Thread: Aluminum Heads

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I'm getting ready to install a set of aluminum Edelbrock heads on a sbc 355. Is it better to use head studs or is it OK to head bolts ? The motor is will mild performance. Also if head bolts are OK can I use the existing ARP bolts on the heads now or should I use new ones ?

I would use the studs, and put a washer under each nut so they don't dig in to the aluminium.

For the motor you describe I would not be afraid to use you exisiting bolts with washers (unless you find some stretched). I'm using stock used head bolts (first re-use) on a mild 351W over 40K so far and no problems.

Make sure to retorque after cam break in like as Edelbrock recommends.

Studs would be ok provided you can slide the head up and off with the engine in the car.

ARP head bolts are great and are what I use since the left head (455 Buick) is not removeable when using studs.

Studs and washers !!!

For the motor you describe I would not be afraid to use you exisiting bolts with washers, mild not wild build. Now with all these differences of opinions you will have to flip a coin.

Did the aluminium heads come with a suggested way of bolting them in, or an optional bolt kit, like the Edelbrock intakes have? If so go with what they suggest. Takes the guess work out of it!

Edelbrocks part number that they sugguest using is a bolt, I was just wondering which would be better to use. I was looking at the motor sitting in place and realized that I would need to pull the motor to install the heads if I used studs. I guess I'll be using bolts. Thanks for the input.

Ok.. I'll bite.. why studs? Are studs the new norm for aluminum heads?

Originally Posted by firebird77clone

Ok.. I'll bite.. why studs? Are studs the new norm for aluminum heads?

From Milodon's site.....
"Studs are required where maximum gasket loading & reduced wear and tear on the block threads are desired."

ive got studs on my iron camel humps. i did it because it was the same price as head bolts from my machinist and besides they offer better clamping load ditribution vs a bolt.

the studs have fine thread you can get a more even torq and clamping of the head gasket btw you use less torq setting its like gear ratio you can actualy squeze the gasket out if you use the 65 lb that you use with bolts .....ted

my head studs said 75ft/lbs

While you can achieve more clamping load with fine threads it also requires more torque. This is because fine pitch threads can take higher loads, not because of any mechanical advantage. the relationship between bolt torque and preload no matter whether fine or course is given by

Torq=0.2*F*d where F is the clamping force and d the bolt diameter in inches. The number 0.2 represents the friction and actually varies a little bit depending on whether the threads are dry or lubricated.

By the way the best accuracy with new bolts or studs is to torque them up a few times before the final assembly, ie, break them in for best results before final assembly.

Kitz

What a great thread (pun intended). Over the years I have learned a couple lessons (some the hard way) about heads and bolts. As mentioned above, studs can be a bad idea if they do not allow removal of the head without pulling the engine! I've only built a couple aluminum head motors and religiously followed the enclosed instructions from manufacturer (Dart). That said, here's a few pointers that I know for sure apply to cast iron which I hope will be of interest to others.

1. If at all possible, buy new bolts. Summit (my favorite) has a complete SB Chevy kit (ARP) for about $60 that includes washers. If you look at $60 versus the time it takes to "re-do", it really makes a lot of sense.

2. If you reuse - make sure the bolts are spotless. Degrease and then a good bath in hot soapy water (I use Dawn) and a thorough dry with a soft towel and compressed air. If you're not going to use the bolts straight away, put them in a zip lock bag with a shot of lube (WD-40) to keep any moisture out.

3. Run a lubricated bottoming tap down each bolt hole in the block. The lube will catch some of the guck and aid in final cleanup. Do this on every hole every time. I always find a few woolly buggers even after expert machine shop work and hot tank. It’s easier to do it than to find out there’s guck in the hole as you torque the head bolt. The tops of the holes should also be slightly chamfered so the top threads don't pull above the deck surface when the bolts are torqued. A small die grinder works well here. Make sure all the crud and such is cleaned out of the holes.

4. Use washers. It just works and helps prevent galling of the head and helps give a more accurate reading.

5. Use a "spot o' lube" on the threads. I use 10W 30. The key is just a tad. Too much and you can get a nasty condition known as "hydro-lock" where oil is trapped in the blind hole. This especially true with ARP bolts as they have nice tight, very precise threads.

6. Don't forget - if your head bolts extend into a water jacket, coat the threads with a flexible sealer. If you do not use sealer, coolant will almost certainly leak past the bolt.

7. Use a good torque wrench. I have a thirty-five year old Craftsman break away style that's a real gem. I've had it calibrated several times and I treat it like fine china. It has a special, protected place in my tool box that prevents it from clanging around with other tools. The beam type are really pretty good, but can be a real bear to read and as we all get a bit older, the ability to smoothly pull the wrench and check the gauge (through the bi-focals at the "in between" distance) is not so easy.

Final Note - If you have TTY (Torque-To-Yield ) bolts, throw them out and buy new ones. TTY head bolts are usually longer and sometimes skinnier than standard head bolts. The long story is that TTY bolts are “an engineering marvel, bla, bla, bla…” The short story is that they’re from the devil and cannot be torqued using standard tools, rather, an angle gauge that is really not easy to use, especially when the engine is in the car.