28Eliminator

It finally happen. I was thinking it was time for a rebuild.
I installed the whipple at 260 hours, and now I have 450 hours on the 97 Gen VI 502 MPI. First day on the lake for the season and we went for a swim. When I started the thing up, it was missing and ticking. I tore it apart on Sunday and found about 30 pieces of machined metal was imbedded into the piston. Further inspection showed that a valve seat was missing. Ironicaly, it happened to be #7. The valve was still intact, LUCKY:

Well now I have to rebuild this thing. I hauled it the machine shop and we will see what is all bad. The cylinder looks ok, but the head is pretty beat up. They are going to check the head for cracks, and they told me that they could clean it up if it wasn't cracked. They will also check the crank and rod. The basic gauges checked ok while under way, water pressure = 18-20, oil = 50, fuel = 40.
My plan right now is to rebuild the whole motor so I am back to a reliable power plant. So I am looking for advise as to what I should have them do, and what I should replace. I am somewhat limited to upgrades unless I reprogram the MEFI 1 computer and probably upgrade the fuel system.

1. New pistons & bored if needed, Obviously 1 new piston
2. rings, what type
3. bearings, what type
4. What about ARP rod bolts and recon the rods?
5. timing chain, oil pump
6. valve springs
7. retainers/keepers
8. Ferrea Extreme Service exhaust valves
8. I was thinking new Comp Cams roller rockers, ARP studs
9. What about new roller lifters?

Any additional input on parts to get and also part numbers for the Crane springs and associated parts would be appreciated. I know the GM pn.12495514 is stock, but should I change to something else, or just use those with 110 pounds seat pressure.
I read a post that said to have a new seat pressed in with .004 of press, because normal auto seats are pressed in with .002 and won’t last in a marine engine, or replace the heads with new ones.
What should tell them to use for seat width? Intake .080 & Exhaust .100

Sorry for the long post, but I have lots of part numbers to find, and I want this done right, so I am reliable again. Thanks, Rockie

kennyo

All those sound good. I did all that and put the "741 Crane cam" in mine.The stock roller lifters worked on mine but be sure to check them closely. I bored it and used JE pistons. Make sure who ever builds it uses enough clearance on the rings. It is quite a bit larger gap being a marine and SC application. If your heads are fried do a search on here and get recommendations. MIne sounded so much better, it scared the sh*t out of me when it started!

28Eliminator

kennyo, Did you have to get your computer reprogramed at that time? Assuming your motor is an efi with a supercharger?

Deltarat

I noticed your in Rapid, my mom has a place up in Silver City.

28Eliminator

That's cool.
I mean way up in the hills where the water stays cold all year. The lake is very picturesque and I have been boating at the lake (Pactola), but the water is like 70 deg in July.
http://www.silvercitysd.com
Does your mom live there, or is it a vacation place.

Deltarat

She lives there, I try to get out on Pactola at least once a year. I always make Sturgis though. How far are you from there? What a cool web site, in the picture from the 1920s you see nothing but the Church. Her cabin is right next door to the Church. I will have to post some pic tomorrow from our trip out last summer. Hey if you have young kids let me know when you go up to Pactola and I will get my mom to open up the old School house for them, you would not believe it but they still have all of the old School books and stuff in there.

28Eliminator

I live in Rapid City, and graduated high school in Sturgis. I have a place at Angustora Reservoir south 50 miles. That is where all the Hot boats and most of the locals go boating. My buddy is having a new 33 Eliminator cat built that will have 2 1500 HP motors. It should be a wild ride, and should place high at the race in LOTO this year.
If you get out here this year and stop by the lake, I would be glad to give you a cruise around the lake. Just ask any of the hot boat guy's for me and they will point you to my direction. We all know each other.

Big Block Billy

Was that seat done in a shop ?
They could have dropped the ball and machined the head without enough crush fit. BBB

Big Block Billy

those 502's had mucho problemos, and alot of valvetrain issues. I wouldn't be suprised with anything that goes wrong with them... BBB

28Eliminator

So what are you saying BBB? Should I look at getting different heads.
I have been trying to figure out if a shop had replace that seat. The last time I had it apart, I had new intake valves installed, but I looked at the documents and there were no seats replaced. When I installed the Whipple I replaced the head gaskets and I had a valve job done, but I don't remember if there was a reason to replace a valve seat. I do know that this machine shop didn't do what I told them for seat width and that is why I had to get them redone a second time, so they will never get my work again. Are these installed at the GM factory, and maybe not the best for Marine use.
Maybe I should have them replace all of the Exhaust seats, since I am using a supercharger.

This is the type of info I am looking for. What should the crush fit be? .004 is what I read on another post.
What is the normal crush that machine shops use for auto applications. Also what seat width should I have them use? .100 or.120