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Barry Eller
05-11-2007, 07:51 PM
I got my heads back from the machine shop today. I will be installing my new camshaft, and installing the heads this weekend.
My question is there any difference in the torque (90 ft lbs) on a gen IV 502 and a gen VI? My manual is the OMC 1985-1995 edition.
Also do you torque the head bolts in the same order with both engines?
I scanned the page on the sequence, but its not very clear. If anyone has this information, I would appreciate your input.

mrfixxall
05-11-2007, 10:25 PM
that pattern looks funky,,,your soppose to torque in a circle,start at 30,go through the pattern,then 60 go through the pattern then 80 ythen done..make sure you seal the head bolts with some sealer or ti will leak water into the oil... and seal the intake bolts as well.BTW what happened to all the materal from the old can? i bet if you drop the oil pan its stuck to all the bearings..Just hate to see you have to pull the engine a little later and redo the bottom end because of no oil pressure..Also look at the cam bearings metal may be stuck to them to..

try this http://www.jerrysmarine.com/cgi-local/show_page.cgi?page=634

Barry Eller
05-12-2007, 07:43 AM
Thanks mrfixxall. I have 16 head bolts, your diagram shows 13 and a different bolt pattern altogether. My bolt pattern is just like the one in my manual. The sequences do start in the middle, and yes I know to torque in steps.

The camshaft damage was a result of "Lifter Bounce". The damage did not grind down any lobes, just restricted to the back side of the lobes. Very little debris in the bottom of the pan, none in the oil strainer and not much in the filter. I have had the cam bearings, main bearings and connecting rod bearings inspected. They are fine. Washed and cleaned entire bottom end and reassembled and re-torqued. I used "Spectro Assembly Lube" (thanks Ken).

The reason the push-rod broke and the other push-rod went through the rocker arm was a result of "Coil Bind". The valve springs were too weak for the camshaft lift.

f_inscreenname
05-12-2007, 07:58 AM
Always, always, always change springs with a cam upgrade in these B/B's.
The springs that come with them is barley enough to cover the cam they install but I guess you know that already.

BigGrizzly
05-12-2007, 08:05 AM
The pattern is correct! The 30deg pattern id good is you don't have the proper torque specs. Follow it!

Barry Eller
05-12-2007, 08:15 AM
The pattern is correct! The 30deg pattern id good is you don't have the proper torque specs. Follow it!


Hey BigGrizzly, is 90 ft lbs on the 502 correct, like my manual says?

f_inscreenname
05-12-2007, 09:35 AM
Hey BigGrizzly, is 90 ft lbs on the 502 correct, like my manual says?
For my 454 its 80lbs. Its kind of strange it would be different. A B/B is a B/B

scott snider
05-12-2007, 10:35 AM
I use the torque sequence that you displayed. Also don't use sealer on gen V or VI blocks they are different then the mark IV blocks they have blind holes and don’t go into the water jacket, it is possible to get incorrect torque readings with sealer on the bolts. Because the blocks have blind holes make sure you use the correct head bolts if you use bolts that are to long you can ruin the block. Just use some oil or assembly lube on the threads. Good Luck

mrfixxall
05-12-2007, 11:26 AM
Hey BigGrizzly, is 90 ft lbs on the 502 correct, like my manual says?


I see what you mean in the pic:bonk: i would torque them at 80 ft lbs,,even at that torque it feels like youe pulling threads out of the block..

Barry Eller
05-12-2007, 11:45 AM
I just got the numbers from the GM Tech manual here at work

On 8.2 GM engines

First pass 30 lb ft

Second pass 59 lb ft

Final pass short bolts 89 lb ft

Final pass long bolts 92 lb ft

The difference is due to the larger bore of the 502 vs 454

BigGrizzly
05-13-2007, 10:16 AM
I assumed you knew about torquing up gradually on multi bolt patterns in no way do you put all the torque on at once. As for the spec being different on the 502 vs 454, yep. however I do 454 with 502 specs on a rebuild but always use new bolts.

p729lws
05-13-2007, 07:12 PM
Yippy-kai-yay fother mucker

http://www.break.com/index/bruce-willis-drunk-at-nba-game.html

I'll see ya Tuesday for a run on the bay if the weathers good.

Dan

Barry Eller
05-14-2007, 06:14 PM
Yippy-kai-yay fother mucker
http://www.break.com/index/bruce-willis-drunk-at-nba-game.html
I'll see ya Tuesday for a run on the bay if the weathers good.
Dan

I may have to go to the movies next month.

Give me a call if you are out and about. Or come by the house and I'll put you to work on the 502!

YIPPY-KAI-YAY ....What he said !:yippie: :cussball: :cussball:

p729lws
05-14-2007, 09:54 PM
Give me a call if you are out and about. Or come by the house and I'll put you to work on the 502!
YIPPY-KAI-YAY ....What he said !:yippie: :cussball: :cussball:

I'm leaning toward running the 22 in the morning. I'll shoot you an e-mail from the office either way to confirm.
Dan