helicoil new aluminum heads?

[mike mopar]

Is it necessary to helicoil new aluminum heads(SR's)before installation?
Mike

[GTXMONTE]

In my exprience, if you run high spring pressures, the threads will pull out over time. Instead of heli-coils, try using the larger type threaded insert, they seem to hold up better in alum.

Monte Smith

[Leigh]

Hi Mike,
My engine builder did every hole in mine. (B1BA) It's an extra step in proffesionalism. You'll be glad you did. I don't like doing them without a drillpress or some means of holding the part on the centerline of the hole being drilled. I don't see how it could be anything other than extra insurance. (Especially in a thrash)

[440 Jim]

Good question! I think thread inserts in aluminum is a good idea if either of the following applies:
1) High bolt loads
2) Repeated assembly/disassemble expected

High bolt loads would be like rocker shaft hold down threads, etc. The larger, solid thread inserts have some advantages over heli-coils as long as you have room for the larger oversize hole/thread that they need. I might prefer them for holes into pressurized water jackets for sealing reasons. Overall, heli-coils are great and the new Edelbrock heads are supposed to come with helicoiled holes.


------------------
440 Jim
E-Body Fish: 12.8 sec 1/4 mile with stock exhaust manifolds, 3690 lbs.

[451Mopar]

When I bought my Brodix B-1 B/S heads the rocker shaft hold down bolt holes came with inserts, but the intake and exhaust bolt holes did not.

When I had to replace my starter, I overtightened (or cross threded) one of the exhaust bolts ans stripprd the aluminum bolt hole, so I pulled the head and installed steel inserts in all the bolt holes.
Someday, I may pull the other head and put the inserts in it too.

[cdignition]

Ok..Im here to straighten out you guys on Heli-Coils and Keenserts....Keenserts are the bigger ones for the folks who dont know what they are. We use more Heli-Coils in a day than Indy Cylinder Head will use in a month...I can honsetly say there is NO strength diffrence between the two, and if the Alum is thin in areas, the Keenserts are actually weaker. Done bleieve me?..test it your self...i actually used Heli coils in wood,(Most likeley Mohagany) to mount down my Relaoding presses...I helicoil all my Iron
stuff too...just way better....torques better also.


[This message has been edited by cdignition (edited January 14, 2001).]

[montrose ram]

Well I did'nt know about anything but heli-coils so I've learned something today! My B1-BS heads came with 'em in the rocker hold down stands, too. Use anti-seize for headers and manifold. One thing on heli-coils, make sure you break off and remove "tang" at bottom of bolt hole! Or bolt may bottom out giving you false torque reading.

[451Mopar]

I also have to add, use plenty of never-seize on any fastener going into aluminum, especially the spark plugs.

When I first got my B-1 B/S heads, I trial fitted a spark plug finger tight. When I went to remove it, it seized (galvanic action?) to the last two threads coming out of the head leaving aluminum on the threads of the $4/each spark plug, and me having to buy a spark plug thread chaser to clean-up the spark plug hole

[montrose ram]

Yup, happened to me, too. Had to chase threads on a couple of plugs when trial fitting headers! Anti-sieze plugs for sure, too!

[mike mopar]

Now that I know that it is a good idea to helicoil the heads,how much should I expect to pay the manufacturer or a machine shop to do this?I think they should come from the factory done already!!!
Mike

[MD]

Besides using some form of anti-seize on aluminum threads, it's important to use bolts or studs with threads that are in good condition. If you feel a drag and have to force them in because of nicked or damaged fastener threads, the aluminum threads will wear quickly. I prefer to use studs where possible so the threads don't get worn out.

[montrose ram]

You can go to your local hardware or auto supply store and ask for a heli-coil kit for the size of bolt hole and type of thread you need. There should be instructions with kit.The kit is around $25.00 if I remember right.

[451Mopar]

For the header and intake bolts, I used the Stainless steel ARP 12-point head bolts.
Actually, these were part of the ARP engine bolt package and there isn't a stock bolt on the entire engine. In fact the only stock parts are the 400 block, and the 440 crank and rods

[DartGT66]

I have nothing against the use of anti size, but I haven't used it and have not have any problems. I have Stage VI's and Indys, I usually put a drop of oil on to the spark plug threads and that's it. Once I overtorqued a rocker shaft bolt on the Stage VI's so there is one hole with a Helicoil now. Both heads are pretty old, I bought the Stage VI's in '93 and the Indys in '95, and they have been in and out at least a couple of dozen times and the threads are still fine. This is just to show that you can do without Helicoils, however I think helicoiling all the threads in aluminum heads (sell, maybe not the valve cover threads) isn't a dumb idea at all.