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Discussion Starter #1
355 inch sbc, 13:1 compression ratio, solid roller camshaft, brodix track 1's. The problem I am having is when we set the timing (locked out) and as the motor grabs rpm it slowly retards the timing. If it's at 34 at idle, then it'll be at about 28-26 at 5000 rpm. We have checked end play in the distributor, thrust in he camshaft, changed distributors, changed dis gears, used 3 different timing lights and all the same result. WTF do I look next. I'm lost bigger than shit..
 

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I have had problems with the timming light (newer ones that you can set the dial for degrees) , the msd ignition is to fast of spark . Maybe try another timing light , otherwise balancer spun or timing chain stretched .Good luck hoping for a different timing light will show results .
 

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Don't know what your issue may be but, when I set timing on a distributer that is locked out I do it between 2000-3000 rpm. Just seems to be more acurate and stable than it is at idle. JMO
 

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Try installing an MSD starter saver. My timing would jump all over till i put one in. Now its steady at all rpm. Also try another ign box and make sure its grounded to the battery.
 

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I just went through this. I had almost a 5 degree variation in timing with my BB mopar engine at 3000 rpm.

Mine was mostly excess clearance in the distributor shaft that was letting the gear ride up on the cam. I had to weld up the bottom of my distributor shaft to tighten things up.

Still have a degree or so of variance but I thing that might be in the timing chain.
 

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I would look at the chain. Being too loose will do this at higher rpm. Also, you didn't mention what chain cover you have and if it is reinforced in front of the cam button, which you are hopefully running with a roller camshaft. If not, the cam, regardless of what clearance you set it at, will walk forward retarding timing.It will do it with a trigger as well. You need to reinforce the front of the camshaft as best you can.
 

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RED ROCKET
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swapping to crank trigger was the best upgrade on my car in the last 4 years
 

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like bad influence says.... definitley cam moving forward.. what kind of timing cover?? stock steel?? or chrome steel?? if it aluminum it wont walk much, but i have seen them still move!! even if you put a crank trigger, the cam is still retarding itself.. need to fix that problem 1st!!

onefast68, i too installed a crank trigger on my junk... best thing i have done in a looong time!! timing is dead on!! and runs and starts waay better than ever!!:cool:
 

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Discussion Starter #18
It has a billet aluminum timing cover with one of the crane roller buttons. I called msd today and talked to them and they said that there will be a variance of 1-6 degrees in the mgnetic pickup in the probillet distributor. It kind of pisses me off because I never had this problem in my 388, but we are running a 355 while my motor gets freshened. Msd's exact words were to add 6 more degrees of timing (bad idea with nitrous IMO), buy a crank trigger, or the starter saver. The starter saver has a magnetic pickup compensation module just like the digital ignitions do. I believe I will just upgrade to a digital 6+ and a crank trigger, so I'll be done with this whole mess of shit.
 

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Discussion Starter #20
I'm probably just gonna upgrade the whole damn thing. I put a new gear on my distributor tonight and made sure it had .010 endplay like msd said. I'm gonna put it back together for now. I just won't be making and nitrous passes until I get a digital 6 box at the very least.
 
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