I am with others that have posted on here, that there has to be a problem with the dampner or the timking marker. I wish that mattilac would post what he found with it. If the timing was set at that for initial timing, it would kick against the starter so bad that you will probbaly never get the engine started. You should have enormous amounts of spark knock with that kind of advance which should destroy the engine. Evidently it is set in the 10 degree area for the engine to run as well as it does.
Im having the identical problem with my 460 setup. Im going to try swapping the polarity of the magnetic pickup in the distributor tomorrow.
I know you have stated you have checked this but I had my <<<NEW>>> harmonic balancer rotate on it self and give me all sorts of weird readings. best of luck. try to turn the outer ring of the balancer and see if it came unstuck from the inner rubber part.
I talked to Mattilac and he still hasn't found the problem. I am having same problem and I cant figure it out either, butt I aint giving up. I think it runs good at this degree of timing because of some other issue instead of timing. I think the high timing is just making it run good but something else is causing the problem, like vacuum leak but I done checked that.
I hope someone figures this out, I am having the same issue.. Freshly rebuilt 350, 11: 1 compression... Old school GM race heads, Performance Products balancer, billet GM distributor, etc.. 35 degrees initial timing... If I lower it, the engine dies. I it was backfiring but I think that was due to overly rich idle settings, which I since set to 2 turns out on the Edelbrock carb. This Chevelle is going to kill me one way or another.
I am going to suggest something that doesn't make since but I have seen happen. I was working with a guy on a blown alky small block, and after he had done some work on it, he put the magneto in and fired it up and it had 60 deg or so of timing. He said "well, the mag is one tooth off" so he pulled the mag, turned the oil pump drive and dropped the mag in one tooth different on the cam gear. He fired it back up and it was back to where it should have been. I don't understand how it changed the timing like it did, because it didn't change the relationship between the rotor and the cap, but you might try it forget and shiggles. Brian
Just a question is your GM HEI used and is the advance weight and springs good, GM HEI are good for advance sticking which cause detonation. If advance is stuck that maybe your problem. I have found this to be a problem with them so you may want to look at that. Just another 2 Cents worth.
I suggest checking the springs on the distributor centrifugal advance. If they are the weakest ones, the advance can start to engage too early (like 800 rpm or less). Had this trouble before with a used MSD. Changes the springs - fixed the problem.
I would hope that after well over two years since the OP was involved in this conversation, he has sorted this out by now
This is a very very old post, but I too have this issue, I have also tested TDC with a cyl stop and matched the timing mark to exactly 1/8" on both sides of TDC so I know I'm spot on, the engine is a new crate engine. Runs at 39inital no vacuum and 57 total no vacuum advance connected and its runs great here. Joke: it takes time for light to travel, so I had the car in california and I was timing from new york, even at the speed of light the delay was enough that by the time the light hit the mark it was 30 deg off. -Kidding- Any case, I did not see any fix for this or cause, but due to this issue I can only time based on best power and noise level. At 39inital the car pushes me back in the seat, at 15 inital the car has no power and runs rough and is noisey. If anyone has any thing else to check? Timing tab matches correctly, its spot on, the chain is new and I've checked the cam to make sure its lined up with the crank.
Go back and re-read my first post on this thread. Low compression and both valves open at the same time you need a lot of ignition lead to make any cylinder pressure. Kinda weak on the bottom end of the rpm range. On the flip side, it likely pulls pretty hard upstairs If you put the compression back up to 9.5 to 1 or more, you would be back where everyone else says you should be (and where you think the timing should be as well) Either put a little blower on it or run it "as is" with the timing cranked up. Note: If your engine is not the 350/290 HP GM Crate engine or built just like it, this response does not apply.
At those timing numbers it should act like this: Be hard for the starter to spin it over cold And nearly impossible for the starter to spin it over hot. It should be rattled with detonation under load. If it's not doing those things then fuck it. Just for shits and giggles what does the vacuum pull it up to? 75 or so?
Hi l seem to have the same problem did u ever figure it out my small block will only run 35 intinal timing
I have questioned how well the spark plug piston stop works on a SBC. Because of the shallow angle of the plug hole and how long the stop has to be to stop the piston. A little flex and the whole process goes out the window. I would double check by checking valve position at tdc exaust.
had this happen to me, hei distributor in sbc 350 pulled old distributor and put in one i got from amazon. the timing was off by 40 , got another distributor from orileys auto parts. tried it, samething off by about 40. motor runs fine. put old distributor back in, samething , thinking i mixed up the old one with one of the newer ones, i put in another one of them, still the samething. then the only thing i had not put back on was the old cap. the timing marks line up now. i was getting complete distributors, just drop in with both cap and rotors on them. so that was what i found, not sure yet if it is the caps are bad, or the coils are bad yet, but going to pull one a part and a old cap i still have and see if i can find out what is wrong with them.
Same problem here. Have a BBC with solid tappet cam. Did the piston stop and everything. When I built the motor, should have been 10-1 comp. I'm beginning to think I made an error somewhere and I have a lower compression causing the problem.. I am locked out at 36 btc and no pinging and the starter turns over great. Runs good but I am troubleshooting an issue running hot and I can't move past this issue until I figure out why this thing need so much damn advance. BTW it would probably take more advance than what I'm giving it but I'm playing it safe for now.
Check valve timing, a camshaft "out of phase" will be doggy down low and show lower cylinder compression. Dialing in lots of ignition timing is common to try and compensate. Even if the "dots are lined up" on the timing set, the valve timing can still be way off. One important reason why a degree wheel is used. You can make a quick check with a straight edge across the #1 cylinder valve springs at overlap and check the timing pointer location and the "0" mark. Usually a few degrees of advance is what most street drivers want.
Sorry I'm not sure I follow what to do with the straight edge. BTW I have a comp 294s cam so it's not exactly small but every post I read on the subject, people seem to think 20 degrees is off the charts regardless of can grind. As far and low end not having power, i havn't noticed anything horrible, I have 411 in the rear and a 3k stall so perhaps I wouldn't notice? I remember when first built the motor I timed It by ear and once I started detonating, threw a timing light on it. If I remember right I think I was over 50 degrees advanced. Not including centrifugal advance. Started and idled fine. But of course it detonated when the centrifugal kicked in. One thing when I built it was I bought "small dome" Pistons as I was using procomp heads and I was unsure about what type of Pistons to use because of the semi-open chambers. I think maybe I could have and should have used wedge pistons but not sure. I've always wondered if perhaps the shape of the piston could be slowing down or interfering with the speed at which the flame travels through the cylinder?.. Anyway if you could please elaborate on the strait edge thing I would appreciate it.
One other thing to note. When I put the heads on I had to use head gaskets that had a bigger bore diameter than my cylinder due to the fact that the chambers in the head were larger. Cuz I didn't want the gasket hanging into the combustion chamber and also I don't think the metal ring would seal. Those are the only things I really questioned on the build. I guess I probably should have degreed the cam but I align the dots and shipped it.
There's a couple different ways (other than using a degree wheel) to determine if a camshaft is at least in the ballpark as far as where it is installed +/-. Just lining up the dots is no guarantee of anything. Due to manufacturing tolerances or tolerance stack ups, or sometimes a defective grind, it can be way, way off. Not necessarily the cause of the problem here but it sure would be something to check. Basically bring the #1 piston up the point of both in. and ex. valves exactly at split overlap. Then look at the "0" mark on damper and the timing pointer and see what side of the fence it falls, most camshafts have a few degrees of advance built in, look for evidence of several degrees "late" valve timing. This method works best with stock cams. Here's another way, scroll down to the bottom: https://www.iskycams.com/cam-degreeing.html
The Jalopy Journal
