Timing Help?

[4G63dsmpwr]

I'm currently running 9deg of base timing. I researched and a lot people say that I'll never be able to keep my knock sum down w/that much base timing. I was wondering what you guys thought about this and how much you run, or think is the best to run? I have a logger, AFC, 510s, and a Walbro. My knock seems to fluctuate really bad. I'll tune one night seeing only 2 knock sum, and then the next morning on a pull I'll see a high of 12. Is this what happens to everyone or..? Thanks

 

[rdrkt]

Its going to depend on ambient temperature, gas type, turbo type, boost settings and intercooler selection. Even a Supra sidemount will become heatsoaked and your knock count will go through the roof.

 

[GRNDSM]

Well, I found out an interesting thing just a couple of weeks ago. The marks on my timing belt cover were 3-5 deg. off the actual position. I put my #1 cylinder in TDC and compared it to the timing mark on the pulley, it was at roughly +3/ +5 deg...

So check if your timing marks are "zeroed out" before you start messing around with timing. I know what I will now start doing this on every car that I am tuning.

Leon
RR

 

[jw]

wow, that sounded like it has jump a tooth or two.

 

[Kevin Jewer]

Nope Leon and I discussed this at the track recently, and it blew my mind. It took a minute for me to figure it out. Leon's not talking cam or crank timing, but ignition timing. With the timing belt setup properly, the damper, its marks, belt cover marks, or whatever were off. I will be checking mine soon without fail. I think this is going to be one of those things that we're all gonna have to do once we start making some power and timing becomes more critical... It would be easy enough to calibrate/remark the cover or the damper. I'm curious to see if Leons is a fluke, or if this is a common thing

 

[jw]

All the timing marks have to line up, from the timing belt cover, the mark on the crank pulley should point to "T". The dowel pins pointing at 12 and cam marks pointing at one another. If any of the marks does not line up, the timing may have jumped. Another reason I can think of that cause a slight off in timing is cams required degreeing. If you still have stock cams and the head or block is not decked/shaved, it should not have any problems having them all lined up.

Ign timing will not cause any of the timing marks to misalign.

 

[4wheelsNmotion]

JW, have you ever heard of ARD there in Houston? Are they work=th talking to about DSM upgrades?

 

[jw]

Yes, my car is currently at ARD rebuilding the bottom end. I spun the b shaft bearing at the last track two weeks ago. I should be get my car back today. John at ARD knows DSM really well, he owns a 1G laser and has done 1G to 2G engine swap and bottom end rebuilt for DSM for a quite a while. You should talk to him. Btw, do I know you?

 

[4wheelsNmotion]

U wouldn't know me. I'm from a different part of texas and I don't race in Houston much. Although I should.
I'm kinda new to the DSM world. I'm so into getting the most out of a 4cyl as you can. My goal is low 12s in an auto. I'm sitting at high 13s with a 55 shot. I need to upgrade the whole thing and have help tuning the damn thing. I just don't trust myself to do all the upgrades, but I want the knowledge of how to do it all. I guess it just takes time. BTW I also have an 02 Camaro Z28, bone stock, running 13.2. I want the DSM to be faster, before I start on the Z. Any advice would be greatly appreciated.

 

[GRNDSM]

>wow, that sounded like it has jump a tooth or two.

It does.... Except that I used a piston as indicator of TDC and not the timing belt marks. I put a long, 1/4" extension into the #1 cylinder and find a TDC. Incidentally cam timing marks aligned up at that point, but ignition timing marks didn't...

Leon
RR