BHG, '88 Supra: Head shims?

[Hachiroku $B%O%A%m%/(B]

As usal, crossed to a few groups because there are some smart people in
them...

I was at a machine shop the other day getting a set of brushes for the
alternator for my '92 Grand Caravan, and I asked the machinist about my
BHG. He said, "That's the one with the long 6 cylinder? There's only one
problem with that. The head gasket can make indentations in the softer
aluminium in the head, and a gasket won't seat properly. They make a
"shim" specifically for that engine for this case, but it's expensive."

"How much?"

"It's custom made for each engine, so it's about $80..."

Eighty bucks? in order to seal the engine rather than pull the block for
machining, etc etc? Sounds good to me!

Has anyone heard of these before?

 

[Ray O]

As usal, crossed to a few groups because there are some smart people in
them...

I was at a machine shop the other day getting a set of brushes for the
alternator for my '92 Grand Caravan, and I asked the machinist about my
BHG. He said, "That's the one with the long 6 cylinder? There's only one
problem with that. The head gasket can make indentations in the softer
aluminium in the head, and a gasket won't seat properly. They make a
"shim" specifically for that engine for this case, but it's expensive."

"How much?"

"It's custom made for each engine, so it's about $80..."

Eighty bucks? in order to seal the engine rather than pull the block for
machining, etc etc? Sounds good to me!

Has anyone heard of these before?

I've heard of them but have never seen them in use.

 

[jim beam]

As usal, crossed to a few groups because there are some smart people in
them...

I was at a machine shop the other day getting a set of brushes for the
alternator for my '92 Grand Caravan, and I asked the machinist about my
BHG. He said, "That's the one with the long 6 cylinder? There's only one
problem with that. The head gasket can make indentations in the softer
aluminium in the head, and a gasket won't seat properly. They make a
"shim" specifically for that engine for this case, but it's expensive."

"How much?"

"It's custom made for each engine, so it's about $80..."

Eighty bucks? in order to seal the engine rather than pull the block for
machining, etc etc? Sounds good to me!

Has anyone heard of these before?

doesn't this block have steel liners? if so, the argument about the
gasket indenting it is b.s. - all you're doing is shimming the head to
compensate for if it's been machined.

as an aside, while i think it's too late for you because you've had the
head off this thing before, it's common for some aluminum motors,
[specifically honda] to have sealing problems if the head's been off and
the block's been skimmed. this is because the deck surface has an
important feature most machine shops not only miss, but aren't in a
position to replace, namely that the steel liners are set at a slightly
different height to the aluminum in the deck surface.

[use mono-space font]

from factory:

___ liner
deck ___|

vs. one that has been skimmed:

deck ___ ___ liner
|

now this is not a big step, but you can feel it with a nail when you
have the head off and it's been cleaned properly [without abrasives].
it compensates for the different thermal expansion ratios of the
aluminum vs. the steel. as the aluminum expands, if there is no step,
it'll lift the fire ring of the gasket off the steel and weaken the
seal. and that's why once the head's been off and the block's been
skimmed, they tend to fail again shortly afterwards.

rebuilders inadvertently encounter this problem when trying to race prep
some honda engines. their solution is to machine out the whole
cylinder/liner assembly and replace with a full cast iron retrofit -
expensive and totally missing the point in my opinion.

 

[Hachiroku $B%O%A%m%/(B]

as an aside, while i think it's too late for you because you've had the
head off this thing before

It's never too late!!!

Short Block $2349
Block, Pistons and rings $1379
Head with valves $1739


Right from Toyota.

 

[jim beam]

It's never too late!!!

Short Block $2349
Block, Pistons and rings $1379
Head with valves $1739


Right from Toyota.

three words. j.d.m.

 

[Hachiroku $B%O%A%m%/(B]

three words. j.d.m.

I know. I can get an engine and trans for ~$2,000...