Hi everyone. I just got done rebuilding my buick 300.prettt much a stock rebuild besides a bigger cam.So I've got about 300 miles on the rebuild so far.ive noticed a few small issues I was hoping to get some help on.i noticed after driving 30 plus miles or so it idles rough to the point it died and I couldn't get it restarted and had to get a tow.i got it home and started with the fuel pump it works carbs getting fuel.next I checked to see if the distributor moved and knocked it out of time.nope that looked good also.so then I moved onto the coil,I have 12v power to it and it also had correct ohms .checked for spark.seems to have good spark.i have the pertronix flamethrower ll installed . ingniter and coil.and I replaced the coil when I rebuilt the engine. Everything is new besides the ingniter that replaced the points.after checking all of this I tried to start it.didnt even act like it wanted to start(turns over fine).im stumped I've got air/fuel/spark .am I overlooking something? I know my way around a wrench but this old technology is something different for me and I'm learning as I go .thanks for any advice.
Update: I did get it to start but I had to retard the timing a bunch. Then if I try to set the initial timing it just dies.
A few questions. What are you trying to set the initial timing to? What distributor part number are you using? Please don't tell me stock, you don't know that unless you have looked at the part number. Have you verified that the vacuum advance works, and do you have it connected to manifold vacuum? Bigger cam? How big? Was it degreed? How many inches of vacuum is it making at idle, in Park? How hot is the engine running?
Thanks for the reply Larry70gs, I've read a ton of your useful knowledge .first off I set timing at 2.5 deg. Btc. But... I did put a bigger cam/lifters in it from t/a performance so im assuming the timing needs readjusted because of that?It has a reman distributor in it that's been converted over from points to the pertronix kit witch was hooked to port vacuum. I just ordered a big cap/coil sbc style conversion distributor kit. Engine runs between 175 and 185.i just ordered a vacuum tester today. I've put almost 300 miles on this rebuild with no issues up until this incident. Only things I noticed during those 300 miles is it seems sluggish on the low end and it pinging at top end revs(like the timing is off )mid range felt fine just cruising. And the coil gets so hot you can't touch it nit sure if that's normal. If this car wasn't so original I would have never rebuilt this engine I would have done a 455 swap.
To me when it runs ok cold and then dies hot, that is usually the ignition module or the coil. I know that both are new. but that does not insure they are working correctly. I would double check the voltage when running (make sure it's not too high or too low), and do everything Larry said. In general, listen to Larry.
To be honest that's why I bought a new ignition setup. I feel that the coil has a issue even though it ohms out correctly. One thing I did also notice I when I first start the car for the first few minutes it was pushing out 16.1v but then it will calm down to 14.5v .but I think I didn't have enough grounds hooked up witch I just fixed so I'll see if that help the voltage. And could be the cause of maybe burning something up in the ignition
When I reinstalled the 350 in my GS (I had marked the rotor position & cap position. Car started and ran a few minutes & would not start again. After some detective work - spark, fuel, air, coil - I then replaced the points & all was well.
OK, so that is why I wrote the power timing article. Remanufactured distributor means the original distributor is long gone or whatever. It also means that the stock initial timing specification is now completely irrelevant. For some reason, owners think that the book initial timing is written in stone for the engine despite anything else they do to the engine. As soon as you go away from the factory equipped distributor, forget that 2.5* initial timing. Buick distributors over the years differed in the amount of mechanical advance built into them. Anywhere from 12* to as much as 34*. The distributor that your 300 came with from the factory probably had between 28 and 34*. That means initial timing of 2.5* had you at 30-36* total timing without the vacuum advance. That's probably where it needs to be. This distributor you have now could have come from any year Buick small block. Some of them had a lot less mechanical advance. That means your engine may have less timing than it needs at WOT, or a little too much. The only way you find out is to learn how to use a timing light to measure and set your maximum WOT timing. Then the initial timing takes care of itself. It ends up where it needs to be based on whatever distributor you currently have installed. The only potential problem that can occur in that case is if you have, say, a distributor from a 71-72 350 for instance. Those distributors had 12-16* of mechanical timing, and when you set them up for 30-34* of total WOT timing, you could end up with as much as 18* of initial. That MIGHT make for hard hot cranking depending on your battery/cables/starter. Or, it might be fine. Not knowing what cam you used, makes it hard to recommend much. A bigger cam sacrifices low end power for higher RPM power. This is even MORE pronounced the smaller the engine. In general, a bigger cam likes more initial timing. I would want to run at least 10-12* initial with a bigger cam. That may mean less mechanical advance, or it may be fine. Again, just because you picked up a distributor to fit the 300 engine doesn't mean it is exactly the same as the factory original, it likely is NOT. Read the Power Timing thread, and get a timing light if you don't have one. You say the vacuum advance is hooked to ported vacuum. That is wrong for 2.5* initial. That means the engine is idling at 2.5*. That will make the engine run hotter than it should. Hook the VA to manifold vacuum. That is how it was from the factory. Read the Pertronix instructions for the kit that was used. They have specific requirements for coils. Measure the primary resistance from coil positive to negative. Make sure you have the right coil. Also make sure about the resistance wire, whether it is supposed to be used with whatever Pertronix you have. I'm not sure what sbc kit you ordered, but I doubt it will help you.
Yes I have a timing light.I will read your power timing thread.out of all the stuff I've done I don't know y I have a hard time figuring out how to time the engine. So no matter what distributor I put back in I should run manifold vacuum instead of ported? Sorry I'm more of a hands on person and it's difficult sometimes for me figuring out things by reading if I were shown how to set this up id never forget it.its just how I learn. I appreciate your guidance.
If you run manifold vacuum to the VA, it is there at idle. That gives you extra advance at idle. That's important if your initial timing is very low, like 2*. That's retarded timing, and more heat goes into the cooling system. If you have a problem following the Power Timing thread, the problem is that you really don't understand the ignition timing basics, and how it all works together. For that, I tell guys all the time to read the ignition section of the chassis manual. Read it until you understand it. Without reading and understanding that, you will never get it. It's just that simple. If I lived near you, I would show you. Actually, I would stand over your shoulder and make you do it.
I will update you i WILL figure it out .and once I do it won't be forgotten. Can you send me a link to your power timing thread?
Ok I did some reading. I only have a standard timing light .I see you have a measurement for the bbb and the 350.what the best option for me to add timing advance marks on my crankshaft balancer?measure the marks on my timing tab off the cover? Think this should be my first step before I can even check it. correct ?
