924Board.org

BionicBalls · Joined: 05 Jan 2009 Posts: 642 Location: Charlotte, NC

I'm adjusting my valves today, got all the intakes adjusted. Was only able to get 1 exhaust adjusted within spec. So I pulled the grub screws:

Cyl 4: 2 notch
Cyl 3: Good
Cyl 2: 1 notch
Cyl 1: 0 notch

My problem is I cannot get the them adjusted loose enough. So I put the 0 notch I had into Cyl 4 and got it adjusted correctly.

I'm hoping that a 0 notch in Cyl 2 will get it into spec, but I have no idea what to do about Cyl 1 which already had a 0 notch, but still needs to go thinner.

Should I just machine some more material off of a 0 notch? I know that not all the screws were machined perfectly and that there was some variance between screws with the same number of notches.

Maybe it not adjusting out with a 0 notch is a sign of a problem. That is the cylinder that had no compression during my compression test. Was hoping that it was something as simple as a valve adjustment. The intake was way out on that cylinder as well.
_________________
1980 924 NA
1982 931

Paul · Posted: Wed Oct 31, 2012 11:09 am Post subject:

Worn valves or seats?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Fifty50Plus · Posted: Thu Nov 01, 2012 2:27 am Post subject:

^ +1
_________________
1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA

Paul · Posted: Thu Nov 01, 2012 3:11 am Post subject:

Just checking what spec are you using for the exhaust valves? Have you done a compression check?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

BionicBalls · Joined: 05 Jan 2009 Posts: 642 Location: Charlotte, NC

.004 intake
.016 exhaust

Cold measurement.

As I had said, did a compression check and cyl 4 (the one in question) only gave me 25 lbs.

I'll have to check my records, but I'm fairly certain that I had the head rebuilt when I rebuilt the bottom end. Not saying that can't still be the problem though.
_________________
1980 924 NA
1982 931

daniel · Joined: 18 Jun 2009 Posts: 686 Location: Sydney, Australia

Beginning to sound a lot like you are pounding out a valve seat or pulling the head of a valve. As a rough check, pull the cam and the lifters and have a look at the heights of the valves, if they do not match, pull the head.

Daniel
_________________
Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet

Paul · Posted: Fri Nov 02, 2012 9:59 am Post subject:

I have a couple of 931 heads if you end up needing one, PM me. I'm thinking you have at least one burnt exhaust valve.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.