Distributor timing with .590 cam

[Ben Treinen]

Hello everyone, im seeking some help setting up my distributor for my 440 with an old stock .590 purple shaft / solid lifters setup. I have a Proform mopar distributor part no. PRO-66995 and do not know how much initial advance to put with this cam, first timer here.... thanks!

Other specs:
30 over, stock rods, TRW pistons, solid lifters, ductile rockers, forged crank, 4 speed, power disk brakes (yes I know they won't have any vaccum)

 

[RemCharger]

It's about a 4800-7200 rpm race cam. You'll probably end up almost locking it in. Might idle well at around 1000rpm

 

[gkent]

15 degrees initial. 36 degrees total - all in at 2000 rpm

 

[Geoff 2]

It is very easy to determine the BEST idle timing. Adjust idle mixture screws for best idle. Engine idling, SLOWLY rotate dist CW until you get the highest rpm. Toggle dist to make sure highest rpm. Now check the timing. It wouldn't surprise me if it was 30-40*. It may have enough vac for p/brakes.

 

[Doorkicker]

Timing is impacted by a few characteristics, such as compression ratio - static and dynamic, arguably - chamber design, piston design, and cam specs, such as duration, LSA, and especially overlap. Nevertheless, most engines will have 12-15 initial timing. It all come down to what total timing.

Anyway...

I typically start with 12-15 degrees. Let's assume (which is easy to confirm) the TDC mark on the dampener and markers on the timing chain cover are accurate, just rotate the mark to 12-15 BTDC on the crank for #1 on the compression stroke. Then drop in the dist. and put the button pointing to plug #1. At least you know you have some basic initial timing. Do you have a timing light handy?

 

[RemCharger]

The cam is about 275° @ 0.050.
Not 230-240 street grind.

 

[65CopCar]

15 degrees initial. 36 degrees total - all in at 2000 rpm

I don't know about that. When I ran 440's (including the 590 cam), granted they were race only, but they liked 38 - 40 degrees total timing. My strokers are more efficient and are around 32 degrees total.

 

[gkent]

On today's gas ??? Be happy with 34 degrees !

 

[Hemirunner]

15 degrees initial. 36 degrees total - all in at 2000 rpm

Are you assuming he’s using a vacuum advance style distributor using manifold vacuum or ported?

 

[RemCharger]

I'm still at what does TRW pistons mean. Like a 2295? 2355? 2388

2266?

 

[Ben Treinen]

I'm still at what does TRW pistons mean. Like a 2295? 2355? 2388

2266?

2295s, i was told 10.5:1 comp

 

[Ben Treinen]

Timing is impacted by a few characteristics, such as compression ratio - static and dynamic, arguably - chamber design, piston design, and cam specs, such as duration, LSA, and especially overlap. Nevertheless, most engines will have 12-15 initial timing. It all come down to what total timing.

Anyway...

I typically start with 12-15 degrees. Let's assume (which is easy to confirm) the TDC mark on the dampener and markers on the timing chain cover are accurate, just rotate the mark to 12-15 BTDC on the crank for #1 on the compression stroke. Then drop in the dist. and put the button pointing to plug #1. At least you know you have some basic initial timing. Do you have a timing light handy?

No timing light but nothing a quick Summit order or harbor freight trip cannot fix, I was told 10.5:1 with this build as far as heads im at a loss, I only remember about half of the specs I was told

 

[RemCharger]

2295s, i was told 10.5:1 comp

So you've got a race motor, that someone potentially put shitty heads on

 

[Crackedback]

Start around 25*, might want more idle timing. Going to have to limit mechanical advance inside the distributor.

Doubt it will run well at idle with less than 20*

4 speed makes life easier.

 

[Geoff 2]

I have 265* @ 050 for the MP 590 cam. No way that cam will run/idle best with 12-15* idle timing.

 

[RemCharger]

The problem is the huge overlap.

 

[Geoff 2]

Yup, & that requires a lot of ign timing at low rpms. One of the reasons racers use locked dists with big cams.

 

[33 IMP]

I've got a direct connection iron tach drive distributor. With the Mopar supplied curve in it, the only time it's not at full advance is starting. At 1200 rpm idle, it's all in. So, I set total at 38°.
And iron open chamber heads on 2295s, with stock deck height (block not milled much) and composition gasket is around 10.5.
Mine will run on pump 91, but I run about 33% avgas, cause I can.

 

[RemCharger]

I don't know about that. When I ran 440's (including the 590 cam), granted they were race only, but they liked 38 - 40 degrees total timing. My strokers are more efficient and are around 32 degrees total.

I ran 42° in the old race 383's with trw domes, now we're at 32° with a flat top Victor head 440