OK finally getting around to this project, thing happen slowly around here !

Whats the usual procedure for ordering custom pistons ?

Hone to size then order pistons ?

Whats the latest trend in styles, coatings , manufacturers etc ?

The first thing you need to do is select the proper ring package that is available to fit your final bore size. There is not much of a choice close to 4.00", as we would take your bore to 4.00".

 

[750H.P.V6]

Have your machinist clean up the cylinders and get them all the same size, deck the block then spec out the pistons. I've had good luck getting rings including weird oddball sizes from Total Seal. Once you have a bore size and compression height you'll be on your way.

Neal

 

[GARY HARVEY]

Options abound for something like this. If you have decided how much you are going to spend, pistons are good from several custom builders. I'd send one of them to Total Seal and let them know what I was doing with the application. Never had ANY ring issues with them by the way. Bob Foster (800-874-2753) was who I was dealing with but he may very well retired and someone else be in his position. Locate someone that will rent you cylinder plates to torque into place to insure the bores are done properly.
Then again, if all you need is a single piston (& want to save a butt load), I'd not have issue with going that direction too. It's only money.. Gary

 

[tttype]

Reading others stage builds it seams like 4.010 is a common size. Or is it better to contact a ring supplier & hope for 4.005 ?

 

[rag231]

I wouldn't bore it to the next common size. For example if your are at a 4.00 bore and then have your machine shop clean up all bore and find out what they clean up at. Then when you have figured out the ring package order an extra piston ( or 2) as well or in the case of my ROSS pistons which dated back to 2002, they can look up the job order and make that piston exactly like the other 6. The job order is scribed on the inside of the piston. For the record the pistons are 4.005 for a 3.59 stroke crank, that motor has had a hard life and is due for a refresh.