I am seeking opinion and advice based on members' knowledge and experience.

I have a 1981 VAM Rally GT (Spirit GT) with the original Mexican 282 inline six.

You can see some pictures of my head by http://theamcforum.com/forum/05-17-18-update-mexican-engine-heads_topic82938_page6.html" rel="nofollow - clicking here and scrolling down to the bottom of the page.

Some months ago I took the head down to have it ported out and reduced in height to increase compression ratio.

The only reliable mechanic I know for this kind of job is from another city and after some time I had the chance to make a trip there and take the head to his shop.

Finally, he called me today saying the head is finally ready and finished.

He told me the head has a half-centimeter crack (about one fifth or one fourth of an inch) between two cylinders (combustion chambers).

We talked this on the phone, so unfortunately, I have not been able to see the head as it is now.

In a few words he told me it's no big deal. The water will flow through it, but it will contained flawlessly by the head gasket. That nothing should go wrong under normal circumstances, no true risk of having the water flowing through and getting mixed with the engine oil.

Ever since I have this head (2009), I did get a blown head gasket once, it broke in the portion separating the third cylinder from the fourth. Despite that, water did not flow into the engine.

However, that was the mechanic's mistake, the gasket being placed incorrectly and apparently being of low quality. He had to fix it again under warranty.

I have no way to know how long has that crack been there. If it was there from the beginning in 2009, if it happened during the blown head gasket, if it happened when the head got a full service in 2017 due to three damaged valves or if it happened recently with the porting/height job.

Can this be fixed?

A friend of mine with a 1975 VAM American Rally (Hornet X) told me he had a hole in the engine block due to a bubble that formed in the block wall during the casting process, and he had it fixed in a car shop using tin or bronze. So far, he's had no problems with it.

I might have a chance later this month to travel and get the head back and I will be able to take pictures of it and post them here and in the Mexican Engine Heads topic as an update.

Any advice on this?

Thanks in advance.

In the mean time try looking for another head at a reasonable cost. You have all the valves, springs ... I assume, so the overall cost may be close.

Hope you can find a replacement...

Thanks guys,

Fortunately, I have been recommended of reliable service shops around my area that can fix the problem, as soon as I have the head with me I will take it to them and check what the actual price would be to have it fixed.

I hope I have the money available with me.

Fortunately, I do have another head with me, which is currently on the car, allowing me to use it until the main head is finished and ready.

American heads won't work since Mexican heads have different specs, mainly larger valves both intake and exhaust.

As soon as I have the head with me I will take pictures of it and post them here.

The valve sizes may not be the only difference. Combustion chamber size may be different as well. But a US spec head will bolt on and the car will run flawlessly -- with a little more or less poser depending on combustion chamber size and how that affects compression. The valve size difference won't be noticeable in normal driving, but would affect high rpm power output. It might make 150 hp instead of 170 at high rpm, but you'd never know it under normal driving because you seldom run the engine at high rpm.

If available I'd go with a 4.0L head if I needed to change. Even with a bit smaller valves the head flows better than any 258 head, even one highly ported with larger valves. Ports just have a better shape, don't need to be huge. 

Thanks for your comments Gman and Frank.

Fortunately, if I needed a replacement head I would be able to find it here with the contacts I have and some friends.

No real need to try to get a head from the US.

Putting a VAM 282 head on an American 258 has been done, you have to modify the engine block due to the larger combustion chambers. The Mexican valves will hit against the block walls due to the larger diameter, you have to make a space for them to move freely in their whole run.

I would consider a 4.0 head but not in this car, I'm keeping this one mostly original. Maybe another VAM project car in the future will do. The only changes I've made so far enginewise are the distributor (HEI), alternator (70 amp with built-in regulator), the pistons (flat) and the exhaust (from single to dual). The rest of the engine is virtually stock original (carburetor, intake, headers, head, camshaft, crankshaft, cooling system).

Something I have been very curious about is to compare the 1982-1983 VAM head with the 4.0 head. The 82-83 VAM has all-new rounded out intake ports and have the best flow of ALL VAM heads produced. Unfortunately we still don't know if this head was ever tested horsepower-wise. The VAM 282 with this head would go from 129 net horsepower of the previous design to AT LEAST 135 net horsepower with the 82-83 one.

It would be very interesting to make a test of how the VAM head would fare against that of the 4.0 head, but so far I have not been able to find a head of this period.

I got my head back from reducing the height to increase compression ratio and the port out.

I am finally able to see and take pictures of the crack. Starting at one of the cooling ducts.

I'll have my mechanic check it out and see what can be done about it. I've confirmed this crack was already there before I had the head ported and reduced in height.

The mechanic that worked on it told me that with just the head gasket I'll be fine without any risk of leaks, but if I can have it fixed right away I'd rather do that now that the head is off the car.

Obvious, looks to propagate from the stud hole through the water jacket and move between the center.

I would tend towards brazing this instead of welding. two reasons 1) welding will likely propagate the crack further and 2) warpage in the center of the head.

Find the end of the crack and shallow drill a 3/16" hole, then taper grind the crack out to the stud, preheat the head to 330 to 400°F and then braze from the drilled hole out to the stud.

Finish with files and check head for flat or better, mill 0.010" off.

This is what I would do, others may have other/better options.