North American Turbocoupe Organization



Timing Cover Marks Off by ~4 degrees?
DR1Pilot Offline
Member
#1
I discovered last night that the timing cover (plastic) that comes on the engine was sitting about two ticks or ~4degrees off. How I discovered this was when changing my timing belt I cam across an issue with the cam timing. The cam timing always wanted to be off by half a tooth despite that the crank was lined up with the TC mark on the plastic cover. This got my thinking and so I pulled the crank pulley off and found that the key on the pulley was not straight up and the little mark on front of the sprocket was not aligned with the associated notch. So I set TDC using the sprocket key and the sprocket mark. Low and behold the teeth on the cam lined up perfectly this time with the belt. This also meant that my ignition was set based on the offset of the cover. So I set the base ignition advanced by 14deg instead of 10deg to match the difference between the cover and the crank. This explains why the car felt lazy.

Has anyone else noticed this issue with their timing cover?
Project 88 T-Bird 74k original miles
and a Loud Moped
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Pete D Offline
Administrator
#2
Yes, every cover I have worked with is off, usually 2-4*. On a stock engine I add 2-4* more advance..
Pete Dunham


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anasazi4st Offline
Senior Member
#3
DR1Pilot Wrote:Has anyone else noticed this issue with their timing cover?

It’s true, like someone said before—the timing cover indicator on our cars is not very accurate, to say the least.

I spent an entire afternoon one Thanksgiving weekend trying to get the teeth to line up “just so”. Sadly several years ago this activity was repeated, having having forgotten the last attempt.

I have never been able to get the teeth to line up “just so”. I’m not sure if it was -4 degrees last time, but I know it was not as close as I would have liked. I usually get it as close as I can, check the distributor, set the timing and “listen” to the engine at idle on on manual acceleration; watch for stuff like the temp gauge/when the fans come on and fuel economy to see how close it is.

That process has worked fine for me over the years.
Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 1 T5OD full rebuild, 5 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....
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