My machine shop guy told me the block was shaved off 7thousandths and the head was shaved off 12thousnadths... he saying he doesnt know the stock thickness of the stock hg.. What size MHG should i get could any1 help me thanks guys!
Metal Head Gasket Size Help
- Thread starter i165mk
- Start date
The best way is to:
measure piston deck height
head thickness (or CC the head)
measure piston dish volume
engine bore
and use a handy online calc to figure out your desired comp ratio w/ HG thickness and bore as your variable.
(Keith Black has a good calc, as well as numerous posts here about it. Search.)
jdub and IJ contributed to a good thread a while back about it. BTW - don't forget about figuring in your squish (or quench, what ever you want to call it).
Or you could just guess and get a 2mm hks..... (at least you would be 'safe')
Stock thickness is 1.37mm compressed (.054")
measure piston deck height
head thickness (or CC the head)
measure piston dish volume
engine bore
and use a handy online calc to figure out your desired comp ratio w/ HG thickness and bore as your variable.
(Keith Black has a good calc, as well as numerous posts here about it. Search.)
jdub and IJ contributed to a good thread a while back about it. BTW - don't forget about figuring in your squish (or quench, what ever you want to call it).
Or you could just guess and get a 2mm hks..... (at least you would be 'safe')
Stock thickness is 1.37mm compressed (.054")
"Safe" is a relative thing......
If you keep boost moderate yes it'll be safe but if you plan on cranking out some big HP you really need to measure it accuratly and get the correct gasket.
If you keep boost moderate yes it'll be safe but if you plan on cranking out some big HP you really need to measure it accuratly and get the correct gasket.
I was begin sarcastic. That seems to be the mentality around here sometimes (not a shot at you).
There are a lot of factors in figuring out the correct HG (I did not want to get into dynamic comp - there is a lot more involved in that - way beyond what you are asking).
Do the measurements that I mentioned above - that way when you get a HG you will know why you bought it, not that it was what everyone was doing. The only thing I can suggest (beyond above) is find one with a bore as close as you can to what your engine is. I don't understand why people use 86mm bore gaskets on 83.5-84mm bore engines, really doesn't make sense to me.
There are a lot of factors in figuring out the correct HG (I did not want to get into dynamic comp - there is a lot more involved in that - way beyond what you are asking).
Do the measurements that I mentioned above - that way when you get a HG you will know why you bought it, not that it was what everyone was doing. The only thing I can suggest (beyond above) is find one with a bore as close as you can to what your engine is. I don't understand why people use 86mm bore gaskets on 83.5-84mm bore engines, really doesn't make sense to me.
not really looking into big numbers maybe 300-350 the most 400 later down the road wen i upgrade to a 57trim..i have all arp hardwares portandpolish head stock turbo my machine shop guy just told me to go with a 1.5mm does that sound right ?
BW: I use the 86mm HKS Stopper with my 84mm bore as that's the only size they make it in and I've blown a few regular MLS's running this thing ragged during development of the fuel system.
165: Measure it it's NOT that hard......
If your "Guy" is saying 1.5mm is near enough find a new "guy"
165: Measure it it's NOT that hard......
If your "Guy" is saying 1.5mm is near enough find a new "guy"
But IJ, that was a conscious decision that you made based on specific criteria. You knew why you made that choice.
I don't how well that applies across the board
I think the creation of hot spots and turbulance by the gap created between an 86mm gasket and an 83.5-84mm bore would eventually cause more problems for DD people here that a gasket with a proper bore would at the end of the day.
If my cometic goes (that I had built to my specs) because of pushing the design beyond what it can handle, you'll be the first I call with questions about the stopper gaskets!
I don't how well that applies across the board
I think the creation of hot spots and turbulance by the gap created between an 86mm gasket and an 83.5-84mm bore would eventually cause more problems for DD people here that a gasket with a proper bore would at the end of the day.
If my cometic goes (that I had built to my specs) because of pushing the design beyond what it can handle, you'll be the first I call with questions about the stopper gaskets!
another question what are some gaskets that i should get that doesnt come in with a felpro full engine gasket set that i should change in my rebuilt motor?
BW: It's only a 1mm step with nicelt chamfered edges so I can't see it being a huge issue, as for the increase in squish I honestly can't see it making a measurable difference in output.
These aren't race motors where you're trying to gain an edge on competitors using the same hardware.
(I think people lose track of this here sometimes)
These aren't race motors where you're trying to gain an edge on competitors using the same hardware.
(I think people lose track of this here sometimes)
True, I see your point. I was thinking more of the carbon build-up with petrol in those areas (after 30-40k mi with a less than ideal tune) and then cranking up the boost on a less than perfect tune (or running lean at partial boost, a la lex mod) and then having a heated area the would lead to a popped gasket or worse, cracked piston.
With propane, carbon build up won't be an issue for you. I guess if there are things that I can do that would reduce the potential of a problem, I have a hard time not fixing (or avoiding) them.
With propane, carbon build up won't be an issue for you. I guess if there are things that I can do that would reduce the potential of a problem, I have a hard time not fixing (or avoiding) them.
All depends on the amount of material removed and as 7M's are so prone to head issues it's always a good idea to measure the head in case it's been surfaced before.
