TR4/4A Aluminum head water leak?

[BigCountryBritish]

Have had a problem with some water up in the rocker area of the TR3(TR4A Motor) ever since I bought it last year. Just now getting to a point where I can pull the head and see if I can see what the issue is. Below are my observations:
1. Did not know it was an aluminum head until today, re-torqued it last year when I first saw this problem at 95lbs. Learned today it should be 70lbs.
2. Runs great, compression checks out good at 150-55 across all. But after getting up to highway speeds then coming back to town it quickly overheats and blows the water past the rad cap.
3. Cannot see any damage to the solid copper head gasket. Is this the right type gasket for an aluminum head?
4. Cannot see any damage to the head, how do you check an aluminum head? I would think that magnaflux would not work here.
5. Drained and checked the oil last fall, no water present in the case.

Any suggestions from the collective wisdom would be greatly appreciated, seems this motor was intended for some level of performance as it also has Moss’s roller rockers.

 

[sp53]

Sometimes on the tr3 and 4 motor the block cracks where thehead stud go into the block. The reason is people sometimes tighten the studsdown then apply the head and torque the head down compounding the torque on thestuds, cracking the block at the stud. This gives the same symptoms youmentioned.
Steve

 

[charleyf]

A novice answer is that you appear to have a water to compression leak. When this happens you get what you describe as the excess pressure in the radiator and overheating. Did you see any signs of water getting into any cylinders? This would happen after the car shuts down especially. Could be the gasket did not seal off the cylinders and allows the compression to leak over to the water passage. There is a chemical that you can use to put in the radiator water to test if combustion gases are entering the water.
Easiest thing is to pull the head off and look at the gasket for signs of water leaking into the cylinders. Much running of the car with water in the oil can damage the bearings. At the early stages you are still good.
Charley

 

[M_Pied_Lourd]

Is your head actually aluminum or are you talking about the aluminum plug in the head?

Cheers
Tush

 

[martx-5]

Aluminum heads are available. Moss has them...

https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=131498

 

[PatGalvin]

If you hot tanked your cast iron head, the aluminum plug can come loose or be porous and leak coolant into the oil. Ask me how I know!!
I had the head threaded and fit a black iron pipe plug in that hole.

Pat

 

[CJD]

I'm with Steve and Pat. Either a cracked head, loose plug, or a crack in the block at the front or rear studs. Those are the only items that give you water in the rocker area.

 

[charleyf]

But what about the overheating and excess pressure in the coolant system? You need compression for that to occur.
Charley