Timing question

[Kw69]

Gents,

Got a typical question. I have a crate drop in 350 GM goodwrench with 195 hp not the 290. So what is the timing on that engine, I have heard from 0 degrees to 10... previous owner told me 0 degrees, but that seems way to low. What’s your thoughts, it is running with AC and 4 barrel Rochester carb. Idle with ac on is set at 750 rpm. Seems to diesel some after shutting it off when set at 2 degrees so I set it now at 8 and have not noticed that. However slow to turn over.... so I’m thinking that I’m getting heat soak on the old starter... if so .. question 2... what can I do about that? Purchase a mini starter? If so what kind? So for all the questions just running into some fun today..lol also to add that it was hard to turn over hot when at 2degrees before top dead center, as well.

Thanks guys as always,
Kris

[AussieinNC]

Timing should be around 7 degrees BTDC with engine idle around 650 and vacuum line to distributor blocked off...

Heat soak on starter...assume you have tubular headers and old large format starter....do all items for best results...

1/ Wrap exhaust pipes close by the starter with heat wrap.
2/ Mini starters move the starter body a little further away from heat source...
3/ Make sure your battery cables are sufficient gauge..and you have good grounds between engine and chassis and battery....clean the chassis really well with wire brush and sandpaper where cables need to ground.
4/ Add a heat shield to the new starter for added insurance....

Have fun...

[RustyPile]

Originally Posted by Kw69

Gents,

Got a typical question. I have a crate drop in 350 GM goodwrench with 195 hp not the 290. So what is the timing on that engine, I have heard from 0 degrees to 10... previous owner told me 0 degrees, but that seems way to low. What’s your thoughts, it is running with AC and 4 barrel Rochester carb. Idle with ac on is set at 750 rpm. Seems to diesel some after shutting it off when set at 2 degrees so I set it now at 8 and have not noticed that. However slow to turn over.... so I’m thinking that I’m getting heat soak on the old starter... if so .. question 2... what can I do about that? Purchase a mini starter? If so what kind? So for all the questions just running into some fun today..lol also to add that it was hard to turn over hot when at 2degrees before top dead center, as well.

Thanks guys as always,
Kris

Is this your engine??
https://www.jegs.com/p/JEGS/JEGS-Sma...gin|0||P_SKU|0

A 195 hp 350 sbc is a very mild engine. Low compression (below 9.0:1) needs low octane fuel and not much initial timing.. Total "all in" timing should be around 30 - 32 degrees.. I'm just taking a shot in the dark here without more specifics, but I'd say 10 degrees initial is a bit much. Probably closer to 6 degrees would work better.. Slow cranking speeds are not always indicative of a heat soaked starter.. Too much initial timing, weak or insufficient battery capacity, bad battery cables/connections, or a worn out starter, among other things will produce the same symptoms..

Before you start slinging parts at it, check and repair as necessary, all the basic items involved in the actual cranking process.

My 10:1, Lunati cammed, header equipped 454 BBC cranks just fine with a 350 cid hi-torque old style GM starter.. Nothing installed to aid heat soak either..

[randy500]

If its hard to turn over at 2 degrees advance your battery cables are probably Walmart quality and or your not actually at 2 degrees due to mismatched timing pointer and harmonic balancer marks.

[68 P.O.S.]

If your crate has Vortec heads, your total timing should be at 32 degrees. If it has standard heads, your total should be at 36 degrees. This is assuming your distributor is set up correctly. Which distributor do you have and which vacuum source is it conencted to? HEI or points? How many degrees of mechanical advance does it have? How many degrees of vacuum advance does it have? This needs to be set up right in order to set your timing up right. Your idle at 750 rpm sounds right.

It's running hot because the timing isn't advanced enough. At 2 degrees the fuel mixture is still burning as it exits into the manifolds/headers; heating up the engine. That's how GM controlled emissions in the 70's/80's and why those engines were such turds.

I agree with Randy on the balancer and cables.

[Kw69]

I have the HEI distributor, standard 195 hp crate drop in. I have the original engine in my shop and plan to rebuild it one day. I have the old style GM starter and will check the cables this week. The battery is autozone series and is new within the year. The vacuum is coming from the intake manifold which is the stock one from 1969 from the original engine. Thanks guys so far I really appreciate the help!

[AussieinNC]

Did you put a new harmonic balancer on the engine? or did you reuse the old one?

If you used the old one, it is quite possible the outer ring that holds the timing index mark has slipped out of position...

What about the timing tab...which one did you use?

Same thing for the starter...if you reused the old one, it could be worn out....

Battery cables...again...did you reuse the old ones or put in new cables?

Are the chassis to engine and cab grounds in good condition?

Vacuum to the distributor should be ported vacuum...not direct to the manifold....there are two sources for vacuum on a carb...one that has no vacuum at idle, meant for the distributor...so it should show zero vacuum at idle...(650 rpm)
and one or more that are full continuous vacuum for various accessories.

[truckster]

Originally Posted by AussieinNC

Vacuum to the distributor should be ported vacuum...not direct to the manifold....there are two sources for vacuum on a carb...one that has no vacuum at idle, meant for the distributor...so it should show zero vacuum at idle...(650 rpm)
and one or more that are full continuous vacuum for various accessories.

Here's a really good article by a GM engineer that explains why you want to run manifold vacuum (not ported) for your vacuum advance:

http://www.camaros.org/pdf/timing101.pdf

[Kw69]

Yea the engine was put in from the P.O. who now sadly has passed away. The starter does appear to be older for sure. I’m not home to check the cables just yet. I’m at work and maybe won’t be home till Wednesday am. I will check then, again really appreciate all the help guys.

[Boog]

That's one topic that will be argued for ever.

[RustyBucket]

I had a defective 6 month old battery awhile back. Maybe get yours load tested.

[Grumpy old man]

Giving timing and tune tips from all over the country is not going to work exactly for the guy at 50' elevation and 90% humidity in FL , as it may if your at 5,000' and 35% humidity, Yeah it might get you close but it's just not the same #'s

There are a bunch of members in the Tampa area hunt them down and use their #'s

[Steeveedee]

Originally Posted by Grumpy old man

Giving timing and tune tips from all over the country is not going to work exactly for the guy at 50' elevation and 90% humidity in FL , as it may if your at 5,000' and 35% humidity, Yeah it might get you close but it's just not the same #'s

There are a bunch of members in the Tampa area hunt them down and use their #'s

Exactly! Timing, mixture and octane demand all depend on the location/elevation and even the local humidity. Having a high altitude (or California emissions) carburetor back in the day meant something. People these days aren't used to that.

[VetteVet]

It's important to note whether the solenoid clicks loudly but the starter won't turn, or whether the solenoid won't click at all. If the solenoid clicks loudly then the heavy voltage from the battery isn't getting to the starter windings due to poor battery, bad cables bad connections or the starter brushes are shot or the windings are heat soaked.
It's also possible that the solenoid internal contacts are for the main cable are worn or corroded.

If the solenoid isn't clicking then a screwdriver jumping to the purple wire from the solenoid battery cable connection might make it work. If that's the case then there is a workaround using a Ford solenoid could be a cheaper fix.

Here's a tutorial on how GM starters work put together by yours truly for your reading pleasure.

http://67-72chevytrucks.com/vboard/s...d.php?t=655903

[68 P.O.S.]

Originally Posted by truckster

Here's a really good article by a GM engineer that explains why you want to run manifold vacuum (not ported) for your vacuum advance:

http://www.camaros.org/pdf/timing101.pdf

There's the science straight from the engineer

[68 P.O.S.]

Here's another follow-up article he did about mapping your advance curves http://www.stl-vettes.com/65Vette/co...ng_Advance.pdf

[Boog]

John Hinckley wrote that. Wasn't that the guy's name who shot Pres Reagan?

[jocko]

He's had a lot of time to study timing curves since then.

[Boog]

[68 P.O.S.]

That is his name. Haha!!

Nice one Jocko lmao

[volksworld]

if you search lars grimsrud timing you'll find his specs on corvette forums about hei distributors and their timing...basically a stock hei is a smog distributor and is all wrong for performance....and pretty much requires a weight and spring kit as well as a performance advance can to behave properly....if you have an aftermarket hei i ave no idea what those specs are, you'd have to find that out

[68 P.O.S.]

x2 on the stock HEIs being smoggers. In general, the aftermarket HEIs have the correct weights and base plates you want, but you'll still need to change out the springs and setup the vac advance.