Starter Cranks Slowly?

[Fourward]

I'm gonna ask this in advance. I have my engine on a hoist, almost ready to go in. I hooked the starter up to a new battery. It seems to crank slowly, I hope its enough to start the engine. Now would be the time to get it going faster with the engine out. Instead of da da da da daaa it goes rrruh...ruhhhh,...rrruuhh. I know Studebakers catch quickly, with hardly any starter cranking, but, what do you think?

[brad]

Make sure it is an R series starter. They have four field coils for higher torque. 

[Fourward]

Brad, How do you tell if it is an R series?

[Fourward]

Oh, maybe on the tag the last figures are 10 S. Starts with an M.

[cursed avanti]

Had the same problem with starter on my '64. Had it rebuilt, spins over nice and quick  now!

CA

[regnalbob]

Avanti and Jet-Thrust engines used two different starters.

Early models used a 3-pole starter, model number MDU.

Starting around May, 1963 a 4-pole starter, model number MDY was used.

[Fourward]

It is an MDU.

[Mark L]

I recently had the MDU-7026 starter on my 62 Lark rebuilt for the same reason.  I removed the end plate to see the brushes, and several were so worn that the brush springs were bottomed out against the brush holder and were no longer pushing the brushes tight against the commutator.

After rebuilding the starter, replacing all the battery and starter cables, and replacing the start solenoid, it turns over super fast now.  It's almost like the spark plugs are missing and there's no compression.  Night and day difference.

Edited June 5, 2023 by Mark L

[Nelson]

Just a thought but did you overhaul the engine while it was out? If so, are you sure it’s together right and spins freely with a torque wrench with plugs out? Probably not the case but it’s always best to check now before you reinstall.

[Fourward]

Nelson, yes, took the engine down to the pistons, honed the cylinders. The engine seemed good, the guy I had helping me remarked that the car probably had 33K on it, not 133K based on the condition of the engine. Put it together, it spun freely at all times when we checked it.

[Fourward]

Based on what I am reading I think a rebuild is my next move.

[Nelson]

Just to make sure all is ok, it might be a good idea to pull the plugs and see if the starter spins it over faster. 

[Dwight FitzSimons]

I once had an R2 engine rebuilt by a diesel mechanics technical school (under the supervision of the instructor, who is a Studebaker fan), and, when assembled, the engine was locked up.  Turned out that there was one incorrect-size rod bearing in the new set of bearings.  So, one never knows.

--Dwight

[Fourward]

How about disconnecting the starter and cranking it?

[64studeavanti]

I assume you cleaned and painted engine, starter, etc. How about scraping off some of the paint where the starter mounts to the engine. Ensure that you are grounding to a clean, bare area and that the cables you are using are of the correct guage. Inexpensive jumper cables may not be able to handle the load, and paint is not a good conductor. 

One more thing to check,  is the valve lash on spec? If valves are not opening correctly, that could be an issue.

 

[Fourward]

I also thought it was paint, and, sanded the areas off. Still slow. I had help setting all the valves. I think I have my heavy jumper on there, but will attach the wires from the car. All good ideas.

[Fourward]

Yeah! Success! 64 Stude, I cleaned all the paint off where I was connecting the cables, used the new cables that are going on the car, it cranked nice and fast. Yeah, cheap jumper cables, and those were my GOOD jumper cables. THANKS!!