The Stovebolt Site Forums The Shop Area Engine Shop Engine will not start some times!

I have just put together a street rod with a SB 350 and electric fans ( 2 - 12"). I took it out for a 5 mile drive and stopped at one place. When I got it home and then went to move it and it would not turn over. I checked the volts and it was 10.6, charged the battery and it started. Next day I check the battery and it was 12.5, drove it to a friends and back (about 4 miles), no problems and the battery was up to 12.77. I took it to a rad Shop and back (4 miles) and no problems. I then took it to two places (6 miles) and back home. I then stopped and tried to start it a again. Would not start. Went to check the voltage but I was called to the phone. 20 minutes or so later I checked the voltage and it as 12.54 and the car started. When ever I check the volts on the dash while driving it is always over 12. The battery is under the floor and the exhaust runs next to it. The engine is running about 190 - 200. Could it be the heat? As the fans are only on when it it hot, could the fans be drawing too much current and causing the started not to turn over. I do not hear anything from the starter when it does not start and the fans are connected to the ignition switch to be on when the car is running.

Any ideas would be welcome!

Very common problem on SBC engines. Heat saturation on the starter. Use heat shielding on both starter and exhaust wrap. We Tri-Five guys are plagued with it.

just curious, why is it in cars that have been modified but not in ones that came stock with a 350? never understood that deal?

I had a stock Olds 350 (not Chev) in a 63 Chev C20 with a TH400. Round town 98% of the time no problem. Any driving distance longer than 50 miles turn engine off, no start till it cooled down. The exhaust pipes came off the the rear of exhaust manifold and down along side starter.

Larry

Waggy,

It seems there might be several things going on with your rig. Your battery voltage readings are all over the place...mostly on the low side of a fully charged 12 volt battery. A modern dash mounted voltmeter should show a continuous reading of just a smidgen under 14 volts all the time (13.8v).

I'm not real familiar with those cooling fans, but I think they draw quite a bit of current. If you had a marginal battery and those suckers came on as soon as you hit the starter, I think you would be in deep schnook!

The starter/solenoid combo can be fussy when it gets hot, but not everyone is. Usually, if it's a problem hot start, the thing will turn over, but very sluggishly. If you only get it to "click", it's telling you that it's the solenoid, and these aren't as heat sensitive.

I would make sure my charging system was working 100%, verify the health of the battery, and figure out if those cooling fans are suppose to pop on as soon as the ignition switch is turned on!

Stuart

Not to rule anything out but I think 'Atomarc' may be on to one possible problem. What is the rated output of your alternator? Make sure it is higher than the total current drain of your complete electrical system. Electrical fans are real amp hogs.

These posts are very good. A fully charged battery should read 13-13.5v. Run your engine and check the charging voltage and see what you get. Should be 13.8-14.25. No more than that. Also check it with your accessories on. Turn on the lights, heater or a/c, stereo and what else you have and see if it drags it down below 13.10v. If it is below that you have a weak alternator and needs replacing. Go with a High Output one. Extra amperage is a good idea as it gives you a reserve capacity incase you need it and pervents you running at max output all the time and then shortens your alternator life. The voltage regulator will prevent over charging your battery. Gives you brighter lights too. Also a battery with a bad or weak cell can cause what you are having. Been there, done that more times than I want to remember. I would recommend the Optima battery. The yellow top is the best. Even the red tops are a great battery. They are a gell cell and can't spill even if mounted sideways. Lots of cranking power! I had them in my Suburban Diesel. I remember the days of the old generators I used to have with the external regulators. Use to put in brushes in them and back on the road again. I bet 53moneypit remembers those! If your volts are high enough when running your battery is probably going out and does not have the amperage needed to do the job. Starter drag will drain your battery when its hot and won't start. If it weak you have to wait till its cool before starting. Also I would insulate the starter from heat and wrap the exhaust near it with heat wrap used on headers. This is a great help to eliminate starters going out too soon. Or you can put in a heat shield next to the starter or both which is what I would do. You may have a drain problem where something is pulling your battery down. Check the battery fluid level as it may be too low. Put in electrolite to fill it up. Electrical stuff is the PITS! Worse than mechanical stuff sometimes. I hope this helps. Henry ... BTW, make sure you have extra heavy duty battery cables. 4/0 is a good size. Check the connection to the starter and the ground. A rusted, caroded or bad connection can drive you nuts trying to find out what in the world is going on. I wire brush them and solved many problems that way. Can run you ragged. Just some more ideas.