3.0SC engine, mechanical weaknesses?
08-23-2002, 02:50 AM
#1
Racer
Thread Starter
3.0SC engine, mechanical weaknesses?
Out of curiousity, what are the generally accepted weak points of a 3.0 engine with regards to increasing horsepower through increased airflow and rpms? I am planning on aftermarket fuel injection over the winter and am contemplating larger cams and some mild head porting. I'd like to net 30-50 more HP than I currently have with early exhaust headers and properly tuned 40mm carbs. I do not wish to raise static compression except to offset any lost compression due to longer valve overlap from a longer duration camshaft. Based on experience with other engines I'm assuming that the following need to be addressed; rod bolts, piston to valve clearance, valve springs, light weight valvetrain and an improved oil cooling system. Induction and ignition will be upgraded with the aftermarket injection system so that's already been addressed. Are there any other items I'm missing to build reliable HP with this engine? I plan to port the heads myself with the help of a flowbench I have access to and hopefully select a custom grind cam based on my powercurve needs. Please no suggestions for turbo or supercharging, that's my next project for a 79 targa body I recently acquired. (Hope your ready for my questions next summer Stephen 
I've decided to keep this one NA and go with a turbo in the "new" one.)
I've decided to keep this one NA and go with a turbo in the "new" one.)
08-23-2002, 03:38 AM
#2
Race Car
Boom, certainly upgrade to hydraulic/pressure-fed tensioners if not already done.
As far as the "weak points", you've pretty much named all of them with the rod bolts and valve springs and retainers being my main area of concern.
Contact EBS, they have some nice valve springs and titanium retainers available - not affiliated with them, but one helluva satisfied customer!
Oh yeah, head studs!! Use Racewear if you're doing what you're gonna do...they have nice washers and barrel nuts too - although I deemed that "overkill" when building my 225HP 3.0L - just used the originals with no issue.
I also used Racewear rodbolts, conveniently named "Rodware".
Again, all available from EBS -or- one of Rennlist's MANY sponsors.
As far as the "weak points", you've pretty much named all of them with the rod bolts and valve springs and retainers being my main area of concern.
Contact EBS, they have some nice valve springs and titanium retainers available - not affiliated with them, but one helluva satisfied customer!
Oh yeah, head studs!! Use Racewear if you're doing what you're gonna do...they have nice washers and barrel nuts too - although I deemed that "overkill" when building my 225HP 3.0L - just used the originals with no issue.
I also used Racewear rodbolts, conveniently named "Rodware".
Again, all available from EBS -or- one of Rennlist's MANY sponsors.
08-23-2002, 11:16 PM
#3
Intermediate
Join Date: Jun 2001
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427 SOHC heads 
Cubic inches oops litres
Look up the 3.0 to 3.2 conversion pistons short stroke bigger bore. Plus you get a better piston dome shape and added piston to valve clearance.
This is a well documented procedure aka piston and cylinder swap. Camb did this and talks about it on the pelican sight.
Or your best bet better gearing in the trans think stock eliminator setup.
Chris
74 3.2L ok well 3.4L since i'm into it this much.
Cubic inches oops litres
Look up the 3.0 to 3.2 conversion pistons short stroke bigger bore. Plus you get a better piston dome shape and added piston to valve clearance.
This is a well documented procedure aka piston and cylinder swap. Camb did this and talks about it on the pelican sight.
Or your best bet better gearing in the trans think stock eliminator setup.
Chris
74 3.2L ok well 3.4L since i'm into it this much.
08-24-2002, 02:29 AM
#4
Racer
Thread Starter
Well I thought about 3.2 P&Cs but I'm not looking for that much HP, basically I want to convert some of the existing lowend torque into more high end HP, a 1000 rpm bump in the powerband along with the associated HP gain will do me just fine. I already have a low geared 901 in the car and recently bought a low geared 915 that I'll install this winter. I love the low gears but the car reaches the redline very fast especially in first and second, being able to safely rev to 7-7.5k would be a blessing to me. I also don't want to spend a huge amount of cash on this car since I'm planning on a modded turbo engine for a 79 widebody targa roller that I have. Once that car is done this one will mainly be for track events and I feel the rpms will help me there. I totally forgot about the 3.0's propensity to break head studs but planned on racewear anyway.
08-24-2002, 05:16 PM
#5
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Well you are looking at around $725.00 (FVD pricing) just for springs and retainers. No K-motion vasco jet spring prices for these cars and the retainers will cost abit more than the typical 1.550 roller spring titanium retainers. Aasse and Eibach make springs and I believe retainers for these.
Steve at Rennsport Systems sells them.
ARP also sells rod bolts and head studs (but I wont get into another debate over them)
Summit sells them
Head studs 204-4206 ARP#
Rod bolts 204 6001
I would go to the ARP sight and double check the #'s
Chris
Steve at Rennsport Systems sells them.
ARP also sells rod bolts and head studs (but I wont get into another debate over them)
Summit sells them
Head studs 204-4206 ARP#
Rod bolts 204 6001
I would go to the ARP sight and double check the #'s
Chris
08-25-2002, 07:07 AM
#6
Racer
Thread Starter
I'd like to hear about raceware vs. ARP. Just browsing Summit-Racing's website (I think) I found out that ARP makes studs for P-cars. I've used ARP in ALL my ford drag race engines and they have proven indestructable. Are their Porsche studs somehow inferior to Raceware?
