Advice for 2.4 Rebuild for my 914/6

TdiRacing · 05-14-2010, 07:07 PM

I have not posted in a while and am now ready to start getting all my ducks in a row for my 2.4 rebuild for my 914/6. I have sent my engine case out for machine work and making sure it is ok and straight. Heads are at machine shop waiting for me to decide on valve springs( stock which I already bought new) or some heavier springs.

What I have:

2.4 with new 2.2 S pistons to give me 9.8:1 compression
Case will be shuffle pinned and oil bypass mod done.
Raceware head studs and case will have case savers installed
Cams: I have new "s" cams and a set of use 906 cams in good condition
Headers and muffler exhaust or open pipes.
Stock Rods will be redone and all rotating parts will be balanced.

Fueling:
I have TWM throttle bodies and all the parts to install this. Just missing ecu and will get a system very soon to complete this.

Questions:

If i run the "S" cams, should I get heavier valve springs? I was told I do not need them as the cams do not make power past 6800rpm anyway? TRUE?

I would like to drive this car on the street, but likely not much. Most will be track time and fun driving.

Anyone have some suggestions on thing I might need or change? I know there are some other cams out there that will work, but I already have new(reground) S cams, so if they will work, would like to stop spending lots of money...

I have been slowly gathering parts, but now want to really get cracking on this rebuild.

Any advice or changes you might think of?

Thanks in advance.

Steve@Rennsport · 05-15-2010, 01:39 PM

Quote:

Originally Posted by TdiRacing

Questions:

If i run the "S" cams, should I get heavier valve springs? I was told I do not need them as the cams do not make power past 6800rpm anyway? TRUE?
I would like to drive this car on the street, but likely not much. Most will be track time and fun driving.

"S" cams perform well to 7K and you don't need anything but stock springs as long as they test within spec.

Quote:

Anyone have some suggestions on thing I might need or change? I know there are some other cams out there that will work, but I already have new(reground) S cams, so if they will work, would like to stop spending lots of money...

S cams or Modified S cams are both good choices for cars like yours. I would NOT use 906 cams at all unless you have good close-ratio gears.

Quote:

I have been slowly gathering parts, but now want to really get cracking on this rebuild.

Any advice or changes you might think of?

Thanks in advance.

I'd use factory steel studs, not Raceware ones.

No open pipes as that kills mid-range power. Use a good dual-in/dual or single-outlet muffler.

Don't go cheap on Engine Management.

TdiRacing · 05-16-2010, 04:30 PM

Thanks Steve.

I already have the Raceware head studs and used them on the engine previously without issues. Reason not to use them???

I have new valve springs and will have them tested for sure before installing them. Will use the factory S cams and save my money for all the machine work and fuel system.

I have two gear boxes. Standard 914 ratios, and a 901 race box with a Factory LSD and 904 short ring and pinion installed.

As for engine management, I have an old electromotive direct fire ignition module that runs off a Clewitt Engineering crank pulley. Unit is old but work perfectly for many years.

I basically need a EFI system for fuel, or fuel and spark if it will work with the current crank trigger wheel I have from Clewitt.

Any suggestions on EFI systems?

kenikh · 05-17-2010, 08:08 AM

Sounds like you have the right spec...the S cams will pull to 7500, so you are in good shape there. I would suggest avoiding stock springs, though. The quality isn't there anymore and have seen the OEM springs break. This happened on my 2 liter S motor and in talking to a mechanic friend he's seen the same too often for comfort. Get some Aasco or other high quality springs and you will be good to go.

TdiRacing · 05-17-2010, 12:00 PM

I had been on the edge of getting stiffer springs, but ended up buying the stock ones. I can return them now, so not sure what to do. You have a link to ones you mentioned?

I know there are a lot of people selling upgraded ones, but not sure which ones are really the better ones?

TdiRacing · 05-17-2010, 12:09 PM

wow those Aasco springs and retainers are expensive...not sure I want to spend another $700+ for valve springs.

kenikh · 05-17-2010, 12:10 PM

Call Steve Weiner above - he'll be able to help you sort it out and he stocks the best stuff. Henry Schmidt also carries some very nice springs, as does John Dougherty (camgrinder). Oh yeah, Pelican also carries the Aasco springs:

Pelican Parts - Product Information: 901-105-901-50-HP-M336

kenikh · 05-17-2010, 12:11 PM

Quote:

Originally Posted by TdiRacing

wow those Aasco springs and retainers are expensive...not sure I want to spend another $700+ for valve springs.

They say use Ti retainers, but they are not necessary...and nothing is more expensive than the teardown I had to do of my motor when the damned OEM spring broke.

TdiRacing · 05-18-2010, 04:59 AM

I hear what you are saying. This is my second round with this motor as well. Do not want to do it again. Will seriously think about the springs now. Will call around and see what is the most cost effective.

DW SD · 05-18-2010, 09:11 AM

Look at the megasquirt II or III opensource EFI controller. It is $500 with great features, support and modest cost ~ $500 pre-assembled and tested. For that price, you can let it control spark and use the FORD EDIS coil packs.

Doug

kenikh · 05-18-2010, 09:14 AM

The new MS3efi is UNREAL. My brain melted when I read the new feature set. It is literally MOTEC for $500.

Steve@Rennsport · 05-18-2010, 09:18 AM

Quote:

Originally Posted by TdiRacing

I hear what you are saying. This is my second round with this motor as well. Do not want to do it again. Will seriously think about the springs now. Will call around and see what is the most cost effective.

JMHO, but I'd be VERY careful about what springs you choose. Many aftermarfket ones are quite stiff and their over-the-nose pressures really accelerate wear on timing chains, sprockets, intermediate shaft (and bearings) and cams.

Cheaper is not always better,......

TdiRacing · 05-18-2010, 11:33 AM

Not looking for cheap, want good springs that will last with the components I have and not wear stuff out right away.

Steve,

Can you IM me some pricing on what you have available as a good upgrade? Heads are sitting at machine shop waiting for me to decide what I want to do now.

TdiRacing · 05-25-2010, 11:51 AM

Would like to get some valve springs but not break the bank either. What are some of the better choices? I realize I am looking at $500-up???

TdiRacing · 05-25-2010, 07:10 PM

Quote:

Originally Posted by kenikh

They say use Ti retainers, but they are not necessary...and nothing is more expensive than the teardown I had to do of my motor when the damned OEM spring broke.

So are you saying that I can just use the AASCO spring kit without the Ti retainers? If so, that is looking better to me.

I sure do not want problems down the road.

kenikh · 05-25-2010, 07:20 PM

Quote:

Originally Posted by TdiRacing

So are you saying that I can just use the AASCO spring kit without the Ti retainers? If so, that is looking better to me.

I sure do not want problems down the road.

I did.

My mechanic buddy with 40 years working on these cars professionaly, didn't complain, either.