lapping block in car w/ steel block + sand paper? HG install

[jt15833]

Ok I'm reinstalling a headgasket (new one of course) since after the last one (done 3 weeks ago) I am leaking from the hg. I have had the head resurfaced and read on a website about taking a flat, steel block to lap the block. it said something like...

get a flat steel block (grinding at machine shop)put 400 grit sandpaper around it securelygo in a back and forth motion across the block

It didn't say anything about when to stop, I'm assuming to use a straight edge and feeler gauges. I don't think its warped/out of spec so much since it's an iron block, but mainly to clean it up and remove any scratches.

What do you all think?

[eh?]

Which headgasket did you use?

If the deck is clean you really shouldn't have any problems. I'd say it's pretty rare to have a warped RB block.

[bigkid]

i agree. are you using a cheap gasket? is the mating surface clean? even an aluminum block is less likely to warp in comparison to the head.

[Sil240]

Umm I wouldn't do that...I would just slap the gasket on.And make sure you torque it in the correct Sequence and Procedure.

[jt15833]

I believe this is the cause of my oil leak. Background, oil was leaking between the head and block, exhaust side, very back. Slow leak, but it was there.Here is the oil passage way.



I can get my fingernail caught in the scratch if I rub over it, so I do not think it's trivial. I may end up doing this ghetto lapping of the block to avoid engine removal and disassembly required to get the block machined by professionals.

Opinions?

[eh?]

It doesn't look that bad to me. Which HG are you using? Are you sure it's not just the valve cover gasket that's leaking? That is a very common area for it to leak.

[240z4u]

Are you using head studs or a multi layer gasket? You have to heat cycle and retorque.

Have you layed a straight edge over that hole to see what the deal is?

Evan

[Darius]

That will NOT seal on an MLS head gasket. Don't even bother trying. My original installed looked better than that and it still seeped coolant into the oil passages.

[jt15833]

def. not on MLS gasket. I'm using a felpro from pepboys. It's got the gray graphite on it and some orings and copper for the cylinder bores. The most forgiving type.

I have not used a straight edge of the passageway, because I think it would be very difficult to try to get in that knick with a feeler gauge. The block is indeed straight and within spec.

I started today with my steel block and sand paper. The top of the block looks good so far and the knick is starting to dissapear. I am trying to be very uniform with my block and the motions. It is way too much unanticipated work to pull the engine, dissassemble and get the block decked. This is my last resort =/

I had no idea of this knick when I was tearing it down, but I did know that it leaked oil. I am happy I found it and I am not a fan doing something the same way and expecting different results.

[eh?]

I've had worse than that and the OEM gasket didn't leak.

But then again I think you're in the wrong forum...

[jt15833]

ya it's a ca18 I was just looking for more response than from the less active ca forum cause this isn't so much engine specific as it is iron block specific. I'm guessing the factory rb gasket is similar in construction to the factory ca gasket as well.

[thenillaz]

If you say the block is in spec why are you resurfacing it? You're risking bringing it out of spec. What makes you think its in spec anyways? Did you take a strait edge to the surface and compare the tolorances with a fsm? I'd imagine that would be hard to do with the motor in the car...