273 Help, Advice!

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66FormulaS273

66FormulaS273

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Have a 66 - 273/4 that was rebuilt a few years ago and finally went to crank it up Friday. After a few minutes the RH cylinder head developed a water leak. Engine had a total rebuild, 30 over and new seats in the heads. The question after reading a few threads "what heads to run" and toolmanmikes rebuild thread, is do I just put a different set of heads on or try to find a 66 - 2536176 head and have it re-machined with new seats? Wanted to keep the car stock but don't know how easy it will be to find the head. The engine is an LA / CAP, I bought the car about 16 years ago and am now just getting everything assembled.

Thanks, any advice appreciated.
 
Let's talk about your water leak. Is it leaking externally or are you loosing coolant internally? Where did you see the leak? tmm
 
Ditto, Are you sure the leak isn't coming from the water port at the front of the intake manifold? That is easy to fix.
 
Will take picture first thing tomorrow morning. Car is 45 minutes from the house.

Thanks
 
At exhaust manifolds, 4 corner hardware is studs instead of bolts. Those enter water jackets and do need sealant on the threads.
If the 273 heads had issues at the exhaust valve seats it should have been seen and corrected during rebuild.

assuming the heads were OK then they should be OK for a very long time.
 
We are the shop that is now working on this car. He had told us that the engine had been gone through and everything looked good so we installed the engine and had just got it running and getting ready to do a cam break in when we noticed water dripping on the floor. Expecting just a loose hose or something simple we found water spewing out of a crack in the side of the head.

Here is a shot of the crack after removing the manifold. Once we get the head off we will have a better idea of the extent of the damage and can provide better pictures for the inquiring minds.

Basically it looks like we will need a new head. Hopefully we can locate a match and just replace the one side.... if not I guess we'll have to do the pair.

Here is a link if you are interested in the build:http://www.facebook.com/media/set/?set=a.10150372048711134.356780.187765416133&type=3

305642_10151123249421134_888857898_n.jpg
 
Crap that looks like a replacement is needed. Could probably be welded with a nickel rod if another cant be found being it is external.
 
I am not a 100% sure of this, but in 1967 some of the 318s and 273s ran the same heads.... casting # 2698920 with valve sizes 1.78 intake and 1.50 exhaust , I am pretty sure all the 318s had the same valve sizes so you should be able to pop a set of 318 heads on it . 318 heads are plentyful and are a dime a dozen and easy to come by. Again I am not 100% percent sure of this and the head cc may differ,
but this is what I will doing if my 273 heads are shot. Hoping to have mine together by spring time. Cheers / good luck.
 
The 1966 LA head was casting # 2536178. Wheels is right. The 67 head, casting # 2658920 was used on the 273 & 318. Both heads have a 57 cc combustion chamber.

All of the later heads have larger combustion chambers. The 64-65 head may be drilled for a different intake manifold and will not work with the 66 intake. Also, casting # 2658234 is also a 57 cc head, but is designed to work only with a water heated manifold.

Hope this is helpful to you. Good luck.
 
If you aren't concerned with originality, you can look for a pair of #302 heads that came on most mid to late 80's 318's. They have a small heart shaped chamber like the 273's and smaller ports that are close to the same size and shape. They also have hardened seats which is a plus. tmm
 
toolmanmike said:
If you aren't concerned with originality, you can look for a pair of #302 heads that came on most mid to late 80's 318's. They have a small heart shaped chamber like the 273's and smaller ports that are close to the same size and shape. They also have hardened seats which is a plus. tmm
Click to expand...

There is another issue with those later heads conflicting with the earlier exhaust manifold on the left side. If you're not using headers you may need to do some reaseach and then some grinding.
 
RedFish said:
There is another issue with those later heads conflicting with the earlier exhaust manifold on the left side. If you're not using headers you may need to do some reaseach and then some grinding.
Click to expand...

Not much grinding is required....I broke 2 manifolds before I figured it out..
I wish I would have known there was a problem. Don't get too argessive though, I've heard there is water behind the hump you will be grinding on.
Also, do it prior to installation of the motor..much easier out of the car.
 
I'll be out in the head shed today lookin for a 920 for another member and see if I have the one you need also
 
The head casting numbers are 2658920-2 which I think was mentioned in a previous post. Anyone have a spare? Not sure we need to replace both if we use the same casting and rebuild it.... Is my thinking wrong?
 
Corbetts_Auto said:
The head casting numbers are 2658920-2 which I think was mentioned in a previous post. Anyone have a spare? Not sure we need to replace both if we use the same casting and rebuild it.... Is my thinking wrong?
Click to expand...

As long as no one has done any porting or other creative removal of metal from the I/E passages and the combustion chambers, you should be fine. These old heads did not have hardened valve seats. If you install them on one head, you'll need to do the other, too. But you already knew that.
 
Check the dimensions from the 4 tooling pads in the 4 chambers from one head to the replacement head. They should be similar, if not you should mill the head so they are close to keep the compression equal from side to side.
 
That crack location is a common problem with the 920's. The earlier 315's were just as bad. I like using the early 70's 675 castings with todays pump gas if you want to keep the "stock" look. There are some minor visual casting differences but they are a bolt-on swap and lower the compression ratio to run regular unleaded.
 
easyrider said:
Please explain what you were talking about grinding to replace the exhaust manifold.
Click to expand...

you need to grind part of the head where the driverside exhaust manifold hits. It's where the manifold turns down towards the bottom of the car. If you don't gring the head, you will end up breaking the ear on the manifold. I did it twice. :eek:ops: It only is a problem when using the early a exhaust manifolds. I am referring to the "302" heads. Found on mid eighties vehicles with smog tubes.
They are a closed chamber head.
 
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