Sale ends todayGet 30% off any course (excluding packages)
Ends in --- --- ---
Forum Posts
Courses
Blog
Tech Articles
Hello, looking for information on piston to wall clearances. I will be running an lm7 gen3 ls block and likely will be mahle powerpak pistons. Whats too tight? Whats ideal for high boost? i was guessing around .0015 but have also seen that may be too tight. Thanks in advance.
EXACTLY which engine and pistons are you using - if the LS7, there are two different alloys used, with two different clearances - BOTH much larger than the clearance you were thinking of, which may be OK for OEM! https://www.us.mahle.com/media/usa/motorsports/ls7-flat-top-&-dish-webpage.pdf
MAHLE will be better able to advise, but I'd expect the minimum + 0.0005" would be in order - but it depends on the fuel, oil squirters, boost levels, etc.
I will be using an LM7 5.3 iron block. Will have tuning for pump fuel and e85. I was told to stay away from oil squirters, but not adverse to them necessarily. Will definitely be going for high dyno numbers but likely 750-800 with twin turbos when settled in the car. I do know the sleeved aluminum blocks do need different clearances.
https://www.us.mahle.com/en/search/?q=LS
There are several different piston options listed, select the one that matches the specific part number you're using, add a half thou' if you're worried.
If you're still undecided, contact Mahle direct.
NOTE, you will need to find yourself a competent engine machinst, and one who can give the correct wall finish for the ring option you've selected.
