On the ground and running, but.


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May 11, 2023
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Long Beach, CA
My Car
1972 "Q" Code Mach1
I finished the seatbelt install and installed the seats. The car was ready for a test run and I just couldn't wait. My buddy and I drove the car around my neighborhood for about for about 20 minutes. Oil pressure was good, temp stayed stable and we made it home without a hitch. Until I shut the motor off. I tried to restart, and the motor would barely turn as if the battery was dead. I couldn't get it started. I went inside my house and had dinner with my wife. After dinner (about 1 hour after I shut the motor off), I went back outside to see if I could re-start the motor. I reached into the driver's side window and turned the key. She cranked right over and started, idling perfectly.
I didn't build the rotating assembly. I bought the engine from a private party who said it had been rebuilt 30 years ago and never started. I installed the cam, timing chain and top end. I didn't have any trouble rotating the assembly with a breaker bar.
Is this just a tight motor that needs to be broken in, or is something else wrong like misfit pistons or bearings. Can I get away with making short runs until the motor loosens up?
Things that can increase hot starting effort:
  • Higher cranking compression due to engine modifications
  • Increased ambient heat in the starter (as Chuck mentions) from headers
  • Increased electrical resistance (old cables, loose connections etc.)
  • Exceesive initial ignition timing
I'm sure I've missed something.

Get it good and hot again and see if you can still sping it over with a breaker bar would be my first step. After that I would get out the multimeter and start checking the cables/ connections.

Good luck!
Mark Jones,
Could be starter heat soak, tight engine tolerances (still in break in mode} or a little too much timing.
Since you did not state that there was any detonation ( probably } not too much timing, but the combination of things going on may be too much for the starter you have.
If it were mine, I would continue with the short trips until the engine is fully broken in, then you can re- evaluate the starter.
Are you using break in oil? and when do you expect to change oil and inspect the oil filter ?
Consider that you may be in need of a permanent magnet gear reduction starter.
I'm assuming you did a cam break in, but couldn't tell from you other posts. If you're concerned about bearing damage you could drain some oil out and check for glitter, just for peace of mind.
I'm with @Sheriff41. I had this happen on my truck. Installed an aluminum heat shield using the same bolts that mount the starter and it solved the issue.

They also make flexible wrap type heat shields that you just wrap around and ziip tie in place.
Possibly timing also. Next time if it happens, to confirm it's timing, disconnect the power wire to the coil, or the wire from coil to distributor and see if engine turns over normally. If so, timing is too far advanced and needs to be retarded a few degrees for initial timing.
Thank you all for your suggestions. Here is the scoop.
Ground cable is new but connection is engine block to frame to battery. The engine to frame cable is new but the battery to frame cable came with the car and looks aged.
Timing is set @ 12 degrees BTC with about 32 degrees total timing. It is hard to see the timing pointer and I used timing tape on the dampener but it doesn't seem to help as much as I thought it would. I will check it again.
The camshaft does have 3 degrees of mechanical advance via the adjustable crank sprocket. I degreed the came to make sure of accuracy.
There is no detonation or run on. Acceleration seems fine and when the key is off the engine stops.
The engine has dished pistons and the heads are 62cc closed chamber type. I wouldn't suspect more than 10:1 static compression overall.
When the engine was first started, I did a 10 minute run up @2000 RPM. When I shut the engine down, I had the same issue. Hard to crank and the engine would not turn over fast enough to re-start (hard grinding like a dead battery). After 1 hour of cooling time she would crank over normally.
Comp Cams break-in oil was used and is still in the engine. I have 10 minutes of run up time, some idling time and a 20 minute drive on the motor. I haven't changed the oil yet.
My goal is to make it to the DMV on Saturday to get the title transferred and the registration. The car has to be there so they can do a VIN check since the car was bought in Arizona. After that I plan to take the car on a 20 minute non-stop drive and see what happens.
The starter looks clean as new but I do not know how old it is or if its a rebuild or not.
I suspect that the battery grounding should be battery to block and then to frame but I cant see where it would make much difference when the engine is hot.
Th saga will continue!
Update ! Update!
I replaced all the battery and ground cables with #2 gauge cables and bought a new Motorcraft starter solenoid. Topped off all the fluids and took her out on a freeway run. Kept the speed around 50-55 and the RPM's around 2500. The loop is about 25 miles. Temp, Oil Pressure all stayed stable and within range. When I got off the freeway, no problems. Idle was fine, temp and oil were still stable. Drove home and stopped the car. Waited about 10 minutes and tried to starter her. She fired right up. Oh happiness! I decided to go get some gas and when i went to turn on the lights, both headlights had burned out. When I drove home they were on. I checked the sockets and they had power and ground. Drove my other Mustang over to Auto-Zone and bought a couple of headlights. I plugged then in and wha lah, the headlights were on. I drove to the gas station and filled the tank. The drive home was a happy one. now it's time to finish the interior and get rid of all the rattles and noises. I do think I have a rear end that needs rebuilding. Another project for another day.
Plus one more on the starter wrap. I use my Mach for towing , as well as everyday driving, and run the stock manifolds on the exhaust. early on, I realized while on a trip up in the mountains towing a boat, after stopping at a rest stop, I had a no start issue. I even yanked the battery out of the drag boat to use as a jumper in addition to the car's fully charged battery.....no crank. After letting the car sit for an hour it started. Soooo, after the weekend I bought an inexpensive reflective starter wrap from summit. It's been many years now since, never had an issue again. I used to have a 1970 Olds 442 W-30 that I towed with that I experienced hot start issues with once, I put a Chevy truck solenoid shield on the Olds starter and again, rectified the hot start problem.

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