im planning to buy an mhg but dont know which size to go with what determines the size you should get ? does it matter ?
HG help
- Thread starter i165mk
- Start date
well it's obvious you haven't searched long enough, (not tring to be mean!)
it depends on how much material is removed from the head and the block
typicaly if alot of material is removed it's better to get a thicker one to get the compression ratio close to stock,
if the deck and head are not warped, and only needed to be surfaced to spec, then a 1.3/1.5 will do the trick,
it's important to surface the blcok, just asmuch as the head,
there have been cases where lapping the block (i belive it's a form of polishing) will due the block good, and a proper RA on the head will seal great,
i dont reccomend it, just cause people tend to overlook how flat there deck is or miss a low spot, like i did,
generaly the ra:25 SPEC tends to work with most head gaskets,
most machine shops do not have the proper tools to measure RA, but through years of exspeince on doing other mls head gasket engines, it shouldn't be a problem if you stress mirrow like finish they should do a good job, and if your not satified, ask how much was remove and see if they can clean it better, make it smoother..
only bad part of a mhg, is to due the instalation properly (in my eyes and many others) you must pull the engine, yank the crank and send the bare block to the machine shop,
at this point, their going to bust your freeze plugs out, surface, and hotank, or some sort of cleaning method,
this is where many decide to rebuild the engine since they realize they will be hard on it ...
hope i have helped, but like many will say, this has been covered, i just know the feeling of being told inaccurte info, or being pushed around so to say,
hope all goes well on the head gasket replacement.
it depends on how much material is removed from the head and the block
typicaly if alot of material is removed it's better to get a thicker one to get the compression ratio close to stock,
if the deck and head are not warped, and only needed to be surfaced to spec, then a 1.3/1.5 will do the trick,
it's important to surface the blcok, just asmuch as the head,
there have been cases where lapping the block (i belive it's a form of polishing) will due the block good, and a proper RA on the head will seal great,
i dont reccomend it, just cause people tend to overlook how flat there deck is or miss a low spot, like i did,
generaly the ra:25 SPEC tends to work with most head gaskets,
most machine shops do not have the proper tools to measure RA, but through years of exspeince on doing other mls head gasket engines, it shouldn't be a problem if you stress mirrow like finish they should do a good job, and if your not satified, ask how much was remove and see if they can clean it better, make it smoother..
only bad part of a mhg, is to due the instalation properly (in my eyes and many others) you must pull the engine, yank the crank and send the bare block to the machine shop,
at this point, their going to bust your freeze plugs out, surface, and hotank, or some sort of cleaning method,
this is where many decide to rebuild the engine since they realize they will be hard on it ...
hope i have helped, but like many will say, this has been covered, i just know the feeling of being told inaccurte info, or being pushed around so to say,
hope all goes well on the head gasket replacement.
If you're doing a complete rebuild then wait till the block and head have been prepped. Then you can measure the deck heights to see which gasket thickness will bring it back close to stock. (We're talking thousands of an inch here), so don't buy any gasket till you know which one you need. If the engine is staying in the car, get the r.a. as good as possible (try to find a hand lapping tool) then measure.
yeah typicaly you want to know how much was removed,
i belive i had .009 removed from my deck, and .003 from the head,
when i had only had the head work done i used a 1.4mm, after words i switched to a 2.0mm
*if you choose to lap it, do a lot of searching, you need to know the compounds to use, what the lapping tool looks like, need to acquire this stuff. and you need about a week atleast to put enough time in lapping the deck to get the surface most desire.*
DO not use a 2x4 and sand paper, it may clean the block and make it shiny, but sand gets into you engine, and usualy doesn't have a hard enough, flat enough surface to do any good with a 2x4.
ps, the dowel pings are easy to remove using a pair of pliers, careful not to do to much damage to them by slipping, twisting them as you pull out helps alot.
the pins must be removed at time of lapping to ensure you cover the hol area' equally.
i belive i had .009 removed from my deck, and .003 from the head,
when i had only had the head work done i used a 1.4mm, after words i switched to a 2.0mm
*if you choose to lap it, do a lot of searching, you need to know the compounds to use, what the lapping tool looks like, need to acquire this stuff. and you need about a week atleast to put enough time in lapping the deck to get the surface most desire.*
DO not use a 2x4 and sand paper, it may clean the block and make it shiny, but sand gets into you engine, and usualy doesn't have a hard enough, flat enough surface to do any good with a 2x4.
ps, the dowel pings are easy to remove using a pair of pliers, careful not to do to much damage to them by slipping, twisting them as you pull out helps alot.
the pins must be removed at time of lapping to ensure you cover the hol area' equally.
sounds good,
is yor casr still drive-able, or did you already lose your hg?
it;s tuff having to do all this work but the results are well worth it.
is yor casr still drive-able, or did you already lose your hg?
it;s tuff having to do all this work but the results are well worth it.
clyinder # 3 has 30 PSI and the rest came out to only 90PSi prolly will be buying a spare head+block and then starting my build my mk3 is my only car and cant be carless for weeks. cant wait till i get my new motor in tho !!
You guys are leaving out the quench, or the bore of the head gasket vs the bore of the block 
. You want a head gasket that has the closest bore to the engine as possible. If you have a block with a bore of 84mm (I think this is .040" over, it's still early, bear with me) then the best gasket to get of course would be one with a bore of 84mm (I think Cometic has one like this).
. You want a head gasket that has the closest bore to the engine as possible. If you have a block with a bore of 84mm (I think this is .040" over, it's still early, bear with me) then the best gasket to get of course would be one with a bore of 84mm (I think Cometic has one like this).
True, true, I forgot about them only coming on JDM's, make sure you clean that old JDM gasket off before you sprey 'er down with permatex .
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