Urgent help needed with pistons.

[vlzman]

Hi, I know it's a long shot and probably too optimistic but it never hurts to ask....
Today I discovered that my recent timing chain failure has caused a minor crack on two of my pistons. It looks like it might be a surface crack but still I find it too risky to run them in my engine. What I was thinking that maybe there are somebody who might have at least two (preferrably whole set) laying on the shelf. Problem is that I have championship race already on Saturday (it means that they should be shipped today).
Pistons are Ross coated pistons, bore 4.020, CR 9,5:1. There's a piston number graved under the piston: 74985C. I add couple of photos also just in case. If somebody can help me then my biggest gratitude is guaranteed

thank you
Veljo

 

[turbo nasty]

Cant help you with replacement pistons but the sharp edges on the valve reliefs should be blended smooth as the sharp edges will promote hot spots, pre ignition, etc.

 

[vlzman]

Probably any other companys pistons with the same bore and CR would go unless there's a big weight difference. Just weighed my piston with the wrist pin and without the rings it was 1 lb 2.8716 oz. Difference probably should stay close to 0.5 oz.
Still kicking myself for not noticing it a week ago

 

[Squid4life]

I have some misc pistons at home, I will see what I have this afternoon when I get home.

 

[Squid4life]

I have some misc pistons at home, I will see what I have this afternoon when I get home.

 

[vlzman]

Please do, my last chance to receive them on time if they fit, is only if they would be shipped out today. It has to be DHL Express or UPS (2 days to europe both). I'll be sitting on the computer nervously and wair for updates

 

[Chris Hogeland]

How long of rod? 927 pin?stage 2 heads?


Posted from the TurboBuick.Com mobile app

 

[vlzman]

6.5 rods, pin seems to be .927 (what are other possibilities?), stage 2 heads

 

[Chris Hogeland]

Could be 6.300,6.350.6.00. Need to know for sure.


Posted from the TurboBuick.Com mobile app

 

[vlzman]

Rods are definitely 6.5, about the wrist pin: when I bought new set of carillo rods last year then I had to machine them a bit because wrist pin didn't fit at first.

 

[Chris Hogeland]

Do you Have A mic to check the pin with?


Posted from the TurboBuick.Com mobile app

 

[vlzman]

I don't, I measured it with tape and it seems to be 2,4 cm (metric here ) which is 0.927. Do you have anything you can help me out with?

 

[Chris Hogeland]

I just looked if you had A 6.300 rod I could fix you right up. I don't have any thing in your bore size for A 6.5 rod. Sorry wish I could help.


Posted from the TurboBuick.Com mobile app

 

[vlzman]

I just looked if you had A 6.300 rod I could fix you right up. I don't have any thing in your bore size for A 6.5 rod. Sorry wish I could help.


Posted from the TurboBuick.Com mobile app

No prob, thanks for trying
It would be a small miracle if I could find something anyway.

 

[norbs]

Will you be using a timing chain in future? Shame on those nice pistons..

 

[Squid4life]

JE for SII heads
4.020" bore
.255 dish (9.0 or 9.5, I cannot remember...)
1.196 CH
.927 pin
2.750 pin length
1/16 1/16 3/16+ spacer

I do not have pins, rings or ring spacer. I have 3 pistons and enough dual spirolocks for them. The dish/ reliefs looks identical to yours.

Weight is 1lb, 5.2 oz with a pin.

 

[Squid4life]

Norbs, they do, they are just shallow and not as noticeable with the dish.

 

[vlzman]

JE for SII heads
4.020" bore
.255 dish (9.0 or 9.5, I cannot remember...)
1.196 CH
.927 pin
2.750 pin length
1/16 1/16 3/16+ spacer

I do not have pins, rings or ring spacer. I have 3 pistons and enough dual spirolocks for them. The dish/ reliefs looks identical to yours.

Weight is 1lb, 5.2 oz with a pin.

View attachment 195650

View attachment 195651

Hey, Weight difference is too big

Anyway, now it's sure that I won't make it this time. Thanks everybody for trying to help me!
Good news is that now I have time to order new pistons and don't have to cut corners
Veljo

 

[J-B Racing]

I have the Pistons you would need. But the 3 I have are for 4" bore and are for 6.5" Rods.

Sorry

 

[vlzman]

I ordered new ones from Ross, few weeks and the beast screams again