Crumpler

Hey gentlemen, just an update.
Went back in last night. Rotor bolt holes were only centered on one of the three positions, as Ken had been suspicious of.
Pulled belt off and adjusted, then re-strung new belt and set tension at TDC.
New 32'vr readings were improved at 0 PS (1-4) and +3 DS (5-8).
Happily adjusted from there with bump stick.

snoz

Sorry to dredge up an old thread/hijack. I'm working on the same procedure and want to make sure I have this right. The clamp rings are marked with #1 up on once side and #6 up 180 degrees opposite. The instructions say "The square ‘key’ should point to the large front indentation on the cam gear". I installed them this way per the instructions. Does it look like I have them oriented correctly in the pictures below. Also, my crankshaft is locked at 45 degrees btdc.

Thanks,

-Ethan

Passenger side.

Drivers side.

FredR

So far so good. The pics suggest you have not yet installed the 32VR spacer to permit adjustment of the cam timing- not a problem at this stage. Just remember that when you come to string the belt the cam sprockets have to be 3 teeth before the notch on the rear casing.. The 1/4 sprocket looks to be in that position, the 5/8 sprocket needs to be moved backwards a similar amount or so the pics suggest. Doubtless you are aware of that but pointing it out "just in case".

snoz

Thanks for the information Fred. I was thinking I had it right but wanted to be sure. I'm gong to try to get to stringing the belt and setting the cam timing this weekend.

aseem

Just to be absolutely certain I don't destroy anything: is the above statement also true for later 32V engines? In my case a 1989 GT. (motor at 45 BTDC, belt off)

My left cam suddenly jumped past the TDC mark from the 45 degree mark while I was putting on the new belt. It seem very hard to move now in either direction...

Thanks

SwayBar

Yes, with crank set at 45 BTDC with piston #1 rising in the bore, you can move all cams without damaging the engine for all 32v engines.

aseem

Thanks.
It seems very hard to move though....

GregBBRD

The reason the cams "jump" is from the spring pressure of the valve springs pushing on the cam lobes.
In order to return the cams to the correct position, you need to overcome this spring pressure, which takes considerable force.
Just be sure to always turn the cams with the 30mm "nut" and never with the 17mm bolt head and you will do no harm.
Also be sure to liberally oil that 17mm bolt.....they tend to get very dry and "chalky" over time.

worf928

Yes. With the crank at 45°BTDC, as indicated by the balancer marks, you can spin the cams all you want.

This assumes that the balancer’s rubber part with the degree marks is still solidly attached to the hub adapter.

At 45° the woodruf key should ‘point’ directly to the driver’s side.


Correct. They are very hard to move due to pressure from the valve springs. More so on GTs. It will take moderate force with a 2-foot long 30mm wrench on the hex-shaped cam gear washer to get movement.

FredR

The chaps have covered what needs to be said.

Remember in round terms the exhaust cam duration is about 180 crank degrees [or 90 cam degrees] loosely speaking. So, if the cam is sat on the peak it has to travel 45 cam degrees to get to the path of least resistance at the base of the cam. The cam wheel has 48 teeth and 45 cam degrees is the equivalent of 6 cam teeth in round terms until it reaches the point of least resistance so the jump is not too surprising. The actual exhaust cam duration is a bit more than 180 crank degrees [circa 200 crank degrees from memory] so that would explain the apparent jump of 7 cam teeth- there or thereabouts.

Crumpler

The dead thunk of the cams falling over will still make the semi-trained like myself pucker every time!