Simple 'Timing for Dummies' question

P

PRattenbury

Neophyte
When setting timing on a 12 valve engine with a p-pump, what are we really trying to time the injection event to? Valves closing? Piston at TDC?
 
When the #1 injector is firing in relation to where the # 1 piston is when traveling up on the compresion stroke. How many crank shaft degrees it is before the piston get's to the TDC
 
The reason I ask is if I'm finding what I think is TDC by using the #1 plunger OR by valve drop method, those two readings being based on the cam gear, if the cam has been degreed I am not seeing true TDC unless I'm basing my observation off the piston, marking when the piston stops rising, and then when the piston begins to fall (both valves being closed). My engine is really noisy, IMHO. And the timing is supposed to be set on the stand at 24 degrees, which shouldn't be too obnoxious. My theory is maybe I'm not using true TDC and I'm running more timing than I think. Could that be true? At what level of timing would the motor start to get loud, all things being correct? 30? 36?
 
Well, at some point or another you should have found TDC on the #1 piston...I use the drop valve method.

Then, you would have set the timing from the #1 injection plunger...there is no way to find TDC from the pump to my knowledge.

Chris
 
Yeah, it's been a couple years since I did timing on a p-pump. I had good instructions, and easily followed them with good results. Maybe I'm barking up the wrong tree. But I wanted to verify my timing is what I think it is to eliminate it as a possibility for the cause of how noisy the engine is. It doesn't sound like something's broken, it just sounds like too much timing. I was warned, though, that trying to fool with too many different things isn't gonna be a good idea, since the cam is degreed and so forth. I guess I'm in over my head, but I gotta learn somehow, I guess. Or start growing a money tree and find someone willing to make money to get it right...
 
Like Sig'600 does, I've always used the drop-valve method of finding TDC and I think it'll get you to within an half degree or better if done carefully.

-Jay
 
if you truly think its "timing noise", then take the time to back her off a few degrees. if she clears up, you know where your at. if not, might be another issue.

good luck either way!

-marcus
 
That would answer the question, either way. We shall see. Thanks for the input, guys. I appreciate it, as always. :thankyou2:
 
what did you find out?

and if timing is related to mm of lift why is there not a sticky with a chart in this forum?

xmm = x°

help

thanks, don
 
Never really got to it yet. I've been fooling with turbos forever. Had it running on a single 64 briefly in April. Now back apart again trying to get the tubular header/S470 setup worked out. Strangely enough, I have an II 13mm pump, and I've never seen a lift chart for that pump.
 
I would set it by dropped valve and then push in the timing pin to verify it. Once you have it verified its at TDC I would mark the balancer at the center of the Tach sensor and pull the timing pin out. Then pull the 15/16" plug near the GSK plug and rotate the engine until the pump tab is centered in the hole. Remark pump TDC on the Tach sensor and measure the distance. For 15 1/2 degrees you will have about 1/4" between marks for reference on a 12 1/2 degree engine stock. Otherwise find someone to loan you the Miller tool kit or buy one to get it accurate.
 
DTanklage said:
then how in the heck do you time it????????
Click to expand...

Timing is more or less when the injection event begins in relation to piston TDC. The plunger lift charts are simply an easy way to set the timing and are not necessary. You can just set the crank to the desired time before TDC (say 18 degrees) and roll the pump over until the point at which the plunger feed ports are just covered up. This is called "spill port timing." If he really wanted to know what the plunger lift at TDC for that 18 degrees of timing is then he could just roll it over to TDC and measure the plunger lift for a bit easier reference.
 
i see

at what lift in a 215 pump does this occur (port just covered)

does it vary from pump to pump?

if so the lift method would not be dead on would it?
 
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