Starter motor test wiring?

[erikgreen]

Well, I'm still trying to get my chevy 350 together and working. The latest problem is that my brand new torque wrench didn't work right, resulting in me snapping off one of the "ears" for a head bolt. I figure oh, well - I'll check to see if I have compression and go from there. I can replace the head later if the motor is runnable now.

So, I've tried to hook up my starter motor to a battery to try to get a compression test done. I connected the negative battery lead to the block (sanded it a bit to clean the rust off), positive battery lead to the + bolt on the solenoid, then another wire to the + battery terminal to touch to the solenoid energizing terminal. It sparks a bit when I touch it, but nothing else happens.

Here's a picture - can you guys tell me what I'm doing wrong?

Erik

 

[thrasher]

Re: Starter motor test wiring?

I can't see the wire that you are using to engage the solenoid. There are two small connectors on the back of the starter solenoid, you need to make sure your wire connects to the right hand one (the one closest to the engine). It will spark when you touch it to the positive terminal of the battery, you should also hear/feel a solid clunk as the solenoid engages the drive gear.
The other terminal (clearly visible in your photo) is used on mechanical points ignition systems to raise the voltage at the coil when starting the engine (you don't care about that for your test).

Gary

 

[Don S]

Re: Starter motor test wiring?

Maybe this will help.

http://forums.iboats.com/showthread.php?t=183904

 

[erikgreen]

Re: Starter motor test wiring?

Thanks Don, I'll see if I can work things out.

It looks at first glance that I'm doing things right... I'm touching the second + wire from the battery to the right terminal (I edited the pic to put an arrow to the terminal in the shadowed area that I'm touching the wire to).

I should note that I had another unidentified component that was bolted to the engine near the starter... maybe this is part of the problem? I see info on a "slave solenoid" in Don's notes. I don't have it on the motor right now (I'm trying to just hook up enough wiring to turn the motor over and see if I have compression).

I'll keep reading.

Erik

PS: Referencing Don's diagram of the back of the starter, I'm putting the large positive battery cable on A, putting the large negative cable on the block, and touching a jumper wire from the battery + terminal to B.

 

[Bt Doctur]

Re: Starter motor test wiring?

Maybe it`s the angle but it looks like the block is cracked just behind the core plug above the starter

 

[Don S]

Re: Starter motor test wiring?

PS: Referencing Don's diagram of the back of the starter, I'm putting the large positive battery cable on A, putting the large negative cable on the block, and touching a jumper wire from the battery + terminal to B.

That should be all you need to make the engine turn over. What happens when you jumper them??????

BT Doc, I think that is the boss that the core plug is in. look in front of the core plug and you can see an similar angle.

 

[erikgreen]

Re: Starter motor test wiring?

I get a couple of small sparks when I touch the + wire jumper to that terminal. Nothing else.

Nope, the block is not cracked there. With all the other stuff I've had go wrong with this, I wouldn't be surprised, but at least that hasn't happened yet.

I'm gonna go test with a multimeter and see if all the connections are good.

Erik

 

[erikgreen]

Re: Starter motor test wiring?

Okay, multimeter results:

battery: 11.36 volts

+battery to engine block: 11.36 volts

+battery to starter motor casing: 11.36 volts

Bolt A to bolt b potential: 11.36 volts

I don't note the polarities here.

Still only a few small sparks when I try connecting the jumper. I'm gonna try a diff. battery.

Erik

 

[Don S]

Re: Starter motor test wiring?

Both those cables have some wimmpy looking cable ends. Are they even tight on the cable???
On boats, I have always made my own cable, crimped and SOLDERED, then heat shrink over them....... I NEVER have cable problems.

 

[Don S]

Re: Starter motor test wiring?

11.36 is a dead battery........... Charge it up.

 

[erikgreen]

Re: Starter motor test wiring?

Yep... I switched batteries, now it cranks nicely.

Next problem: figuring out how to compression test... the gauge always reads 0, even though I can feel the air pumping out the exhaust holes :\

Nothing makes you feel humble like working on engines.

Erik

 

[erikgreen]

Re: Starter motor test wiring?

Can I compression test without the intake manifold, carb, etc on the block? My understanding is that the valves and head will seal the cylinder provided the rockers, pushrods, etc. are in place....

Erik

 

[Don S]

Re: Starter motor test wiring?

How much of this engine is together? Do you have the rocker arms on and adjusted properly?

 

[erikgreen]

Re: Starter motor test wiring?

I've got the rockers on. Adjusted properly, dunno, I'm checking that now against my books.

The block, heads with new gaskets, starter are there. No valve covers, alternator, plugs, plug wires, distributor are on. No intake, exhaust manifolds, coil, water pump, power steering pump either.

Basically I was trying to get enough of the engine together to do a compression test and see if it's worth trying to put this the rest of the way together.

Thanks for helping out a complete noob... this is the first engine I've ever put together, and although I have the "how to rebuild your small block chevy" book, I'm still wandering around in the dark.

Erik

 

[erikgreen]

Re: Starter motor test wiring?

Okay, I re-did the valve adjustment process, using a different books' description this time - I had them too tight last time I think.

Now my compression test works, but still puzzles me. Here are the numbers for the V8:

160/0/160/60

160/0/0/130

I interpret this to mean that I probably don't have the valves adjusted properly yet. I think I need to verify TDC with a flashlight instead of watching the lifters like the book says.

That said, this block could still have some major valve leaks or my busted torque wrench could have cracked something else. The new torque wrench says everything's at 60 psi or more (I hope not much more) now. The block did run and fire on all cylinders before I took it apart to install marine gaskets/etc.

I'm out of town for a couple of days now, but I'll check back with you guys when I re-do the adjustment.

Suggestions appreciated, and thanks again Don/everyone.

Erik

 

[erikgreen]

Re: Starter motor test wiring?

Well, I finished my testing.

With further tweaking of the valve lash (I had it too tight... for those familiar with the techniques, be very careful if you rotate the rods to determine lash) I was able to get decent compression on all cylinders but 1.

Oddly, one cylinder actually had 185PSI compression, and the others were at 160 or so.

But, the one stayed at Zero. I had a new gasket on both sides, but I thought I'd best pull it apart and look at the head. The head was ok, but what I'd missed earlier was a 3 1/2 inch crack running horizonally across the lifter gallery right next to the #3 cylinder - the one without any pressure.

Sooo, I'm pretty sure this is preventing a good seal on that cylinder... it doesn't seem to go all the way into the cylinder, but I'm sure it projects into the water passage at least... so this block (bought used for $300) is worthless.

I'm going to clean up the garage a bit, recycle the two cracked cores I have, and save the rest of the parts for a few weeks, when I'll get a long block from rapido marine.

In the meantime, look for more puzzled questions from me about trailers, hull repair, and friends' boats

Erik

 

[krisnowicki]

Re: Starter motor test wiring?

what is the brass item in the background of this pic?

 

[Haut Medoc]

Re: Starter motor test wiring?

what is the brass item in the background of this pic?

The shiny one is a core plug, the one to the right, block drain......

 

[erikgreen]

Re: Starter motor test wiring?

Yep, brand new core plug.

Turned out the block was internally cracked, anyway....

Erik