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Pre-ignition / starting problem. Ripping hair out.

Well a hot engine, esp one with milage on and carbon build up on the piston can easily have pre ignition.
You have your spark plug ignite at the top, piston carbon at the bottom, flame fronts meet in the middle earlier than planned.
Not really confident this your issue.
So we now know the timing marks at the balancer are good and point to 0.
Now we need to check the distributor install. Put engine on tdc compression stroke. Find #1 spark plug wire tower, remove cap and see if rotor is pointing at that tower.
Was a reluctor pick up coil included in the new distributor parts?
Also what temp t stat is in this engine?
 
Wes Harden said:
Well a hot engine, esp one with milage on and carbon build up on the piston can easily have pre ignition.
You have your spark plug ignite at the top, piston carbon at the bottom, flame fronts meet in the middle earlier than planned.
Not really confident this your issue.
So we now know the timing marks at the balancer are good and point to 0.
Now we need to check the distributor install. Put engine on tdc compression stroke. Find #1 spark plug wire tower, remove cap and see if rotor is pointing at that tower.
Was a reluctor pick up coil included in the new distributor parts?
Also what temp t stat is in this engine?
Click to expand...

I will check distributor as you suggest.

Currently has a new 195 thermostat. The problem may have gotten a little worse after installing this thermostat. The old one that came out was a 180 or 185 is memory serves.

This was the distributor that arrived today:

https://www.amazon.com/dp/B074VFXMZR?psc=1&ref=ppx_yo2ov_dt_b_product_details
 
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yes a 195° has no business in a non computer controlled engine, the margin for error is to thin, go back to 180° esp if you are in a cold winter climate. I run a 170° in the Hottest area of AZ. The 195° is an emissions control thermostat, the catalytic converter works better, but is a fine line between unburnt hydro carbons destroying the cat and High nox emissions. With out a computer to control the air fuel ratio or timing the 195° is loaded Russian roulette revolver pointed at your cylinder heads and gaskets.
 
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Wes Harden said:
yes a 195° has no business in a non computer controlled engine, the margin for error is to thin, go back to 180° esp if you are in a cold winter climate. I run a 170° in the Hottest area of AZ. The 195° is an emissions control thermostat, the catalytic converter works better, but is a fine line between unburnt hydro carbons destroying the cat and High nox emissions. With out a computer to control the air fuel ratio or timing the 195° is loaded Russian roulette revolver pointed at your cylinder heads and gaskets.
Click to expand...

I have a new 160 in hand that I have not installed yet. Would that be too cold?
 
Maybe I should install the 160, and if the problem goes away just stop there? Could this all be related to over temp for this particular engine?
 
definitely related, cooling system age and condition count as well, go ahead a use the 160°. Trust but verify that it is acttually working at 160° new T stat's aren't known for great quality these days.
 
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So the rotor points toward #1 on TDC, but its not perfectly lined up. Close though. Maybe 3/16 or 1/4 inch off (2 to 2.5mm). Its to the clockwise direction off.
 
it is clock wise past the #1 tower ? At tdc. If you have a crayon mark the dist body at #1 tower, help you judge. That doesn't sound bad to me I means you are advanced some.
 
Flushing the cooling system. Tons of "stop leak" must have been put in by previous owner. It had a leak at the radiator hose, which is what they must have been trying to "fix" with the stop leak. A layer of muck in the bottom of the drain bucket, after it settled for a bit. After that I will put in the 160 Tstat.
 
sounds like a good plan, maybe back flush while t stat is out, pop the lower hose off the rad keep the crap in the block outta radiator.
 
Wes Harden said:
sounds like a good plan, maybe back flush while t stat is out, pop the lower hose off the rad keep the crap in the block outta radiator.
Click to expand...


Ya, I did the back flush thing on the radiator, motor, heater core etc. LOTS of stuff came out then ran clear. Reverse the flow and the water went dirty again for a but but cleared up.
 
160 is installed, timing is @12 degrees. Starts and runs perfect as usual, but only timer will tell. I will run some cooling system flush tomorrow for about 3 hours of driving around and then flush everything again with distilled water and then put antifreeze in.
 
So far so good. Drove it about 15 miles and shut it off. Restarts perfectly every time so far. Will need to drive more to be sure though. Temp Gauge sure doesn't go very high.
 
A similar issue I had with my old Jimmy back in the day turned out to be the vacuum advance mechanism being sticky. My theory is that I'd shut it off at idle of course, so the vac advance would be adding timing. Then when the engine would be shut off the mechanism would be sticky enough to retain some of that advance, so then I'd try for the hot re-start and I'd get the same brutallly slow cranking. Once it sat long enough the mechanism would have enough time to slide back to the correct timing. I replaced the whole vacuum advance unit, thoroughly cleaned the guts of my distributor and never really had that issue again.
 
I guess since the point ignition distributors went away in the early 70's, every one forgot about the little felt lube pad under the rotor. Just be cause the felt pad was left out in the HEI distributor doesn't mean maintenance free, even I have forgotten, and I have lubed up/ free'd up a few 100 HEI mechanical advance mechanisms.

So everybody that reads this, go lube your distributor mechanical advance today, HEI or Points
 
tRustyK5 said:
A similar issue I had with my old Jimmy back in the day turned out to be the vacuum advance mechanism being sticky. My theory is that I'd shut it off at idle of course, so the vac advance would be adding timing. Then when the engine would be shut off the mechanism would be sticky enough to retain some of that advance, so then I'd try for the hot re-start and I'd get the same brutallly slow cranking. Once it sat long enough the mechanism would have enough time to slide back to the correct timing. I replaced the whole vacuum advance unit, thoroughly cleaned the guts of my distributor and never really had that issue again.
Click to expand...




tRustyK5 said:
A similar issue I had with my old Jimmy back in the day turned out to be the vacuum advance mechanism being sticky. My theory is that I'd shut it off at idle of course, so the vac advance would be adding timing. Then when the engine would be shut off the mechanism would be sticky enough to retain some of that advance, so then I'd try for the hot re-start and I'd get the same brutallly slow cranking. Once it sat long enough the mechanism would have enough time to slide back to the correct timing. I replaced the whole vacuum advance unit, thoroughly cleaned the guts of my distributor and never really had that issue again.
Click to expand...

I had tried bypassing the vacuum advance while hot, as well as blowing the distributor out with air - but it didn't help. Maybe the mechanism was stuck, who knows. Something expands when hot and gets hung up maybe. I have a brand new distributor that I could install, but I tried the 160 thermostat and system flush first. After thorough testing, its confirmed that the problem is 100% fixed (or at least symptom free). I went through so much work, and all it needed was a colder thermostat. Bitter sweet I guess. Oh well. At least its fixed. Thanks for all the pointers people. Maybe I should install the new distributor and try the 195 thermo, but... Why? I guess with the 195 the heater would work a little better. Not worth the trouble though I suppose.
 
Any reason to run the engine when flushing with a garden hose without a thermostat? I so connect a hose and put the hose in there and let it push all the water through the system, and then I remove the heater core hoses and flush both directions. Sufficient? (highly filtered garden hose water, followed by distilled water, followed by antifreeze concentrate)
 
sounds good to me. I'd say your about as flushed as you can get, w/o power flush. this was after chemical treatment and warm up ?

Keep an Eye on your heater core for a little bit, it may spring a leak depending on how old it is.
 
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