Team Chevelle banner
Status
Not open for further replies.
1 - 7 of 7 Posts

·
Registered
Joined
·
25 Posts
Discussion Starter · #1 ·
My 350/330 crate engine with HEI feels better upon acceleration when the initial timing is set to 16btdc. When set here however the engine turns over very slow when hot. If I set back the Initial Timing to 12btdc the slow start goes away but I feel a seat of the pants difference in acceleration. Is there something I can do to modify this condition. I run vacuum advance. The car idles and otherwise runs fine.
 

·
Premium Member
Joined
·
1,955 Posts
Don, Do you know what the total mechanical advance is set at and at what RPM it is all in by? Are you running the vacuum advance off a ported source or manifold source? Do you know how much advance the vacuum can is pulling in?

It may be as simple as dialing in 4 more degrees of mechanical but you'll need to answer the q's above to get your working baseline.

Dan

------------------
Awww, fer cyrin out loud, there's that IMPALA guy again.

http://photos.yahoo.com/bc/ss3964spd?d&.flabel=fld1&.src=ph
 

·
Registered
Joined
·
94 Posts
mine does the same thing i have 18 initial timing. the only thing you can rerally do is retard it by hand or get a msd start retard which does auto maticly. as long as you CR is fairly low you souldnt have to worry.
 

·
Registered
Joined
·
714 Posts
One other option if everything else above is checked out and you don't want the expense of the retard kit or messing with your distributor. On my 68 Z/28 the previuos owner installed a kill switch on the ignition. He didn't do it with the problem of too much timing but wanted to spin the engine freely for a little bit to get the oil pumping before dry starts. But what this does is spin the motor freely with total disregard to where the timing is because there is no spark going to the plugs. A flip of the switch and a well tuned motor should fire right over. My 302 used to fire right over all the time untill I disconnected the electric choke...but that is another story. Now with just a little coaxing it fires right up

I have heard of others doing this but it is not a common practice. I was having similar issues with my 70 SS 396/350 motor last year but this spring I played with the timing and moved my vacuum line to the manifold and seems to be OK now. 12-13 BTDC intial with vacuum plugged. I was toying with the kill switch idea until I got it worked out this way to my satisfaction.

Another side benifit is if the switch is hidden a little bit but accessible from the drivers seat it can also work as a theft deterrent.

Maybe someone else will chime in that has actually done this to be able to run more timing and still get the car started.

Hope this helps

'Da Mouse

------------------
67 SS396 350HP 4 sp 3:55 Posi Butternut Yellow w/Black Vinyl
68 RS Z/28 302 350+Hp? 4sp 4:10 Posi, Euro Red on Black
70 SS396 350HP 4 sp 3:55 Posi, Black on Black

Mytmouse A.K.A. Robert Stacho
ACES Member # 04359
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #6 ·
Sorry for the late replies. I had originally followed the Total Timing approach and this showed that it ran best at around 36 degrees and all of this is in by 3000 rpm. If I take the initial 16btdc away from the total then I am left with 20 degrees of mechanical. Right?
 

·
Registered
Joined
·
2,142 Posts
right. If you initial is @ 16 deg. btdc and your advance taps out at 36 deg. @ 3000 rpms, this means you have 20 deg. of mechanical advance. AS long as your seeing this with the vaccum adv. disconnected and plugged.
------------------
'70 SS 396 4spd
TC# 1341

"You're just jealous because the little voices are talking to me"

[This message has been edited by Midnight Marauder (edited 11-02-2001).]
 
1 - 7 of 7 Posts
Status
Not open for further replies.
Top