Holy crap-a-mundo I guess it is possible given a long enough bolt. Looks like I dropped the ball on this one. Nice photo shot EastCost 
Intake manifold bolts?
Thread Starter
Burning Brakes
Joined: May 2010
Posts: 840
Likes: 4
From: High Point NC
Intake manifold bolts?
I changed the intake manifold gasket on my 90 L98 this week. When I went to put the intake manifold bolts back in I noticed that there were 2 different lengths of bolts. Of course I didn't notice this when I took them out so I had no idea where the longer ones went. I guessed and put one longer one and one shorter one in each location then torqued them in the pattern that the FSM said to.
Now when I fired it up it seems like something is binding up. It idles along and there will be like a pop/bang noise.
Is it possible that the longer bolts are in the wrong location and interfering with the pushrods?
Thanks,
Jeff
Now when I fired it up it seems like something is binding up. It idles along and there will be like a pop/bang noise.
Is it possible that the longer bolts are in the wrong location and interfering with the pushrods?
Thanks,
Jeff
Advanced
Joined: Jan 2010
Posts: 90
Likes: 4
From: Henderson Nevada
I did my 90 intake over the summer. If memory serves me right the longer bolts go on the outer corners of the manifold and are also torqued a little more to seal the front and rear of the manifold.
I dont think they were long enough to hit any pushrods or anything though. did you check you timing? just a thought
I dont think they were long enough to hit any pushrods or anything though. did you check you timing? just a thought
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
Why did you change the gasket in the first place?
Your sure you got the distributor has been fully dropped back in on the "correct" tooth?
Oil pressure is good?
Wires on the dizzy are correct?
Checked the base timing?
Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
It is possible. I had that issue when installing mine the fist time. the shorter bolts go in the middle if I remember correctly.
Instructor
Joined: Jun 2008
Posts: 138
Likes: 0
From: Bridgewater Ma.
I changed the intake manifold gasket on my 90 L98 this week. When I went to put the intake manifold bolts back in I noticed that there were 2 different lengths of bolts. Of course I didn't notice this when I took them out so I had no idea where the longer ones went. I guessed and put one longer one and one shorter one in each location then torqued them in the pattern that the FSM said to.
Now when I fired it up it seems like something is binding up. It idles along and there will be like a pop/bang noise.
Is it possible that the longer bolts are in the wrong location and interfering with the pushrods?
Thanks,
Jeff
Now when I fired it up it seems like something is binding up. It idles along and there will be like a pop/bang noise.
Is it possible that the longer bolts are in the wrong location and interfering with the pushrods?
Thanks,
Jeff
This is how I organized my bolts...
This is a close-up off cyl. #4. The exhaust pushrod sure is close to that bolt hole. 1 & 5 exhaust look tight also.
If it were me, I'd tear it down and install the bolts correctly. GM used long and shorts for a reason.
I did my 90 intake over the summer. If memory serves me right the longer bolts go on the outer corners of the manifold and are also torqued a little more to seal the front and rear of the manifold.
I dont think they were long enough to hit any pushrods or anything though. did you check you timing? just a thought
I dont think they were long enough to hit any pushrods or anything though. did you check you timing? just a thought
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
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Interesting. The intake-to-head bolts on my 89 were all the same length (1 1/8"). There was a thread that pointed out if 1 1/4" bolts were used, contact with the push rods holes would occur. And, that contact would be on the center two holes on each side.
If you had shorter bolts, it seems like they should have gone in the middle.
If you had shorter bolts, it seems like they should have gone in the middle.
Thread Starter
Burning Brakes
Joined: May 2010
Posts: 840
Likes: 4
From: High Point NC
I'm thinking I might just pick up 12 3/-16x1-1/8" SS allen head screws and swap them out one by one so I don't mess up my seal.
Any opinions on if I might have messed anything internal up?
Any opinions on if I might have messed anything internal up?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
When GM redesigned the heads to accept intake gasket retainers, they made the outer water jacket bolts longer. Didn't think any of those heads or gaskets made it onto anything other than the '91. If you take it back off, see if the outer bolt holes on the heads are counterbored for retainers. If so, that's where the longer bolts go and you should use the gaskets with the retainers as they maintain perfect intake gasket alignment which stops most of the leaks.
Safety Car
Joined: Jan 2004
Posts: 3,759
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There are some guys who replace the stock GM intake bolts with some ARP bolts. As alot don't like torx type bolts GM liked to use.
One thing you could do is get a C4 parts catalog and see what intake bolts call for a different part number.
One thing you could do is get a C4 parts catalog and see what intake bolts call for a different part number.
Race Director
Joined: Feb 2004
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I did my 90 intake over the summer. If memory serves me right the longer bolts go on the outer corners of the manifold and are also torqued a little more to seal the front and rear of the manifold.
I dont think they were long enough to hit any pushrods or anything though. did you check you timing? just a thought
I dont think they were long enough to hit any pushrods or anything though. did you check you timing? just a thought
Safety Car
Joined: Jan 2004
Posts: 3,759
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I say you'll have to chase the threads and put new sealant on the bolts. I'd look to see what ARP bolts others are using for their intake bolts.
Le Mans Master
Joined: Aug 2007
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From: WV
When I put the intake on my 383 about 4 months ago I ordered new intake bolts from GM and they were all the same size from the factory.I also have a set of Summits intake bolts with hex heads and they measure 1" instead of the GM length which are 1"1/8..You may be able to replace them one at a time like you were saying. I would start in the middle and work my way out just like the tightening sequence,just remember to redo the sealent on the threads..You really have nothing to lose, if it leaks then you can replace it. ..WW
Last edited by WW7; Oct 6, 2010 at 08:58 PM.
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