What could cause my engine to seize?

[sapote]

So I have a single mass flywheel. I'm not entirely sure why it still has some wiggle to it. This is for sure friction welded on though.

So your clutch has a few springs? I wonder if the friction disk and the center splined core are solid under nominal torque or there is some plays between them. This is the only way to have 1 -2mm plays on the crank if the clutch core is welded.

[sapote]

Day 2: Started with a plug out crank, same as day 1 everything seemed good. Went to put the engine under compression w/ plugs in and starter click. Nothing else to it. Stumped I decided to pull the starter thinking this may have gotten wedged in the flywheel and caused a jam, this was not the case. After I tried to hand crank the engine to find it completely seized.

If the welded clutch is true, then it can't happen on Day2 as the engine never crank on this day. But your wording sounds like you did hand crank it with plugs were out.
Are you sure you did hand crank on day 2?

On Day1: the engine fired up the first time then it shut down by itself or you did? In hind sight, if you had let the engine continue to run longer then now you don't have to cut the holes to deal with the welded clutch, as the running engine will not let the melt metal of clutch/guide tube to stop it, and eventually there is a gap between the twos.

[Darbshaw]

If the welded clutch is true, then it can't happen on Day2 as the engine never crank on this day. But your wording sounds like you did hand crank it with plugs were out.
Are you sure you did hand crank on day 2?

On Day1: the engine fired up the first time then it shut down by itself or you did? In hind sight, if you had let the engine continue to run longer then now you don't have to cut the holes to deal with the welded clutch, as the running engine will not let the melt metal of clutch/guide tube to stop it, and eventually there is a gap between the twos.

Day 2 is likely what caused the permanent weld. This was my mistake when typing it up.
Day 2's crank with plugs out was under starter power. I ran the starter for a few seconds which probably welded and cooled. While this was cooling I went and put the plugs in and cranked under power to no success. I immediately suspected it was a power/ground issue.

Day 1 shut itself off. I forgot to clear the DME of codes and reset it after the last engine. Maybe this caused a premature shutoff.

Hindsight, maybe if I just ran the engine on the start of day 2 then it would have formed its own gap like you mentioned.


The hole in the bell housing really annoys me but at this point I'll just have to deal with it. Bright side is I cut a clean square, should be an easy patch if I can get away with just this hole

[sapote]

Wonder why Day1 it didn't weld itself with engine actually running?

[bigjae46]

If you save the square that you cut out then you can just get it welded up. Shouldn’t affect strength too much. In fact, the weld is going to be stronger than the cast aluminum. The key will be to get the weld area really clean so that the heat affected zone is minimized which is what weakens the weld area.

I don’t understand how this happens? Clutch disc backwards? With me ZF320 and OEM pressure plate, I have to install an E34 M5 clutch disc backwards so the spring pack clears

[332]

This is what prompted me to ask you if it was a smg or manual, I have the same transmission setup on my car. ZF 5 speed, 10lb JB racing flywheel, fx400 4 puck.. proper fucked you are.

[jayjaya29]

If you save the square that you cut out then you can just get it welded up. Shouldn’t affect strength too much. In fact, the weld is going to be stronger than the cast aluminum. The key will be to get the weld area really clean so that the heat affected zone is minimized which is what weakens the weld area.

I don’t understand how this happens? Clutch disc backwards? With me ZF320 and OEM pressure plate, I have to install an E34 M5 clutch disc backwards so the spring pack clears

OP didn't install the clutch disc backwards from the way its marked.

Also, Sapote, you lost the bet. 😘

I welded the 2 squares I cut out of my bellhousing back on and the trans has seen much more abuse without any negative effects.

[bigjae46]

OP didn't install the clutch disc backwards from the way its marked.

Also, Sapote, you lost the bet. 😘

I welded the 2 squares I cut out of my bellhousing back on and the trans has seen much more abuse without any negative effects.

So what causes this?

[jayjaya29]

So what causes this?

The clutch is not symmetrical. The splined tube does not have equal stick out relative to the clutch friction surface. If you install it as marked on the clutch then the clutch friction welds itself to the clutch fork guide tube.

[sapote]

The clutch is not symmetrical. The splined tube does not have equal stick out relative to the clutch friction surface. If you install it as marked on the clutch then the clutch friction welds itself to the clutch fork guide tube.

Then it’s the wrong clutch for the box.

Why people used it?

[jayjaya29]

Then it’s the wrong clutch for the box.

Why people used it?

This is aftermarket parts. Single mass flywheel, so you need a sprung clutch.

[Darbshaw]

Out of curiosity and saving a couple bucks. Is it possible to reuse the TOB tube and clean it up a bit? Or to prevent a future mistake just cut it a hair shorter? Or would this cause more issues since the TOB needs this length?

I welded the 2 squares I cut out of my bellhousing back on and the trans has seen much more abuse without any negative effects.

If you save the square that you cut out then you can just get it welded up. Shouldn’t affect strength too much. In fact, the weld is going to be stronger than the cast aluminum. The key will be to get the weld area really clean so that the heat affected zone is minimized which is what weakens the weld area.

Great to know. It's more the extra work that goes into it now. I also have a TIG welder, but no experience with it and no gas. It's a purchase that I need to make, but I've been avoiding it. Let alone learning to weld aluminum.

Out of curiosity Jay, did you TIG weld yours together? I'm curious if I can get away with my flux core welder for this. I'm sure the answer is no.


Thanks again for all of the help, I would have been extremely stuck and puzzled when I tried to drop the trans without your pointers.


Edit: Looking at this in hindsight, there was a obvious clue that something was not right. The trans was slightly pushed out/not sitting flush when I bolted it up. Once I loosended the trans again, it pushed itself out immediately.

[jayjaya29]

To remove the clutch from the guide tube, I had to destroy the guide tube. You will need a new one.

I had a buddy tig weld the squares back in but its not pretty. Cast aluminum is extremely difficult to weld because its hard to get it super clean. To weld aluminum mig you will need a spool gun, solid core aluminum wire, the correct gas, etc etc

To be honest, epoxying in the cutouts would probably be my recommendation.

[bigjae46]

This is aftermarket parts. Single mass flywheel, so you need a sprung clutch.

Pretend I'm an idiot and that I still have no idea what you're talking about...🤣🤣🤣

Does this involve aftermarket parts?

[bigjae46]

Great to know. It's more the extra work that goes into it now. I also have a TIG welder, but no experience with it and no gas. It's a purchase that I need to make, but I've been avoiding it. Let alone learning to weld aluminum.

Out of curiosity Jay, did you TIG weld yours together? I'm curious if I can get away with my flux core welder for this. I'm sure the answer is no.

You need a spool gun but it probably won't work too well. Really need TIG on AC with Argon. The challenge will be getting the cast aluminum clean. The aluminum is somewhat porous so you have clutch material and oil in there. You can use a MAP torch to burn it all off, not sure what it does to the metal. Could strengthen it, weaken it or make it brittle...no idea.

I repaired an oil pan which...its repaired and doesn't leak but it ain't got no dimes to stack. I'll leave it there. This job is probably worth paying someone to TIG.