VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 235 hard start when warm. Looking for advice

I am in the fine tuning stages of this 235 engine. The engine will crank fine when cold and start pretty quickly. I'll let it sit and idle so a while allowing it slowing to get to normal opp temp. The Tstat opens at 185/190* and hangs out there unless it's hell hot outside. When I attempt to restart, the engine cranks slowly as if the exhaust valves are not opening properly. If you're commenting on the post, you know the situation described.

What I've done to this point:

- New championship aluminum radiator (three core I think, maybe two) It was a long time ago when I purchased.
- Timing set near as perfect as I can set it with clean points, new condenser, cap, rotor, plugs, and wires
- Brand new vacuum advance on distributor (and distributor moves freely at acceleration)
- New carburetor rebuilt and adjustment (single carb setup)
- Flushed coolant system multiple times
- Brand new Duracell 6volt
- Large ground cable from battery to frame. From frame, braided ground to bell housing and starter
- Starter was tested and confirmed fully operational
- Fully cleaned and red-coated my fuel tank and have clean fuel pump & screen
- Clean and new oil line going the the head/lifters therefore plenty of lube to the top end
- Have adjusted the rockers twice (hydraulic lifters). After the second adjustment, I thought it was fixed as I was able to start the engine again most of the attempts aft second adjustment. Weeks & months have passed and the non-start gremlin is back.

I feel there are further rats in the head adjustment area. Are my hydraulic lifters losing pressure? Is 190* too hot for it not to restart? Maybe a bad adjustment on the carb float? I'd like to not limit myself to only parking on hills when I do go for a drive! haha

Has the engine been recently rebuilt? It's common for a recent tight rebuild to tighten up a but more and exhibit this symptom when hot and everything has expanded.
Does it crank normally if the engine sits and cools for an hour or two?

I honed the cylinders and installed new rings. That was the extent any engine work.
Once it cools down, it'll start back up again. If I had to loosely estimate, the engine has roughly 15hrs of run time since I honed the cylinders and installed the new rings.

I support Tim's thoughts about clearances getting tighter when everything is hot. One other thought is that the starter acts up when it gets hot due to the under-hood temperatures.

What car is this engine in? Are you running a 6 volt system?

Did you reinstall standard size rings and pistons? How hard have you driven the car since the work was done? It takes load to break-in rings. If you are just driving around town I doubt if they have seated.

Did you make any changes related to the crank or rod bearings?

One simple test is to turn the engine over by hand when it is cold and then again when it is hot and you have a no start condition.

Another test is to jump start it with a 12 volt battery when it will not start.

You did not say anything about the positive batter cable, make sure a large enough cable for 6 volt and not the smaller gauge that is used on 12 volts.

Starter may do well and test okay but it may be dragging when hot.

Take it apart and check it the armature is dragging abainst the fields or the burshes are about worn out or that the end bushings are loose.

The recent rebuild will tax even a brand new starter when engine is hot.

Just a thought given the information you supplied.

Best,

Charlie

It will not be the lifters...................
You said a 1954 engine with hydraulic lifters. That engine came with a four field starter when new. Has a replacement two field starter been installed over the years?

Ryan, when you installed new rings, did you measure the new rings' end-gap?

Rusty,
Yes, I am running a 6volt system. The 235 sits inside a 2-ton 6400 platform truck so I've enough room for two 235's! :) haha.
Yes, standard rings. The majority of the running has been ideal on the farm. I've driven around the farm lightly a few times and have taken out on the roads for a total of roughly 15miles to 'open 'er up'. No changes to the rod bearings and crank. I'll give a hand crank this weekend when I'm back both warm and cold to see the difference along with the 12volt jump.

I would need to swap the coil to a 12volt and disconnect the generator right? If it starts well, would that suggest a weak starter? Though more cranking power may overpower a problem elsewhere.

Dens,
I likely have a 12v size cable. I'll replace to a larger and see what happens.

Charlie,
It'd be good idea to recheck the brushes and armature. Come spring '19 it will be 2yrs since I started the engine from the install. It's been a while, just not a lot of run time on the engine.

Gene,
Great question! I do not recall. I'll confirm this weekend and I am back.

Bill,
It's been a while since I installed the rings but I can nearly guarantee I did.

Hi Ryan,

I would not worry about changing the coil just to jump start the car with 12 volts. Just disconnect the jumper cables as soon as the engine is running.

I think you will learn more after you manually turn the engine over by hand when it is cold and then when you are having the hot hard-to-start condition. Based on the minimal amount of work done on the engine my thinking now is that it is a starter or cable problem.

Do not worry about the 6 volt coil when jumping with 12 volts. 12 volts will not harm a 6 volt coil.

The "thin" 12 volt cables shold be replaced ASAP.

in hot hot sacramento summers, long ago, my '53/216 pickup would vapor lock; started again usually after cooling down a bit, like an hour. jim

I've turned the engine over (using screwdriver in the clutch assembly) while cold and then warm at 190*. My T-stat opens at 190* and stays right there. Should I use a 180* T-stat?

Any how, easy turn over while cold with tension during the compression strokes. After I shut the engine down at 190* it was slightly harder with no compression but noticeably stiffer on the compression strokes. I was still able to turn the engine over but with more effort than cold. What are your thoughts regarding this description?

The positive cable was approximately 1/2'' wide. I'll replace that here shortly.

In 1954 the cars camw with a 170 Deg. thermostat. That rating is no longer available. A 180 should not affect starting.
i still think that you have a starter problem and there is no test for that problem other than trying a different starter.

Do this:

a. Remove the starter.

b. Take the cover off.

c. Take the ends off.

d. Take the brushes out. Re C & D. Do whichever you like first.

e. Check the fields to see if the armature is dragging on one of them.

f. Check the commutator. Use a piece of sandpaper and clean it up.

g. Check the ends of the armature in their bushings to see if either is sloppy. Change if necessary. Take your time on getting the brushes on the commutator. They can be downright hateful sometimes. There are tricks to doing this without a-cussin but I don't know any that will guarantee prompt success.

h. Check the height of the brushes for wear and see that they have good spring tension.

i. Reassemble the starter after making sure you've replaced everything that needs it. And, make sure the brushes are mated to the commutator.

j. Install the starter.

k. Piece-o-cake.

l. Send me tribute.

Best,

Charlie

BTW: I assume (I know, I know) that the battery, cables, selinoid (sp) (whatever) etc, ate in good shape. All must be in top notch condition to properly turn a hot, fresh rebuild.

Charlie and Gene are pointing you in the right direction. Get some good starter and ground cables. If that does not help follow Charlie's direction's to check the starter.

I took the starter off yesterday, I did not have time to take it apart but am having my dad drop it off to have tested and rebuilt as we expect it will need.

Ryan, make sure the shop that works on your starter doesn't paint over the ID plate.

I did not tell my shop that and they painted over it. When I took a rag to wipe off the new paint, the old paint on the tag came off too.

Dean

Make sure the starter shop knows it should have four field coils.

Thanks guys!
And I forgot to mention it is a 4 field coil not a 2 field as previously inquired by Gene, I believe.

I spoke with the electric motor shop this morning. They mentioned that nothing major was wrong with the starter. They clean all the contents and stress tested on their machine and is registering full strength. I'll be able to work install and retest on the truck this weekend and will repost with results.

Hi Ryan,

Sorry if I lost track of the details. Based on the detail work you are doing I am now starting to think it might be an electrical circuit issue.

I noticed that you have a "large" cable from the battery to the frame and a braided cable from the frame to the block. You did not mention what size cable you have from the battery to the starter.

I also do not remember if you are using a solenoid in your starting circuit or a mechanical starter switch. With either one there could be corroded or heavily pitted primary contacts that have too much resistance.

Here are some ideas for simple tests you can do the next time it will not start when hot. One is to connect jumper cables directly from the battery to the engine block and starter terminal. Leave the existing wires connected.

Another is to connect the large ground cable from the battery directly to the block. This will bypass the braided cable.

A 6 volt system will work just fine if the cables are sized properly and all the connections are clean.

I just had an issue with a reluctant starter on my '31/'32 test engine. Hadn't used it in several years so had to clean points to get fire. Starter didn't want to crank it very fast. In fact wouldn't turn it over on first or second try a few times. Rolled over fairly well once past compression on a cylinder. Had a woven negative "cable". In the past it cranked over without problems. Remembered that Gene had commented that often there were problems with woven cables even if both ends were clean. After saying some not so kind words both silent and oral went to Tractor Supply and bought a new 24" cable. BTW the battery is only a couple months old. When that cable was attached to the top bolt holding the starter to the clutch housing rolled over like it should. Bad words ceased. Don't know what happened (if anything) to the woven cable during its rest. Never mind as new ground cable attached directly to starter housing solved the problem.

Rusty, the positive cable is in fact a larger one as well... though not as large as the John Deere ground cable I used! ha. The positive cable is approximately 7/16 - 1/2 inch thick. The starter is mechanical which I had not thought to mention before.

I'll relocate the ground cable from battery to the starter this weekend when I'm home.