72 350 won't stay running
Administrator
Joined: Oct 2009
Posts: 42,513
From: Poteau, Ok
In a cautiously optimistic twist of events, the car is now running like new under its own power. I've not yet test driven it but it starts and solidly idles in park and gear as before and timing is back on the mark at 15 degrees at 4 degrees BTDC.
I don't understand the 15* at 4* BTDC?
It wouldn't start or run first thing this a.m., as it was when I left it last night. After indexing the #1 plug to TDC again I noted the rotor was parked at the #2 plug socket. I don't know how it repositioned itself from the #1 position that I had originally set it for but I ultimately pulled it out and reset it back to where it had been. That hadn't been an issue before when I had checked the TDC position, so I have to presume it was something that changed today.
That will keep it from starting.
Currently the coil is wired only with the 2 distributor wires and the yellow I ran from my fuse box IGN terminal to coil (+). Both engine harness wires (the interconnected yellow/black) are off. Distributor ground is bolted to the intake and its gray lead to the tach. Per the tach, park idle is about 900 rpm, gear idle about 700. Gear idle is currently solid even with the a/c on.
Sounds like good idle.
Still at issue - car is still struggling to crank - as if it were trying to turn a high compression motor over. There's still something else needing attention but I'm not sure if possibly a starter or under-dash ignition switch issue. Both are essentially only a bit over 1 year old.
See question above about timing settings. In addition you need to follow the instructions on how to set your timing curve with the bushings and springs. You also need to set up your vacuum advance.
Since I'm not experiencing any other issues which might indicate a switch problem (all dash lights and accessories work as they should), starter has me concerned.
I don't think its an ignition switch issue, however I would make sure the bulkhead connector for your new engine harness is tight and the connections at the power stud attached to the horn relay. You also need to monitor your battery voltage to make sure its getting fully charged to 12.7 volts. If its staying in the 12.4 range your battery may be weak.
battery cables are new M&H - Alternator is a new Powermaster 100 amp with internal VR and charges properly. My engine harness is a newer M&H as well, properly adapted for the alternator (firewall VR is eliminated).
Now sometimes doesn't mean serviceable, I've seen a lot of parts that were bad right out of the box.
Plan is to let car sit for a few hours to cool off, then try firing it up again - if it runs ok, I'll take it out for a test drive.
I don't understand the 15* at 4* BTDC?
It wouldn't start or run first thing this a.m., as it was when I left it last night. After indexing the #1 plug to TDC again I noted the rotor was parked at the #2 plug socket. I don't know how it repositioned itself from the #1 position that I had originally set it for but I ultimately pulled it out and reset it back to where it had been. That hadn't been an issue before when I had checked the TDC position, so I have to presume it was something that changed today.
That will keep it from starting.
Currently the coil is wired only with the 2 distributor wires and the yellow I ran from my fuse box IGN terminal to coil (+). Both engine harness wires (the interconnected yellow/black) are off. Distributor ground is bolted to the intake and its gray lead to the tach. Per the tach, park idle is about 900 rpm, gear idle about 700. Gear idle is currently solid even with the a/c on.
Sounds like good idle.
Still at issue - car is still struggling to crank - as if it were trying to turn a high compression motor over. There's still something else needing attention but I'm not sure if possibly a starter or under-dash ignition switch issue. Both are essentially only a bit over 1 year old.
See question above about timing settings. In addition you need to follow the instructions on how to set your timing curve with the bushings and springs. You also need to set up your vacuum advance.
Since I'm not experiencing any other issues which might indicate a switch problem (all dash lights and accessories work as they should), starter has me concerned.
I don't think its an ignition switch issue, however I would make sure the bulkhead connector for your new engine harness is tight and the connections at the power stud attached to the horn relay. You also need to monitor your battery voltage to make sure its getting fully charged to 12.7 volts. If its staying in the 12.4 range your battery may be weak.
battery cables are new M&H - Alternator is a new Powermaster 100 amp with internal VR and charges properly. My engine harness is a newer M&H as well, properly adapted for the alternator (firewall VR is eliminated).
Now sometimes doesn't mean serviceable, I've seen a lot of parts that were bad right out of the box.
Plan is to let car sit for a few hours to cool off, then try firing it up again - if it runs ok, I'll take it out for a test drive.
Thread Starter
'72 Cutlass ragtop
Joined: Jun 2016
Posts: 1,328
From: Tampa, FL
The timing I've set is showing 15 degrees on my dial-back light when TDC mark on my balancer is aligned with the 4 degree BTDC pointer mark, - light registers approximately 20 degrees initial timing at the 0 mark. This was with the vacuum unplugged. It may need further adjustment but this is what got the car running well. I've not yet had a chance to check engine vacuum and set the idle screws.
The car ran strong and ping-free when I took it out earlier - so far no hesitations or erratic running issues. Distributor came with a couple of additional spring sets and bushings, both spring sets are lighter weight than what was installed according to the instructions.
I'm not well-schooled on distributor curving so not yet sure how any changes would potentially improve the engine's street performance manners even more. I did check the ignition switch, connections are tight, agreed I don't think it's at issue.
Battery is a 1+yr old Optima red but I will be monitoring the volts to see if it has issues.
I'll be reading the distributor instructions a bit further about the springs/bushings, but will likely leave well enough alone until I put some more miles on the car and ensure I'm past the unknowns.
The car ran strong and ping-free when I took it out earlier - so far no hesitations or erratic running issues. Distributor came with a couple of additional spring sets and bushings, both spring sets are lighter weight than what was installed according to the instructions.
I'm not well-schooled on distributor curving so not yet sure how any changes would potentially improve the engine's street performance manners even more. I did check the ignition switch, connections are tight, agreed I don't think it's at issue.
Battery is a 1+yr old Optima red but I will be monitoring the volts to see if it has issues.
I'll be reading the distributor instructions a bit further about the springs/bushings, but will likely leave well enough alone until I put some more miles on the car and ensure I'm past the unknowns.
Last edited by 70sgeek; Jul 1, 2018 at 03:46 PM.
Administrator
Joined: Oct 2009
Posts: 42,513
From: Poteau, Ok
The timing I've set is showing 15 degrees on my dial-back light when TDC mark on my balancer is aligned with the 4 degree BTDC pointer mark, - light registers approximately 20 degrees initial timing at the 0 mark. This was with the vacuum unplugged.
20* initial may be too much and the engine is trying to kick back, try 16 for now. Later when you get a chance, you need to figure out how much mechanical timing your distributor provides. How to do this is to see at what RPM your timing stops advancing and then subtract the initial. This is done without vacuum advance.
The car ran strong and ping-free when I took it out earlier - so far no hesitations or erratic running issues. Distributor came with a couple of additional spring sets and bushings, both spring sets are lighter weight than what was installed according to the instructions.
I'm not well-schooled on distributor curving so not yet sure how any changes would potentially improve the engine's street performance manners even more. I did check the ignition switch, connections are tight, agreed I don't think it's at issue.
Battery is a 1+yr old Optima red but I will be monitoring the volts to see if it has issues.
I'll be reading the distributor instructions a bit further about the springs/bushings, but will likely leave well enough alone until I put some more miles on the car and ensure I'm past the unknowns.
20* initial may be too much and the engine is trying to kick back, try 16 for now. Later when you get a chance, you need to figure out how much mechanical timing your distributor provides. How to do this is to see at what RPM your timing stops advancing and then subtract the initial. This is done without vacuum advance.
The car ran strong and ping-free when I took it out earlier - so far no hesitations or erratic running issues. Distributor came with a couple of additional spring sets and bushings, both spring sets are lighter weight than what was installed according to the instructions.
I'm not well-schooled on distributor curving so not yet sure how any changes would potentially improve the engine's street performance manners even more. I did check the ignition switch, connections are tight, agreed I don't think it's at issue.
Battery is a 1+yr old Optima red but I will be monitoring the volts to see if it has issues.
I'll be reading the distributor instructions a bit further about the springs/bushings, but will likely leave well enough alone until I put some more miles on the car and ensure I'm past the unknowns.
This article will give you a basic idea on how timing works and what the settings do and what your looking for.
http://www.camaros.org/pdf/timing101.pdf
Disregard the pn's for the different vacuum cans because yours is adjustable, although you may need a stop if you need to limit it. This is a good read.
http://www.crankshaftcoalition.com/w...ance_Specs.pdf
Thread Starter
'72 Cutlass ragtop
Joined: Jun 2016
Posts: 1,328
From: Tampa, FL
many thanks for the resource reads and for all the great help along the way - your direction definitely helped to sort through much of these issues. Still need to recheck coil volts, engine vacuum and adjust idle screws later this week. Will try adjusting the timing back just a bit as well to see if any effect on the hard start condition.
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