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914World.com _ 914World Garage _ 2.4 six to 3.0 six swap

Posted by: goose2 Jul 19 2005, 03:55 PM

I'm going to swap my 2.4 Zenith carbureted six for a 3.0 CIS injected six. I know some of you here have experience with this....what do I need? I know there will be issues with clutch, flywheel, wiring, fuel pump, linkage. I'd like to minimize down time by collecting info and parts in advance. I need counseling please!

Posted by: Travis Neff Jul 19 2005, 04:03 PM

External oil cooler maybe? I forget the technical term for a secondary fuel tank before the pump, as the CIS 911;s had. I think Zois had done this on the old rocket.

Posted by: ! Jul 19 2005, 04:15 PM

Get a conversion flywheel and clutch KIT....from Kennedy Engineered Products.

The CIS 3.0 needs ALL the stuff, fuel pump, accumulator, etc.....

I found that a 3.0 while having an engine mounted cooler needs another one externally.....also the FI most likely needs to have the trunk cut for clearance....but Wayne at Pelican claims to have done it w/o.....he might have a tech doc on it...dunno.

If I did it again, I would go with carbs.

Posted by: brant Jul 19 2005, 04:19 PM

Randy,

whatcha' gonna do with the 2.4?
(I need a -6 motor for my street car)

brant

Posted by: lapuwali Jul 19 2005, 04:48 PM

You do NOT have to cut the trunk to fit a CIS 911 engine into a 914. It's a snug fit, but it will fit. You will have to remove the engine lid latch and either use pins, or move the latch off to one side. You'll also need to dump the trunk springs. If your mount allows you to run the engine a bit low, this will help. Access to some of the bits really sucks once installed, as the trunk wall is RIGHT THERE, but nothing hits or rubs.

I can't remember when the flywheel changed. I thought you could just use the flywheel you're using on the 2.4, but maybe not.

With CIS, you'll need to beef up the fuel system a tad. If you haven't already run stainless tube down the center tunnel to replace the plastic stuff, you should do so now. You'll need all new fuel injection hose, and not D-jet stuff, but stuff rated for at least 150psi. The fuel pump, filter, and accumulator are all CIS specific parts.

Posted by: pete-stevers Jul 19 2005, 05:00 PM

Think i need to watch this thread too

Posted by: Eric Taylor Jul 19 2005, 05:01 PM

Randy - That car is going to be a power house! PM Me if you need help with the conversion or body prep for the paint or whatever. I love 6 stuff
Eric

Posted by: gus Jul 19 2005, 05:04 PM

QUOTE (Manfred Z @ Jul 19 2005, 02:15 PM)
also the FI most likely needs to have the trunk cut for clearance....

That could be avoided by removing the airbox when you convert to megasquirt efi... Had I done it over again with my 911, I wouldda kept the 3.0 CIS motor and done an MS conversion with the tbitz kit.

Posted by: carr914 Jul 19 2005, 05:22 PM

Sounds like fun to me, Randy. Can never have enough power. Good Luck.

T.C.

Posted by: J P Stein Jul 19 2005, 05:23 PM

The 2.4 has a six bolt crank, the 3.0 has a 9 bolt.
Like Mikey said, Kennedy Engineering.

Posted by: LvSteveH Jul 19 2005, 10:05 PM

I know I read that someone did the 3.0 swap without moving the latch over, I'm sure someone will come up with the details.

The external cooler on a 3.0L is a hotly debated topic. I know Brad mentioned some time back that if a 3.0L sees a lot of track time, it should get an external cooler, otherwise it works fine without one.

Posted by: ! Jul 19 2005, 10:07 PM

It WILL need an external cooler....I've done three 3.0 conversions.

Posted by: LvSteveH Jul 19 2005, 10:38 PM

Mike, I have no doubt that you could over heat a stock 1.7 in short order.

Per Brad R. on 4/04:

"YES !! I love the oil cooler debates.

First off.. Kiss my ASS. (Thought I would get that out of the way)..LOL

Daily driving and even the occasional AutoX will not require an extra oil cooler over a stock 9146 cooler in a 3.0 or 3.2.

I really dont care what the 911 came with.. it also came with an engine facing backwards with half the amount of clean air available (nevermind the AC or catalytic converter and ALL the exhaust wrapped around it..including a muffler hung 3 inches from it)..

You will NEVER convince me otherwise. I can show you case after case (and let you drive the cars I'm referencing) to prove my theory.

Oh.. your 9146 tranny is fine, but you will want the 5th gear from a 4cyl box. The 9146 stock tranny has a taller second gear but a shorter 5th than the 4cyl 914 tranny."

Bruce and his books go way back... oils have changed... gas has changed... he also told us to install chassis stiff kits and control arm kits 20 years ago... Now he doesnt.

Everytime I install a front mounted oil cooler in a 3.0 or 3.2 car.. I end up blocking half (if not more) of it off to keep the car from cycling the thermostat. I honestly beleive the earlier engines need a front mounted cooler, but with the advance in oil pumps in the 3.0/3.2 and synthetic oil.

I have also said it depends on where you live. I know where this guy lives (Castro Valley) it is only 8-10deg. warmer there than it is here on the Penisula. He would be just fine with a stock cooler."

Posted by: ! Jul 19 2005, 10:48 PM

I seem to be using this term a lot lately...BITE ME....

As to 3.0s....they seem to be fine for AX and around town....but it's wierd, the temps tend to keep climbing on long drives.....180-200 for an hour then after that a slow climb to 300....happened to ME on two cars and once on another that I helped build....both were bone stock 3.0s with CIS......one later had a 964 cam upgrade....another carbs....

I kept getting told by Bradhole that they shouldn't need an extra cooler.....but hell my first conversion was done before I even heard of or met the weenie...

Just MY experience.....nothing that anyone should take to heart.

Posted by: goose2 Jul 20 2005, 12:37 AM

Ah...I love a lively debate. I have an extra cooler I could mount. Seems like I could just monitor oil temps closely and hook it up if needed, yes? The latch is no problem...I can either relocate it or use some sort of pin system to keep the lid down. As to the flywheel/ clutch...there are alternatives to using the Kennedy set-up, right? I have friends in machine shops. Is the CIS similar to the system used by VW a few years ago, K-Jetronic I think? I'm semi-familiar with that. And Steve....is there an accumulator with the motor? Access sounds like a problem...has anyone put a removable panel in the trunk? Yeah, I know...lots-o-questions. Thanks all!

Posted by: lapuwali Jul 20 2005, 01:10 AM

CIS = K-Jet, they are one and the same. There is a difference between early and late SC CIS systems. The early engines had no O2 sensor, and were purely mechanical. The late systems had an O2 sensor, and had a small all-analog ECU that controlled a valve which in turn altered the control pressure to vary the mixture v. airflow curve. A late system will obviously require more wiring, and will require you to add a bung to your exhaust to fit the O2 sensor. I *think* the '78-'79 engines were "early", and the '80-on engines were "late".

The accumulator is inline with the fuel line from the pump to the fuel distributor. You can get one from any VW that used K-Jet, they're the same part.

There's generally little need to access anything the trunk wall will block. The adjustments can be reached from the sides or above quite easily.

Posted by: brant Jul 20 2005, 09:21 AM

I think you'd be better off buying a flywheel than trying to make one... but none of my business really.

the 3.0SC added the oxysensor mid 1981

so whatcha' gonna do with the 2.4/stock flywheel?

brant

Posted by: goose2 Jul 20 2005, 09:48 AM

QUOTE
I think you'd be better off buying a flywheel than trying to make one...

No....I wouldn't try to make one. Thought maybe it was just a matter of some changes, like machining the 2.4 flywheel to fit the 3.0 crank. The 2.4 motor, carbs, and anything else I don't need will be sold....gonna need cash to pay for all this foolishness.

Posted by: ! Jul 20 2005, 09:49 AM

If the carbs are Webers...."I" would keep them and use them....

Posted by: J P Stein Jul 20 2005, 11:18 PM

QUOTE (goose2 @ Jul 19 2005, 10:37 PM)
As to the flywheel/ clutch...there are alternatives to using the Kennedy set-up, right? I have friends in machine shops.

There are always alternatives.
Write when you find some.

Posted by: goose2 Jul 21 2005, 12:32 AM

QUOTE
If the carbs are Webers...."I" would keep them and use them....

The carbs are Zeniths. I love carbs for the sound, the look, the adjustability....and they appeal to my traditionalist tendencies, but...I've been spoiled by FI cars that start without elaborate procedures, run smooth when cold, have no flat spots, don't pop and fart if you don't baby the throttle just right, and use less fuel while delivering more power. My opinion...one among many I'm sure. Wanna buy some Zeniths?

Posted by: goose2 Jul 25 2005, 04:31 PM

I've been doing my homework on the clutch/flywheel requirements and have found some options.

Patrick has a kit that bolts a custom ring gear on the 3.0 flywheel and uses the Kennedy clutch. Comes with everything....pp, disc, release brg, fasteners. $680.

GPR has a similar kit but uses a different p plate and is a few bucks less than Patrick's setup. Dave (GPR) says their clutch is MUCH nicer than the Kennedy version and plenty good for up to 300 HP. He tells me that this is by far the best solution, mainly because his clutch is far superior.

Kennedy's solution is to machine out the center of a stock 914 flywheel and weld in a new center...then machine and drill to fit the 3.0L 9 bolt crank. The charge is $250, if you supply the core flywheel....add $100 if their core. Early 911 clutch will bolt to this flywheel? Not sure about this. They have a pressure plate that will handle up to 400 ft.lb. torque for an additional $225. Add fasteners, release bearing, pilot bearing and it comes to around $600. Mr. Kennedy did say that a 914 clutch will handle nearly 200 ft.lbs. torque on a street car if you're careful.

My question is, will the 914 clutch do the job? Doesn't the early 911 clutch interchange with the 914-4 and wouldn't it be a adequate unit for a stock 3.0 street car? Are there still unexplored alternatives?

Posted by: brant Jul 25 2005, 04:35 PM

send them a core -4 Flywheel instead of the 6 bolt core, if you go the welding route.

yes I think the early 911 clutch and 914 clutch are the same.

I don't know of other methods.
good research!

brant

Posted by: ! Jul 25 2005, 04:58 PM

Patrick's stuff suxz......

Been using KEP for 30 years, I have no reason to suggest anyone else.

Posted by: carr914 Jul 25 2005, 05:50 PM

Randy, For the flywheel/pressure plate, check out JB Racing in Tavares, FL. They are right next door to Alex Job Racing and are very big in Vintage mostly 911 engines. They just came out with a 5 lb flywheel. They have been making a BMW lightwheel flywheel for some time and this Porsche item is aimed more at their customers. If I hadn't bought a 906 flywheel from Mike Bruns, their Engine Manager I would have this new item in my car.

T.C.

Posted by: goose2 Jul 26 2005, 09:37 AM

Thanks for the tip TC, I'll check them out. I'm not sure I want a super light flywheel for a street car but it'll be interesting to see what they're up to.