Stabilizing heads
 

Most commercially available heads these days have bolt holes that are bigger than 7/16" (some are as large as 1/2"). When I put the heads on my last build, I could literally move them around on the block when all the bolts were in but not tightened. I did not think this was a good situation, so I decided to find a way to take care of this problem. Of course, in a perfect world we would all live in New York and plan ahead enough to send our components to "GOSFAST"s shop and get alignment pins a installed to solve this, but I am 1500 miles away and already down the road with this build. Here's how I have attempted to solve this problem.

I procured some 1/2" OD .030 wall aluminum tubing. This results in a tube with an inside diameter of .440" (remember, 7/16" is .4375). I then bored the bolt holes between the cylinder pairs out to 1/2" (one set of heads I did were already at this dimension). The heads are 1.840 thick at these bolt holes. Since the compressed gaskets were around .055", I cut lengths of the tubing off at 1.870. I also beveled the end of the tubing.

I then put some long guide studs I made into the block and installed the head over these. I the ran the tubing pieces over the guide studs with the beveled side down. When I wiggled the head and gasket enough, I could feel the bevel on the end of the tube slide into the bolt hole in the gasket. After this, I put a couple of more bolts through the head into the block to secure it, removed the studs, and inserted a couple of bolts (using the special hardened steel washers I DID get from Gary).

The result is a head that does not move on the block. I used ths procedure on the 255" Merc I did for my '51 club coupe and everything worked out well. The attached pictures are from doing this same procedure on the 258" hot rod engine I am just finishing.

Re: Stabilizing heads
 

I have no idea if this it right but wonder it the over sized hole were to allow for expansion and contraction.

Re: Stabilizing heads
 

No, more likely to allow for sloppy tolerances during the machining operation.

Re: Stabilizing heads
 

Tubman, Thanks for sharing that, I like to make things a little better myself.

Re: Stabilizing heads
 

I think the real reason that the holes are oversize is due to how tough it can be to get these heads on/off an engine. Having a really tight fitment - along with corrosion . . . can cause the heads to be "junk" by the time they're removed. When using studs - you may NOT get them back off without serious damage to the heads . . . or even destroying them.

I've seen many situations where the installer didn't use anti-seize in the sides of their studs/bolts, sometimes water leaks past the block (think corrosion of the steel and aluminum, etc). Then there are guys that "fix" leaking studs/bolts with O-rings at the top side (leaving water to corrode the heads/hardware down in the hole).

Personally, I like the holes being larger - just makes my job a lot easier. I've never had an issue with heads "moving around" on a normally aspirated flathead (blown race conditions, they're a bit different!). Part of this is due to my using ARP studs/hardware on my engines (yes, expensive for sure) - they hold their clamping force as they should. Also, ARP studs have an allen head provision at the top, so I can REMOVE studs prior to the head coming off - which is how I disassemble them if I'm having issues (if needed).

Another method is to use 'Hat Washers' at the top of the stud. These washers have a section that goes down into the hole and centers the hole around the stud/bolt. I use these for many situations with aluminum heads (think aftermarket SBF heads, when running 7/16 studs). One word of caution - only use a couple of them per head - like one on each end . . . or you'll never get the heads off.

Here is what I use:

Part#: ARP 200-8598

Attachment 332959

Re: Stabilizing heads
 

Yes, Thanks for the tip. Where did you get the tubing??

Re: Stabilizing heads
 

Hi Marv, a number of years back I spoke to Edelbrock about why they opened up the holes on all the newer castings, was curious AND foresaw head gasket issues coming up from this change. We were correct!

Edelbrock stated they had gotten too many complaints from buyers about not being able to get the heads on when the blocks came from Ford with studs already in play (mentioned above here). Many simply wanted to remove the old iron heads and install the new aluminum's, it was tough getting them back on with the studs. I believe this particular issue to be a fact, true.

After speaking with them I knew we would be needing a good "fix", so we decided on the pinning method.

I have some older (but still new) Offenhauser and Edelbrock heads here for builds, these early head bolt holes measure .468" (15/32"), I also have some newer castings and these holes measure .500" (1/2"). They opened EVERY hole about .032" (nominal).

"Tubman" above found a nice way to overcome the problem, when you don't have the opportunity to pin the heads/gaskets, his is a good method. We now pin all our builds going in!

(Add) We "move" so many of the washers he mentions above we just ordered another 1000 pieces. We use them on numerous builds not only the Flatheads.

Thanks, Gary in N.Y.

P.S. In the past I've posted a shot or two of the pinning up here but I'll put a couple more below for those who haven't spotted it before! Over this winter we'll be working on a tool to send out so the "backyard" builders can do the pinning with a simple hand drill, we're working on the plans now. Hopefully we can pull it off at a very reasonable cost? We'll see after this year.

Re: Stabilizing heads
 

I used to work at a shop where aluminum tank truck and trailers were made. Whenever steel or other metals were required to be bolted to aluminum we used a product called aluminastic between them. I have removed parts that were installed for years and they would separate and little corrosion would be present. I don't know if this product is still around or not but it seems that something would be as lots of these trucks are still being made.

Re: Stabilizing heads
 

I get it from a place called "Online Metals" on the web (Google it). They have all kinds of stuff. One of the nice things is that they offer samples quite cheaply. In the case of this tubing, you can buy a 10"-12" sample for less than five bucks. One of their samples is enough for a set of heads. If you order from them be careful to choose the USPS shipping option or else the shipping charges will far outstrip the product cost.:rolleyes: