Wont start when hot

[loadtoad87]

I bought a 1967 1600 that had not run in 5 years. I got it running like a top in a day, but once I turn the car off and then try to start it again, it wont fire. I even tried starting fluid, so I don't think it is a fuel issue. I changed the coil, still having the same problem. After it cools down, it starts right up again and runs great. Any ideas? I ordered some new condensers, cap, rotor, and points, but I am unsure if that will help because it starts no problem cold. Any ideas? Thanks.

[GeoffM]

I had that problem and it turned out to be the starter.

[loadtoad87]

Thanks. Was it still cranking? So that would be an issue with the wiring on the starter?

[redroadster]

Thats a hot soak condition (thats the term)
how long before it will crank over?
Yeah you can have a weak starter too

Many things can cause ,over fueling , over heat, ign timing over advanced , hot spot in the head
Radiator , blowing out hot air ?

[greydog]

From your description, it sounds as tho the starter spins the engine over the same hot or cold. Correct?
But it won't "fire". Meaning, no sputter, cough or anything? If you start when cold and shut the engine off after a minute, will it restart (in other words, this only happens when the car reaches operating temperature)?
Is the heat shield in place beneath the carbs?
Mechanical fuel pump and stock (glass body) gas filter?
When you turn the car over when hot, have you checked to see if the plugs are firing?
Other than buying new parts, what diagnostic work have you done to pinpoint the issue?

Dan

[spags1986]

Had the same problem in my 66 1600... ended up getting the timing set correctly (was way off) and it fixed all my problems.

[loadtoad87]

Thanks everyone. The starter does run when cranking, I just dont get any cough, sputter, nothing. I just put a new starter on it (the forklift starter from ebay), the old one was shot. I was having the issue with the mechanical fuel pump (which was leaking) so I put on an electric fuel pump. Yes, it only happens when at operating temp, or at least close to it. I ran it for about 5 min at idle, shut it off, and it started right back up. Ran for about another 5 and then it wouldn't start. I have not checked the spark after it wont start, that will be my next step, but I don't have a tester. The heat shield is in place for the carbs. The heater doesn't work right now, it could be getting hot. I also have a thermostat coming. Do you think that would keep it from firing though? It just seems like a spark issue maybe?

[greydog]

When the car doesn't want to start. Pull a plug wire off a plug and stick a phillips head screwdriver in the boot.
Then hold the handle of the screwdriver and, while someone cranks the engine over, bring the stem (metal blade) of the screwdriver near a metal grounded part on the engine.
You should get a spark between the blade of the screwdriver and the ground. If not, the issue is electrical. If you hve spark when cold but not when hot, check wiring connections, condenser, coil. You'll need a voltmeter.
If there's a spark, it's fuel or timing related.
If you have spark, I'd pull the feed line at the front carb tee and stick it in a can. If fuel runs into the can, when ignition is on, you know fuel is getting to the carbs. If no fuel, connect the line back to the tee and pull the outfeed line at the fuel pump. Its a matter of back tracking until you find fuel. Then you know where to look.
Dan

[Datrock]

I would check the carb bowls to inspect the floats, cracked brass floats with fuel in them are what to look for, you want to make sure they are not brass sinkers. If they are brass, remove them and shake the float to see if they have any fuel inside of them. A few years back I chased the same issue until I found out the floats were not doing their job. The 66spl would start right up when cold but when hot and sitting for a short time it cranked and cranked without a sputter since it was flooded. I put the plastic floats in and the starting issue went away.

[GeoffM]

Yeah sorry.... mine whould not turn over when I tried to start it when hot. It was a heat soak problem so when I replac3d the starter the symptom went away.
That was after replacing the wiring, battery etc...lol.

[loadtoad87]

Great, thank you all for the help. When i get some free time I will try those suggeations and report back.

[notoptoy]

Do you still have the points distributor? If so you might want to check and replace the ballast resistor, the ceramic Doohickey on the firewall that leads into the coil. It’s a cheap part that is designed to create resistance to the ignition, it could be failing once it heats up

[GeoffM]

+1 on the ballast resistor.

[Lorna c]

check to see if your gas cap has a vent hole on it . take it off and try it again . take the rubber out if no vent hole so it'll leak air back behind the gas to push it .. it's very important you have everything closed tight or no vacuum system . the Pump is only like 5lbs of pull or something close . and check your fuel lines for clogging . and go into the MacGyver hatch in the trunk and check inside your tank too . sediment seems to clog up on these curves they have by the tank and inside the motor . make sure none are pinched a little from others pushing and pulling them around to make room . and accidentally get them closed off with one little slick of dirt or rust from your tank.. then when the car sits for a bit the pressure will kind of fill everything up again slowly and the car will start until everything drains and it can't keep filling it up fast enough because it's clogged..then the car dies again and won't start until it all fills up again sitting . if that makes sense . good luck . I had this same thing and threw parts at it until I noticed the fuel line getting clogged up or being clogged up was a common denominator every time I had this issue and started focusing on that.. it worked on mine. no more issues until it tries to clog again but it takes months now because I clean my tank out really good I went through 30 fuel filters completely full and clogged in less than 6 months.. so ... keep it in mind and if it's not your fuel lines cuz it might be down the road.... and your gas cap . check it .. that'll stop everything also ..

[loadtoad87]

Thanks again, everyone. I tried new points, cap, rotor, cleaned up the gas tank real nice, and still had the problem. Then I checked the spark plugs like I should have in the first place (dumb dumb) and number 2 had a lot of oil on it. Replaced the plugs and it fired right up. Soo looks like I have some work to do. Any recommendations for buying new rings and gaskets for a 1600?