Timing a 318. What does 2 degrees below book mean?

btravlin2

Petty Officer 2nd Class
Joined
Sep 7, 2010
Messages
108
I've got an LM 318 Chrysler that is a remanufactured engine. On the engine it states for timing: "2 degrees below book". My book calls for 5 degrees BTDC. I don't know if that means 3 BTDC or 7 BTDC. Anyone?

And why would the timing be different than the original anyway?

Thanks.......
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Re: Timing a 318. What does 2 degrees below book mean?

Just some guesses.....If it came with a distributor it may have more 2 degrees more mechanical advance than OEM and need to be backed down by the 2 degrees. It may have a more modern and efficient cam in it. Or it may have different compression and/or newer style heads maybe. Could be a combination of all that. And I would take "below" as "lower" or less advance than book. I think I would call them also just to get more info, I bet they will be glad to expound on the reasons behind the instructions.
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Re: Timing a 318. What does 2 degrees below book mean?

Another thought I had, maybe the sticker advice is for the break-in period?
 

btravlin2

Petty Officer 2nd Class
Joined
Sep 7, 2010
Messages
108
Re: Timing a 318. What does 2 degrees below book mean?

I've tried googling them, but no luck. On the motor it says TCM 318.
 

btravlin2

Petty Officer 2nd Class
Joined
Sep 7, 2010
Messages
108
Re: Timing a 318. What does 2 degrees below book mean?

Well, I did find them, but the number on their website had been disconnected. They were an outfit in Austin, Tx that sold reman engines. This engine is at least 12 years old.
 

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,269
Re: Timing a 318. What does 2 degrees below book mean?

Most all rebuilders want the max timing set lower than the original settings. Keeps the combustion temps a bit cooler and less chance of damaging an engine.
 
Top