Camshaft gear broken clean off [pictures]

[malone]

One of my friends wasn't so lucky today with his newly purchased 1980 Rabbit 1.5L D:









Fortunately he also bought a 1982 Rabbit 1.6L D around the same time, so he still has transportation until this '80 is fixed. The '82 motor looks clean, approximately 130,000km old. Starts like a champ every time. I was gonna purchase that car, but he needs it now...

Here's a snip of the story leading to the breakdown:

(note: He's a previous owner of a trouble-free '80s 1.6L D Rabbit. This brown 1.5L Rabbit always ran good until the actual failure occured. The stalling is entirely due to being rusty with using the clutch. The 1.5L head has been rebuilt by previous owner right before the car was sold. We noticed some oil immediately surfacing in the coolant after it was warm, assuming it was remaining oil from the previous engine failure. We extensively flushed the coolant system twice on separate days, turning it nice neon green. Unfortunately 100km later the oil surfaced again. We decided to retorque the head soon to check. FYI There is no oil/coolant heat exchanger on this model. There was also a radiator leak so we replaced it). This may not be directly relevant to the cam gear problem, though. Back to the story:

at my exit [50km from home], i stalled the car at the top of the hill like a newbie... then tried to restart it & the starter motor got stuck on. i frantically searched around for something to pop the negative lead off & did so. (wasn't thinking/didn't think of pulling the plug to the starter solenoid - my bad) starter got good & hot...

i went and did my thing, went and ate brunch at the hotel restaraunt etc & call jose of jsperformance.ca for advice. he told me to hit the solenoid to free it etc - but i didn't need to, after i returned to the car & attached the battery lead it started right up.

decided to drive to his shop since Malone was driving my other car out there to talk to jose & figured i'd head on into town. on the way, i stalled the car (what a newb! you'd think i hadn't been driving stick for the last 5 years...:roll:) some cutie stopped by to offer a hand & see if it just needed to be jumped etc.. but no dice, starter was definitely toasted.

soooo, i pushed it into the closest driveway & walked the rest of the way to the liquor store (naturally ) & called jose's from a pay phone.

Malone drove my other car out to meet me and we push started it a couple times (stalled, again.) & were on our way back to the shop.

almost to the shop there was a road construction flag crew holding up traffic, so sitting there i hit the throttle to WOT a couple times and blasted some good ol' smog in Malone's general direction.

then I floored it & held it for a bit over a count of 1 & heard a *pop* sound & the car stalled. figured the exhaust had built up some back pressure and it was no big deal... how wrong i was.

we tried to push start it once again with no luck (using the other car, of course - as running down the street got old a couple days ago, nevermind the one time i did it today) popped the hood and saw some oil spray by the top of the timing belt - figured i blew a seal of some kind - so we decided he'd just use the other car to push this one all the way back to the shop (in neutral, of course).

off we went... popped the hood and removed the timing belt cover first, so we could pop the valve cover & keep delving in to find the problem... but there was no need to look much farther, have a looksee here [pictures shown above]

He's looking forward to swapping in a healthy 1.6TD The Rabbit will also be repainted, and interior completely restored... all of it done by us (so watch for a new Rabbit project thread by this Fall!).

Here's a quote from a vwvortexer:

Cams are SUPER fragile. Try dropping one from about 3 feet in the air.  I did it and it broke into three pieces.

On Monday I'm going to expose the 1.5L head and we'll find out if the rebuild job was done correctly, and what damages there are.

[malone]

Was there some reason for overreving it aside from being a show-off?

Nope, no other reason. This is also the only time he did it, from what I've seen anyway.

[fspGTD]

I think that must have been caused by piston-valve contact.

Maybe the timing belt was loose and it jumped a notch when the motor was revved?  I've got a broken cam lobe and a bent valve sitting on the mantle from when my timing belt broke (from the alternator belt jumping off its track, winding around the crank, and burning through the plastic timing bent cover.)  Anyway, tell your friend I said "welcome to the club." :lol:

When I mis-shifted into first instead of 3rd and drastically over-revved my engine that way (possibly hitting 8-9k RPM), the valves floated and a couple cam follower shims got spat out of their buckets, which got shattered as well as the lifters, and those cam lobes were pretty badly gauled up.  But the camshaft was still in one piece, and the timing belt was still even OK.

[vwmike]

I was sort of wondering if they had measured the piston height incorrectly (or not at all?) when they rebuilt it. Perhaps that could have caused piston/valve contact when revved like that.

[Master ACiD]

as i read the story i dont see where he said they over revved it. i just see that he pressed the accelerator to blip it a couple times going to wot, but not nessassairly full rpm. maybe he was only going wot to 3000 rpm?

[Master ACiD]

these engines take more than 1 second to reach a high rpm in neutral though.

[vwmike]

Hey, it's the only possability I can come up with besides the camshaft physically seizing due to low oil pressure.

[malone]

Yes he held down the throttle only a second or two each time. Also according to him the RPM dropped to idle level in between revs. We can't confirm that the 1.5L engine didn't overrev though (didn't sound like it did).

Maybe the timing belt was loose and it jumped a notch when the motor was revved?

I think that [cam gear breakage] must have been caused by piston-valve contact.

These may be the case since revs are quicker while in neutral and I guess the timing belt is more likely to loosen & skip at some point (no continuous load).

With the cam gear already broken off I couldn't determine if the timing belt was too loose prior to the problem.

[dieselweasel]

That Rabbit is CLEAN.  If only I lived in a place where cars don't rust out like they do here.  *sigh*

[malone]

That Rabbit is CLEAN.  If only I lived in a place where cars don't rust out like they do here.  *sigh*

German Rabbits here always have rust too, not as bad as Ontario though.

This Rabbit surprised me; there's hardly any rust on the rockers, behind rear wheels, the windshield frame and some other critical parts.

We'll check for rust on the floor boards after pulling the carpet.

I want to strip the undercoating under the strut towers and then recoat. I dislike seeing rust build through strut towers.

[malone]

BTW that brown paint was actually a rattlecan job by previous owner. It was applied over the factory crayon red (?) colour.

The flaws in the brown paint are noticable within 5 feet. Orange peel, runs, underspray, oversprays. So we still want to strip all the paint and do a respray, maybe back to the factory colour or a different one.

[dubCanuck1]

Any ideas on how to get paint off of the rubber bits? I just picked up a free parts car that had been resprayed and the rubber trim had been hit.

[malone]

Any ideas on how to get paint off of the rubber bits? I just picked up a free parts car that had been resprayed and the rubber trim had been hit.

http://forums.vwvortex.com/zerothread?id=2125112

[dubCanuck1]

Thanks meng!

[malone]

the valves floated and a couple cam follower shims got spat out of their buckets, which got shattered as well as the lifters, and those cam lobes were pretty badly gauled up.

I went to the Rabbit yesterday to pull the head. What you described is almost exactly what happened. 2 shims got spat out and one of them shattered. The lifters were shattered as well. Cam lobes are damaged. Looks like it was over-revved.

Pictures will be posted if my friend takes them. One of the four broken cam pieces is quite interesting... an entire bracket is still attached to it, broken right off the head.

then I floored it & held it for a bit over a count of 1 & heard a *pop* sound & the car stalled. figured the exhaust had built up some back pressure and it was no big deal... how wrong i was.

we tried to push start it once again with no luck

This is likely what caused the severe cam + head damage, and unfortunately piston damage. If he had replaced the battery and fixed the starter in the first place, he would have simply tried to crank the motor (still a bad idea, but...) and we would've avoided push-starting. Sitting behind him I thought he simply stalled the engine for the third or fourth time (clutch action), hence another push-start attempt :?

Realizing that the motor is actually damaged from his brief idle/revving, we left the tranny in neutral and pushed the car out.

Ah well, the 1.5L goes out and a 1.6L will go in