Intake manifold bolts keep coming loose!

[Jayru 17]

Hey Everybody,

 

So I'm having this weird issue. I changed the stock intake manifold on my 302 to an Edelbrock performer back in the summer. Now I'm no stranger to swapping intakes, and did everything right as far as i can tell, even bought new SS bolts for the install and re-torqued after a heat cycle.

 

But the damn bolts keep coming loose! The fist time I noticed antifreeze in the oil, so i re-torqued, changed the oil and thought problem solved. But they came loose again. Re-torqued, and again they come loose! The car sits for a few days and they all loose their torque-spec.

 

Any idea why this is happening?

[bnickel 10,004]

sounds like either some kind of wierd intake gasket problem or you need to use lock washers.

[69RestoRod 10]

Use Red loctite and it should prevent this from happening again.

[Jayru 17]

Use Red loctite and it should prevent this from happening again.

 

Won't the loctite seal be broken when i re-torque after a heat cycle?

 

Also, should i have used lock washers? I've just got flat ones on there now.

 

Thanks guys!

[69RestoRod 10]

I would skip the re-torque and see if you have any problems with the combo of loctite and lock washers.

[69gmachine 15]

I would skip the re-torque and see if you have any problems with the combo of loctite and lock washers.

 

Just make sure you use the blue loctite. Red will make it hard to break them loose in the future.

[SlimeGold 69 15]

What kind of gasket are you using? Some compress quite a bit and when you first torque them down, ( like printoseal) so you have to keep going the first time to get them compressed.. Use a torque wrench so you can make sure ALL bolts are torqued to spec. Start in the middle and work out and when you get done, the middle bolts will be loose. So do it all again, then when you get done the second time, do it again and again and again ( as many times it takes to get all the bolts torqued to spec) then you should not have to re-torque or use lock washers/locktite. If you have aluminum heads, I would advise NO locktite at all and actualy you should use anti-seize on them or you will be fighting broke bolts or stripped threads when it needs to come apart one day.

Edited January 20, 2009 by SlimeGold 69

[coz 108]

I've been going through a bit of the same thing and currently have my intake off also. From what I've learned....

 

Yes to a torque wrench

Yes to having to do it several times

Yes to doing it even more often if you have aluminum heads

NO to locktite

Yes to anti-seize especially aluminum heads

Torque only when the engine is cold

No to lock washers (they will gouge the aluminum intake)

Yes to grade 8 bolts

Yes to RTV around the threads. Many intake bolts go through the head and sit in the oil galley beneath the intake. If you don't RTV the bolts oil may leak from the bolts. At least on Cleveland 4V's its that way.

 

Add regular torquing habits to your once a month walk around. Once a month I re-check my intake, header, water pump, valve cover, hinge and carb bolts. All have been found hand tight in the past.

Edited January 20, 2009 by coz

[jmlay 80]

It has been a while since I worked on a SB but the last one I worked on I had to go around the bolts 3-4 times as the intake seated to get all bolts torqued the same. Yes i would use some type of sealer/thread locker as those bolt holes are not blind.

 

Are you using quality bolts? You will have a certain amount of bolt stretch but they should do not stretch any more after they have been torqued.

 

Mike

[d.reese 13]

I'm not a engineer here, but I bet on the high heat of the block exspands the head metal futher than the SS bolt, thus allowing for the backing off when the engine reachs full temp. You don't see that on ss exhaust systems cause the metal ( bolt and nuts ) are consistent with each other.

 

SS is corrosion proof and maintains the polished look, but are most likely not the correct bolt for the application. Water in oil is not consistent either. I'd throw them away and save the motor if it was mine.

[MrD2 10]

Have you considered stud bolts with flat washers and lock nuts? MrD2

[69gmachine 15]

I've been going through a bit of the same thing and currently have my intake off also. From what I've learned....

 

Yes to a torque wrench

Yes to having to do it several times

Yes to doing it even more often if you have aluminum heads

NO to locktite

Yes to anti-seize especially aluminum heads

Torque only when the engine is cold

No to lock washers (they will gouge the aluminum intake)

Yes to grade 8 bolts

Yes to RTV around the threads. Many intake bolts go through the head and sit in the oil galley beneath the intake. If you don't RTV the bolts oil may leak from the bolts. At least on Cleveland 4V's its that way.

 

Add regular torquing habits to your once a month walk around. Once a month I re-check my intake, header, water pump, valve cover, hinge and carb bolts. All have been found hand tight in the past.

 

I guess my starting assumption was that he was following the torque sequence and knew to go around several times. That may be the only problem here. As for grade 8 bolts, they are way overkill. These bolts should only be torqued to 23 or so ft-lbs. I don't even use a torque wrench on these bolts. Grade 5 is more than enough. I use a dab of sealer on my bolts, but I'm not very consistent with what type and it doesn't seem to matter much. As mentioned by SlimeGold, If you follow the sequence and repeat until they are all tight, you shouldn't have a problem.

[Jayru 17]

Hey Guys,

 

Yes i have a Torque wrench and followed the sequence/correct torque specs.

 

I've literally tightened this intake 10+ times already and it just keeps coming lose (not even from driving, just by sitting in the garage).

 

I had used SS bolts on an old 600+ HP supercharged race mustang i built years ago and never had a problem with the intake coming lose. I've got Iron heads currently. I'm going to try Lock washers with the blue loctite. If that doesn't fix it, i guess I'm going to try new intake gaskets with steel bolts.

[coz 108]

Yeah grade 8 is an overkill - I should have stated a "strong" steel bolt. For some reason SS bolts don't stay tight in my experiences. I also have iron heads....

 

Lock washers will probably work but put a flat washer down 1st. Lock and star washers will gouge the intake.

 

Torque specs are 18-23# for the 3/8" bolts and 21-25# for the 1/2" bolts.

 

Blue loctite is a waste. The heat will eat that up in a heartbeat. I used blue on my valve cover bolts. Worked great until I ran it for 5 minutes.

 

Not to overlook the obvious - are these the correct length bolts? Too long/not long enough may be the problem.

[bnickel 10,004]

i also wouldn't use loctite either, if it's teh gasket squishing more than it should then using loctite could make the problem worse, the bolts may be tight but the intake may not be. if you really want to find out if it's a gasket problem or a bolt problem torque the intake bolts down and mark them and the intake with a sharpie and see if they bolts have moved after a couple of heat cycles

[Jayru 17]

Well, it seems all the re-tightening over the past months have finally just screwed up the gasket. I'm getting a lot of antifreeze in the oil now, even with the bolts torqued/tight.

 

Guess I'm going to have to re-do the intake gasket when the weather warms up a bit. Hopefully i don't have the same problem after it's done again.

[bnickel 10,004]

i'm betting that the gasket was the problem all along. quick question, though, do you know if the heads or block have ever been milled? if they have maybe the intake needs to be milled to match

[d.reese 13]

Jayru,

 

You state SS bolts, I've been reading up on 'em and found out that if they ar grade 2 or less , then you can have problems. You need to get a set of ARP's to cure the problem after replacing the gaskets! They are grade 8 or better. The cheap one's don't stop stretching.

 

But I've been wrong before!!!!!!!!!!!!!!

[Jayru 17]

Jayru,

 

You state SS bolts, I've been reading up on 'em and found out that if they ar grade 2 or less , then you can have problems. You need to get a set of ARP's to cure the problem after replacing the gaskets! They are grade 8 or better. The cheap one's don't stop stretching.

 

But I've been wrong before!!!!!!!!!!!!!!

 

I bought a cheap set of Summit SS bolts. Maybe it was the bolts stretching.

 

I think i'm going to buy these, what do you guys think?

 

http://store.summitracing.com/egnsearch.asp?Ntt=arp&N=700+4294892120+4294908331+4294840126+115+302685&autoview=sku&Ntk=KeywordSearch

[SlimeGold 69 15]

Also make sure you get the right gaskets for the year model heads you have. Late model heads have bigger water ports and use gaskets with large cut-outs to match. The newer style gaskets will not seal on older heads and leak water. I have made that mistake before and ordered gaskets for a late model 302 thinking they all are the same but... no. They leaked on my 69 model heads and no amount of tighting the bolts will help. Look at the pic I added. These are a no-no for 76 back stock 289-302 heads.

Edited February 4, 2009 by SlimeGold 69

[69gmachine 15]

I bought a cheap set of Summit SS bolts. Maybe it was the bolts stretching.

 

I think i'm going to buy these, what do you guys think?

 

http://store.summitracing.com/egnsearch.asp?Ntt=arp&N=700+4294892120+4294908331+4294840126+115+302685&autoview=sku&Ntk=KeywordSearch

 

If you're stretching a bolt with 23 ft-lbs of torque they would have to be made of plastic! C'mon guys. 23 ft-lbs is the max you can put on the bolts without lifting the heads, so you really need to keep it closer to 20. Maybe the SS bolts are just not able to get a good grip. Toss 'em and try regular bolts from the local hardware store.

 

Even though you are following the correct sequence and torque value, do you start over and repeat until they stop feeling loose? If you don't continue to repeat the exercise until they all feel snug, you haven't followed the advice given previously. It's a critical part of the success criteria.

[69RavenConv 286]

If you're stretching a bolt with 23 ft-lbs of torque they would have to be made of plastic!

 

I have to agree. Are you sure the intake isn't warped? Are you using proper washers on each bolt to prevent them from gouging into the aluminum intake? Something's fishy....

[Jayru 17]

It was a brand new intake from Edelbrock. I've replaced intake manifolds on various 302's at least 60 times in my lifetime. So i definitely know how to torque them. And yes, i follow around and around till they were all properly torqued.

 

It's a smog motor out of a 79 granada, and i ordered the intake gaskets as such. I don't think the intake (Edel performer), would have a problem bolting to these heads. Unless i'm missing something somewhere, it should have all worked just fine.

 

I'm just gonna do it over with fresh ARP bolts and gaskets and see what happens i guess.

[69gmachine 15]

Try using a softer gasket (like the Fel-Pro 1262 IIRC). The stock replacement gaskets don't have much give to them and work better on an iron intake.

 

I didn't mean to insult your intelligence, I just wasn't able to tell from your post if you went around multiple times. Good luck with the next gasket set!

[Jayru 17]

Try using a softer gasket (like the Fel-Pro 1262 IIRC). The stock replacement gaskets don't have much give to them and work better on an iron intake.

 

I didn't mean to insult your intelligence, I just wasn't able to tell from your post if you went around multiple times. Good luck with the next gasket set!

 

No worries! Thanks.