Guys, need help with my 2.8!

[BigD9146gt]

So heres the shimmy... a few months back I picked up an engine that had been sitting in pieces for over 15 years. It came out of a '72 2.4 E, and had been modified with 92mm Mahle RSR P&C's, '74 3.0RSR cams, and the MFI pump matched while keeping the stock heads (33int,32exh).

There is some bad rust pitting on the cams, but if they can be fixed I'm going to. My question is this, besides the obvious shuffle pinning, time-certs, turbo oil pump, twin plug, etc..., should I open the heads up? And how big? Should I find some early SC heads instead? I am shooting for ~230hp because I want this to be a weekend fun time & short track event engine.

Cheers, Don.

[Steve@Rennsport]

Don:

A few questions if I might,...

1) Do you have 98mm P/C's or 92mm 2.8 RSR ones?

2) 3.0 RSR cams are pretty aggressive for any street use, especially in a 2.8 or smaller; are these truly RSR or perhaps RS cams? Regardless, these can be repaired as long as the bearing journals are OK.

33/32mm port sizes are FAR too small for RSR cams so you might confirm the above,...

The ports should be opened up but the exact configuration will depend on camshaft choice and how the car is to be used. I'd start at 36/35mm for sure.

SC (and later) heads have totally different stud spacing so those will not fit.

[Eagledriver]

How can you have 98mm cylinders on a Mag case engine. The stud spacing is too small for that. Either you have a 3 litre case or you have 92mm cylinders.

Ports were 43mm on the 2.8 RSR and the 3.0RSR as well.

-Andy

[BigD9146gt]

Thanks for the replies.... Your both correct, hey are 92's.... my bad.

They are RSR cams, apparently they worked really well with the stock E heads. The guy I bought the engine from was the crew chief for John Bauer's 935 back in the early 80's.

Back on the heads... would opening up the E heads be ok? What would be the max porting size I could get away with before the valve size needs to change?

Again, thanks.

[Steve@Rennsport]

Originally posted by BigD9146gt
They are RSR cams, apparently they worked really well with the stock E heads. The guy I bought the engine from was the crew chief for John Bauer's 935 back in the early 80's.

Back on the heads... would opening up the E heads be ok? What would be the max porting size I could get away with before the valve size needs to change?

Again, thanks.

RSR cams BEGIN to breathe when E or S heads are well beyond peak HP & torque. IMHO, you'd be much better served by using either an S cam or something like GE-60's unless you are racing and have close-ratio gears.

Open those head ports to 38/36 for a good 2.8.

[BigD9146gt]

Steve,

Thank you for your input... one more thing. What should I do about the MFI stacks? They are 33mm for the stock E heads... should I bore them out (cause I would love to keep the MFI system on the motor) or should I just go to standalone (cause I have a friend at 034 Motorsport).

Cheers, Don.

[Steve@Rennsport]

Don:

Engines are integrated systems that are carefully designed & configured to work together for what the engine was intended to do.

Intake systems, like exhaust systems, must be matched to the camshafts and operating RPM range. If you are really going to use the RSR cams, you need an MFI system with 40mm-42mm throttles and at LEAST S stacks.