maroon88iroc

iTrader: (7)

i am having issues setting the timing on the car and i cant figure out what it is, the mark on the balancer is jumping around and not consistant. i am guessing its the timing chain but it is a new chain so it "shouldnt" have gone bad already. i put a new cap and rotor on and still no fix, i also added the 6al and a new balancer and timing tab, still the same problem. before the 6al and the new cap and rotor the timing light was sporatic and wouldnt shoot consistantly now it will but the mark is jumping around so needless to say i will not be running the nitrous this weekend unless i get it squared away... the motor is stock with a xe268 comp cam and a cloyes double roller timing chain. the balancer i installed is the larger 8" and the timing tab matches it. i am pulling around 13-15 inches of vaccum. it is running good but i still feel like the timing is off, it doesnt shut off hard or crank hard but it does have some bucking at low rpm when you get in it slightly.

someone help me PLS so i can run it on the spray this weekend.

spurgeon76

There is a connector at the back of the drivers side valve cover that has one brown and one black wire on it. you have to unplug it.

maroon88iroc

iTrader: (7)

what? this is a carb'ed car... when i had tpi i had to disconnect a wire but it was up by the ac box..

Apeiron

Is this a computer-controlled carb setup or no?

Tobias05

IIRC he has a holley.

lukn4trbl

From what I'm reading you no longer have the stock ignition setup?

Do you happen to have a vacuum advance connected to the distributor?
If so, you need to plug the line so that only mechanical advance is active.

Another thing to check is the spring selection on the weights. If they're
installed loose, the weights will fly out sooner and advance the timing.

The reason it may be jumping around could be several reasons:

- Faulty timing light

- MSD compatibility with the gun's induction pick up. Since MSD fires
multiple times, the gun may have trouble finding a good "peak" to trigger on.

- Weak spark plug, coil, or wire(s)


When you look at the strobe from the gun, does it appear to be steady and
rhythmic, or does it flash randomly?

Try another wire and see if the strobe is steadier. This will rule out a
bad wire/plug on cyl #1

maroon88iroc

iTrader: (7)

the car used to be tpi it now has a holley 650 dp...

i do not have the stock ignition setup. i have an acell billet hei distributor with the accell coil and i have the 6al hooked up with a two step.

the light from the gun is coming out steady but before i put the 6al on it was random like you say

the springs "should be correct" but i will put some new ones in.

the light i am using is a craftsman advance timing light, it has the dial on the back.

and i thought you are only supposed to use the #1 wire when setting timing?

lukn4trbl

Yes, only use #1 to set timing, however if you are troubleshooting a bad
wire/plug you can clip onto another wire to check the strobe from the gun.

Damon

How much does it jump around? If it's a big jump- like 20* or so, that's your timing light not knowing whether to trigger off the first MSD strike or the last one. I've got an older Craftsman light and it does that sometimes.

If it's jumping around just a few degrees that's likely to be either your centrifugal or vacuum advance kicking in partially at idle RPMs. Can also give you an unstable or "rolling" idle becuase of this. Always check your base timing with the vacuum advance disconnected and plugged to prevent a vacuum leak through the hose. I always slow the idle down as much as possible when checking my baseline timing, just to make sure the centrifugal isn't kicking in a little bit as well. If it is, slightly stronger springs are usually called for (or a lower idle speed). Two Blue springs is my usual starting point for an MSD Pro-Billet distributor centrifugal advance.

Movement beyond those things involves either a loose chain (not likely in your case) or the gear at the bottom of your distributor being worn out and causing a lot of "slop" between the distributor and cam. That last one would be a bad one becuase when the distributor gear is chewed up, the cam gear usually is as well, requiring cam replacement. So let's hope it's not that.

maroon88iroc

iTrader: (7)

when i installed the 6al i went ahead and pulled the distributor out to make sure the gear was ok and it was. there was a couple marks but i think it was just normal wear. i always remove the vacuum advance when setting the timing. i think what you are saying about the light knowing which spark to trigger is what it is. b/c it is a couple years old. what light would you reccomend?

five7kid

iTrader: (14)

I use a cheap parts store timing light, Actron or something like that. It doesn't have problems with MSD.

Apeiron

I use a cheap Equus light and it's never had a problem either.

maroon88iroc

iTrader: (7)

ok well i tried mw66nova's digital light on it and it was steady but the mark on the balancer is WAY off. the car was reading 63 degrees of timing lol. the car is pretty fast and i know the timing isnt right. it is crackin up all through the powerband. hopefully i can get it figured out by tomorrow. track day..

Apeiron

You've got the wrong balancer for your timing tab.

Damon

Yep- I think Apeiron is right. If the mark is way up over the top of the balancer but your timing tab is down at the 1:30 position it's mostly likely a balancer/tab mismatch.

GM used balancers with the timing mark in both the 12:00 position and the 1:30 position when #1 is at TDC. If you got the mismatch your timing will read off by about 40* (that's approximately the number of degrees difference between the two styles of balancers).

Hotrodrobert

I agree with the wrong balancer opinion!!
It seems the better timing light you have, the worse the MSD makes it jump around. Try the correct timing tab/balancer or remark your balancer and a cheap light.

maroon88iroc

iTrader: (7)

it is a new 8" balancer and an 8" matching timing tab... i set the car on tdc and made a new mark on the balancer at 0 on the timing tab. i went to wally world to get my slicks mounted for the track, well i got them mounted and while i was waitin for my friends truck i messed with the timing, i set it at 15 degrees with the new mark i made. well i didnt drive the car around or anything so idk if the car was timed right but it sounded ok when i reved it. well my buddy got there and we loaded the wheels and tires up and when i left i was messing around and launched off the two step, well the car immediatly shut off and would not crank back up. i was guessing it had jumped time. i got it home barely and just left it there. i didnt mess with it, well i went to crank it the other day, it is really hard to crank and i had ALOT of smoke coming out the valve covers even with the car not running. so i am guessing i messed up one of the pistons or rings. i got it to run but it wouldnt stay running and it was running really really rough and smoking out the valve covers pretty bad. any ideas. i talked to a guy at the machine shop and he said do a compression check so i will do that but he siad it could be the head gasket as well. i hope it is that and not the other.

five7kid

iTrader: (14)

How long were you on the 2-step?

maroon88iroc

iTrader: (7)

i just bounced it off the two step for a second and then launched it. it bogged and cut off, it didnt make any wierd noises or anything.

black89ws6

Are those "clock times" precise, or approximate? At 30degrees/clock hour, that would figure to be 45 degrees between the two timing tab styles.
A friend of mine did cam&heads on his L69, and put on a new shiny chromey timing cover...We fought like hell with that thing to get it timed right, breakin in the cam, until we looked at the old timing cover and noticed the timing tab at 12:00.

Apeiron

They're approximate.

black89ws6

damn.

thanks.

Apeiron

Use a piston stop and make your own TDC mark.

black89ws6

It's my friend's car, and he's 3 states away.

Once we figured out what was going on, we set the timing by eyeballing what should have been 12:00. Not the most accurate, I know.

The piston dwell near TDC makes it tough to find TDC precisely with a stop.

I was hoping to find a different timing pointer that would like up correctly, but the ones I've looked at don't say where they mark timing at. Judging from the pictures, all the aftermarket ones are for the approximate 2:00 position.

I really thought with enough internet searching, I would find somewhere that said the difference between the timing points was "x" degrees, and we'd be able to use that number to calculate where on the damper to put a new mark, or a timing tape, or something. That, and it's really the only way I could help out by email.

Apeiron

Only because you're doing it wrong. To use a piston stop, you rotate the engine forward until it hits the stop, and mark the balancer. Then rotate the engine backwards until it hits the stop, and mark the balancer again. Divide the distance between the two marks in half, and that's your TDC mark.