Starting problems

[Dozers72]

I recently did a motor swap in my 72 C-10 and I have been having trouble setting the timing. The motor I put in is a 355 with 550 hp. when I started it today it ran fine until it warmed up and didn't want to start again, I adjusted the distributor and got it started and tried to readjust the timing, when I reved the motor it backfired through the exhaust and now it wont start, it turns over fine but it wont fire. What do I do??

[PanelDeland]

That's a stout engine.Did you build it?There are several things that come to mind.
1.are you unhooking and blocking off the vacuum line when you time it?
2.You must have a lot of cam to get 550 out of a sbc.Are you using a vac canister?
3.How are you timing it?You need to use a timing light.
4.Have you checked to see that it's not 180 out?
5.Checked firing order?
These are the "low hanging fruit" things you check first.

[Dozers72]

I didn't build it but I know what was done to it, the timing I'm not very concerned with at the moment, I'm pretty sure the distributor is a tooth off but the problem is I'm pretty sure its not getting spark and it started acting up earlier when I was messing with it and it continued to turn over after I had turned the ignition off and removed the key

[franken]

Get some test tools, or google backyard ignition testing, thoughts about how a 4-stroke works, etc.

"Pretty sure its not getting spark." You should know absolutely if its getting spark. Hold the #1 plug wire and get the wife to turn the key. Or the other way around as the mood strikes.

[Dozers72]

I know how to test it I just didn't get the chance today I'm going to in the morning and I'm going to check and make sure the distributor is getting juice but I'm really confused with why the starter would continue to draw juice and turn over after the ignition is turned off

[68c10airstream]

hey Dozers72, As a past dealer mechanic with my share of electrical and drivability work, i'm guessing orange paint on everything? Most likely as you adjusted timing you lost distributor ground. Remember that hei, and points must have a good ground to work. That thick wire bringing 12 volts (plus a lot of amps) to the distributor needs just as good of a ground. Fixed many fresh overhauled sbc (all full of orange paint) by removing the hold down clamp and bolt and shine up the clamp, bolt, area of contact on intake manifold, and last but not least the shoulder of the base of the distributor where the clamp touches (all the way around too). Another words the neck has to be grounded through the hold down through the bolt to the intake. My old quick test with a 12 volt test light was, turn key on, put the test lead clamp on the negative battery terminal and take the tip on the 12 volt tester and scratch the neck and watch the test light turn on brightly! Bingo, needs a good ground! Good luck, Brian F.

[Dozers72]

It's not a fresh build its an older motor but it's low miles on the rebuild and no orange paint lol but I will check the grounds I might have forgot one when I put the motor in

[franken]

Cranking, Starting, HP, torque, ground...
Interesting that after a while spark comes into the conversation.

[Dozers72]

I got it fixed, turns out it was just a faulty distributor cap I changed it today and it fired right up thank you guys for your help