Technical How Much Timing Do You Have ?

38-32, by 2200-2400. All depends on the build.

Way too many variables to have a universal number.

 

<<< 389" SBC, IK180 Brodix heads. 9.2 c/r, 264*-270* Comp roller, B&M 144, 4-5# boost on 87 octane, 750 Edelbrock, 460 HP - 590 TQ @ flywheel, 3:25 gear, 2700# car, 20 mpg.

15* Initial
10* Mech
10* Vac.
All in at 2200.

The vac. advance pulls 10* out at full throttle.
If I run premium I can turn it up to about 18* Initial.
Tested at 1000 ft. elevation 70*.

I asked JV why such low timing numbers and he said if that's what it likes, run it. He also added that the more efficient the combination is the less timing it wants. OK!

 

Is this “38-42” ?

How many here are timing up to spark knock and backing off a degree or two ?

 

I can't get away with more than 34 degrees total all in on my SBC in my Austin gasser, but it's about 10.7:1 CR. On the other hand my SBC in my '39 Chev can push 39-40 total and not ping with the 9.25:1 CR it has.

 

36* @ with 1500-1800 RPM. SBF......High test fuel helps keep it safe. 9.5:1 CR. Windsor Jr. IRON heads.Manual transmission.
AFR type "good" flowing heads(more effecient combustion chambers) require less.
Use a timing tape....a STANDARD timing light.....insure TDC with a piston stop.
After getting timing dialed in.......re-adjust carb.
6sally6

 

Heavily modified 406 limited street motor. 35-36 total at 2800rpm

 

So you spend a lot of money to build an engine and your too cheap to spend $300 to dyno it.

 

Jenkins Competition has it right. All these numbers mean nothing. Even two “identical” engines will not need the exact same timing numbers. Push the timing until the engine complains then give it just a bit of slack. This is not rocket science by the numbers unless you’ve a dyno and know exactly how to use it. I don’t have one for my hot rod, do you? And I’m sure as hell not spending $300 to borrow one to set my timing.

 

Recently had my 427 SBC on a chassis dyno and picked up 30 hp by dialing back from 38 to 36.

Didn't expect that.

 

There’s more to it for a person wanting all he/she can get. Say you have an out of the box distributor that allows 25 degrees advance. Say your engine likes 15 initial. Now you need to limit the stops. 40 most likely will be too much, right? So your other option is to lose off idle performance and dial initial back. But say you have all that sorted out, but something isn’t quite right yet, maybe you feel some lag in there, so you then use lighter springs to get to full advance sooner.
What you are describing is just as most will do using an out of the box unit, kinda like those who know carbs real well (not me) who know that it’s not just a matter of changing jet sizes when tuning one.

 

I was at a show one time where they had a free chassis dyno with your registration, so I went out and ran it first and just timed it by the seat of my pants where it felt good. Came back and made the pull, it was right where it needed to be on the first pass...

 

Profiling cams is an interesting thing to do because you get a much better perspective on engines.
A dial indicator and a degree wheel and then taking the time to record every degree of lift and where the piston is in the cylinder at that same time helps you to understand more about timing an engine and just why it is important.

Measuring ramp speeds in degrees and how much dwell you have are all part of the puzzle of making one engine perform better than another engine.
Knowing where the piston is in the cylinder when the intake and exhaust valves open and close is interesting stuff to learn which leads you to understand more about the valve overlap and how to make it work for certain engine combinations.
Degree a cam is something that's very important to learn and use at the same time.
A vacuum gauge is also a handy tool to use.

One other thing is keeping records for every cam you degree and writing everything down so that if someone questions you about something you can show them exactly what you did and why!

When you have a history of every degree of crankshaft rotation written out in front of you on a chart things make more sense.

Jimbo

 

LOL, your not spending the dyno money to just set the timing. I've had engines dyno'd and grabbed 60 hp and more for that 3oo bucks. And they ran correctly, made better mileage ect...I'm thinking thats cheap compared to buying a bunch of parts then putting it together and hoping it performs correctly. Lippy

 

This is a great feeling, isn’t it ?

Not to divert but,
I filled out the lengthy AED form and submitted only to get back “You’re dead on the money, can’t help you” !

 

Lol......Lippy, you’re 100% correct
Thanks for that.

 

What did you change for the 60 HP gain ?

 

???? He's right about what? He's the guy who started this post, and asked the question.

 

Jenkins, Timing, plugs and jets. And I believe we changed valve lash settings. Solid roller in a 408 stroker Ford. Funny thing. We started at 32 degrees total in it and ended up at 29! That engine just did not like a bunch of timing. Took about six pulls. Lippy

 

I have a friend with a dyno, had a customer running a 350 with Vortec heads in a Stock Car, had been running 38 degrees for a season. On the dyno, they pulled the timing back to 32, and picked up 100 hp.

 

Marty Strode,

Me thinks there’s
more to this
story !

 

The more efficient, too much advance hurts, not helps. a 292" Flathead we ran, responded to less timing, pulled it back from 25 to 23, and picked up 25 hp.

 

28-32°.

Got to stop drinking and posting!

One problem with the advance it until it pings, and then back off method is that preignition is underway before it becomes audible.

Our electronic sensors can "hear" it long before a Human ear can.

 

What fun would that be?

 

Jim Linder made some posts about this for Ford FH V8’s, I think in regards to doing an 8ba conversion to Chevy distributor. He pretty much said 20-22 BTDC was all they would need/want.
Your dyno #s have proved it

 

What I'm trying to say I guess is. You can go by what someone says, but what's good for their combination might not even be close to what yours needs. And I do understand not everyone has or is willing to spend the money to dyno their engines. To me, it just seemed like a quick way to get the engine running correctly for your combination. And I do remember back when going to the dragstrip and making many, many passes to get the engine right. Though those were for maximum wide open performance. But that differs in a lot of ways to street performance. This is JMO. And you know what they say about opinions. I meant in no way to say anyone is wrong, just what has always worked for me. I have almost worn out drag engines before just getting them right. By then I was losing ring seal ect... then you freshen the engine again and start all over. A dyno with a good tuner running it is money well spent. Again, but hey thats hotrodding.JMO Lippy

 

37* at 2300 RPM . I set my timing vac advance connected 37* at 2300 RPM and I have no idea where it falling to at idle , it falls where it falls .

 

Around here , I wouldn't let the dyno guy , aka " blow it up chad" dyno my bicycle....besides , its more fun on a blacktop road with a Garmin...

 

I’m running 25 all in at 2200 on my 40 coupe with a 53 Merc with Chevy dizzy(best change I’ve ever made)
Guess I need to lower it a couple of degrees, but all I have is a “butt” dyno! I’d love to pickup 25hp!
I imagine even my old butt could feel 25hp!

 

I try to get it within a couple seconds a day and the amplitude between 270 and 300 degrees. This one from 1911

Sent from my XT1585 using The H.A.M.B. mobile app

 

Norris I love your car! Lippy