Need a set of 4.0 high comp pistons

4Runner

Well-known member
May 24, 2007
660
110
Boise Idaho
I am doing a 4.6 rebuild and am looking for a set of 4.0 high compression pistons. The 4.6 ones are shot and I might as well make the most of it. Let me know and thanks for your time.
 

terryjm1

Well-known member
Jan 23, 2011
1,486
375
Don’t regular 4.0 pistons give high compression when paired with a 4.6 crankshaft and rods?
 

4Runner

Well-known member
May 24, 2007
660
110
Boise Idaho
Yes. You are right but I thought that there were low compression pistons for 4.0 as well. Maybe I am wrong. I thought one was like 8.5 and the other was 9.3 roughly.
 

terryjm1

Well-known member
Jan 23, 2011
1,486
375
Yes. You are right but I thought that there were low compression pistons for 4.0 as well. Maybe I am wrong. I thought one was like 8.5 and the other was 9.3 roughly.
Geez, what does 9.3 become when you pair it with a 4.6 crank and rods? will this require octane booster?
 

robertf

Well-known member
Jan 22, 2006
4,781
358
-
10.6

Low compression 4.0 pistons have the same dish as the 4.6

Dynamic compression with the 229 cam works out well. It absolutely requires premium and not lugging it in gear if its a manual
 

4Runner

Well-known member
May 24, 2007
660
110
Boise Idaho
I will. It will have a different cam and just some port matching as well. I don’t have much to compare it too. Even in its “ about to blow up” state it was still felt like it had more power than my 3.9. In all fairness my 3.9 has 200k and is still going strong and the 4.6 has two major rounds of engine work at 140k from the previous owner before I lost my mind and bought / rescued it.