Re: 500 EFI Power Increase
 

Knock sensor looked OK. Well, it was there. I plugged the computer in to the Diacom software and did not see any error codes. I think I will just replace it for as hard is it is to get to.

First motor is complete other than I had to order longer push rods.

After porting the heads the chambers cc at 122. I milled the heads .050 to get to 112cc. I used a .027 Cometic head gasket that got the final compression to 9.38. That should keep the pump gas in good check.

I was thinking after milling that much off the heads and a thin head gasket, I would have to cut off the side of the heads to get the intake to line up. These 500EFI intakes are like some of the blower intakes, They seem to be setting way down on the heads and were border line needing a 1/8" gasket. The intake lined up with the 121 gaskets without any reaming.

The lifting lugs can not be used because they use the bolt hole over the intake ports that Dart and other aftermarket heads do not provide.

I had to get .100 longer intake pushrods and .150 longer exhaust push rods to get the rocker back in the center of the valve tip.

I got Mark @ Precision to recalibrate the ECU's. Also I will be getting the second motor dyno'd the end of next week or the first following by MDG in Maryland. He is set up for Marine dyno work. That will tell me if I what I got from the mod's made.

Re: 500 EFI Power Increase
 

It is amazing how much we got done without the (Saturday Crew) Keep me informed on when you are going to dyno the motor I really want to go.

James

Re: 500 EFI Power Increase
 

Linnie Whats your deck height .Did you figure out what might caused the head gasket prob?Are you changing enything else ?


I think I am going to have to cut the the intake face on mine with the blower intake ?Mine is moving real slow :(

Rob

Re: 500 EFI Power Increase
 

Rob,
The deck is about -.020, which is standard for a 502 from the factory. I do not knot know for sure why the head gaskets did what they did. I assume it was from being just too old. When I pulled off the gaskets they were mush. I think water had been leaking into the cylinders very slightly. The GM head gaskets are really not that good for too long in a boat. Everything else was good.

Push rods fit perfect today. Just finished porting the second set of heads tonight, going to the shop tomorrow. First motor will be back in on Saturday and will fire it up. I will be tearing down the second tomorrow night to get the block honed. Will try to get more pictures.

Lets see some more posts of yours. You had a lot more to fix than me.

Later

Re: 500 EFI Power Increase
 

That reminds me I have to get a push rod length checker for the BBC.Post some picks when ya get a chance .

Linnie your moving real fast. I am kinda of slow ,but been waiting on parts and just started back on it.The blowers just showed up after being paid for for 2 months. It should come along now.I have been taking a bunch of picks and will start back to posting soon.

Let us know how the first motor does and good luck

Rob :D

Re: 500 EFI Power Increase
 

First Motor installed

Pictures of the Igloo.

Same Head gasket problem on second motor

Re: 500 EFI Power Increase
 

Notice the other head on the second engine Two valves look real white, abnormal for a EFI motor.

Pictures of parts,

Pictures of new heads assembled.

Re: 500 EFI Power Increase
 

hey linnie you know where a guy could get a nordic flame trailer for the weekend????

Re: 500 EFI Power Increase
 

Linnie that one head looks like it was blowing inbetween all the chambers? I wonder if head temp might of gotten them ,do you have a water presure gage?I am guessing :eek:


You said you were going to dyno them?

Rob

Re: 500 EFI Power Increase
 

No water pressure gauge. I do not have any water temperture problems. I have nose cones with low water pickups right under the point. I installed 120 thermostats per Marks request.

Both engines were in the same shape. They probally would have gone futher with better head gaskets. The rings in both engines seemed to be not buring oil bad but seemed wore out. When rolling the motor over, you could not hear them drag at all. I installed the Speed Pro standard tension moly file fit rings.

I want to start the first one this Wednesday afternoon if weather permits.

Second motor will be completed this weekend. Hope to get to the dyno on next Tuesday or Wednesday. 7-8 days. I decided to dyno the second motor since he was backed up a little. We head to Sarasota on March 26 for a week. Time is getting short so I have to keep moving.