Intake Manifold swap caution
Thread Starter
Drifting
Joined: Jul 2000
Posts: 1,861
Likes: 1
From: Bremerton WA
St. Jude Donor '09
Intake Manifold swap caution
I've seen a new issue today that I've never seen happen before and I wanted to share it so others can be cautious.
When tightening down an intake manifold bolt it was noted that the "post" that the intake bolt goes through started to mushroom out under the bolt as it was tightened down. This occured while using a torque wrench set at 7.5 lbs (89 in/lbs is the spec). I've never even heard of this happening before. The bolt jsut continued ot draw down and never exceeded the torque setting... no "click."
In any event, take care when swapping out intakes and retorquing them down. Just pay close attention to the bolts and how they draw down. Apparently at least one is capable of being damaged in this way.
Now, if it is too late and you have some mushrooming you can use a oversized washer to spread the load a little better over the entire surface and retighten.
Personally, I will no longer be using the torque wrench for this procedure. Simply tight will be good enough and will keep you aware of what is going on rather than simply focusing on the "click."
When tightening down an intake manifold bolt it was noted that the "post" that the intake bolt goes through started to mushroom out under the bolt as it was tightened down. This occured while using a torque wrench set at 7.5 lbs (89 in/lbs is the spec). I've never even heard of this happening before. The bolt jsut continued ot draw down and never exceeded the torque setting... no "click."
In any event, take care when swapping out intakes and retorquing them down. Just pay close attention to the bolts and how they draw down. Apparently at least one is capable of being damaged in this way.
Now, if it is too late and you have some mushrooming you can use a oversized washer to spread the load a little better over the entire surface and retighten.
Personally, I will no longer be using the torque wrench for this procedure. Simply tight will be good enough and will keep you aware of what is going on rather than simply focusing on the "click."
Burning Brakes
Joined: Jul 2006
Posts: 849
Likes: 2
From: Southern Florida
I wondered if that would happen on the Vette's too. That is a common problem with the 3.8-K motors. The higher the mileage/heat cycles the better the chance is of splitting those posts. Snug with a 1/4 inch drive is good enough for those bolts.
Thread Starter
Drifting
Joined: Jul 2000
Posts: 1,861
Likes: 1
From: Bremerton WA
St. Jude Donor '09
Originally Posted by GMautotech
I wondered if that would happen on the Vette's too. That is a common problem with the 3.8-K motors. The higher the mileage/heat cycles the better the chance is of splitting those posts. Snug with a 1/4 inch drive is good enough for those bolts.
I would agree with the 1/4 drive or simply "choke-up" on the 3/8 drive so you hand is on the ratchet point. Run it down to snug and give it just a little more. 1/4-1/2 turn should do fine in my opinion. The gaskets on these are quite thick and one need only compress them evenly to obtain a seal.
Burning Brakes
Joined: Mar 2006
Posts: 800
Likes: 0
From: Las Vegas Nevada
Originally Posted by achilds
Was that my intake you were working on?
P.S. charris85vette thanks for the advice on the intake porting I had. I installed it today and it works great, thanks again
Thread Starter
Drifting
Joined: Jul 2000
Posts: 1,861
Likes: 1
From: Bremerton WA
St. Jude Donor '09
Originally Posted by Abomination
P.S. charris85vette thanks for the advice on the intake porting I had. I installed it today and it works great, thanks again
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Burning Brakes
Joined: Jul 2006
Posts: 849
Likes: 2
From: Southern Florida
Originally Posted by achilds
Define snug. Do you mean tighten down the intake manifold bolts evenly by hand then add an extra 1/4 to 1/2 turn?
Instructor
Joined: Apr 2006
Posts: 194
Likes: 0
From: Sumner WA
Originally Posted by achilds
Was that my intake you were working on?
PS - and Cory offered to replace the intake without hesitation... I wasn't worried about it... He does great work and offers great customer service.. I would definitely do it again... especially since the mishap happened when he was installing my intake for me... should have been my job. Thanks Cory!!
Last edited by robotpedlr; Jul 10, 2006 at 12:02 AM.
Melting Slicks
Joined: Oct 2005
Posts: 2,515
Likes: 3
From: Goleta California
Originally Posted by robotpedlr
No, it was my intake...but I was right there with Cory watching and the torque wretch never clicked...the post just starting muchrooming. Luckily, I was on the other side looking in and noticed it quickly...so not a big issue. Just be carefull. The bolts are a pretty fine thread, so you would have to turn a few complete revolutions past the danger point to mess them up...just dont put your trust in the torque wrench on these...or at least not the ones that have the metal sleeves (only 6 of them do).
PS - and Cory offered to replace the intake without hesitation... I wasn't worried about it... He does great work and offers great customer service.. I would definitely do it again... especially since the mishap happened when he was installing my intake for me... should have been my job. Thanks Cory!!
PS - and Cory offered to replace the intake without hesitation... I wasn't worried about it... He does great work and offers great customer service.. I would definitely do it again... especially since the mishap happened when he was installing my intake for me... should have been my job. Thanks Cory!!
Thread Starter
Drifting
Joined: Jul 2000
Posts: 1,861
Likes: 1
From: Bremerton WA
St. Jude Donor '09
I glad you're happy, Mark. I always try hard to do the right thing. I also like to share my hard lessons so maybe someone else doesn't have to!
I was thinking more about the potential "shroom" issue. If it happened to a guy he could cut off an inch or so (however much was required) of the damaged post and simply buy a shorter bolt for it. No real harm done. Those posts are very long and don't really need to be. Cosmetically, the issue is hidden by the Fuel Rail Cover, so again, no real harm done.
Just be cautious.
I was thinking more about the potential "shroom" issue. If it happened to a guy he could cut off an inch or so (however much was required) of the damaged post and simply buy a shorter bolt for it. No real harm done. Those posts are very long and don't really need to be. Cosmetically, the issue is hidden by the Fuel Rail Cover, so again, no real harm done.
Just be cautious.
Safety Car
Joined: Jun 2005
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From: DFW This user does not support or recommend the product or service displayed in the ad to the right
Just use the proper tools, If you had used an inch pound tq wrench you would have had a click.I have found that most ft pound tq wrenches do not stay accurate at that low of setting.
Thread Starter
Drifting
Joined: Jul 2000
Posts: 1,861
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From: Bremerton WA
St. Jude Donor '09
Originally Posted by Cavallo GT
I agree. A 150 Ft. Lb. torque wrench will not be accurate below 20 Ft.Lbs. Most of them are now labeled 20-150 for that reason.
Safety Car
Joined: Dec 1999
Posts: 4,148
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From: Roxbury NJ
Originally Posted by C6400hp
Just use the proper tools, If you had used an inch pound tq wrench you would have had a click.I have found that most ft pound tq wrenches do not stay accurate at that low of setting.