Thread: head resurfacing, deck heights and gasket sizing.

all may not be lost with my fully worked sr20ve head. by that i mean it can be returned back to 86 fairly easy and fairly cheaply.

here are some pics.





thats pics of the port work and port matching and the smothing of the valve guids to increase flow/velocity, i dont have any pics of the worked bowls. the head also recieved fully hand lapped valves.

we all know what a stock combustion chamber/deck looks like. i was under the impression when the machinest milled it out to 90mm it was similiar to what mazworx or head games would do to a head. quite simply i recieved the complete opposite. either way it worked and im glad thats all they did and heres why.



you can see here how the pistons stuck out of the block, this was la sleeves decking the head with out the timing cover (even though i told them too and included a brand new oil pump from gregv bolted to the block) forcing me to have the deck re-decked a second time with the timing cover.

i figured the thick mazworx headgasket would compinsate for this, i figured wrong. first time around the ends the outer edges hit the deck of the head head and also the upper most corners kissed the inside of the combustion chamber. motor was disassembled and the head was then milled out to 90mm so the outer edges of the pistons wouldnt touch the head and some material taken out of the upper inside of the chambers. the second time around they did not touch, and the motor ran for atleast 800miles before i hit the dyno.

heres a pic of what the machinest did.



you can clearly see here all they did was mill a 90mm circle step about .028 of an inch deep out of the deck matching the mazworx 90mm gasket.



heres a pic of a .026 feeler gauge, its a bit small and if i had to take a guess .028 would be dead flush as .030 is to much.

so basically if i mill whatever needs to be taken off .027-.029 ill be back to a perfectly square 86mm combustion chamber.

id then have to figure out what size mm head gaskets in 86 or 87mm are offered to compensate for the orginal deck of the head and the .028ish of an inch they took out. say run the thickest gasket avaliable or whatever.

then figure out if you'd wich i imagine you'd have still have plenty of piston to valve clearance on off the shelf pistons, if not you could always mill the pockets down some. regardless if i ever decide to build a ve of any sorts agian id have the motor clayed.

id just like to hear some feed back, and possibly some of your guys views and info on this. if im correct in thinking what i am, and if its possible with the use of the right head gasket etc.

what a nightmare this whole 2.4 thing was but im glad it seems the head is still salvagable it cost me some really good coin and i knew it would help me obtain my goal.

stratton.

Only thing is there is a limit on how much you can deck the head but I know thats with use of stock gaskets. I wouldnt see it hurting anything to deck the head down to the step and use say a 2 or 3mm gasket if available. I dont know how many thicknesses they make the ve gaskets in if at all much thicker than the stock gasket. From what ive seen most of the ve gaskets are between 1.1 to 1.3mm thick. I know they make de/det gaskets in 2 and 3mm thick varients. Something you will have to research.

So it seems your whole initial problem to begin with was the pistons sticking out above the block. Seems as though they didnt get the pin height right or something because thats a lot of piston sticking up above the block. Usually when you deck a block you only remove about .001-.003 off the top so even if they had to redeck with the timing cover they should have been able to shave the cover down and then take at most .001 off again to make sure it was perfectly flat with the block. Your piston looks like its sticking up about .020 or more above the deck.

Not good either way. Even though everything may have checked out with clearance wise during assembly I still wouldnt have assembled the motor with the piston like that. Some motors come that way such as the F20 motor in the s2k. Piston sticks up above the deck of the block about the same as yours is. But SR's have always come pretty close to flush or just below the top of the block. So seems some numbers went wrong somewhere or the machine shop really jacked up and took way too much off the top of the block.

I say give it a shot, sounds doable, so what exact size gasket sizes to they offer for your setup,de-ve block?.

Ashton, if headgasket in the size I or someone would need is not available custom pistons then would be the answer.

Gio, im not sure in the next few days I will call around and do some research, it would be a ve block. im curious if you can run a det gasket but drill out the hole that the ve motor needs for oil.

If my car doesnt sell im am becoming tempted to send my head up to jaime, have him fix the head and build me a high comp 2.1 liter bottom end, have him install it , swap my intake mani and header over and tune it. he knows more then i do and has clearly has access to better machine shops then i.

Stratton.

Cosworth has an 87mm gasket that is 1.8mm thick. Which is .0275 bigger than a 1.1mm gasket. You could most likely cut out the oil feed hole or just run a line the de block/ve head way if modding the gasket is not an option.

How about using a DE/DET block, tapping the head for the oil feed then using a thicker DET style gasket.

They seem more readily available with a better selection than the VE gaskets.

I would imagine with a clean block that is more normal ie pistons not sticking up that you would be fine with another mazworx ve metal gasket. You might lose a hair of what ever compression you were shooting for with the little notch in the head but I doubt it would be much . Didn't you go for 14+ compression on that setup ? I would imagine that's a possible reason why the piston stuck up out of the block . A hair to much shaved and a hair to big of a piston dome . I say make a 87 or 88 build and enjoy it !

i agree with running a line to the from the block to the head... but thats just my 2cents

Mrspecv has a good point. The problem was that the block seemed to be decked a lot and this is most likely the reason the pistons were sticking out of the bores. So with a different block I'm sure you'll have no issues.

From my assumption I think what he is planning on doing is slapping that head on his stock Vvl motor that's currently in the car, so he would need a Vvl head gasket tyPe but thicker to make up for the material that was removed from the head.
I would go slightly thicker than factory and adjust the cam gears,it would raise his compression.