1996 4.3 gen+ broke intake bolt

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fen-isl

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So was putting engine back together today, chased the threads, and cleaned threads on bolts, applied Mercury quickseal to threads installed new intake gaskets and gray rtv to front and rear. Specs call for intake bolt torque to be 35ft lbs, either my torque wrench is bad or the bolts are weak, any way #1 broke off in the head, I quickly pulled apart and cleaned the rtv off block and gasket, and by some miracle was able to take it out with my fingers( no tools needed)........... My question is did I trash the new intake gasket, it was 80.00, or is safe to use after I get all new bolts from merc?? When I was tightening, i did it in a 2 step process, the wrench wasn't clicking so i tighten all of them pretty tight, then started to go back around again and that's:confused: when #1 broke off. so the gasket was compressed but it looks ok just wanted some opinions.:facepalm:


1996 mercruiser 4.3 Gen + 0f824941

Thanks Rich
 
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HT32BSX115

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Re: 1996 4.3 gen+ broke intake bolt

fen-isl said:
So was putting engine back together today, chased the threads, and cleaned threads on bolts, applied Mercury quickseal to threads installed new intake gaskets and gray rtv to front and rear. Specs call for intake bolt torque to be 35ft lbs, either my torque wrench is bad or the bolts are weak, any way #1 broke off in the head, I quickly pulled apart and cleaned the rtv off block and gasket, and by some miracle was able to take it out with my fingers( no tools needed)........... My question is did I trash the new intake gasket, it was 80.00, or is safe to use after I get all new bolts from merc?? When I was tightening, i did it in a 2 step process, the wrench wasn't clicking so i tighten all of them pretty tight, then started to go back around again and that's:confused: when #1 broke off. so the gasket was compressed but it looks ok just wanted some opinions.:facepalm:


1996 mercruiser 4.3 Gen +

Thanks Rich
Click to expand...

Howdy,


I wouldn't hesitate to use the gasket over (use a thin bit of RTV again on both sides)

Also, I would probably just replace the bolts and get a new torque wrench!

Someone (YOU!) might have previously severely over-torqued those bolts! (35 ft-lbs is not a LOT of torque and should not break them)

Regards,


Rick
 
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fen-isl

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Re: 1996 4.3 gen+ broke intake bolt

Thanks Rick, I have never tightened them before. Will definitely get a new torque wrench, as for the gaskets they are aluminum with green silicon sealant, no extra sealant should be required except for the front and rear. I did a Google search and found a Mercruiser Service bulletin, #97-1 It came up on another boating forum but its states that the torque needs to be done in 3 steps and the final torque is 133 lb. in. which if i did it right basically equals 12ft lbs???????

Torquing Intake Manifold on Gen+ Engines

All V6 and V8 Gen+ Engines

Situation

The intake manifold on all Gen+ engines use a special torquing procedure. The following procedure
must be used whenever an intake manifold is installed. Failure to follow this procedure could cause
the intake manifold gasket to leak coolant into the oil or on top of the manifold.

Torquing Procedure

Torque the intake manifold bolts in 3 steps and in sequence shown below

1. 27 lb. in (3 N.m)

2. 106 lb. in. (12 N.m)

3. 133 lb. in. (15 N.m)



Thanks Guys, any input welcome
 
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Re: 1996 4.3 gen+ broke intake bolt

Why take the chance ruining a engine??? Since you've already tightened them once buy a new gasket.
 
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fen-isl

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Re: 1996 4.3 gen+ broke intake bolt

Glad to see you guys have a sense of humor!!! As for the gasket I ordered one yesterday it should be here on the 29th. Also ordered all new intake bolts since I obviously cant read the difference between ft lbs and inch lbs. So I cost my self 160.00 for gaskets and bolts, those dam bolts are expensive at 7.95 each plus shipping (the head bolts were only 5.45 each) and the gasket was 82.00 shipped, but Hey I learned a lesson, don't rush it.

Thanks for all the advice

Rich
 
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