DIY: Install 964 cams in my SC any suggestions?

[82SC]

well I have a nice set of 964's with the power steering part removed...

I have read over the procedure to remove the cams in wayne's book and the Bentley...

I will be doing a complete valve adj afterwards...do I need to do a cam timing?

what about checking the parellel of the sprockets???

are there procedures to minimize having to do more and more???

thanks

MJ

[Vipergrün]

82 -

Sorry, not much to offer, but are you gonna document the procedure for us other SC'ers? What are your expected gains? I have heard 10-15HP.

cheers
-Brad
80SC

[speeder]

You most definitely need to time the cams, if you want the car to run. Other thing is where are you going to set the cam timing? It is adjustable. I would suggest setting it at stock 964 specs, other more expert people might chime in here. (I'm planning the same upgrade).

[82SC]

one concer...on 2 of the lobes on one cam there are small pit marks....I have attached the worst...all other 10 lobes are are very good condition...

the 2 pitted areas are toward the edge of the lobe...is contact made along the whole width of the lobe, of in the center???

would that make the pits a non-factor?

bought the cams used...I am taking it to the machine shop that machined off the power steering pump to get their opinoin tomorrow...

so looks like I will need the timing tools...what about sprocket parellel measurement...

I assume when I take the rockers off I will need them resurfaced...I will need new gaskets for the cams...anything else??? in terms of new parts...

I will document extensively for the SCWDP...

[82SC]

[Wayne 962]

Pits should be repaired by a good cam shop like Webcam or Elgin.

Uhh, your questions scare me, as they indicate that you might not completely understand the entire procedure:

"I will be doing a complete valve adj afterwards...do I need to do a cam timing?"

First of all, I'm pretty sure that you will need to at least partially drop the engine. I don't think that you can replace the camshafts without at least gaining a minimum of clearance. Secondly, you will need to remove all of the rockers, which will make a valve adjustment automatic. Thirdly, you definitely need to time the cams.

There's no such thing as a stupid question, but the fact that you have asked these questions leads me to believe that you may have a high likelihood of messing up your engine. We have heard of many people who have smashed valves just doing a chain tensioner install. To do a camshaft switch is much more complicated, and offers a great risk to your engine if not performed properly...

This is something that I don't really cover completely in the 101 Book. The new Engine book would be a better resource, as it covers the reassembly of the camshaft sprocket assemblies, and the checking of the alignment of the sprockets. I wouldn't rely on the info in the 101 book alone...

-Wayne

[82SC]

well I had assumed that a cam timing was necessary...but I've read posts of how when people do the tensioner upgrade, they vice grip the chains in their original orinetation so it does not mess up the timing...obviously mine is a bit different since the entire cam is coming out...

And I agree with you...if I were doing this today without my books and this BBS there would be a high likelihood of messing up my engine...

But that is why I am asking my "stupid" questions before diving into unknow terrirtory...

I've read the 101 and bentley manual on cam removal...the bentley has a section on reinstalling and timing...that will be my main reference

also like speeder said...which timing settings should I use...964 or SC...

MJ

[Superman]

I had the same thought as Wayne, but I also noticed you asked some advanced questions (sprocket parallelism). To answer your question, I did not bother with sprocket parallelism issues. I just put the shims back where they were. Yes, all the rockers must be removed, and the shafts that hold them in are interesting to deal with, even on a bench. I have rebuilt my engine (I'm comfortable with tools), and if I were to change cams, I would surely remove the engine to do it.

On the other hand, it is a job you can do. You will need a dial indicator and the special (P-207) holding fixture. My cam upgrade, to 20/21 grind which is A.K.A. "964+" has made a huge improvement in the way this car drives. I can't say enough.

Oh, I think you'd use the 964 timing specs.

[82SC]

hey superman...I was gonna ask you some ques cuz you had done this recently...

what cam removal tools did you need?
I know there is a pin removal
a cam holder
a large 42 or 43mm crow foot
yup the dial holder...and the dial indicator...

I guess my question is do I need all the special tools...I am hoping to be able to buy the crows foot at sears or something so I don't have to pay some outrageous Porsche amount...the pin removal looks essential...what about the cam holder...looks like that will be needed to hold the cam...

are their sunday mechanic tools that can substitute for some of the tools?


I guess I try to ask even the most mundane question to see if there is anything I am missing...especially if more experienced members have cool tricks up their sleeves...I think I have a pretty novice understanding of an engine...but I am working my way up from oil changes...to brakes...pedal rebuild...SSI...clutch replacement...and my current cam change...

I am learning as I go and this BBS is a great tool...

MJ

[Doug Zielke]

Mark,
Before you decide to rip into your motor "just" to install cams, realize that a cam change alone will *not* necessarily give more power.

If that is what you're looking for, you need to match the cam with other changes, like exhaust, CR, heads, etc. It all works together. A cam change by itself may move your power band around a bit, but little else.

[Superman]

True and false. Doug, you're not getting out of your decision so easy. Even if you retain your stock exhaust, the cam upgrade is STILL a most excellent upgrade with very noticeable results. I made the cam upgrade first, and then the exhaust upgrade later. The cam upgrade was the really big improvement. I'd agree that top end was not changed much by the cams, but there is so much more power at 3000 rpm that it feels like a different car. I agree that the exhaust upgrade is necessary for improving top end performance.

MJ, you are still asking the right questions. The price you should pay for the pin removal tool is $0. The thread is the same as the threaded end of a spark plug. So, a spark plug is perfect. I especially appreciate the ergonomically advanced porcelain and steel handle.

I did not have any special cam holding tool, and I struggled as a result, but got it done. IN one direction (removal I think), the chain itself keeps the sprocket from moving if the crankshaft is prevented from turning. Of course, this puts some stress on the chain but I'm not that easy to scare.

In the other direction you risk putting stress on the tensioning system. Perhaps I secured the chain in that direction too, like with a block of wood or something. Like I say, I probably struggled with the rocker shafts more than the cams, chains and sprockets. And even they are not impossible to overcome. I'm going to stick by my suggestion to remove the engine though. I certainly would.

My cams have the 19mm bolt, rather than the HUGE nuts that the earlier cars had. I was glad for that.

BTW, I got my dial indicator at Harbor Freight Tools for six dollars. I continue to use it, and the P-207 tool each time I adjust valves. This works best for me.

[CamB]

I gotta ask (I'm not trying to be confrontational, just trying to help). Last time I remembered you talking about your engine it was tired and worn out with dodgy rings and valve guides.

Has this changed yet?

[Tinker]

82SC,

I have a set of 964 cams that I am planning on installing on my 930.

I was told that you need to reset the valve heights and perhaps use sport (Aasse) valve springs if you plan on beating on it after converting to 964 cams. I was told if you ever overrev there WILL be coil binding/dissaster due to the higher lift of these cams.

Food for thought.

Tinker

[82SC]

hey CAMB...

yep my engine is the same...

I need to do a spark plug change, one of my wires is bad and a valve adjust...also there were some oil leaks...so all of these combined I decided to drop the engine and do other stuff too...

my engine actually pulls very strong...every shop I've taken it too...precision tech and callas, say the engine feels good...

but when I look under the engine it don't look too good...oil and gunk...

honestly if the oil leaks and oil consumption was gone the engine would be great...plus I am always "down" on my engine because I really want to start my 3.4L MFI engine...I've got 3K in parts waiting and no where to put them...

SO...I am trying to track down these oil leaks...hoping it is not worn rings, but maybe leaks off the top or maybe loose head studs...but I fear the worse...

Plus having to do a valve adjustment should give me alot of access to do some snooping around...check valves and head studs...maybe do a leak down or a compression check...

As for the cams...I've had them lying around for a while...what do you guys think...should I put them in? I mean the engine is almost at 200K...hopefully I can solve some of these oil leaks...I was thinking if I end up selling my car there is no way I can do a rebuild and recoup my costs...but maybe the addition of 964 cams makes the car a little more desirable if someone were interested...I am just trying to get the most bang for my buck with what I have...worth it or not???

just got in from dropping the engine...I am going to prod and poke around the engine tomorrow...try to figure what is going on...any suggestions are welcome...even confrontational ones...

MJ

[CamB]

Have you ever compression tested it?

Clean it up, check the stuff your gonna. It could be fine.

[A Quiet Boom]

Just a note here on where to set the cams i.e. time them. In very general terms advancing the cams 1 degree will lower the powerband 100rpms and retarding them 1 degree will raise the powerband 100 rpms. Typically I like to advance cams on street driven vehicles to around 4 degrees for a little boost in lowend torque.

[82SC]

so should I or shouldn't I switch cams...

MJ

[Joe Bob]

I did it....914/6 powered by a 3.0. 120K on the motor, rings looked good and the pistons and cylinders were good as well. The head studs were all replaced.....well worth the addition.

The bad.....

Cam wheels are different, you have to grind off a lobe that will hit the oil cooler.....the 964 cams have a power sterring take off....few other issues that were a bitofapisser....

[Superman]

Sounds like you're on the right track. I don't think rings are responsible for leaking. The most common leak places are at the rear (flywheel end) top of the engine. Oil thermostat o-ring (under the round thing in the top of the engine case near the oil cooler), oil pressure switch, breather hose, breather plate. Also, rocker shafts. If you do remove rocker shafts to change cams, be sure to install them with the fancy seals to prevent leaks.

At 200K miles, I now know that some of your internal engine parts are showing wear. John Walker knew that before I opened my engine. Doug's engine which is much younger, may not be showing much wear. But yours is. So, if you take the head off your engine you are asking for expense. Cams can be changed without removing heads, but I just want you to be aware of what you'd likely get into if you decided to 'freshen' the engine.

As far as the cam decision, I'd say "yes." Because I know how much they improve the SC engine. Also, it sounds like the 964 cams are not part of your future 3.4L MFI project parts pile. If they're just lying around, and your engine is on the ground, I think it's an easy decision.