I want to bolt a tpi setup on my 327. I have a lead on a decent 87 setup.. I know I have to modify the center bolt holes and put on some valve covers with provisions for ventilation. Can I just use the road draft tube in the back of the block as crankcase ventilation or what.. I know someone must have put a tpi set up on an older engine.. any help would be great.

Thanks,
Don

 

With port injection you do not need an anti-backfire/flame arrestor device (usually built into the metering valve) bacause a backfire cannot migrate past the throttle valve. Many modern EFI systems just vent the crankcase to a point downstream of the air cleaner and upstream of the throttle body. The slight vacuum in this area of the inlet system combined with a slight pressure in the crankscase will force blowby gas to migrate into the inlet tract and be mixed with the incoming air.

The OEM "ventilator" in the valley functions as a liquid vapor separator and is reasonably effective, but if you notice any oil passing, you can put a tee into the system with a plugged down line that will act as an oil trap.

I implemented this architecture with great success on my Cosworth Vega. Despite it's port injection, GM designed a conventional PCV system with a fresh air inlet and valve typical of carbureted engines. The clean air was drawn from a nipple on the air cleaner and routed down to the bottom of the crankcase, through the engine and out through a nipple in the cam cover and to the manifold through a conventional PCV valve. The design caused a significant oil ingestion problem.

After trying one design that failed, I removed the inlet line and plugged the crankcase inlet, removed the outlet circuit and valve and plugged the manifold inlet. Then I routed a single half inch line from the cam cover nipple to the former fresh air inlet on the air cleaner. The line has a tee with a length of clear vinyl tubing that routes to the bottom of the car. It has a removable plug to drain any oil that gets trapped. With this system the is no more oil ingestion, no more crude in the manifold, and no more oil soaked air cleaner elements.

Duke

 

Thanks Duke,
I should have known you would have the answers. I figured as long as I changed the valve covers or drilled the repo Corvette finned covers I would be fine. I figured since I need a new carb anyways and with the price of them now adays I might as well go for the fuel injection for a driver non original corvette anyways...
I have installed a tbi setup on a 76 motor with no problems but I didnt know if the old motors with the "oil fill tube" would present any other issues..

The fun part will come when I go to modify the sending unit for a return line..wish me luck

Don :chevy

 

An 86 TPI manifold would have fit your older heads without modification. They changed the center bolts in 1987. Don't forget to grind the useless lobe away right behind the throttle body. This should run very well on a 327. Get a cam with a powerband up to about 5500 and you'll make very good torque. TPI's have a difficult time going higher than 5500 rpm without very expensive aftermarket plenum and tubes.

The stock TPI crankcase ventilation method will work fine. I run my TPI on an old 70's era 4-bolt truck block, with zero problems. Best improvement that engine has ever had bolted on!!!

:rofl:

 

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