WHY IS MY 13B A SLOW TURNER?

[bldn10]

Ever since I got this ex-SpeedSource car it has been somewhat difficult to crank. I hear other cars crank right up like a street car but this one doesn't. Now I can't get it to start.

I have changed the starter, charged the battery, and have it on a battery booster pushing 22+ volts but it turns over very slowly. (I'll worry about firing later but I'd like to get this issue behind me.) Probably 120 rpm. Often it will get slower and slower. It is not battery posts because I get >12 volts in the wire inside the cables. Can the engine itself or flywheel do this? Makes no difference if in neutral w/ clutch in or out.

[dickita15]

well rule one with electrical problem (and this may or may not be electrical) is check for bad ground. run a jumper cable from the engine block to the negative battery post.

[seckerich]

Bill it sounds like you have a current problem to the starting circuit. Check the size of wire used to run the loop to the kill switch, the kill switch itself, and the ground as mentioned in the previous post. Don't overlook the cable ends to the battery as well. With a new starter it should really spin fast. Might want to pull the plugs with the fuel pump unplugged and see if it spins faster. Bad timing will cause it to spin slow and the no plug check will help eliminate this.

[bldn10]

The block is already grounded in 2 places but I made a good one w/ a jumper cable and that is not it.

I decided to check the wires to the starter by applying current directly to the + starter lug. When I do that on the bench w/ the old starter, it spins like crazy. I am not applying current to the solenoid so, correct me if I'm wrong, the starter should not engage the flywheel, the engine should not turn over, and the starter should spin as it does on the bench. Right? Noooooo. The engine does indeed turn. So the starter is apparenty at all times engaged w/ the flywheel and is being turned when the engine is running. Right? No wonder it gets so hot! The solenoid is working properly so do these starters need to be shimmed so that the starter teeth clear the flywheel? FWIW I can see where the teeth have been in contact w/ the flywheel and it is a good 1/4". Is there a spec on this?

[Eagle7]

Bill, I believe the solenoid is simply a high-current relay that connects the battery cable to the motor. When the motor turns it also extends the gear to engage the flywheel. Steve's post suggested that you check for a voltage drop between the battery and the battery post on the starter. Your cutoff switch is in this circuit and it or the wires to/from it could be the problem.

Put a voltmeter on the battery and measure while cranking. Then put the meter from the motor terminal to the starter case and measure while cranking. If it's significantly lower, you've got a problem in either the supply circuitry or the ground. Progressively move the meter leads out further away from the starter to determine where the problem is.

[bldn10]

Marty, it is my understanding of starters that the solenoid is what allows the gear to jump out and engage the flywheel. Indeed, on the bench you can see and hear the gear jump out by applying current to the solenoid terminal. If you just apply current to the + lug the solenoid is not activated and the gear does not jump out, but the motor spins. I called myself testing the voltage theory by connecting a hot jumper cable directly to the starter - no cable, no kill switch, no nothing in between - so doesn't that eliminate that as a problem? The question at the moment is about the engagement between starter and flywheel; I don't think it is supposed to be unless you are cranking it.

[ITS51RX7]

Bill,
There is not any engagement of the fly-wheel and the starter unless you apply 12 volts to the solenoid.

Do you have a lead ( 6 awg min ) from the neg side of the battery directly tied to the engine ?

I had a starter that was also turning over very slow, I changed the starter then I could not crank it at all.
Turns out that I had one bad starter motor and one bad starter solenoid.

Do you know if you have a know good starter.

[bldn10]

Michael, both starters spin fine out of the car. I just got under there and looked through the hole in the bottom of the bellhousing and I could see that the starter pinion gear is indeed meshed w/ the flywheel. By a good bit too. I'll have to shim it w/ thick washers. Has anyone ever had to shim their starter? If not, what's the deal here - can the flywheel be protruding too much?

As to the ground, I don't have one from the battery to the block except for the OEM one that goes on that long bolt that goes through the block and through the upper starter "ear." However, I did try that directly w/ a jumper cable and it made no difference so I think I'm adequately grounded.

[ITS51RX7]

Bill,
As you stated that both starters spin fine off of the car, But there is zero load on them at that time.

The only time the starter gear should come in contact with the fly-wheel is when the solenoid is engaged, as for shiming with thick washers this should not be required.

If the starter gear is in constant contact with the fly-wheel you have a problem with that starter, sounds as if the gear does not retract after the solenoid is de-energized.

[lateapex911]

Right...that could be, i suppose, an improper flywheel, or a solenoid that is sticky on the return, or has a broken return spring. On the bench, I think the gear should pop out when the solenoid is engaged and the thing should spin like crazy. If it's already out, then the solenoids the issue and it isn't returning.

Try looking at your spare to see the range of travel t the starter gear should be traveling through, and compare to the version in the car.

I've never seen or heard of a case where there was shimming needed.

[bldn10]

Guys, I'm, tellin' you that both starters appear to be OK. I checked out the "new" one before I installed it and checked the "old" one when I took it out. On both the pinion does not jump out unless and until the solenoid is energized. I suppose it is possible that neither have enough torque to spin the crank but right now I want to resolve this gear engagement issue.

[lateapex911]

OK, so, both starters pop the gear when the solenoid is energixed. Measure the distance in in and out conditions from the mounting flange to the gear, and compare it to the car. IF the flywheel to mounting flange dim matches the "IN" poistion, you know that you've got the wrong alignment or flywheel (wrong year??? (I have seen that on 12As).

If the distance matches the "OUT" position, then theres an issue with the solenoid hanging up and not disengaging. NAPA might have a cheap swap?

[dickita15]

It would be bizarre if the starters were staying engaged. Shimming is a bad option. My hunch is you are going down the wrong road. Has the motor run. If not can you push start the car and get that out of the way. do you have another car available to try one of the starters. Street, race, whatever. If you drive a hour to test the starters you will save time in the long run. You need to eliminate variables.

[AntonioGG]

Bill are they rebuilt starters? New? Used?

I ask because on my Miata I had a similar problem. I rebuilt my starter and I put the yoke from the solenoid to the gear backwards and it actually left the starter engaged all the time.

As far as spinning the starter on the bench, that is not a good test since you don't have a load on it.

[bldn10]

HISTORY: I bought this car for the 2004 season. From the outset it turned slowly. From time to time it has been better and worse. In 4/05 I actually had the reverse problem - the pinion did not extend far enough! Bought a rebuilt starter at AutoZone and installed it but it did same thing. I widened the mounting hole a bit and it then worked. (Not using same tranny now.) The other day I replaced the AutoZone starter w/ one from my '89 parts car. So, 1 starter is a year and a half old and the other very old but w/ around 75,000 miles on it.

I'll pull the starter and take the measurements.

[Daryl DeArman]

How easy is it to turn the motor over by hand?

It is not like a piston motor, it should be MUCH easier to turn over by hand for comparisons' sake.

Did it turn over faster without the plugs firing?

[bldn10]

The motor turns normally by hand and it made no difference w/ the coils unplugged.

OK, forget the shim thing - the starter pinion is not in contact w/ the flywheel when I first insert it. However, after engaging the flywheel it will not let go. Either there is too much contact/friction between the 2 or perhaps the flywheel just needs to be spinning faster for the pinion to release. I'd like to think the latter.

So, back to the initial issue - why is it turning so slowly? If I leave the start button on for several seconds it will literally grind almost to a halt. And I am on a booster.

[dickita15]

did you try the voltmeter at the battery and then again at the starter terminal while cranking

[bldn10]

"I called myself testing the voltage theory by connecting a hot jumper cable directly to the starter - no cable, no kill switch, no nothing in between - so doesn't that eliminate that as a problem?"

[dickita15]

Sorry you are right I had forgotten you said that. Doing this should eliminate a voltage drop problem. The only long shot is that if at the battery end you clamped the jumper to the terminal end you could have a problem between the terminal end and the battery post. Like I said that is a long shot, but you have ruled out the easy stuff.

I really think you need to either borrow a third starter or put one of your two in another car. There must be a race car or street car somewhere near you or another racer who will let you test using his spare starter.