502 upgrade/teardown the project begins...

[fasttrucker]

Ive started my upgrade this week.Ordered the new crane cam,gold race rockers,comp.springs,ect.When tony pulled the motor he found 3 burnt valves in the heads.He ordered new 2+1/4 s.s. valves then hes sending the heads out to the machine shop.I put stainless marine exhaust on last year. we will have to extend the tail pipes, so as to avoid water reversion.Iam turning my engine into a hp500. :cool: But were painting it metalic red instead of merc blue,so as to match the boat.Tony is also putting a used low water pickup/lower unit on that he has in his shop.Hes also putting a race mounting plate on that will support 1000hp. eek! Will post pictures when finished wink

[Bryan Tuvell 33ZX]

TRUCK, post those cam and head specs and get some of the motor heads opinions.
Sorry I wasn't much help, just know what I read in the books.
Best of Luck.
Bryan

[Shanghied Again]

truck, best of luck with the upgrades

[BigGrizzly]

Poodle is correct about the 502 burning valves. I can give all the reasons but my hands will get too tired. The head design is the main culprit, The next is the cam has too wide of a lobe center the third is I have mentioned before before that the block/head design runs hot on one side partially due to the raw water system, whether it be with a crossover or circ pump problem. These are the reasons I changed my heads and used a closed cooling system, BTW my son also changed the heads on his 99 454 for the same reasions. Before you guys jump in to dispute this just remember I don't spend money nor time unless it is absolutly necessary and this is NOT up to debate with me. These are facts from a guy who builds his own motors and doesn't buy them- me. I know the pain of a blown motor!

[fasttrucker]

When doing reserch for the new cam i called,DOUG HERBERT,AZ-SPEED+MARINE,TEAQUE CUSTOM MARINE.I bought my package from dino at TEAQUE.My mech.,also said this cam would be what they use when or if they replace a cam on a hp500.Dino said this is a better cam then the one that comes in a hp500....anyway here are the specs,
586-intake. 610-exhaust 112-degrees lobe-sep
deration at 50 is 226-intake+236-exhaust
CRANE CAM PART #168731

[fasttrucker]

When tony was checking the motor he found that he needs to put new bearing in the crank.A piece of trash got into them,most likely when the motor was produced.He also said he would check the circulation pump.Also hes going to replace the TIMING CHAIN.he said it should be done.

[BigGrizzly]

The cam sounds safe enough just wondering about the heads. Sounds that the tech is checking and replacing all the right stuff. I always replace the cam chaign and sprockrts when I'm in a motor too. good luck.

[fasttrucker]

Thanks for the responding.Big grizzly,others.It is tuff to spend money on this right now,BUT it has to get done.Donzi boating season is almost here. wink

[BUIZILLA]

very interesting topic..

what are the spec's of the STOCK 502 cam ??

J