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Outlaw 911 Outlaw 911 is offline
Outlaw 911
Join Date: Apr 2008
Location: Northern Colorado
Posts: 66
Opinions wanted....

Hi Boosted Pelicaners –

Here is the situation- about 3 weeks ago I bought a 77 vintage 930 3.0L Turbo motor complete. Pretty darn original. The exceptions are the eliminated thermal reactors and the missing air pump.

The motor was disassembled when purchased and after a few hours of inventory – it appears to be all there from the fly wheel to the muffler, including electrical harness, injection, engine tin, AC compressor. The only exceptions are the driver’s side chain tensioner oil line and some of the cylinder cooling air guides.

The Good –

77K mile engine – appears to have had a top-end rebuild recently.
WebCams – stock grind? Has the number 150 under the Webcams stamp.
No broken rings or damaged pistons.
Crank and rod bearings in good shape.
Updated to Carerra tensioners.
Heads rebuilt with new guides.
Heads professionally ported to 36-38mm size – very well done.
Rockers appeared to rebushed.

The Bad –

2 broken head studs.
2 of the cam lobs on the same cylinder are rough. Looks like someone ran it with valves misadjusted - way too tight?
2 of the rocker arm shafts were stuck in their bores – and it took a little work to get them out their bores – and those bores were slightly scored – is this OK?
And in general the it is an oily, stinky mess.

I am planning on rebuilding this engine in the coming year and do the following:

Install late model Carerra intake.
Swap over to electronic engine management.
Run crank fired distributorless ignition.
Install an intercooler.
Upgrade the cams (SC or 964)
Use a modern turbo header/exhaust.
Use a modern turbo (a K27 version).
Gut the stock muffler and run duals out of it.
Use a modern blow off valve or recirculation valve.
Use a modern waste gate.
Run either a short G50 or re-geared 930 transaxle.

The goal is a 350hp to 400 hp engine that is happy on the street, but can handle track duty, with a useful power band from 2500 to 6500. I am NOT interested in a dyno queen with big numbers - this 911 will be used for DEs, autox, fun rallies and OLOA.

I need some help deciding a few items:

1 What sort of compression ratio should I aim for? Currently, it is at 6.5 to 1. I will not run more than 14 psi of boost and would like a peppy off boost engine.
2 What is the cost effective way to increase the CR? I have heard of folks machining the heads to allow the cylinders to fit in deeper (1.0mm) to get a CR bump. Is this a good way to do this?
3 What cam shaft grind should I run? Since this is a 3.0L – is the 964 cam with ported heads too much?
4 Suggestions on the K27 turbo are welcome. It is still running the 3LDZ. Should I have this turbo upgraded with a more modern compressor side or just pitch it and start over?
5 This engine has 901 part numbers for the cam boxes – yet my 83 3.0L SC motor has 930 part numbers. Is something a miss here?

Any other input would be more than welcome.


Outlaw 911.
Old 10-22-2009, 04:02 PM
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