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Discussion Starter · #1 ·
Hi there. Had the boat out this weekend and had an interesting thing happen. After about 2 hours of running up and down the river, one of the intake manifold bolts backed completely out and left a small pool of oil in the valley of the intake right under the bolt.:confused: It's an Edlebrock Aluminum intake. The bolt next to it was finger tight. I never lost oil pressure, there was no water in the oil, and the engine ran real smooth the entire time.

The prior owner told me the engine only had between 20-30 hours on it when I bought it and I've only added 4 hours max of running time on it since the purchase.

From what I was told, the head or intake bolts were never re checked/re torqued since the rebuild. Given what happened above I think it might be a good idea to check them and that is where the question comes into play.

Can anybody tell me the torque specs and pattern for the head bolts, and intake manifold bolts?

Like the title says, it's a 7.4L 454 big block. Thanks.
 

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Discussion Starter · #3 ·
Not sure. I'll take a pic and post it in a bit. I was told the engine was rebuilt by Bucket Marine in LHC. It didn't look like there was any type of Lock-tite on the threads.... then again the oil coming out might of hidden that.
 

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E-7 Sheepdog (ret)
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From my "Performance Rat Motors" book:

Timing Chain Cover: 75 inch pounds (6 foot pounds, divide by 12)
Oil Pan to timing chain cover, 80 inch pounds
Valve Cover, 25 inch pounds
Oil Pan, 13 foot pounds (165 inch pounds)
Intake Manifold: 25 foot pounds, use oil or anti-sieze on Al. heads
Water Nerck (thermostat) 20 foot-pounds (anti-sieze)
exhaust manifold: 20 foot pounds (anti-sieze)
bell housing 30 foot pounds
water pump inlets, 30 foot pounds (anti-sieze)

cylinder head:
long bolt, 75 foot pounds, waterproof sealant (I use pipe thread dope)
short bolt, 65 foot pounds, sealant
Alum. head valley stud, 55 foot pounds, sealant
GM head stud, 65 foot pounds
rocker arm stud, 50 foot pounds (lubed with oil)

There is also a torque sequence, for heads and intake manifolds.
There is an exact sequence, but, IMO this will do:
Torque the 2 center fasteners (1 each side on an intake, 1 long & 1 short on a head)
Go to next fastener set either fore or aft and torque those 2.
Now go opposite direction, to other side of center, and torque THOSE 2 (6 total done now)
repeat the swap ends/jump/torque untill all 16 are tight.

Basically, as you see, torque center down and progressively pull the ends down with it together.

Let sit overnight, re-do the next day, re-do the NEXT day (insurance).

Now re-check/do after the next engine run, I doubt they will move after this.
 

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E-7 Sheepdog (ret)
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I used flat bearing-surface washers on my Al. manifold, then split-ring lockwashers against the bolt head, never had any issues with them working loose, in 4 years.
 

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Boat Nut
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ARP bolts use the J thread bolt, and washer to keep them put. If using a standard bolt, then lock washer is needed.
 

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Discussion Starter · #7 · (Edited)
Smokin thanks for the specs, that should do the trick.

As far as the bolts that are in there, they look like pretty basic intake bolts with the built in flange/washer on the head. I didn't find one that had any visible silicone or lock-tite on them so that would probably explain why it backed out. It was the first time I was anywhere I could really run WOT and of course I had to try to show up the friends in their newer boats so I figure if nothing else it was a good shake down run. Just glad I caught it before it came all the way out and covered the engine compartment with oil.

I took the intake off pretty much out of curiosity. I can't tell if the intake and heads have been match ported or polished slightly but they do have etching in them where it looks like someone did some work. Then again I have never torn apart a big block so for all I know it's stock.

Another question for you. On the passenger side their is a PCV valve on the Valve cover and on the driver there is a blank copper tube (looks like a gutted PCV valve) connected to a hose that runs back up to the carb. I notice that there is oil all the way up the hose and feeding back into the top of the carb. When i took the spark arrester/air cleaner off the top of the carb I could see a visible film of oil on the carb. Is that normal in a boat motor to have that much oil in there? Like I said, the engine runs great, but I did notice at the end of long runs it's blowing a litte smoke. I didn't notice it at start up. Should I replace that blank pipe with another PCV or filter, or is that normal?


Figured I would post some engine porn pics just for fun.
 

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