SB 4" strokers and timing ?

Posted By: Guitar Jones

SB 4" strokers and timing ? - 10/09/11 07:38 PM

So I have small chamber W5's, 53 cc's, a pretty tight quench at .031 and about 12.7 compression. I ran my old 360 at 34* and never screwed with it. I guess what I'm wondering is with the increased piston speed of the stroker I probably don't need as much advance. I had it set at 34 initially and I just knocked it back to 30 and it sounds better just running in the garage.

I know I need to experiment but I can't get out to the track now until November. I was going to go today but there is a storm system to the south of us that is just wreaking havoc on the weather. So what have you all found your car likes?

Posted By: SB412DUSTER

Re: SB 4" strokers and timing ? - 10/09/11 07:41 PM

My old W5 engine only had a 3.800 stroke and liked 32*

Posted By: viperblue72

Re: SB 4" strokers and timing ? - 10/09/11 08:16 PM

My 408 only liked 32 degrees. Any more and power would go down.

Posted By: justinp61

Re: SB 4" strokers and timing ? - 10/09/11 08:25 PM

Mine picked up going from 34* to 32*, it has .034" quench. In one of Ryan's posts a couple years ago he posted some dyno results on one of his engines. The engine had good quench and small chamber heads with dual quench pads. IIRC it made the most power at 28*.

Posted By: Guitar Jones

Re: SB 4" strokers and timing ? - 10/09/11 08:28 PM

Quote:

Mine picked up going from 34* to 32*, it has .034" quench. In one of Ryan's posts a couple years ago he posted some dyno results on one of his engines. The engine had good quench and small chamber heads with dual quench pads. IIRC it made the most power at 28*.

That was my thinking too, These heads have double quench pads, I may knock it down to 26 to start with.

Posted By: W5Duster436

Re: SB 4" strokers and timing ? - 10/09/11 08:52 PM

My 364 made most power at 39*. Same topend on my 4.125 stroke 436ci and dyno session it appeared the timing was at ~38* where it made most power but I don't think Ryan's light was working correctly so the distributor was just marked. Unfortunately I had to take the distributor out when putting the engine back in so the only thing I could do was line up the mark as close as possible and that's where it comes up around ~38.

I still have gremlins on this car and it still doesn't appear to have the power that it should have. I am hoping to get it to a chassis dyno soon so I can find out exactly where the timing should be. Will keep all informed. :-)

Posted By: dartman366

Re: SB 4" strokers and timing ? - 10/09/11 09:03 PM

started out @ 32* went to 34* and it seemed to like it,,,that is where I am at today.

Posted By: dusturbd340W5

Re: SB 4" strokers and timing ? - 10/10/11 12:11 AM

mine liked 35 the best

Posted By: moparacer

Re: SB 4" strokers and timing ? - 10/10/11 12:34 AM

Quote:

mine liked 35 the best

Same here.

Posted By: emarine01

Re: SB 4" strokers and timing ? - 10/10/11 01:47 AM

W5s with 59cc chambers 12 to 1 , on race 110 34/36 on AV gas 100ll 32/34 on 3/4 AV to 1/4 shell 93 mix 30/32 this mix makes the most power so far but still foolin with it

Posted By: 72demon416

Re: SB 4" strokers and timing ? - 10/11/11 04:44 AM

My 10.6-1, 439" with small chamber W5's was at it's best @ 32*, anything more and it lost significant power according to Ryan J.

Posted By: dogdays

Re: SB 4" strokers and timing ? - 10/12/11 08:05 PM

It's 100% the combustion chamber and doesn't matter what shortblock is under it. (Of course, the top of the piston is the bottom of the combustion chamber.) The better the chamber the shorter ignition lead required for max power.

R.

Posted By: Guitar Jones

Re: SB 4" strokers and timing ? - 10/12/11 09:29 PM

Quote:

It's 100% the combustion chamber and doesn't matter what shortblock is under it. (Of course, the top of the piston is the bottom of the combustion chamber.) The better the chamber the shorter ignition lead required for max power.

R.

Hmm, I have a 20cc dish piston including the .350 deep valve reliefs so it's not a lot of dish.

Thanks for the answers, I guess I'm in the ballpark at 30 and I'll work from there.

Posted By: MR_P_BODY

Re: SB 4" strokers and timing ? - 10/12/11 09:48 PM

Quote:

Quote:

It's 100% the combustion chamber and doesn't matter what shortblock is under it. (Of course, the top of the piston is the bottom of the combustion chamber.) The better the chamber the shorter ignition lead required for max power.

R.

Hmm, I have a 20cc dish piston including the .350 deep valve reliefs so it's not a lot of dish.

Thanks for the answers, I guess I'm in the ballpark at 30 and I'll work from there.

I would think that you would be better off with a
bit more timing... my W-9 likes 34* and most of my
W heads like right at 34* or a touch more... I'm talking
W-2, W-5, or W-9... I'm gonna have to test with my
W-5s on my 416 and pump gas to see what it likes...
I set it up for 34* to start with

Posted By: Crizila

Re: SB 4" strokers and timing ? - 10/13/11 02:46 AM

Quote:

It's 100% the combustion chamber and doesn't matter what shortblock is under it. (Of course, the top of the piston is the bottom of the combustion chamber.) The better the chamber the shorter ignition lead required for max power.

R.

Posted By: B3422W5

Re: SB 4" strokers and timing ? - 10/13/11 06:31 PM

Quote:

So I have small chamber W5's, 53 cc's, a pretty tight quench at .031 and about 12.7 compression. I ran my old 360 at 34* and never screwed with it. I guess what I'm wondering is with the increased piston speed of the stroker I probably don't need as much advance. I had it set at 34 initially and I just knocked it back to 30 and it sounds better just running in the garage.

I know I need to experiment but I can't get out to the track now until November. I was going to go today but there is a storm system to the south of us that is just wreaking havoc on the weather. So what have you all found your car likes?

i had w5's on a 416 shortblock about 11.5 compression with a 260/266 flat tappet that through trial and error found it was fastest with 40 degrees of timing...turn it back and the car fell off,..was a tenth slower with 34/36 degrees in it on back to back laps.

fast forward, same heads on a new 13.3 roller 422 shortblock, car ran best at 32 degrees, i could put 28 in it and that killed a tenth....so, it depends...