? on using NA block for turbo application

[wes200x]

Okay I am on spring break so it is time to put a motor together. I took 3 motors apart and the best block is a carbureted block that I had before the car went turbo. My question is will I have any ill effects of putting turbo pistons in a NA block. I noticed the NA block does not have the 3rd blow by passage on the back of the motor.

 

I know people have run the entire short block with NA pistons, So I just wondered if anyone has thought about this or do some NA blocks have the 3rd blowby passage.

 

Thanks for all feedback

[GeneralDisorder]

I noticed the NA block does not have the 3rd blow by passage on the back of the motor.

 

What exactly are you refering to here?

 

GD

[Caboobaroo]

The PCV port on top of the motor on the passenger side, next to the knock sensor is what he's referring to.

[TheSubaruJunkie]

I used a SPFI block when I built my RX motor. Cant remember if it had that 3rd PCV or not. I ran stock boost and it felt great. Better than the EA82T block at 12psi (stock is about 5 to 7ish). With the intercooler installed, it was max boost at 5psi

 

I wouldn't use a high compression block without an intercooler.

 

 

If you want a N/A Block WITH the 3rd passage, look for a MPFI block from a XT. They will have it.

 

-Brian

[Caboobaroo]

SPFI block doesn't have the third PCV on it like the MPFI and turbo cars but does have the threaded insert for the knock sensor. I had mine at 12psi but holding it to the floor for too long caused it to blow the rings out:rolleyes:

[wes200x]

yes I was talking about the 3rd pcv vent. I was worried cause I know turbo motors usually produce a little more blowby and not only do those vents go to the pcv but they also vent crank case pressure. I just thought there might be an issue with 2 much positive crankcase pressure without the 3rd vent. thanks for the responce

[idosubaru]

if it exists on other EA82's could it be as simple as creating that same hole? probably has the boss or something marking where it should be already right? then thread something in it? not that i typically suggest drilling into blocks but and EA82 is an EA82.....is....maybe?

[silverhelme]

I used a carbed block on the last turbo rebuild. All I did was cap the port that goes to the rear vent. I have had no problems and no exessive oil usage. If I understand you correctly you are going to rebuild a non turbo block using turbo pistons which is what I did.

[joostvdw]

if it exists on other EA82's could it be as simple as creating that same hole? probably has the boss or something marking where it should be already right? then thread something in it? not that i typically suggest drilling into blocks but and EA82 is an EA82.....is....maybe?

 

I wouldn't do that, the change of getting metal shavings and debris from drilling inside the engine is very large, even with some sort of debris sucker (read vacuum cleaner) you won't be able to suck up everything

 

Maybe you could use the dipstick hole as a main crank case vent?

[MilesFox]

i have a carb block with turbo setup in the 87 rx. runs just fine stock.

 

i simply bypassed the 3rd vent on top of the block, for lack of having a proper TEE. the pistons themselves should swap no problem, but you have to split the block

[idosubaru]

I wouldn't do that, the change of getting metal shavings and debris from drilling inside the engine i

ding ding ding - nice call!

 

i've always wondered that about spark plug hole threading/chasing and tapping too...they chase and drill those from time to time and i've always wondered how they do that without dropping something right in the combustion chamber?

[silverhelme]

We use grease on the tap and remove it, clean and regrease about every full turn. Slow but it traps 99% of the chips.

[Turbone]

My last turbo engine I had (and blew) was missing about 1.5in of the edge of the piston. There was no trace of it when I removed the head. And there was only small marks of the top of the piston with no damage to the valves. Little alum shavings are going to just get blown out the exhaust.

I know when the PCV system/hoses start to get plugged with junk and back pressure builds, the dip stick likes to pop out to relieve pressure in the block.

[testy]

Alluminum shavings will do less to a motor than most think.

[Gloyale]

the pistons themselves should swap no problem, but you have to split the block

 

No you don't. In fact, the proceedure for tspliting the block is to remove the pistons first. The main *caps* in the block prevent the pistons from dropping though the bottom of the cylinder.

 

Only other way to split a block with pistons in place is to fanangle the bolts off of the rod caps for both pistons on one side, PITA, requires 12mm swivel socket. So no, no need to split the block for pistons.

 

 

Just remove the wrist pin plugs, then access the wrist pins and remove them. The pistons will then pop right out of the top, rod stays in place in the block. Try not to let the rods knock around inside the cylinder while swapping pistons.

[wes200x]

Here are a couple ansers to some of the replies I have read. My block does not have the cover or the castings in the case to run the 3rd vent it is completely different than the turbo block. Also you can not split a ea82 block without first removing the wrist pins. The base of the pistons will hit the main journals in the case.