headgasket prep "?"

[bountykilla0118]

You guys that have kept the motor in the car how did/do you guys prepare the block for a OEM style headgasket? The only way i am aware of besides taking it out and sending it to the machine shop is to use the big square grey brick i call it an "oil stone" i am not sure if thats the right technical name for it but thats what i have always called it. I do remember reading some where that the OEM headgasker does not require the RA "fine details" like the cometic and MHG. No i dont have a BHG i just did not see any info on that specific topic

 

[againstdawall06]

If the top of the block is straight and clean, there should be no need to machine it for an OEM head gasket. The OEM can conform to inperfections in the block and head, the only thing you need to machine is the head. I think the only reason you do that is because it always warps a tad bit.

What i was wondering is if its a good idea to use a spray on sealer on a OEM head gasket, iv seen that topic covered on MHG alot.

 

[bountykilla0118]

Yea i belive they say do not use on the MGH .... but use one the OEM style

 

[JustAnotherVictim]

Sealer is not needed for an oem.

A lapping tool is what you're referring to bk.

 

[JDM 1JZ]

you can spay a sealer on the stocker hg, i always do, 22lbs on a t4 set up with arp studs on a stock motor for over 2 years and she held like glue

 

[bigaaron]

If the top of the block is straight and clean, there should be no need to machine it for an OEM head gasket. The OEM can conform to inperfections in the block and head, the only thing you need to machine is the head. I think the only reason you do that is because it always warps a tad bit.

What i was wondering is if its a good idea to use a spray on sealer on a OEM head gasket, iv seen that topic covered on MHG alot.

I beg to differ. Most older 7m blocks will have some low spots, especially in the #6 cylinder area. I would surface the deck. The stock hg might conform better to small surface irregularities, but not to low spots in the deck.

I know you specified "straight and clean", but that would be the exception some people would not pay attention to, and that is not what you usually find when you pull the head off.

 

[suprarich]

Aaron is right about that. It takes a well trained eye, a feeler guage, and a very nice machinist straight edge to detect that the block is with in spec. IFFF it is, then a good clean up of the block will usually do the trick with a composite gasket. Lapping, or stoning of the block is not going to cut the surface enough to make up for out of square or heavy rust and pit marks. Kinda like sharpening a lawn mower blade with a sheet of sandpaper.

 

[bountykilla0118]

So what the solution? Sounds like you guys are saying send the block to the machine shop.... Most of my mechanic friends say just get the block nice and clean if there was no damage before and in my case i dont have any

 

[bowsercake]

With the head machined and the block in good condition you should be ok. Just check the block first and don't run too much boost.

 

[JustAnotherVictim]

You can have the head and block checked to see how flat they are.

 

[suprarich]

So what the solution? Sounds like you guys are saying send the block to the machine shop.... Most of my mechanic friends say just get the block nice and clean if there was no damage before and in my case i dont have any

No we are saying to check the block for squarness first with a straight edge, and if out of spec., then take it to the machine shop.

 

[bigaaron]

So what the solution? Sounds like you guys are saying send the block to the machine shop.... Most of my mechanic friends say just get the block nice and clean if there was no damage before and in my case i dont have any

Are those mechinic frends willing to do the whole job over again for free when you take their advice and it blows?

I'm just offering some friendly advice, it's ultimately your decision to make.

 

[MassSupra89]

It didn't blow in the first place though, he's saying he didn't get a BHG, just replacing the Headgasket I believe.

 

[bigaaron]

The question of "should I surface the deck for a new hg?" is like:
::dead horse::

There will always be people who say to do it right, and other people who say you should cut corners to try to save money.

 

[againstdawall06]

Well what is the best thing to do if you dont pull the motor out? Lets say the deck is straight, should you take sand paper to it or anything to make sure it is clean and smooth?

 

[JustAnotherVictim]

No sandpaper.
Ever.

 

[bigaaron]

The best thing to do is to pull the motor out. That is definitely not the easiest, cheapest, or fastest way to do it. If you leave it in the car then just clean the deck with a razor blade and some carb cleaner, but don't get a bunch of old hg stuff in the oil and coolant passages.

 

[americanjebus]

If all else fails man a new putty scraper and some greese covered rags in the pistons and just have at it over and over for a while until you get that metal shine back. just be carefull not to grind the edge of the scraper or to use anything like a brush.

 

[bountykilla0118]

Hey thanks for all the feedback guys well how about this i rebuilt the stock motor back in feb i have put maybe 12,000 miles on her would it be a good idea to re-tq the HG? I have seen a couple threads saying not too but i assume they were saying not to b/c the motor probably has over 100,000 and he been like that for years ..... sooo dont re-tq b/c it will create a problem that you did not have. I mean a mushed HG thats going to blow. But i am not in the position mine is still kinda fresh

 

[MDCmotorsports]

Does any one ever search... I'll try and find my write up about how to do a BHG on a budget.

And yes, Aaron is right. If the head & deck are warped you are wasting your time without machining first.