Engine timing and cooling

[Heckeng]

Hey all, since adding the new heads, I had been tinkering with the idea of making some new bushings to adjust the amount of mechanical advance that the MSD distributor would add in. I had been running 16 initial, and 37 fully advanced for several years. I also have a 3000 stall which is when all of my advance is "in" too, so I figured if the engine isn't loaded, why not advance it a little more? Anyway, I am now running 20 degrees initial, and 37 fully advanced and I am shocked to see the results. The throttle response is improved (less sluggish) and my engine temp is WAY cooler and steady. The engine would get hot in traffic (210-215) with the 16 initial, but with the 20 initial, I am running between 180 and 185 in 100 degree heat. It is seriously shocking as this is the lowest it has ever run idling around. I may try 22 and 36 next to see if the throttle response continues to get more crisp.

 

I just thought I would pass this on in case anybody else was having "hot running" issues this summer. It might be worth a try if your engine will allow for some more initial timing.

[wallaby]

I went through a similar deal a while back...turns out in my case the mixture was way lean and that's why it liked so much initial. The advantages of lots of timing went away at higher rpms under light loads though, and it never sounded entirely smooth in that condition.

Once I got the mixture fattened up, it was happy running with more typical timing numbers and was smooth thru all rpms.

Anyway, it's a thought...there might be a reason your engine likes a lot of advance. Fuel mixture can play a big part in engine and exhaust temp also.

[72 LS5]

Why not just run more vacuum advance and keep your 16/37?

 

Keeping 16 initial should be easier on your starting, and if you run a 10 degree vacuum can, you will have that timing your are looking for during light loads, and it will drop back down to the mechanical advance when you get on it.

 

I'm at 14/34 mech advance. I just changed over to a 10-12 degree vacuum can this weekend b/c the one I had on there was like 20 degrees, which gave me over 50 degrees (mech + vacuum). I felt that was too much although I didn't hear pinging. Now its like 48 - a number I feel safer with.

 

I agree that extra advance makes the engine feel a lot more responsive.

[Heckeng]

I don't have any vac advance ability actually.

 

I have richened it up to stock specs when I did the head change because my buddy with the LM-1 has moved to Kansas City and I wanted to be safe. It still ran hot though. I would like to get an A/F meter on it though, just to be safe.