Re: 502 mag efi rebuild
 

I scrapped the stock fuel pump ,vst and all the other garbage feeding my efi,ran a -10 from tk to larger than stock filter into a large inline sx pump,runs through a fuel cooler thats actually a small oil cooler. Drilled out fitting holes on efi rail,threaded and plumbed with twin -8 hoses feeding it. Ran 2 tees out of fuel pump,2 of lines are ones feeding rail,third goes to bypass return regulator to suction side of pump. If you re-design fuel system and change the pump,don't try to run new pump off old pump wires in harness,instead use the power wires to energize a nice hd relay,Smitty

Re: 502 mag efi rebuild
 

Boatally Insane

Listed are the 3 camshafts in question. These EFI motors like high vacuum and strong intake signal, so overlap must be kept to a minimum. Of the two choices available to reduce overlap, pulling duration out of the cam would have a greater impact on performance than spreading the lobe sep, hence the LSA of 114* and 115.5*
502 HP carb
284/292.... 222/230.... .576/.598 110

502 EFI
292/298.... 230/236.... .598/.610 114

502 Mag MPI
................224/224.... .483/.483....115.5
The carb Crane recommended was essentially the HP 502 with the LSA spread from 110* to 114*
Bob

Re: 502 mag efi rebuild
 

Boatally,
Specs on the 525 EFI camshaft
298*/306.....*236*/244......610/.632.....114*
Bob

Re: 502 mag efi rebuild
 

502 HP carb
284/292.... 222/230.... .576/.598 110 ........ is this right the LSA at 110 on this came ????

Re: 502 mag efi rebuild
 

Crane spec'd that cam with a 114 LSA because I'm running Revolution Marine Manifolds and short risers with Captain's Call, and didn't want any reversion issues. I certainly wouldn't mind going bigger if I can. My two limiting factors are definately the EFI system and my exhaust but I don't want to give up either one..so could I get away with more cam?

Thanks,


Doug

Re: 502 mag efi rebuild
 

Rob,
Here is the cam card. Even though it's on a 110* LSA, becase of the relatively short seat duration it has 64* overlap as compared to the 731s 69*.
http://www.cranecams.com/?show=brows...11&lvl=2&prt=5
Bob

Re: 502 mag efi rebuild
 

It looks like Merc is using the Gen VI 731 on 114s for the 500EFI and the Gen VI 741 on 114s on the 525, correct?
Will the MPI intake support the hp this combo is going to make?
Also, beings you have just kissed off the decks are you considering using the Cometic .027 gaskets to improve the squish area and bump the CR a tad?
Thanks,
Dave

Re: 502 mag efi rebuild
 

So the 525 cam is a 741 with a 114 lsa.. I wonder if the 741 Crane would make much diferance between the 112-114 lsa

Is the 731 close to what came in my 500efis?


Rob :D