Grinding from starter/flywheel

[blueghost510]

Wayno,
It's a 720, and no doubt about being parked for a reason. The price was right though and was up for a challenge. It's an L-20 with an automatic. The upper half of the dust plate is there, the lower is missing.

[jayden71]

I had a 720 with L20...Loved it!!

[datsunmike]

Wayno,
It's a 720, and no doubt about being parked for a reason. The price was right though and was up for a challenge. It's an L-20 with an automatic. The upper half of the dust plate is there, the lower is missing.

If the plate was off the auto may have been replaced or worked on. Additionally, mice may have started a nest up in there by there torque converter. May be full of nuts.

Good info in this thread.....the first few posts anyways

Speaking of nuts.... I'm wearing shorts too.

[wayno]

Wayno,
It's a 720, and no doubt about being parked for a reason. The price was right though and was up for a challenge. It's an L-20 with an automatic. The upper half of the dust plate is there, the lower is missing.

I first thought this was a standard transmission, so that is why I was asking about the model, as the L16 engines had a separate lower dust cover, but as dmike mentioned, the autos had an upper and separate lower plate on the L20b for access purposes.
Are the torque converter bolts tight?
Are the transmission mount bolts tight?
Is the noise constant while running, or is it getting quieter as engine run time goes by?

I don't really know anything about automatics other than basics.

[datsunmike]

Wayno,
Are the torque converter bolts tight?
Are the transmission mount bolts tight?

Good points wayno.

The automatics also have a small plate covering over the end of the crankshaft that the flex plate sandwiches. It's purpose is to line the torque converter up. It's not aligned just by the converter bolts. It's a bit early to suspect it missing just yet.

[blueghost510]

The noise is ONLY when trying to start the truck. Once it's started the noise is gone. It's 100% related to the starter/flywheel. Had a friend start it today while I was looking under the hood and it's coming from the starter area. I'll post some video tomorrow so you guys can hear the noise..... I remain baffled.

[510freak]

A bit of a shot int the dark here.

Are there any broken teeth on the ring gear?

[flatcat19]

If it happens every time, probably not flex plate/flywheel.
Replace your starter.

Have a good day.

[wayno]

I would then check to see if the flywheel is loose or damaged in some way.
Also make sure the transmission is mounted solid, the lower plate/dust cover is missing for a reason.

[blueghost510]

I pulled the starter and put another one I had laying around in. Grid isn't as bad, but still no good.

Noticed that some of the teeth on the flywheel are getting shaved. The upper portion of the dust cover is still there and sandwiched by the bell housing and starter.

[flatcat19]

Is this the truck you listed on Ratsun for sale?

[510freak]

Must be it, Its a auto 720(see page 1)

Might be that the spacer is missing between the crank and flexplate?

[wayno]

Must be it, Its a auto 720(see page 1)

Might be that the spacer is missing between the crank and flexplate?

There's a spacer between the flywheel and crank?, that would likely make it sound funny if it was missing.
If one had the correct mirror, when the starter is out, could you use a mirror and light to look in there and see if the spacer is missing?
How thick is this spacer?

[flatcat19]

Not very thick.
Less than 3/16"

[datsunmike]

Wasn't the bottom cover plate off? Just look up in there. It would go together without the spacer and the flex plate would be that much closer to the starter. The starter would engage slightly deeper. (not sure if this would matter much really) Besides all this the torque converter being off center.

[510freak]

the spacer missing,might explain the grinding(dragging?)

[izzo]

I had a similar issue. My flex plate was hitting the starter. Turns out the bottom two bolts in the bell house were missing. So the motor and trans were mated like this /\ instead of |. See what I mean? Crawl under there and take a peak. You shouldn't have to shim it. If that's not the case, then well.... The ring gear can look OK but doesn't mean it is. Flex plate could be bent or busted like mentioned above. the ring gear is also spot welded to the flex plate. meaning the welds could have busted, another thing is loose crank bolts. That would cause some shit, too!! It's happened!! Check to see the trans is mated properly. If so, then you have other problems. You can try and jimmy the flex plate back and forth to see if something is loose, even if it doesn't seem like it is, something could be.

Wish you luck on this man. Almost sounds like something may need to be removed to check for.

And believe me, what you just described in your last post is exactly what was happening with my datsun

Ill see if i can find the pictures.

see my starter and ring gear? that's cuz it didn't have the bottom two bell housing bolts just the top two, creating it to not be flush. The top picture shows how the bell housing was not lined up because of missing bolts. the starter was getting eaten by the ring gear, and the ring gear was eating the starter housing and whatever else inside the inside there.

[blueghost510]

Thanks for the post on this one. I've kind of hit a wall on this truck. If it were a 510/620 or something else..... I would dig deeper. I posted the car since the motor is good.... Half temped to crack deeper into it for knowledge, but 3 datsun projects and a one car garage might be pushing it. HA.

[flatcat19]

Thanks for the post on this one. I've kind of hit a wall on this truck. If it were a 510/620 or something else..... I would dig deeper. I posted the car since the motor is good.... Half temped to crack deeper into it for knowledge, but 3 datsun projects and a one car garage might be pushing it. HA.

You don't even need to remove the tranny to figure this one out.
You do have to unbolt it and the torque converter though.

Tranny unbolted, push it as far back as possible. Remove flexplate. Inspect for missing ring.

I can't imagine this taking longer than a couple of hours.

[datsunmike]

You can inspect the starter ring through the starter hole. Turn the motor by hand to see if the flex plate turns straight. If the starter is chewed it or at least the small drive pinion gear will need replacing.