FRporscheman

Don't want to spend over $100 on a stupid toothed tool? Can't find one in stock anywhere? Don't want to wait 2 weeks for it to be shipped from Germany, or for it to be custom made (my situation)? You might try this...

I've heard many stories of using a screwdriver to jam the flywheel teeth, but I never lent any credence to them. Today, I found myself standing outside by my new baby, thinking 'this is a nice day and I can't use it because of that buck futting tool'. Then I remembered all the screwdriver-flywheel lock stories. I decided to try it, since I just want to get the 968 back on the road, and the weather in SF is not exactly reliably pleasant. I had my brother put a 1/2" drive ratchet and a 2-foot jack handle (pipe) on the crank bolt, and I went under the car and put 2 screwdrivers into the flywheel teeth (not the starter ring gear teeth on the pressure plate; the flywheel teeth are bigger and more towards the front of the car). I used one "normal" size screwdriver (like you'd find in a kitchen drawer) to jam the flywheel against the side of the opening in the bellhousing, and i used another, larger screwdriver to jam the flywheel teeth against some metal hump, where the starter rod would be seated.

While I held the screwdrivers in place, keeping pressure on them to keep them in, my brother pulled on the wrench and the crank bolt gave way after only 2 or 3 tries. I may just cancel my order for the flywheel lock and use this method for re-torquing crank bolt... $120 for something I can do without seems silly.

Anyway, just thought I'd put this out there, in case anyone is having problems deciding whether to buy the tool, or wondering if it's necessary.

H2

I don't see how you can make it work reliably. The tool is expensive but really saves on patience.

Harvey

josephsc

Dude, next time, give a hollar on Rennlist or the other boards before sticking screwdrivers where they don't belong. I have one, a couple of other 968 guys have one, and we're all in the Bay Area.

BruceWard

I assume you are changing or removing the timing belt?

One of the reasons for the flywheel lock is to keep the crank locked at TDC while the belt is off. Please be very careful as you reassemble.

I would not risk damaging the $800 flywheel with a screw driver.

FRporscheman

Oh, sweet. I gotta get to know the 968 people around here. Thanks for the offer! Unfortunately I just got the tool in the mail a few days ago so I got that part covered for now.

Yeah, I'm doing the belts, rollers, WP, seals, cam chain, and variocam tensioner pads. I'm also forced to get all new bolts for the bridges that hold the cams, and of course a new bolt for the cam sprocket. New cam cover gasket, rubber grommets, etc. I used Harvey's list that I dug up from an old thread (THANKS!).

I hear I shouldn't replace the chain (since I'm not replacing the cams). What do you all think?

BruceWard

If you want to listen to the guy that promotes that idea, then sure go ahead and use your chain until it breaks.

Personally I am going with the guys that know about 968s.

Before you take a risk on his opinion, perhaps you should ask him what his qualifications are and verify them.

FRporscheman

So I should replace the chain? Someone on 968.net told me not to, saying that the chain and cams wear into each other, and that slapping on a new chain will accelerate the wear of the cams...

I compared my old chain to the new one and it was not longer at all. If there is any stretch, it's less than 1/10 of a mm.

Do people here typically replace just the chain, and everything's OK?

BruceWard

There is an inspection howto online at http://www.968s.com/DIYPDF/Procedure... Camshafts.pdf . It suggests a stretch of as little as 2mm can cause cam teeth failure.

If you go to 968.net and search "subject only" for "chain" or "variocam" you will find many previous posts on this topic.

In my opinion Derek from Sweden who put together the inspection procedure and Joska are the leading experts on the variocam.

flash968

stretch can cause issues, but the biggest cause is disimilar hardness of materials - a new chain on cams gears with hardness worn, creates more wear - chains and cam gears go together - so do lifters and cams - you can do one without the other, but the life expectancy of the parts involved is greatly shortened

the reality is that, to do it right, you end up doing a complete top end, if the head has any real miles on it - otherwise, you're buying yourself some time, but you'll be back in there

spend it now or spend it later

FRporscheman

There are 153k miles on the clock, and the car is a '95 model. Since the cam sprockets and chain look good, and there appears to be no signs of wear (visually, at least) I think I'll keep the old chain in there. I'll just check the health of the cams every couple weekends, and as soon as anything sounds or looks bad, I'll swap out the cams and chain and pads and belts and seals and head and engine and car :P. I'm usually the kind of person to spend any money necessary for preventive maintenance, but I'm not sure if replacing the chain is OK since there are conflicting opinions on the issue. Anybody replaced just the chain, and how much mileage have you put on since?

flash968

yeah - that ones is a tough call, since you can't check the sprockets other than a cursory visual inspection while they are in the car

i'd measure the chain against a new one to see if it is indeed ok

has the head been done? if not, at 155k, you're probably due anyway - this would be a great excuse to breathe new life into a tired motor

someday somebody will come up with a replcement cam set with removeable sprockets

FRporscheman

I don't have money for something like a head job right now, but I hope to have it done sometime in the near future. When I do, I can worry about new sprockets and chains at the same time. It's going to be one heck of a bill... The chain looked to be exactly the same length as the brand new one I bought. This, and the arguments of sprockets and chains wearing together, has made me decide to keep the old chain in there for now, and to check the condition of the sprockets and chain VERY often. Popping the cam cover is easy, so this kind of routine should make up for not using the new chain yet. I hope!

flash968

yeah, sounds right - ya gots ta pick your battles

jgporsche5

I guess another way to look at it is.. you can check the teeth visually periodically by just turning the motor over slowly with a 24mm socket and ratchet. Seems to be a real pain to pull the chain off and measure it. I don’t have a problem admitting that I changed my chain.

FRporscheman

It's a fat pita to pull the chain, but I'll worry about that when I need to worry about it.