High Performance Starters

[Ron Earp]

What are your water temp readings when you attempt to start?
Bill

Here is the way it has behaved since March of 2005 when we started racing the car:

175F or less, starts with starter 100%

175F - 195F - Luck of the draw, cranks fine, it might start, it might not

195F or higher, definitely will not start without a gentle push start

I'll move this into the race section since it doesn't have a heck of a lot to do with GT40s.

 

[Jac Mac]

Why not borrow the reduction starter off the other racer & see if that fix's it, at least that way you would eliminate the other possibilities. Have you checked out some of the Nissan Diesel starters for compatibility.

Jac Mac

 

[Ron Earp]

Have you checked out some of the Nissan Diesel starters for compatibility.
Jac Mac

Hot dang - that is a fantastic idea Jac Mac! I've got a good Nissan parts man and ex-racer that I can call about that.

 

[Alex Hirsbrunner]

Hi Ron,

From a debugging standpoint, after a no start, have you ever tried pushing the car up to speed and:

1. trying to use the starter while it is rolling?
2. trying to use the starter after it stops rolling?

This would at least rule out any kind of mechanical issue that happens with the car sitting while hot. Stuck floats, bad trace on the MSD pcb ...

Best Regards,

Al

 

[Randy V]

Diesel starters are definitely high torque starters - but they also typically draw a lot more current..

 

[Sandy]

Hey Ron -

Very interesting thread Ron. I hate to suggest this, but have you hit the cabs with, gulp, some ether (Quickstart) to rule out fuel system issues. I think Jac Mac mentioned the choke but not sure I caught the outcome.

One other issue is what do the plugs look like after you shut it down? Wet anything like that?

Sandy

 

[Jac Mac]

I have re-read the whole thread. You say that the cranking speed is not affected by the heat- Do you still run coolant for heater etc thru the manifold, if so stop it/block it, same goes for egr or hot spot from exhaust, sometimes with ether or quickstart it will evaporate in the manifold before it gets to the chamber if simply applied prior to cranking in a situation like this. Simple check for your ignition is to hook your inductive timing light up to the Coil HT lead when hot, tape the trigger down & crank it over, if you have spark then its got to be fuel. Make sure that the MSD has not eaten the towers out of the cap after this time, could be that the gap is to big at cranking speed, same goes for rotor button as well.

 

[Russ Noble]

The fact that it starts easily with a bump start indicates to me that either the starter is not turning it fast enough or, despite all your tests, insufficient spark is getting to the plugs when the starter is operated. Since you say it's a mission to fit a gear reduction starter, I would tend to temporarily wire the ignition only, to a completely separate battery to eliminate the voltage drain scenario.

Also, what happens when you throw a bucket of cold water over the starter motor? Play a hose on it for a minute or so might be a better bet! Since temperature is an issue. You have done that, right?

 

[Ron Earp]

Well now naturally with a thread title as it is I had in mind what I wanted to try....

But I'm not married to that being the problem. I've got some time between flights here, let me see if I can answer some of these good troubleshooting tips:

Al - no, I've never tried to use the starter in those two instances. The "problem" doesn't take long to develop - it is more or less instantaneous once the car is shut off while good and hot. For instance, in a recent 1.5 hour race with 5 min pit stop the car wouldn't restart and I had to get pushed out of the pits. I will try it though this weekend if we still have the problem, which I assume we will.

Sandy - we've tried starting fluid in an attempt to get it get it fired up while hot and it didn't help. When really cold out, like 25-30F, it likes a bit of starting fluid to get fired up.

Jac Mac - we don't run coolant through the manifold, blocked all that stuff off and to the carbs too. And I added a nice heat shield earlier in the year to keep the carbs from getting heated up and to help a bit with keeping the manifold cool. IR thermo says it helps. Also put on new cap and rotor a couple of times last year as well as plugs in attempts to make sure the ignition system was good. Always had spark for this issue, big and fat from the MSD.

Russ - haven't tried the bucket of cold water! We've used jump start batteries before on the system to no avail.

I think Jac Mac is right as it must be air/fuel related in some way. Maybe my most recent change to some air filters that actually pass air will have something to do with it, but as you know you can always fit a theory to your observations as you hope for a solution.....lets see, cold car, bad filters, rich mixture, starts easily when cold out......hot car, air filters won't pass air worth a damn, too rich a mixture, no starting......

Fun thread as I wait for plane number two in DC, thanks for all the ideas too...

 

[Sandy]

Ron -

What do the plugs look like? I would think that they might show something. Not much basis for my guess, but smells like carbs. The starting fluid when hot should fire up a corpse unless something is really out of whack, like saturated plugs. It seems you have created an audience now, better then reality tv...

Sandy

 

[Doug S.]

Ron, I had a similar problem with a 351-C. It turned out to be heat soak problems with the starter--there just wasn't room for all the heat to escape in that little Mercury Comet (AKA Ford Maverick) engine compartment and the headers wrapped right around the starter, essentially baking it. Had it rewound by a racer shop and wrapped it with an asbestos (!?!?) heat "blanket" type wrap, problem went away. After that, I'm always suspicious of the starter windings when it happens only when hot.

OK, so this sounds too simple--how about some ducting aiming a cool air flow at the starter while you're running? Might be a cheap fix, might not, but a pretty easy experiment.

Doug

Doug

 

[Alex Hirsbrunner]

One observation for what it's worth - assuming the following:

Walking/Jogging/Pushing speed = 5 MPH
Tire Diam = 24"
Rear end ratio = 3.5
Second gear ratio = 1.75

Cranking speed when push starting ≈ 425 RPM

Regards,

Al

 

Moderator Man,

I am certainly NOT as knowledgeable as the gents that are trying to help you here, but have you considered MSD Retard Module for Racers?!!

My car starts like a champ until the temp gets to 180-190 then it becomes a chump! My timing is locked at 34 Degrees. The MSD retard module ($50 off e-bay) retards the ignition at start up 10-20 degrees, as soon as the RPM reaches 1000 it locks back up at 34 Degrees. It only re-activates when the car is shut off

Imam of Bling, Iron Sheik

 

[Alex Hirsbrunner]

For Infidels with more limited means that are seeking retardation, an ignition cut-out switch could be installed to provide a similar effect. All for the cost of less than a pair of disgusting McDonald's Chicken Flavored Sandwiches from the dollar menu.

 

[Sandy]

I think Ron said that it does crank fine, just won't kick off (Is that right?)

The ignition retard is built in to most of the later Digital MSD's as I recall. I run it on my mustang and it does seem to let the motor spin nice with the small battery in the car, but it does not start easy. I have not locked out my ditro like the Iron Sheik's but it helps spin up the starter easier with the high compression the motor has.

Just looked it up the MSD 6 Digital has a 20deg start retard that kicks until it hits 800 rpm then it's locked out.

Sandy

 

[Howard Jones]

Ron, Please provide the following data.

Measure the following voltage's at the positive post of the starter in reference to the ground post of the battery. Fluke pos lead to starter post and fluke ground lead to battery neg post. Sorry if I am getting too simple here.

V1 - When dead cold, I.E. no problem present and starter is turning just before the engine starts.

V2 - When hot and starter is turning but engine is not starting.

Make observations within a few seconds of turning the key both times.

What I am looking for is a difference in voltages. My guess is lower when hot but if they are the same V1 = V2, they both should be 12VDC, then in fact the electrical question is indeed answered. If they are both much lower, say 10V, then my guess is a dead cell in the battery. 6 cells at 2V's each in a 12V battery.

How about compression numbers both colds and hot? Could the distributor advance be sticking when hot? Could you have a look at these when testing the V1-V2 issue?

 

[Ron Earp]

Hey Fellows,

time is out for me and testing/troubleshooting. Test day is Friday, race is Saturday, and I've been in the Midwest all week doing business. Hanging out in the Windy City right now waiting on a flight home. Planning on towing down at 4am Friday morning for the test day, so the first "diagnostic" will occur about 910am Friday morning after I get in from a test session and the car is good and hot. I'll keep you posted!

Hope to have some in-car video of the new Carolina Motorsports Park (CMP) layout. CMP might be my favorite track as the racing is close and I like the layout. Of course, like my favorite beer, my favorite track is the one I'm on right now or going to soonest....

On the MSD6AL I don't think it has any sort of retard. And like Al suggested, my starter is separate from my ignition. Cranking it over with no ignition, then switching it on, doesn't help either.

Best,
Ron

 

[Mike Christian]

I just got bored and did some googling...seems like vapor lock with that carb is a known issue:

"The iron-block L26 is plenty durable, and it's not uncommon to see them go 200,000 miles on the original headgasket. Most issues with the engine seem to surround the carburetors. Vapor lock was common to the flat-top emissions-era Hitachi SU carbs, and the higher underhood temperatures in emissions-era cars didn't help. Cold-start crankiness, hot-start unpleasantries, and cutting out or surging on the highway were all part and parcel of the early Z driving experience, and the 260Z is no different. Car and Driver blamed the Hitachi-SU sidedraft carbs squarely for "a serious driveability problem," which didn't let up until the fuel-injected 280Z arrived in mid-1975. The obvious solution is to swap out carburetors: One popular conversion is to use a set of Weber downdrafts, or pre-emissions-type SUs. "

Can you manually control an electric fuel pump to surpress vaporization?

Mike

 

[Ron Earp]

Hey Mike,

That is very true for the stock carbs on stock motors. Most 260Zs you saw on the street tossed the flat tops and used the round tops. My motor has none of the circuits, heaters, etc. that these carbs had stock - mine are boiled down to their basics and are essentially round top carbs at this point - piston, diaphragm, jet, float, and needle - the simple carb at its finest. I have twin electric pumps with recirculation back to the fuel cell as well.

Ron

 

[Ian K]

Ron, I know you're out at the track, but when you get back ...

1) Have you swapped out your starter yet?
2) Have you checked the freeze plug inside the bell housing that,
when it fails or starts to fail, will drip coolant right onto the
starter.

I killed 2 starters before I dropped the tranny on my 260Z.

Ian