Engine/Transmission (1994 - 1998) 7.55mm lift spec...

[JHastings]

Tried to time my truck today b/c it seems to be pretty retarded, but I got a lift spec of 7. 55mm. It is an 841 pump. On the table that would be like 21+*. What did I do wrong. Here is how I did it. Got TDC, put on DV holder adapter, put in gauge and set between 7. 0 and 9. 0 mm. Then turned motor counterclockwise until no more movement on dial. Zero the dial and then return to TDC. This is the correct method right? Anyhow any chance my pickup would cough at high RPM's if my timing is really that advanced?

TIA



Jamie

 

[JGK]

I'm not familiar with the 841 designation of your pump. But since it's a '98 5-speed, I assume its a 215 hp pump (CPL 2023 or 2175). If I extrapolate the table correctly on Pier's site, 7. 55 mm of lift would be more like 26* !!



In any event, it sounds like you did it correctly. My only question would be how you determined TDC. The timing pin on the gear case is not always perfect. It can be off a little. But I'm not sure it would be off by so much that you're still running 20+ degrees of advance. I would think that would make it tough to start and run sorta rough off idle!



Serious sled pullers run it at 21-plus degrees of advance. Not typical of daily drivers.



Anyway, how did you determine you were at TDC? And what makes you think its retarded?



-Jay

 

[JHastings]

The pump is an 841 I think which is a 175 hp pump I think. I has been changed and is no longer the stock 215. I did use teh timing pin and I didn't know that it could be off. Maybe that is my problem. I think it is retarded because it runs really bad in the mornings and at the top of each gear, even when it is warm, I get a white cloud. It also runs really rough above 2500 rpm. How should I better determine TDC?

 

[JGheen]

You can use the drop valve method which is prefered by most on here. Just get the #1 cylinder close to TDC and back it off some. Tighten down the #1 exhaust rocker adjustment and then bring the engine back up to TDC very slowly until you feel it stop, in which it will be hitting the valve. Make a mark on the crank damper, then roll the engine backwards until the piston comes back up and hits the valve again. Make another mark on the damper and your exact TDC is right in the middle of the two marks you made.



Joe