Steam holes in M&A heads

[jamesmac]

Do my M&A heads need steam holes drilled in them for use on my 4.1 o/c block. I'm sure they do , but wondering why they were not put in by previous owner.

They have 1.94/1.60 valves, so they really don't fit on a 3.8 bore without touching the cylinders. I got them off a stock block motor & saw that every intake valve had touched the wall. I think they have been on 4.1 blocks before & I'm wondering why thier not drilled.

What problems could I run into without them, & to drill them do I just drill straight down from were the gasket lines up to intersect a coolant passage

TIA James

 

[EightSecV6]

Drilling steam holes is not necessary, you wont have any problems related to drilling or not. Kind of an OLD theory with siamiesed cylinders (just like the 400sbc) about bubbles escaping.
Bill

 

[jamesmac]

Thanks Bill.

 

[lazaris]

Bill,

Do you still drill the steam holes in the block on a 4.1?

 

[EightSecV6]

I personally do not, but that is me, I had one used S2 block that cracked from the drilled steam hole upwards and that did it for me, if they are already there, not much you can do about it. This is something your builder should decide on if you are using a new or undrilled block.
Bill

 

[jamesmac]

Bill

That is the type of problem I'm worried about having. My block has the steam holes, but the heads don't. Did the heads on the block that cracked have the holes. If they didn't could air trapped in that area possibly be the cause.
BTW the heads are on the motor now, & have have only been on for about 400 miles(street miles). So if there is a chance of doing any damage, it is worth a set of head gaskets to me.

Thanks James

 

[EightSecV6]

James,
You have answered your own question.....(400 miles)
Bill

 

[LikeMy6]

Bill,
If you can remeber what was the diameter of the steam holes on that block that cracked? I know some builders use different dia. holes. If the block is already drilled would it make any difference to drill the heads too or not? just looking for a more direct answer to this.

Thanks

Frank

 

[EightSecV6]

If holes are in the heads or block, leave them alone, I PERSONALLY would not purpose drill either one even if one or the other already had holes in it. This may be disputed but that is how we do it and have had success with no steam holes.
Bill