924Board.org

[Rick MacLaren]

Here's my Phase II rebuild instructions to my mechanic. All the engine work and balancing is now complete along with metal hardening, treating etc.

Mechanic Work

Short block - Engine balanced, rod flashings removed and balanced 4 ways, magnafluxed, shotpeened, flywheel lightened and balanced. Rebuild and reinstall including bearings, check all important details. Cleanliness most important. Perfect. Check everything.

Head New Porsche valve guides, valves measured and are within spec. Head cleaned.
New seals. New head gasket. Tappets.

Camshaft New Porsche camshaft Very $$$.

Intercooler - The intercooler is a top mounted custom-made 924 Carrera GT intercooler from John in New Zealand.

Intake manifold - has been honed inside by hand to remove all flashings and casting errors, diameter widened 0.01 overbore. Webbing between each of the four intake tubes removed, dremeled and polished to shine inside. Install carefully with gaskets matched to the diameter of the intake.

Throttle - Casting flaws removed inside the throttle by hand and machine tooling. Polished to shine.

Install scoop repaint hood.

Wastegate - I have inserted a boost spring that brings boost to 0.8 bar (12 PSI).

Check all vaccuum lines for potential loss in the boost pressure. New lines if needed.

Pistons New Mahle (OEM) high compression Carrera GT racing pistons 0.020 overbore from Engine Builders Supply, Reno, Nevada.

Turbo - When the engine blew, a streak of oil appeared on the firewall in front of the battery. Did the turbo blow this out? How did that streak of oil get there? Check radial play tolerances, check axial play tolerances. Rebuild as required. Rebuild and get new hoses and all oil lines as required.

Transmission - Very slight almost unnoticable trouble shifting into these gears - looks like synchros wearing out. Very slight. Check 1st and 4th gear synchros and replace if required.

Axles - drive axles were reversed 5 months ago. Now is the time to replace.

Clutch - No problems noticed. Replace anyway. Or rebuild.

Radiator - Check all cooling hoses.
Check hoses into the heater box core at the firewall. Are all the pipes ok and strong?How can we get more cooling?

Oil cooler - Is it functioning properly?Check all oil lines to cooler. Any way to make them stronger? Cooler? Is a second cooler possible? How will this affect oil pressure?

Electrical - Ground straps, sparkplug wires
solder joints on ECM etc., worn wires
voltage drops, battery cables, check coil,
new spark plugs.

Brakes - flex hoses brittle or bulging
rusted hard pipes, calipers and pistons
flush system,

Fuel system - new fuel filter, check hard lines, check flex lines, check pump,
check and clean injectors,

Misc - Check:

All ball joints
CV joints repacked withnew boots
Wheel bearings repacked
Check all suspension bushings
New cam belt


[ This Message was edited by: Rick MacLaren on 2002-02-15 03:09 ]

[numbers]

Rick, you have way too much money.

[Rick MacLaren]

It's a wallet killer! But the way I'm going at it, I have to get it right, correct, or else I'm going to have a great engine inside and still be waiting for the shoe to drop when something else fails, and I'm also tired of tow truck drivers. That last oil leak was financially really hurtful. So we'll see.

[Peter]

Hi Rick,
I just got my parts from the machine shop. I had the shop balance the lower assembly, from pistons to pressure plate, including all nuts, bolts, pulleys etc. I also had them press in new connecting rod bushings. (As you know, it is always good to replace these even if they are not significantly worn as they are (1) cheap and (2) you are not going to tear down the engine to replace them later on.) It cost me $250.00 NYC dollars. How much would similar work cost by you?
I myself did the other things you referred to: polishing connecting rods, polishing crank counter weights, micro-polishing crank journals, radiusing and cleaning all oil passages on crank and rods, smoothing intake port, polishing, etc, etc. However, when I opened up the throttle body, it was perfectly smooth. There were no casting marks. I am just curious at to what you did to the throttle body, because if I missed something I would like to go back and do it now.
I did not have the crank or flywheel lightened; to me personally it was not worth the money for the performance gain.
I was thinking about purchasing one of John's intercoolers. However, I have decided to challenge myself and install a 951 intercooler into the front badge panel without removing the panel! I will be going from the engine bay, and with the engine already out, I think I will have enough room. Let us know how the intercooler works and about the installation process.
You don't mention having the head ported and polished? Was this done or put on hold for next time?
I will take some picks of my connecting rods and post them. Let me know how close I came to a professional job.
The only pic I have is of my block. I really like the color and it will look much better after a few heat cycles. I used POR-15 engine enamel. Aston-Healy green.

-Peter A. Holiat

[dwak]

Peter,
If the rest of the car looks as pretty as the engine, you might win the contest after all and we sure as hell arn't using any shtinkin' ice skating judges! I wonder if anyone's done a 924 in Brooklands green?

[John H]

Nothing wrong with the judges - as long as you're Russian

[Rick MacLaren]

Hi Peter,

I didn't port and polish the head. Wasn't worth it. And the other mods will more than make up for it. I just don't think the 931 needs it.

The cost for me of my entire engine was $1500 CDN, $700 CDN for the cam and $1600 CDN for the pistons (tax, duty etc). But that included boring and honing the lower end too.

Pre clean engine block
hone cylinders
clean engine block
replace all gallery and freeze plugs

clean and check crank to spec
polish journals
clean

machine flywheel rear surface (0.100 tool)
machine flywheel face
machine flywheel rear surface

clean cylinder head
Decarbonize and dye test
replace all valve guides and fit to spec
machine valves
machine stellite valve seats
machine deck surface
preclean preassembly
assemble with new seals and flow test

machine connecting rod beams
size and match pistons
clean ring grooves
balance pistons rods wrist pins
balance crankshaft, flywheel, rotating assembly
balance assembly

Connecting rods upper 108.5, lower 649.6 total 758.1 grams.

Pistons less pins and circlips 633.7 grams

Assembled weight 1547.2 grams

Bore sylinders to 0.50 MM and fit to spec
pre clean engine block

shot peen connecting rods
freight
tax

$1500.00 CDN

BY THE WAY: Engine Builder Supply sent these pistons and they were sold to me as the GT pistons - light and higher compression. However, the pistons sent had incorrect an pin in one of the pistons, and the weight seems to be 100 Grams over weight. (I saw them on the scale myself. So either our 924 board is WRONG, or the 0.020 overbore accounted for fully 100 grams overweight, or EBS sold me the WRONG piston. I'm discussing it with them presently). Anyone know how much more an 0.020 overbore piston will impact on weight?

[ This Message was edited by: Rick MacLaren on 2002-02-16 04:43 ]