Oil relief setup for a 2.7 engine

[teveo]

Having gone through the various oil relief discussions i still am a little unsure about setup for a std 1974 2.7 engine, no bypass mods.

From the parts I have (the kit from pelican) it seems like it will be:

2 short springs
2 late style pistons ( no holes )
1 guide

Just did the vertical one today, will give the horizontal a try tomorrow, had to soak the exhaust bolts with rust penetrating oil and hope they will become easier to handle..

I used the guide in the vertical relief valve, leaving me with just a short spring for the horiz. relief valve.

My configuration will be:

Vertical relief valve: short spring, new style piston + guide
Horizontal relief valve: short spring, new style piston.

Please advice, would not like to get this wrong!

[Eagledriver]

What did you have in the engine before? If you didn't do the bypass mod then you should use the old stuff. I don't have my books with me right now but I'm sure Waynes book would have this as well as Bruce Anderson's book.

-Andy

[teveo]

Am working on loosening the exhaust header, so dont know sizes on the horizontal relief valve ( it is stil in so to say )

The vertical spring was identical to the the size in the kit, noticable softer and with the old style piston, no guide however.

That one is already fixed, and from what I read the new style piston is a better choice as it does not have the holes on the side of the piston.. but all in all i suppose the sligthly stiffer spring will make most of the work here.

Right now I am soaking the exhaust nuts/bolts with WD40 and hope they loosen up. Will give them a try tonight, need to buy a new 8mm long hex socket as well, but if I have problems with the manifold I may as well just change one for now..

[MBEngineering]

HI is this a help to you. from the 1977 update paper work.




just check the oil pressure if you are fitting solid pistons, as the system was not designed for them, you may get to much??

regards mike

[teveo]

thanks.. i will install the solids and check.. too much and i will only fit the new springs! ( the hassle of this work is the manifold... stuck bolts )

[Eagledriver]

I don't know for sure but I suspect you need to keep using the old style piston since you don't have the bypass mod. Unless someone has tried your combination with the newer pistons and springs you're just shooting in the dark.

-Andy

[eapcpa]

The purpose of the by-pass mod is to route the return oil directly to the pump so it can return to the oil tank directly. Thus it bypasses the crankase and reduces the amount of oil accumulating in the case. I think I would go with the porsche engineers on this one and use the original spirings and pistons if you don't have the by-pass mod on the case. JMHO

[Eagledriver]

Ed,

That's only partly right. The bypass mod returns oil to the input of the pump not the tank. It sort of has the pump working the oil in a circle back to itself instead of dumping it into the bottom of the engine. I don't know if the holes in the old style piston have something to do with how the old bypass works or not. I do know that with the bypass mod you have to use the new pistons and springs so it's likely that the reverse is true as well.

-Andy