Last few days things have been going pretty good installing the new engine. Working about 2 hours a night after work I get a few things checked off the list.

Last night I was focusing on the water pump along with A/C bracket (Right side) and alternator bracket (Left Side). Houston, we have a problem. Seems the Brodix heads are just a tad wider than stock heads. I am about 1/4 off on having all the brackets line up.
I am using Fel Pro 1404 exhaust gaskets and they are about 1/8" thick. So my question is this.....
1. Can I run stock manifolds with aluminum heads and no gasket? While this won't give me all I need it will help. If I do not run a gasket what should I use as a sealer?
2. There is enough meat on the alternator bracket to open the 3/8 hole up or move it slightly over. This might work and I think there is plenty of strength left.
3. The A/C brackets are another story. They are cast not stamped parts. I could consider shaving about a 1/8 - 3/16 off the bracket that mounts up against the ex manifold, then open up the two 3/8" holes on the cast part that mounts to the water pump as well as the 3/8 hole that mounts to the exhaust a/c bracket.




I really hate bubbageneering this but I have racked my brain in looking at other options. I plan to call Brodix and discuss with them as welll.

If I go down the path of doing the above modifications I will just order Repro brackets and bubba them. Not the originals.

I know there are lots a brains out there so maybe there is a solution I am missing. Thanks for any suggestions.

Thanks, John

 

Shave the spacer ?

 

Be interested on what Brodix says on using manifolds without a gasket.

plasticman

 

I have no idea, but as you undoubtedly know, Chevy did not use exhaust manifold gaskets on these cars when built. I'm not sure why new aluminum heads wouldn't seal adequately to iron exhaust manifolds like to iron heads, as long as the manifold mating surfaces are in good shape? Maybe the heat expansion coefficient difference between aluminum and iron, but I'm just speculating now.

 

I can shave (grind) for a better word the bracket to move it a little closer to the manifold and pick up at least an 1/8 " or better. Have to take the same about off both mounting bosses to keep it accurate.

See my circles in red.

 

It looks like you need thinner spacers if I am seeing this right, as someone else suggested. If this is correct, let me know what thickness you think you need and I will make them for you on a CNC lathe for free. I think I have some 1" O.D. x 3/8 I.D. DOM tubing on hand that should work nicely. Kindy let me know what you need. Michael
P.S. I can machine the bracket mounting surfaces on my mill if you prefer. Or fabricate a whole new piece.

 

Well that was an interesting conversation in itself. The tech I talked to seemed to not realize Chevy did not use gaskets. "You should always use a gasket" Maybe he was just mind locked on Aluminum heads.

One of the things he did state is the ports are .200 higher than stock. And they are cast at 23 degree plane and that might be what the problem is. Surely I can't be the only person to install these heads on an A/C Car?

I have sent them some pics so we will see if they have a suggestion, but I am pretty sure it will be up to me to solve.

 

mrichard,

There are no spacers being used at all to mount to engine.
The mounting bracket that bolts to the ex manifold mounts flush to manifold. The part that looks like a spacer is actually a double ended bolt and the exact size as the OEM bolt. The bracket that mounts to the water pump mounts flat to the bolt bosses as well. I appreciate the offer for milling this and I might reach out to you as a last resort. Thanks so much for the offer.

Maybe this is a better pic of a correct mounting.

 

Let me know if I can help...

 

I used copper permetex between my cast exhaust manifolds and aluminum heads, no gaskets. I had the manifolds surfaced to ensure a flat surface. No leaks, but I only have garage hours on the engine so far.

Patrick

 

Thank you sir! Will be in touch. My project tonight is to determine just how far off center this is so I know where the adjustments need to be made. I can take my time on the a/c bracket as that is not critical for the moment. The Alternator bracket is a different story.

 

One thing to beware of is making a change that gets you "part way there". It's fine to figure out you can steal an eighth here and a 16th there, but I'd suggest not actually drilling or shaving until you know you will have all you need in one manner or another. A bolt that lacks 1/8" of going in is no more use than a bolt that lacks 3/4" of going in.

 

Aluminum and Cast Iron heat and grow at different rates. I believe bolting cast iron manifolds direct with no gasket will cause problems but I have not done this to tell you first hand. Even Aluminum intakes bolted to cast iron heads need a special gasket to allow for the excess movement due to the different growth rates when exposed to heat and cold. A standard gasket used on the aluminum intake and cast iron head will fail in short order.

 

GM uses all metal gaskets (thin) on LS3 engines. I know, I have one that has aluminum heads and cast iron exhaust manifolds. See if you can find this type of gasket online.
I will have a look.
The solid copper gaskets are only .041" thick. That might do it. That's pretty darn thin and copper seals great and works well with aluminum.
Michael

 

if you loosen up the 2 bolts that go into the water pump, how close can you get it to lining up with the manifold bracket? I've dealt with this in the past and if I remember correctly, sometimes there is enough play when loose to get the bolt in, then tighten all the brackets.

 

I'm trying to understand exactly where you need more movement. If I'm thinking right when you put the bracket on the stock exhaust studs it's out too far. If that's the case remove the studs and just use bolts to hold the bracket and manifold in place. Also I see a washer sitting on top of the integral nut. Remove the washers and see if that's enough. If you manifolds are flat there should be no reason you couldn't go without gaskets. Same as MRichard if you need them cut I can do it. I would do what I suggested. Just make sure to use hardened bolts. If you need anything call.


Mark I don't get the special gasket for an aluminum intake on iron heads. All we ever used and I still do today is a 1204 Fel Pro. Never had any problems.

 

Yes, interesting that he did not know "no gaskets were used"...
Thanks for the info. Since my Brodix heads are "suppose to be in the stock exhaust position", I should not run into the issues you are seeing. Hopefully, if I ever get motivated to install the new motor.
Best of luck in solving your issues!

Plasticman

 

Ok.....I worked on this some last night. I got one problem sorted out to a certain degree. Not perfect but to a point I can get the job done with a little finessing.It is a good thing I do not throw bolts away. Seems the new bolts I bought for A/C mounting are made totally wrong.The bolt with the integral nut is not to spec by any means. That kicks the exhaust bracket way out to the left of the bracket that mounts to the water pump. At least this problem is workable. I somehow bought 2 sets of the special bolt kits for a/c mounting from two different specialty stores and both of them have the integral nut bolt made wrong. I wanted new fasteners to go with my new engine, but the originals are so much better. One thing I learned a long time ago.....NEVER throw out old fasteners.

The other problem is the alternator bracket is just not gonna go unless I massage the bracket. Looks like I will have to become very intimate with a rat tail file and work all three mounting holes for the water pump bolt and the two exhaust manifold bolts. That problem will be delayed till I get back from Florida. I am going fishing!

I appreciate all the feedback!

Repro on Left, OEM on right. What a difference! Stupid me should have checked.


After I put the original OEM integral nut bolt in.Close and workable. Not perfectly aligned but can get a bolt through both holes now.

This shows how far off the repro fastener was.

This is the next problem to solve. I have to massage the two holes to mount this to the manifold.

Hard to see but you tell the bolts not going in without some opening up.

 

Thanks for the tip. I think I got this A/C mount problem solved but I will try this tip on the alternator bracket when I return next week.

 

On the alternator bracket see if you can oval each end a little instead of trying to do all one end. Might help. Or cut the bracket and have someone weld it.