Intake bolt problem

[llama man]

I was changing intake manifolds yesterday and was going through the second torque sequence when one of the bolts went slack. I pulled off the manifold to discover that a female threaded boss on the block had cracked. The top 1/4" was off. I am guessing that the bolts were a bit too short. I am planning to use bolts that are 1/4 to 3/8" longer. Any other suggestions? Would JB Weld work in putting the broken pieces back on?

[ERA Chas]

Originally Posted by llama man

Would JB Weld work in putting the broken pieces back on?

There's a good chance it would-worth a try. It takes threading very well if mixed right and allowed to harden.

Aluminum welding is better but more costly.

[madmaxx]

When I was getting some polished SS intake bolts everyone was trying to sell me ones that would only have 3 or 4 threads of engagement, same old incompetent sheet. I ordered from ARP and now have 9 threads of engagement exactly as the ford racing instructions indicate. I doubt I will ever have a problem. When dealing with aluminium it is not the fastener stregth it is the aluminium strenght and you want alot of thread engagement and antiseize.

[madmaxx]

If I had a penny everytime an idiot would tell me he had been doing it that way for 20 years I would be rich. They dont have 20 years experience they have 1 year 20 times!!!!!!

[llama man]

I had the same 3-4 threads of engagement. What is the correct bolt length?

[madmaxx]

The bolts you want assuming a 351 is the same is ARP-454-2003. I had to order from summit.
Incredibley enough they do not list the lenght, I can measure when I get home tonight.

[madmaxx]

I called arp the bolt is a 5/16x18 x 2.250" so it is 2.25 inches long, everyone wants to sell you the 2".

[madmaxx]

ONLY 15LBS-17 LBS OF TORQUE!!!!
Usually stainless in aluminium is a huge no no, but ARP rolls their threads etc and with anit seize galling is a non issue. If you run down to the local hardward I would not recommend just getting stainless bolts, more than likely it will gall one of the holes, just get carbon steel.

The proper way to fix your head is with a heli coil, the question is if the hole alows for the larger drill bit for the heli coil threads. if not you just have to grind out but ensure you cover everything to prevent aluminium from getting in your engine

You might luck out with the longer bolts and just use the good threads left, obviosly I would torque that one last and only to 15 lbs

[madmaxx]

From the ford racing intake manifold installation instructions:

Make sure that the bolts have at least nine turns of thread engagement and that they do not bottom in the bolt holes. The use of a .090”-.125” thick by 5/8”-3/4” O.D. washer under each intake manifold mounting bolt is highly recommended.

Yes I am bored today!!!!

[madmaxx]

Do not use pos loctive black rtv for the end seals!!!! Get the permatex ultra black, it will be about $1.50 more.

I had my intake off many times and know which is better, the loctite allow the intake to just lift off, the permatex I had to cut the bead with a razor blade to get the intake off. It is 1000% better.

[llama man]

Thanks. I've ordered the set for the 289. Should be in by the middle of next week. Lots to do in the mean time.

[Mus408]

Get the ARP intake manifold stud kit. Best thing to use with aluminum heads!

[bobcowan]

Don't try and fix it with JB Weld, unless you want a temporary fix. It will work for a while, but will eventually fail. Sometimes that's exactly what you're looking for.

For a permanent fix, use a Time-sert. It will work better than other thread repair types when you have a chunk missing. http://www.timesert.com/