Need a Turbo Patron

[nando]

i always thought that people welded heads and modified head gaskets at cyl 4-5 to avoid steam build up. That's the primary cause of head cracking, so opening those coolant passages allows coolant to free-flow.

nope!

the reason is because the head is really thin right in the center of those openings, the head flexes and pushes the gasket out. The gasket then blows and you either have oil/coolant mix or you steam clean the combustion chambers clean/pressurize your cooling system.

BMW actually fixed this on the late M30s. Originally they came with the same coolant passage design as the M20, which had severe issues with cracking and blowing gaskets. Later they were cast solid (like if you weld an M20 head), but they never fixed this issue on M20. Maybe because it's only a big issue when you add boost to the equation. Somehow I doubt the kraut engineers of 25 years ago thought people were going to boost these old cars some day. ;)

Filling in those channels doesn't hurt the cooling capacity at all either. Just looking at how the headgasket is designed makes it pretty clear.

[nando]

i thought that welding the head was a must do thing. not so much for containing the boots, but for head stregnth. looking for a head now to start P&P and building, since i am going S/C on the motor i though i would go a head and get it done after i P&P it and send it out for the rebuild.

i am going to run a MAX of 15 psi (12 more likely), but it will end up seeing 8 most of the time for sure.

so o ring it or weld it or ....both?

if you are just doing 8-15psi, o-ringing will be enough. Both is more of an overkill thing to give you peace of mind.

[Aptyp]

Alright, first question....


My turbo has coolant lines, and I need to know, where is a good place to tap for coolant and where to drain. Pics would be greatly appreciated. GO.

[Aptyp]

damn it, so much excitement and as soon as I ask my first serious question I get nothing but crickets.

[nando]

I think some guys are using the TB heater lines

[Aptyp]

it's kind of a long route, isn't it? But I guess it could work.

[yberther]

it doesn't really matter right? just as long as it flows...

[Aptyp]

it has to cool, as well, coolant for the throttle comes straight out of the back of the engine.

I may use E pump and run hose off the pump. Hope it works. I'd like to see pics of what others have done.

[whiltebeitel]

it has to cool, as well, coolant for the throttle comes straight out of the back of the engine.

I may use E pump and run hose off the pump. Hope it works. I'd like to see pics of what others have done.

Just a thought, why not tap into the outlet of the water pump?

[Tchao]

Why not just leave it dry....

[Aptyp]

why do Honda boys put dual exhausts on, when one side is clearly non-functional???



Because it's there and it would make for a great and safe install.

[nando]

it has to cool, as well, coolant for the throttle comes straight out of the back of the engine.
.

that coolant is still going to be way, way cooler than your turbo. EGTs are like 600-700+ degrees, your coolant is maybe 180-190 after going through the engine.

[lifeiskaos]

+1 to using the throttle body coolant hoses. subscribed so i can try to help with any other questions, as i've turbo'd m20's before.

[yberther]

that coolant is still going to be way, way cooler than your turbo. EGTs are like 600-700+ degrees, your coolant is maybe 180-190 after going through the engine.

exactly what I was thinking.

So what's next?

[Tchao]

Safe install?

Thats one more thing that can go wrong. The probability is higher then you think.

It doesnt need to be watercooled, you are not running it in a crammed engine bay, like a Audi or Vdub.

But if you insist on tapping the water pump, go ahead lol.