6 bolt head on a n/a 7 bolt block

[camas90gsx]

Alright, i threw a rod on my 1g gsx and the block has a hole in it so obviously it's destroyed.Now i found a 7 bolt n/a 4g63 with 2g block,2g pistons,1g big rods,.50 bore over,new turbo pistons,new water pump,new seals etc.. for a really good price.I would get the complete longblock but there might be 2 bent valves and needs new hydraulic lifters.So i was thinking i could salvage my 6 bolt head from my gsx and use it on the new shortblock.But the problem is i dont know if it would match up as far as the cam position sensor,and crank position sensor etc..And this longblock is 3 hours away and if so i want to drive to pick it up tomorrow.But if there might be issues with every thing matching then i might look elsewhere.Its just that with this shortblock being rebuilt 2,500 miles ago with reciepts to show everything like crank machining,seals, etc,i hate to pass this up.So what do y'all think i should do?PLEASE HELP Y'ALL!!

 

[bryanwheat]

No, that would indicate something is wrong. In fact, overboring might actually increase compression test results even with identical compression ratio pistons simply because you are now compressing more volume.


Definitely. You MUST bleed the lifters. If you don't, the valves will still hang open even when the rocker is off the lobe and contacting the base circle of the cam. Pistons go up, valves get bent.

The lifters will bleed down from the spring tension after being in the head for a few hours. you don't have to manually bleed them if you aren't going to start it right away.

 

[delta448]

You're correct, but why risk it?

It'll depend on oil used and the ambient temperature as to how fast they'll be safe. If you use a higher weight and it's cold out, they can take quite some time to self-bleed.

I'd rather just pre-pressurize by spinning the oil pump with a hand held drill or just simply crank the starter for a couple more seconds until the oil pressure allows the valves to open. No risk that way.

 

[camas90gsx]

I will pass all of this information along to my mechanic.And you were right it was a .050 bore on the paper work.After looking at the block the only issue at all that i see is that the oil filter housing is still a n/t style attached to the block.Would i be able to attach my turbo oil filter housing to the n/t block without a fitment issue?I cant see if the turbo oil filter housing bracket will bolt to the n/t block.He installed the motor in his talon and ran it as a non turbo set up with turbo internals and was goint to install a t/3 set-up on it later when he could afford it but ended up with the valve issue.He said the compression was different from when it was n/t internals though which would make sense because the n/t and tubo engines have different compression.He did a test where he put a certain amont of oil in the cylinders over time it sealed perfectly and then he tried the same test on his other turbo tsi 2 of the cylinders ended up empty after awhile.I guess that is maybe here nor there but i guess my main issue now is going to be getting the turbo oil filter housing bracket to mount on the n/t block.Does anyone know if this should be an issue? Ofcourse the guy with the block says it will be no issue at all.