Cam & Valve Timing & Power Loss

DavidH · 06-11-2003, 05:11 AM

Well I have been scratching my head for some time now so I'll try this forum.

Car was running great with a few oil leaks, decided to fix the leaks requiring case split and new sealant. (Didn't have Waynes book during the rebuild 1.5 years ago and I used the wrong case sealer).

Put everything right back together and now I have to feather the clutch to get started in first gear, once I get up to speed everything motors along fine, but if I have to start from scratch it's the same thing over again. The strange thing is I can put it in reverse and she pulls great (can even get her up the steep driveway).

At first I thought cam timing causing low end power, but I just finished checking it and on the left cam I have .051 and the right cam .060, which for the 964 cam is perfect on the left side and from what I can tell it's ok on the right (I will get it to a nat's butt tonight).

So the only other clue is maybe something is wrong with the clutch. That is where I installed some new hardware (Shift fork, helper spring & throw out bearing)

I also thought I might switch back to the non-platinum plugs.

Any other ideas, Johnny Walker, Wayne, Warren, Tyson. Somebody help I want to drive....

As always, Thanks...

Wayne 962 · Wayne 962's Garage

Up to speed, and on the highway, how is the performance? If it truly is fine, then I'd say something is amiss with the clutch...

-Wayne

DavidH · 06-11-2003, 11:39 AM

Wayne,
Thanks for responding. It really does well at speed in 2nd 3rd 4th and on up, very smooth. I'm going to drop it down again and separate the transmission to see if ther is anything staring me in the face. Do you guys have the aluminum pressure plate for a 78 sc. That's the only piece that is not new. And while I'm in there... (famous last words)

snowman · 06:51 PM

Did you replace the rings, keep the rings in the same place that they come from? Same cylinders in the same spots? Check the valve clearences?

Check the compression, the leakdown and timing (electrical) and then recheck the cam timing, just because. If these are ok, check the intakes for leaks. You can use propane to do this. If you are not familiar with this test, try just retightening all the intake nuts.

The compression test is pretty much a gold standard, go , no go. If its ok then it has to be in the electrical timing or cam timing, or fuel mixture, there isn't anything else.

The clutch, it could be the clutch, but you should have some symptoms. Starting with pedal feel. If it feels ok it most likely is. About one or two inches of free travel, max followed by a definite increase in pressure. If you got this you almost certainly have a good clutch. A double check, with the engine ideling, in first gear, let the clutch out without touching the gas pedal. Let it out suddenly, as quickly as possible, with the brake full on. The engine should die immediately, no hesitation. If it does be assured the clutch is ok.

DavidH · 06-11-2003, 07:06 PM

snowman,
I didn't replace any rings, as a matter of fact I only took one bank of cylinders off as I knew I was just going to re-seal the case, everything went back in the same place it had come from.
I rechecked the cam timing this afternoon and everything was withing .010 left to right but I adjusted it and now all is within .002. For the 964 cam I used 1.26mm or .050 as the set point.
Next step is to do a partial if not full drop as someone has suggested vacuum leaks or a cracked boot. The compression test is a good thought as well. Thanks..
The mystery to me is why it would drive with power in reverse, backing up the steep driveway but have so little in 1st gear.

dad911 · 06-12-2003, 02:53 PM

Wild guess, but could shifter coupling be misaligned so it is really going into 3rd & lugging engine instead of first gear?

DavidH · 06-12-2003, 05:05 PM

Alan, It might be possible I suppose. But as I sit in the car I can shift through all the positions. If something were bent would there be any way I could line up third and fourth where 1st and second should be and also hit 3rd & 4th again in their normal position? Would it be possible to get to reverse with that much mis-adjustment?
But, that is the exact symptom of how the car drives. Like I'm starting in 3rd gear.
I'll do some checking. Thanks for the idea...

DavidH · 06-12-2003, 05:28 PM

Alan,
You are the king. I owe you at least a six pack as I was going to start dropping the engine this weekend. Got into the tunnel and found the coupler in pieces, although it appeared I was in first I was in third. No wonder I had no low end power and reverse still worked. It's amazing it found any gear consistantly with both plastic bushings busted out.
Send me a PM with your address, there is a gift certificate headed your way...What a good feeling to finally find a smoking gun, I thought I would be chasing this ghost for many weeks to come.

snowman · 06-12-2003, 06:35 PM

Great call Alan.

Elombard · 06-13-2003, 03:51 AM

Hey since you saved all the money on the aluminum PP I think a call to Stomkis for there $100 shift coupler is in order :-)) Maybe Wayne sells them?

DavidH · 06-13-2003, 05:48 AM

Eric,
It was good to find the problem, I would still like the alumin. Pressure plate at some time. As for the Stomski, 192 plus S&H. Ouch I think for what I do currently the factory bushings will have to do.

Wayne 962 · Wayne 962's Garage

Yup, we now carry the Stomski coupler, but the stock one should work fine for you at about 1/4 the price:

http://www.pelicanparts.com/cgi-bin/dbsql/db.cgi?db=partsearch&mh=20&view_records=yes&uid=default&description=911+shift+coupler

-Wayne