The Stovebolt Site Forums The Shop Area Engine Shop hard starting when warm

My problem is with a 46 chevy pickup. I put a 54 235 overhauled engine in it. When I drive it about 10 miles and try to start it it won't. I have put in a rebuildt starter,new voltage regulator,checked generator-good,new battery. Any Ideas would be appreciated.

b51r

6 volt or 12 volt? Check the starter to see how many amps it drawing? Some of the rebuilds are not that good.

Hard to start leaves a lot unanswered. Does it crank OK but won't fire. Does it try to fire but won't catch? Does it crank too slow? Does it not crank at all? More specific info will help us to help you.

More info would help- any gas dripping from carb, what is the condition of the fuel pump- do you smell gasoline- is your engine to full temperature? what carb are you running?

On my trucks when then engine gets warm and I park it, then try to restart, I have to pull the throttle knob all the way out, no choke, and hit the starter, it turns over about three times then fires up- If I just try to crank without the use of full throttle, I can crank till the cows come home and it won't start.

Someone here told me about percolation- where the hot gas expands and such. Try searching it and see what you find.

3 of my trucks are 216's with carter w-1 carbs, the 4400 is a early 235 with a rochester. they all do the same thing.

b51r,

It has to be asked (to put this possibility out of the mix): if you have a 6v system, what size battery cables do you have?

Tim

to all: no gasoline dripping. Carter carb. 6 volt, same fuel pump as in old 216, correct size battery cables, cranks over slowly but draws down battery quickly, temp at or about 180 with a 165 thermostat,starter was out of another truck but was tested as ok.

b51r

Years ago, everyone would have said you had a bad coil. It might be worth it to check it out.

<CLICK>

check your timing, also, have the battery checked as it sounds like it may need to be replaced.

ex gabster: new battery timing checked several times
b51r

So after 6 months, have you still not found the problem? I didn't see the post when it was active. However, your information is very vague. If it does not turn over when it is hot and the starter, cables and connections are good, it could mean that whoever overhauled it got the bearing clearances too close. When it warms up and expands, it becomes hard to crank. If thats the case, you have 2 choices. Either run it and don't turn it off away from home and be prepared to let it cool before you start it. However, if the clearances are really close, you risk having a bearing seize and spinning a bearing shell. Or you can pull the pan and recheck clearances with plastigauge.

The battery really shouldn't "wear down quickly". If you have too much voltage being dropped in the circuit it can give the impression that the battery is wearing down quickly.

A weak coil may not deliver enough spark when the starter is drawing a lot of current. I would get it good and warm, park it at home and then disconnect the power lead to the coil. Hook the coil up to a different source, like a six volt battery charger and try and start it. You may get quite a surprise.

would using a higher compression 1954 235 cause hard starting when warm with my 6 volt system?
b51r

It puts more strain on the battery, cables, and starter, but if they are all good and the right size and the timing is set correctly you should not have a problem.
Even a 1954 261 used 6 volts with no problem.

I see you say in an earlier post you have the correct size cables. I question that statement. What size cables do you have?

the 6 volt cables sold by Jim Carter truck parts

b51r,

What is the part number of the 6v ground cable you got from JC?
What is the part number of the other/positive 6v cable that you got from JC?

My experience has been that it is common for vendors to sell a 4 gauge (12v) braided ground cable for a 6v system. 2 gauge or bigger is better (I like 00 gauge). The ground cable does not have to be braided - Tractor Supply should have large-gauge non-braided cables.

Just in case the "8v battery solution" is soon suggested, check the cables, first.

JC shows "heavy 1 gauge" cloth covered cable [$39] or a "heavier 2 gauge" vinyl covered cable [$20] .... guess JC doesn't understand the AWG numbering system as Tim prefers, 0 or 00 is best, and "heavier"

the 1 gauge should be OK if everything else is good, particularly clean and tight connections, the 2 gauge will require everything else to be perfect, including engine tune, and even then may be a problem in hot weather, which affects connections as well as affecting the current carrying capacity of any wire - length has an effect as well, the longer the cable the more resistance, keep cables as short as practically possible

Bill

That is why I asked for part numbers, Bill

I agree with you that the following progression of sizes are preferred to 4 gauge or even 2 gauge:

4 gauge - OK for 12v (and maybe for farmers with 8v)
2 gauge - OK for 6v (and fine for an 8v, which is not necessary)
1 gauge - even better for 6v
0 gauge - (sometimes shown as 1/0, I think) - very nice for 6v
00 gauge - (sometimes shown as 2/0, I think) - probably over-kill but often no more expensive than 1/0, but still pliable (and battery terminations/ends are available).

yes, lighter than #1 is false economy, but I would assume most folks would order the cheaper cable [half the price] when it's called "heavier"

considering there probably are few locations in N America that wouldn't have nearby shops carrying cable by-the-foot and appropriately sized solder-on terminals, buying cables from the vendors really isn't necessary just because it's for a vintage vehicle

Bill

Just put aluminim pistons, new rings, and re shimmed the rod bearings in my '51 235. With fresh rings and tighter bearing clearances, it definitly rolls over harder, especially when hot, and I have good cables and fresh starter. I just keep driving it, and don't shut it off until I get back home, that way I can figure out the new hot start procedure. As the engine breaks in it keeps getting better and better.

Do you have a ground from the frame to the engine block?

yes
b51r

I had 00 gauge or 2/0 [Overkill size) made at my local International Harvester/Case implement dealer,Very reasonably. Have never had an issue with slow cranking or hot cables Etc. Whatever you do, DO NOT USE those mickey mouse bolt on repair ends especially with 6 volt system. Jerry