Looking for G50 Clutch Replacement Options

[wrxnofx]

I'm dropping my engine on my '87 this summer and during this time I thought it's probably not a bad idea to replace the clutch. In my 11 years of ownership I've never separated the gearbox from engine so not entirely sure what to expect.

Anyway, I'm looking for peoples' experience with what they went with for replacement clutches/pressure plates/flywheels. As I see it, there are 3 options:

1. Stock flywheel, stock pressure plate, stock clutch.
2. Stock flywheel, lighter pressure plate, clutch.
3. Lightened flywheel, lighter pressure plate, clutch.

Engine is stock so not concerned about increased torque.
I use this car for morning/weekend drives, road trips, and rallyes.

The lighter mass means freer revving which some have told me is awesome. Other have told me it's a nightmare in city traffic because revs fall so quickly you can't match rpms so every shift is clunky.

Thoughts from anyone here?

[jlex]

Haven't replaced the rubber-center clutch on my '88 yet, so am wondering if getting another rubber one may be a good idea. I understand the non rubber replacements are a bit noisy...

[Bill Verburg]

Originally Posted by wrxnofx

I'm dropping my engine on my '87 this summer and during this time I thought it's probably not a bad idea to replace the clutch. In my 11 years of ownership I've never separated the gearbox from engine so not entirely sure what to expect.

Anyway, I'm looking for peoples' experience with what they went with for replacement clutches/pressure plates/flywheels. As I see it, there are 3 options:

1. Stock flywheel, stock pressure plate, stock clutch.
2. Stock flywheel, lighter pressure plate, clutch.
3. Lightened flywheel, lighter pressure plate, clutch.

Engine is stock so not concerned about increased torque.
I use this car for morning/weekend drives, road trips, and rallyes.

The lighter mass means freer revving which some have told me is awesome. Other have told me it's a nightmare in city traffic because revs fall so quickly you can't match rpms so every shift is clunky.

Thoughts from anyone here?

the rubber center clutch was introduced sometime during the SC run, the whole assembly is heavier and does slow down rev changes

The purpose was to quite gear rattle in the 915 and later g50 trans

I've never owned a 911 w/ rubber center clutch and have never objected to the gear rattle or any drivability issue w/ any of the 3 915s I've owned or any of he other 911s I've driven, mostly at a track somewhere but some street time too.

as the years went by other steps were taken to quite gear rattle, among them using the heaver 1 and eventually 2 integrated into the main shaft eliminating one possible source of gear rattle

my 993 originally had a g50 20 w/ integrated 1, I later installed a g50/30 w/ no integrated gears, neither had any issues w/ noise oor driving.
the one caveat is that I have heard a cou-le of g50/30s that sound as if they had rocks in the trans, these are racing transmissions the owners didn't care. I can only put i down to the way they were assembled.

Most people for their street 911s will be happy w/ a spring center clutch and possibly lightened flywheel

the only caveat w/ the lite weight flywheel is potential stalling, this was common in earlier 993 when a lightened f/w was installed, usually a chip change solves it. Never heard of this issue w/ 911 or 964 though.

[RobFrost]

If you want to get revs and do a wheelspin at every set of traffic lights then definitely get a lightweight flywheel.

Sent from my SM-S918B using Tapatalk

[Bill Verburg]

Originally Posted by RobFrost

If you want to get revs and do a wheelspin at every set of traffic lights then definitely get a lightweight flywheel.

Sent from my SM-S918B using Tapatalk

What exactly does that have to do w/ anything?

[Techno Duck]

I went with a lightened pressure plate from KEP, spring centered disc and stock flywheel on my '88.

The pressure plate is the KEP 'lite' which falls in between the stock and stage 1 kit they had. Pedal effort is slightly more than stock, probably close to a turbo pressure plate. Forgot the weight savings as i did this like 9 years ago.

The car is not difficult to drive in traffic or in the city due to rpm's dropping. Couldn't tell you if its more responsive, like i said i can't believe it was 9 years since i installed it . I also don't find the clutch to be noisy, the g50 is a loud gearbox in general.

I didn't want to overdue it on lightening the rotating assembly... a friend of mines 964 was really difficult to drive in traffic with lightweight pressure plate / clutch. It rev'ed really quick though!

[AlBackus36]

On my stock '87 3.2, I did a PMS lightweight flywheel and standard sachs clutch/pressure plate/TOB. OE PP so no change to pedal feel and maybe more free revving from the reduced rotational mass. No regrets on the choice of ingredients for the application.

Maybe already on radar, but I recommend replacing your clutch slave and the rubber line to the slave at the same time if they're original. Bleed with a motiv or similar. I find I can bleed with just the driver wheel removed, but it's helpful to do it before the engine is completely in, while you still have a few extra inches in there.

Be prepared to also look at your shift fork bushings/shaft/wear/etc. Guide tube, input shaft and shifter seals too.

This is a pretty rewarding project The first drive after is a thrill.

[Peter M]

I would recommend the stock Sach replacement kit with the stock flywheel.

My '88 is plenty responsive and revy due to the induction upgrade from Motronic to a speed density aftermarket ECU. The need to add a lighter flywheel and/or clutch assembly is simply not there.

I've used both a spring centred clutch plate and rubber centred plate on this car and can report absolutely no difference in noise. However, I notice with the change to the sharper induction system, the rubber centre plate gives noticeably more snatch on closed throttle than the spring centred clutch plate that I wasn't expecting. Consequently, I'll swap back in the spring centred plate next time I have the engine out.

I would suggest you would be best served by keeping the stock replacement clutch and standard weight flywheel and spending the money you save on any of the following: Wong chip, modern multi hole pintle injectors, cat delete and a Monty or M&K muffler. Anyway, that's what I'd do if I ever buy a 3rd 3.2!

[WMichelsen]

My only comment on this is that 30 years ago, I had to limp into a parking lot under severe vibration and with rubber popcorn bits falling out under the car. The rubber center of the clutch had disintegrated. I had to tow home 200 miles.

I know I'm not the only one who has suffered that failure. I'm just saying I switched to spring center because I never want to deal with that again.

[Peter M]

Originally Posted by WMichelsen

My only comment on this is that 30 years ago, I had to limp into a parking lot under severe vibration and with rubber popcorn bits falling out under the car. The rubber center of the clutch had disintegrated. I had to tow home 200 miles.

I know I'm not the only one who has suffered that failure. I'm just saying I switched to spring center because I never want to deal with that again.

From what I can tell they stopped making the rubber centred clutch plates over 30 years ago so even if you can find one new, which is difficult, they aren't that new.

I agree, go spring centred.

[dkirk]

My friend owns an '88 911 with less than 60,000 original miles. During a PCA drive, his OEM rubber-centered clutch disc failed. He was able to limp home but the vibration was severe. These discs can fail at any time so the spring-centered disc is the way to go. When I did a top-end overhaul on my engine, I used the Sachs spring-centered disc. I noticed a slight increase in noise with my G-50 transmission when compared to the OEM disc but the tradeoff in reliability is well worth it.

[Marko888]

My ‘87 received the lightweight KEP pressure plate when a bearing went in the transmission. My engine is close to stock…cat bypass, 964 cams, Wong chip. I use the car mostly for sport-touring.

I would 100% do the lightweight KEP unit. It takes about 12 pounds (IIRC) of rotating mass out of the driveline, without changing the engine character. The improved response made my car feel a bit lighter…less lazy. Love it! Be sure to ask for the “light” option…no increase in clutch pedal pressure.

[88911coupe]

I can't speak to the benefits of a lightened flywheel but last year I replaced the clutch disc, flywheel and pressure plate (all stock) and the car drives like a dream. Back in '08 when the engine was rebuilt I only replaced the clutch disc and had an annoying, faint shudder in stop and go traffic. When I did the clutch job last year I also sent the injectors out to be refreshed. The car drives like a dream in even the worst traffic, which is all the time in Dallas. I assume the PP or flywheel was worn but the car revs a bit quicker than before. Should have done all this in '08!

[wrxnofx]

This is all great info, thanks everyone! Been reading a bit more, and I think I'm going to go with the KEP "Light" pressure plate.
I did shifter bushings last year. I also replaced the slave (and master) cylinder 10 years ago so that should be good.
I already have a cat delete pipe and Bisimoto muffler (if you even want to call it that), and a Wong chip.

I think the car would definitely benefit from either cleaning the existing injectors or replacing them with modern pintle injectors.

[wrxnofx]

I posted this on another thread, but I reached out to KEP about purchasing what folks on here described as the "Light" version of pressure plate, which was between stock and KEP's Stage 1.

Per KEP, they've changed their terminology:

We changed the way we call our pressure plates in 2017, you may be referring to old information that is out there on the internet.

Our Stage 1 is what we refer to as our “stock” load diaphragm.
Our Stage 2 is what we use to refer to as our “Lite” load diaphragm.

We also have Stage 3 and 4.
Our Stage 1 paired with an organic clutch disc is rated for 375 ft. lb. torque at the flywheel

Our Stage 2 paired with an organic clutch disc is rated for 460 ft. lb. torque at the flywheel.


So I assume I would have to go with their "Stage 1" now.

[Mr. Merk]

I was told my original clutch wouldn’t make it to California — that was 7 years and 65,000 miles ago. The car’s now at around 105k miles, and the clutch still holds strong. However, the throwout bearing sounds like it’s about to “exit the chat.”

Today, my new KEP Stage 1 (Stock) pressure plate arrived. According to KEP, it's about 8 lbs lighter than the factory unit. At roughly the same price as a stock replacement, it felt like low-hanging fruit.

I’ll be pairing it with a Sachs spring-centered replacement disc, which I believe is around 2 lbs lighter than the original rubber-centered version. I’ll try to resurface the original flywheel, but if it’s beyond saving, the AASCO lightweight flywheel is a solid backup option for under $600.

[Packin4]

I’ll try to resurface the original flywheel, but if it’s beyond saving, the AASCO lightweight flywheel is a solid backup option for under $600.[/QUOTE]

Per the factory, G50 flywheels should not be resurfaced (although some report success machining the pressure plate "to match"). Plenty of members have cited the "Porsche Technical Specs", etc. I'm about to embark on replacing my original rubber centered clutch as well. Good luck!

[Mr. Merk]

Originally Posted by Packin4

I’ll try to resurface the original flywheel, but if it’s beyond saving, the AASCO lightweight flywheel is a solid backup option for under $600.

Per the factory, G50 flywheels should not be resurfaced (although some report success machining the pressure plate "to match"). Plenty of members have cited the "Porsche Technical Specs", etc. I'm about to embark on replacing my original rubber centered clutch as well. Good luck![/QUOTE]

I read that too, but it was explained that it was because of the thickness of the rubber hub which is no longer an issue with the sprung hub.

That being said, it won't take much to twist my arm into buying an AASCO