The Stovebolt Site Forums The Shop Area Engine Shop too much compression? starter weak even at 12v?

Hello fellas,
I'm very close to firing the rebulit 235 (1961) in my 51 pickup. Without the plugs in i was using the starter for verifing moving oil and primming the engine a little more than with just the screwdriver drill trick. once complete i put the plugs in and MAN the compression wont let the starter turn like it needs to in order to fire. Although i'm not reday to put gas in the bowl yet, i don't think i've got the starting power needed. its a 6v starter and i've tried it both with 6v and 12v. its better with 12 but not near enough. I'm i missing something? is this a common symptom of a bad starter? its not new form the orig 51 216.


thanks mike

Well normally I would ask about the cables you are using but 12 volts should really make it spin. After turning it over a bit I would feel the battery cables, especially the ends to see if they are hot. A hot connection means it is not very good. This would apply to the starter to franme connection too.

The cables were warm. i used jumper cables direct to the starter only. (pos on bolt and neg on back of starter housing.

you think it could be the weak connects that jump cables usually give? I could go ahead and make up some temp cables with big wire and compression ends and bolt them on and try that.
mike

It really depends on the size of the jumper cables. Jumper cables can be anywhere from 10 guage to 2 guage for a really good set.

12 volt starting usually requires 4 guage to 2 guage wire depending on distance.

6 volt starting requires 2/0 cable, not to be confused with 2 guage wire which is much smaller. Don't forget about grounding the block, chasis, and cab.

Mike.. if you're battery is good.. and you have good cables.. if it's turning slow and heating up the cables, then in all probability you need new busings in the starter. No a hard fix, I think there is a tech tip on doing it.

do you have good connections? (the wire crimpings as well as the bolted connections.) Is your battery any good? I am just using the standard off the shelf wires that are probably for a 12 volt system and have no such issues. (I was only concerned about length) If you have installed a new cam, be careful how much you crank your engine over before you fire it up. If you haven't already, go to any of the major cam manufacturers web sites and read up on cam break in procedure, if you have cranked your engine over more than about 10 times you may have already caused damage. The cam lube you used was gone the first revolution. The cam lobes rely on oil flinging from the crankshaft for lubrication, which is why you bring it up to 2500 rpm immediately upon obtaining oil pressure.

I don't see how, unless you put special high compression pistons
in and shaved the head heavily that you could possibly have
compression high enough in a 235 to cause problems for the
stock 6v starter.

After making sure the electrical to the starter was assured the
next or maybe the first thing I would have looked at was
whether the timing is advanced way to far.

Denny G

If things are all painted fresh you may want to remove connections and clean paint off the cable connection areas...

I once had two sets of jumper cables hooked up on top of the wimpy battery cable and couldn't get the engine to go... it struggled like your describing, but once I put REAL battery cables on it like the guys are suggesting it fired right off. All those electrons trying to scoot along single file on the outside of 20 or 30 strands(total for both sets of jumper cables when I actually looked) of copper isn't near the same as scooting along 70 or 80 strands (of larger dia. wire to boot). A serious traffic jam comes to mind and the associated 'heat' that comes with them... Did you see that last bit from the Rally to Restore Sanity/and or Fear where all those cars had to merge down into two lanes for a tunnel? Something like that

What are the symptoms of the brushes needing repalced in a starter.

Thanks Mike

Slow hard cranking

Put real battery cables on it, jumper cables will not get the job done on a new engine. Then if it won't turn, look into the starter.

A new engine should never be turned over with starter just to prime it, especially with a new cam. Prime the oil pump with a drill motor.

Also, read up on engine break-in. Chances are the cam is still OK if you haven't spun the engine to much and you have the right oil in it. I would go back and add cam grease to the lobes and get the battery problem solved before turning it over any more. Rebuild are expensive, doing it twice really hurts!

Get the battery charged and install the correct 00 gauge wires, and it will turn.

Joe