new build with some questions

We may earn a small commission from affiliate links and paid advertisements. Terms

Magana559

Magana559

The Warden
I have a p75 head that was ported and polished by JG engine dynamics with oversized 31.5 millimeter intake valve and 28 .5 exhaust valves. So my question is I'm going to have to replace the valve guides on this head and might have to replace the valve seat. So if I have to replace the valve seats can I replace the valve seats with the valve seats of a p8r b20 head that uses 33mm intake valves on my p75 head?

Also will this affect the port flow in a bad way if i was to change the valve size?

Engine is going to be a 82mm 13:1 comp with my full built ported ls head with forged pistons and rods running on e85 with crower 405 cams.
 
Hmm not sure- maybe you have to weld in the seats a little? Possibly too large for your valves? Or just go to 33mm valves?
 
Thats what I'm trying to do. I want to know if p8r valve seats (33mm) will fit in a p75 LS head. If they can I can do 33mm valves (same size as VTEC)
 
14711-PH3-000 as close as I can get but this one is 104.4 ol and LS valve is 105.5 ol.

I'll give a valve place a call see if they can stretch one for me (custom valve).
 
No I have a jg P&P head with 31.5mm intake valves. The p8r has 33mm intake valves (same size as VTEC head) so I was wondering what if I dropped some p8r valve seats and valves in a p75 head would I gain flow and velocity?

I would also want to know if the p8r and and the p75 use the same valve diameter and same valve length.
 
Also according to sivalves.com the prelude 2.0 has the 33mm intake valve same ol length and same valve steam diameter of 6.6.

I need a spec sheet to see if they are interchangeable.
 
Ask some head porters? I'm sure they've been asked to fit large valves into heads- I don't think they'd refuse to tell you if it could be done since they'd stand to gain your business if you ended up thinking it was too difficult to do yourself. ;)
 
Problem is the best guy in town is a older guy and hasn't been seen in a while and he did awesome porting and polishing and had his own flow bench.
 
Close this thread project abandoned, too much money and nobody wants to try it unless the head is stock. Uhhh I'm done I'll just stick with 31.5mm valves.
 
God forbid these shops mic stuff up and make something work. They don't know who JG is and are probably worried what exist and how it might make them to blame if it don't last.
 
[OTE=Calesta;17]:( Did you talk to the shops?[/QUOTE]



Dude it was like talking to monkeys or special ed machinist......"uuuuuuhhhh if the head flows why do you want to mess with it" because i want more flow you idiot!

"Im not going to take a chance destroying your head, if you want, bring in a stock head and we can try it" if I want to take the risk let's do it! lets try to give these guys with ls heads a chance to make the head flow better without going vtec.
 
CAFROG said:
God forbid these shops mic stuff up and make something work. They don't know who JG is and are probably worried what exist and how it might make them to blame if it don't last.
Click to expand...

All three guys noticed the three jg stamp and said " that's a great head because it was done when good jg was great" when jg went bad it was a hit after they started stamping JGE
 
You must log in or register to reply here.
Back
Top