Engine/Transmission (1994 - 1998) P7100 pump timing question.....HOW?

[The patriot]

It dont seem like I'm going to get the weather I'd like to do this, so I spent some quality time under the hood today. :{
I did find TDC with the timing pin in the cam gear. This method will have to be accurate enough. I'm not dropping a valve.
According to my dial indicator I'm running about 27. 5 deg (+/- . 5 deg) advance.
It was just shy of . 300" lift.
Can this be? Can timing slip forward? Could have the factory set it this far advanced? I'm the original owner and it's never been touched.

I dont know what to do?
Help!

 

[hsmith]

You drop the intake valve with the piston up, the valve can go nowhere.

 

[The patriot]

I found TDC, I dont think I need to do that now.
I know it's TDC, I felt it slide in. Pulled it out, moved the crank, tried it again (no go) then slowly moved the crank while pushing the pin in. It's DEFINITELY TDC. I could feel it go in further. 100%.

I'd remove the injector and use a dial indicator though there, but now that I established TDC it's unnecessary. Besides, I dont have the tools to do that.

Could my truck really be @ 27+ deg BTDC?

It runs and starts fine, even in the cold. Just the MPG's are sucking. That's why I'm going through all this. Little bit o smoke (370's) but otherwise stock.
Smoke is mostly @ high RPM's IIRC. I dont drive it much anymore.

 

[GAmes]

I found TDC, I dont think I need to do that now.

I know it's TDC, I felt it slide in. Pulled it out, moved the crank, tried it again (no go) then slowly moved the crank while pushing the pin in. It's DEFINITELY TDC. I could feel it go in further. 100%.

Really? Did you know that the timing pin mount is adjustable? Are you absolutely sure that the guy who pressed the cam gear onto the shaft put it exactly where it belongs?

 

[The patriot]

I'm sure, I did it myself. I pulled the fan so I could wrench the crankshaft from the top. :{#@$%!

The only thing I can think is if there is a second hole, which I doubt.

I pulled the valve cover, both valves are closed. I backed it up until the exh started to open then went forward from there.

The amount of lift on the #1 injector plunger is right around . 298-. 300" which translates to about 27 deg BTDC. (I have the chart outside. 27... 28... . something ridiculous like that)

Can the timing slip backwards?

I seem to remember long ago when Dad was driving, he caught the wrong gear and the rpm's were up there a bit. Maybe 3500 rpm's. Could this cause it to slip forward?



Please dont suggest to drop a valve.

I'd rather pull an injector if it can be done like that.

I dont mind having to order a long extension for the dial indicator.

 

[The patriot]

GAmes, I did notice it had torx bits holding the pin assy in, but I didnt loosen them or take them out. I was tempted to to try to see the hole it was supposed to drop into.

I'm the original owner. Nobody has ever timed this truck up, or messed with anything remotely having to do with timing.

 

[GAmes]

Someone installed the timing pin on the cover long before the cam was installed in the engine. I can virtually guarantee that no one checked it's accuracy. Most people use it for valve adjustment where exact TDC is not required.



You don't really "drop" the valve. If you read the instructions all you do is take the slack out of the rocker and tighten the adjustment screw enough to depress the valve below the valve seat. Rotate the engine slowly until the top of the piston makes contact with the valve. Mark the damper, etc, etc. Quick and accurate.

 

[Nyoest]

Are you standard dial indicator with a mag base? If so I doubt you will ever get a correct reading due to all the flex.

Also could you be losing something in translation? most timing tables are in millimeters of lift, not thousandths. It took me a bit to do my first one bc I couldn't get my head around a metric dial indicator.

You can pull an injector and see the top of the piston but you'll never get an accurate reading With a dial indicator. You will be at angle no where near 90 degrees.

 

[The patriot]

Thanks guys.

Guess I'll have to do the drop valve. :{



Yes, my dial indicators are a magnetic base type. I have some aluminum stock, so I could make a job specific bolt on base, but if it wont be accurate, no point. :{

 

[The patriot]

Well I finally had some success today.

I did the drop valve thing to determine TDC. The pin TDC was off, by about 1/4".

I also think I was reading the dial indicator wrong yesterday.

Anyway, now @ TDC my plunger lift is at . 195" which translates to just under 13deg BTDC. I believe that's @ or very close to factory spec for a 2175 engine.

I'd like to go around 15. 5- 16. 5 deg. Would like to err closer to 16. 5.

Does this sound like a good number?

Truck is stock except for 370 injectors and a BHAF.

Reason is I'm getting terrible MPG's on the highway.

Thanks all for the help/insight.

 

[GAmes]

The downside of a 12 valve is the timng is not variable to engine RPM. I found that my best mileage is in the 15* range because my operating RPM on the highway where I drive most is 2000 to 2200 rpm. If you drive slower then14. 5 may be better for you, faster then 16 may be good. Then you throw in the variable of bigger injectors so my settings may not be right for you. Once you have gone thru the process you will find that experimenting a little is not that difficult.

 

[The patriot]

I always seem to find myself at 2100-2300 rpm's just to keep from being rear ended. If I set it at 2K, I'm almost a road hazard around here.

Maybe 15. 5 deg.....

Seems like the only time I drive it anymore is 1000 miles at a time.

Last year I only went 4K miles. That included 3 trips to Maine and 1 trip to Virginia.

*sigh* the real answer is another hi gear.....

 

[The patriot]

Well finally got er done today.

I had a few distractions so I had to pop the gear an extra time.

We ended up at . 222" @ TDC, which is a little more than I wanted, but within what I feel I need. I took it for a short ride and cant really feel the difference, or maybe it's just I dont drive it enough.

It "sounds" maybe a little lopey at idle.

Thanks all for the help. I'm disabled, so this isnt as easy as it should be for me.

I didnt even have any extra parts. :-laf

 

[The patriot]

Oh, I also added one of those fancy adjustable overflow valves while I was under there.