Jaguar piston clearance problem

[camelotr]

Greetings!

We have an xk150s engine under rebuild. We wanted to use Mahle pistons. Factory pistons-bore clearance was 0.025-0.04mms. Mahle suggests 0.1mms, I find it HUGE.

- pistons are cast
- bore diameter 83mms
- solid skirt
- 3 rings
- 9:1 cr

What do You think?

Gergo

[camelotr]

Hi David,

Thanks for You input. And also nice to hear from You.

I will take a few pics and measurements soo that we can decided what to do. Only going for 0.1mms if it is realy necessary.

Gergo

[camelotr]

This requested clearance is stemped into the piston crown.

[camelotr]

Piston height: 97,3mm

Pin center-crown: 49,2mm

What else do You need?

[camelotr]

I just chacked my gauge and it is out 0.05mms. Please subtract this amount from the total values.

[camelotr]

Same things I have on my mind. I wrote them an email, but no real answer yet (instead THEY asked me about MY bussiness activinty, which I find funny).

I have one source telling me that they run a set at 0.08mms, which is fine (even with occasional club level drag racing).

Two differences I could see in piston design copared to the originals were: first of all the Mahle is much-much lighter, with reduced material at the crown area and secondly the top has no strenghtening ribs. Unfortunatly the original piston was soo dably seized, that I had to destroy while taking it out, but I think the skirt is also thinner then the original.

I also have a suspect on my mind: theese cars are prone to overheating even with perfectly working cooling systems. Dont You think that it might be a prequotion to avoid unnecessary complains?

Edited by camelotr on Friday 11th October 22:41