Unbelievable injection timing?

[Strick-9]

The timing tools from Snap-On arrived today. After work I tore into my truck to advance my timing to 15. 5°.



After I found TDC, I wanted to check what the stock timing was before I just blindly set it.



At TDC I had 7. 15mm of lift on the #1 cylinder. I expected the value to be near 5. 7mm. I checked it three times.



My CPL is 1549 and according to the data from Fritz's website 6. 3mm should be 15. 5°.



This value isn't even on the charts. I would guess the value is near 19° BTDC, but is that even possible.



Does that explain why my truck hammers so loudly at idle and takes a few revolutions to start?



Is there something simple I could be screwing up? I followed the directions directly from my service manual. Everything seemed to work according to plan until the 7. 15mm value.



Need help and ideas,

Chris

 

[ramman]

This setting with your mods should make for a hot running truck,I know of some running 21 degrees,I'd leave it alone as for the knock maybe you have the thin washers under the injectors which lends to knock. Run hard, Ramman

 

[Don M]

This could be part of the reason the HX-40 is not workin for you as well as is does for others. That much timing on an auto trans and the lag of the HX-40 spells bottom end power loss.

I have seen pullers running 21 degrees. With a stick transmission though.





Don~



my book says 5. 9mm is 13. 5 degrees on an auto.



Has the engine been timed before? Did you buy it new?

Has the engine been changed? Maybe a yahoo screwed the timing up.

 

[sewman]

How did you find TDC?

 

[SmokinCummins]

Hey guys... . I'm running 21 degrees of timing as we speak, My truck runs great, very responsive, runs cooler , but it is a lil noisy... As soon as I get a govenor spring kit I will probably take it on up to 23 degrees... Dave Mitchell put mine at 21 he has a chart to tell u exactly were your at if u need to know the plunger lift to degree timing coversion... give him a call 740-246-6329. . Thanks

 

[Cooker]

SmokinCummins,



Is your truck an everyday driver? 21 degrees of timing sounds a bit steep for an everyday driver, especially towing.



Maybe I'm way wrong



-Ryan

 

[ramman]

No ,mine is set at 18. 5 but I know of two trucks that are daily drivers and weekend truck pullers and highly bombed,I tried 21 but was a bit high for me but it is a daily driver,takes me to KTP to build fords everyday. Also my truck does pull the 5ver when I can and dynoed 400/1087 at Terra Haute last week which made me SMILE. RAMMAN

 

[Joseph Donnelly]

Best mpg at 2000 rpm will probably be gotten from about 15. 5 deg. You can put the valve compressor on a #1 valve, compress to get some slack, put a dial indicator on the tool, and see where true TDC is. It is likely that either your TDC is off or the pump was rebuilt with a higher lift spec at spill port closure. This would offset your lift specs vs. timing.

 

[SmokinCummins]

Hey guys..... to answer your question, yes, it is a everyday driver. My truck has 166,000 miles on it as we speak it's been at 17 degrees for most of it's life but the extra 4 didn't do anything different but cool my egt's down when I put Mitchell's delivery valves in with my 370's. I can't wait to get my govenor spring kit. .

 

[JohnE]

I was talking to the owner of a local diesel performance shop on Saturday on the importance of adjusting injection timing. Mike says he "flow times" 12 valves to 19-21° in order to drop EGTs.



Mike's personal towing vehicle is a 12 valve 3500 with many pump mods and a custom 5" exhaust system.



Do any of the mechanical injection pumps have variable injection timing?



John