Lotus Elan and Lotus Elan Plus 2 Forums

Hi,

Had my engine rebuilt and head ported and polished. It is beautiful, and during the dyno run it performed great except they could not get it to idle. Upon further review, it turned out the head was porous. The engine builder provided another head and finished the engine - which is great. He also sent me the porous head. I assume nothing can be done with it, so if anyone needs a big paperweight it is yours for the postage. I am in Alabama USA.

Bob

Some people reckon you car pressure inject a ceramic sealant?

Depends where and what the problem is. I am assuming it is an old original head. Actual casting porosity is rare so you would need to diagnose more closely what the issue is. Do you have details of the leak location ? If not you can get the head pressure tested to detect where the problem is and then determine if a repair is cost effective.

Some photos of each face of the head would help understand the issue.

cheers
Rohan

Bob, is this a Weber head?

I used a twin Cam head that wasn?t salavable for a cut away ?sculpture?. Turned out rather nice

Hi Bob,

If you still have it I'll take it. I will send my contact info via PM. I have family in Florida it can be shipped to.

Thanks,

Here's a head that was Stromberge converted to Weber and it became porous
It has been repaired as in photos, sorry about order of photos

Bob,

It may be possible to have the porosity sealed. It's a long time ago when I was working in the chemical industry about 1975. We had a bronze casting made that was porous, and the foundry took it back and sealed it with a resin. I know that's vague, but it might be worth considering.

Richard Hawkins

Thanks so much for all the replies and info. It is a Stromberg head that had been welded several times in the past. My engine builder, a TC expert, ported and polished it and did not realize it had a problem until the dyno runs. He said he should have checked the head more thoroughly, bought me a replacement and ported and polished it, all at no charge. I am pretty sure if this one was salvageable, he would have done so. I may look into it further, but wilkl probably give it to another member who sent me a PM shortly after I posted this.

Bob

It looks like the porting thinned the casting on the inlet port bottom section through to the water jacket to much. Any casting becomes porous if it becomes to thin

This is a common problem when you port these heads as the casting core locations tend to vary from head to head.. I had a similar break through when John McCoy was doing a head for me that was picked up at the time and a new head sourced. It was a risk I consciously take when going for his maximum Stage 4 Race porting. Repair welding is possible though often not economic versus buying another head. I had a head repair welded when porting broke through into the valve spring pocket many years ago when heads were harder to source than now, I would probably just get a new head if that happened again.

When working on heads or blocks myself I always keep a very close eye on the wall thickness with an ultrasonic thickness probe if i am taking off metal in areas known to be potentially thin

cheers
Rohan