Hey guys.
I read that great helpful post on the timing, I realized that i was not running enough timing. I have a fastburn 385 GM Crate motor with the hot cam and lifters. Its a great motor but i was a little disappointed with it. I thought that more timing would help me with that. The factory suggested 10 Deg inital, and that would bring me around 29-30 Deg at WOT. I hear some of you guys saying that you can run 36-38 and even more. I dont really hear any knock becasue the cam is rather agressive. The car runs like I have never felt before. Very Strong and will start Rather easily. But when i am setting the timing the headders are Cherry red!!! Very scary!! Any ideas??


http://www.sallee-chevrolet.com/fram...ckV8s/385.html

 

Thats what you get with the hot cam.

If your A/F mixture is too lean or too rich you can get red hot headers.

Question: Do the fastburn heads require less timing advance than normal heads since the combustion happens faster?

 

GOOD one! any thoughts about the timing? Too much why would it be? It is only a 9.5 compression motor.

 

I just found on your link it says the fast burn timing should be set to:

32° total @ 4000 RPM with vacuum advance disconnected, on 92 octane.

 

doesnt this seem a little low? and they are glowing at this setting too.

 

I'd love to get this on a dyno and get some emmisions readings.

I run 12 degrees initial, 34 @ 2500 and 48 all in @ 3800 in my BOSS 302 (10.75 -1) on Sunoco 100 race gas, and pull it back 6-8 degrees for pump 91 Unocal with no problems. If your seing hot (glowing) pipes, something's up and I'm guessing mixture or cam timing...

Hans

 

What kind of carb do you have & what kind of tuning have you done to it?

If your A/F mixture is too lean the exhaust gas can get hot enough to make your headers red hot.

If the carb is way too rich you can get 'flames' in the headers from the unburnt fuel, which can make the headers red hot as well.

 

I have a holley HP 750 with a # 6 Power valve. It came off of a 383 and might be way rich. Im thinking that there are flames in the headders. Lean condition is definatly out as far as i am concerned.

 

Your 385 is bigger than the 383 it came off of.
Sounds like you're running rich

 

Screw the initial timing and do what Lars says. Do a search for his how to set timing tech paper. I had the same issue with mine, 8.5 compression set timing to 8-10 degrees and headers got orange in 20 seconds. Set the timing using a set back timing light so I had a max of 36 degrees at 3K RPM. When I checked the initial, it was about 18! No more orange headers. You're right. it is VERY scary.

 

if you are running the stock hei that comes with the engine try 2 msd blue springs initial @ 12 to 14 degrees and change the vacuum advance. the stock vac can has 20 degrees of advance we use a ac/delco unit part # D1370a ( i when ever possible use ac/delco units this brand preference may be different than most others but i am loyal to the companys that supported us with factory training)

good luck henry @ oles carb

 

Variable advance is required for optimal engine performance because as you drive, different A/F mixtures require different amounts of time to burn. So if the A/F mixture ignites quicker in fast burn heads-- you would require less advance than traditional heads.

So you can follow the timing procedures by Lars and others-- but probably not the actual value of 36 total advance. A previous reply of 32 total advance at 4k RPM is definitely believable.

 

Some of the best advice I seen on the forum lately.

It's refreshing to see someone say something intelligent instead of repeating the same old nonsense. Some engines require a different amount of total timing based on the components. It's not one size shoe fits all. I didn't click on the thread that stated 32*, but if it was from Sallee than that should be 'in the ball park'. They seem to know their chevy chit and share it with others.
I do agree with others that total advance is what should be looked at, initial plus mechanical. However, if you know how much mechanical is in the distributor, you can then set the timing using the initial value. Where the problem occurs is using a different distributor with a non-stock engine. A non-stock engine at idel will already be using some mechanical due to the higher idel speed. GM, as well as other car manufactures, had all the data they needed to determine what the initial timing should be set at to get to the desired total timing at the rpm they wanted. It wasn't a guessing game. Thats why they used a bunch of different distributors over the years based on the engine. Finding the sweet spot for total timing will require a dyno. Some engines may like closer to 32* while others will like up to 38*. As time went on, GM also had to consider emissions. They may have recurved the distributor based more on emissions than performance.

If you purchased the engine from Sallee, call them and talk to their tech support. They should be able to answer a basic timing question.

 

Duke, So let me get this right? You gave it more timing and the glow went away?? I was thinking just the opposite of what i was thinking in my head. how much dammage if any do you think that this will do to a motor?

 

If there is insufficient timing advance, then the fuel is not completely burned in the cylinder - and finishes burning in the exhaust path = glowing headers.

 

Got it, thanks guys, on to the timing light it is for me tonight or tomorrow. Just pray that i didnt mess anything up!

 

How do you figure that? The 385 is the Horse power of his 350ci crate motor and the 383 is the cubic inch of the motor the carb came from. I don't know but 383ci seems bigger than 350ci to me... And my 383 has 425hp which also seems bigger than 385hp. But I'm no math-magician...

 

Yes, give it more timing. Worked for me and as long as you keep the total advance below 36 as Lars says, you shouldn't get any spark knock. I have Side pipes on mine, and the paint started to burn where they came under the rocker panel............really scary!
Here's Lars paper if you couldn't find it.

 

100%

It wouldn't hurt to verify that the timing mark on your dampner lines up with "0" on your timing tab when #1 is at TDC. This will give you confidence that your results are accurate.

 

Sorry --I thought he meant ci. (And the carb came off of my engine)