'91 6BT snapped camshaft
 

My first post on this site......the killer dowel pin did some major damage!!

The dowel pin cam out (while hunting in the middle of the Nevada desert mountains last weekend), went between the cam and injection pump gears and snapped the camshaft right behind the cam gear. (Yes, I came to an abrupt stop coming down a steep hill ideling in first gear.) I've pulled the timing cover, pulled the cam and am considering what to do next. Thanks to BC847 for this excellent write-up on tearing everything down: https://www.dieselbombers.com/1st-ge...s-n-stuff.html

There's two bent pushrods and one broken tappet. On the tappet, the pushrod bent and broke the side of the tappet off. I assume it's in the oil pan. I know I'll have to replace that one and am considering using the "string & hanger" tool to pull them all for inspection.

I don't really want to pull the head unless I absolutely have to. The valves all appear to be fully seated since they are at the same height and I can push them down with the wooden handle end of a big hammer without resistance.

So...my questions:

Is there a simple way to test compression without the cam in?

Will the valves bend if the pushrods absorbed the impact? Has anyone NOT have the valves bend in similar circumstances?

I've visually inspected the rocker arms and they appear to be o.k., but can they be bent?

I'm thinking about purchasing and installing a camshaft, removing the injectors and turning the engine over to see what it sounds like. Good idea or bad?

The injection pump gear is fine and I don't think the IP shaft was bent but I'm not 100% sure. When I place a straight edge on the face of the timing gear housing it's the same distance between the edge of the gear and the straight edge. Any suggestions on further testing? The IP shaft is a little loose. I can move the IP gear about 1/16" by holding opposite sides of the gear and pushing/pulling it back and forth.

Is there a member or sponsor here who would rebuild the pump to stock specs for a fair price?

This is a stock engine with 170,000 miles on it that was well maintained by the prior owner (original owner) and it started every time with just a bump on the starter. It WAS in great condition.

The engine ID plate is missing from the timing gear housing so I can't provide specific info on the engine. It either fell off, was broken off or intentionally taken off.

I've got a lot of experience working on my diesel VW's, Volvo and Mercedes so nothing scares me when it comes to testing or doing the work on this non-computerized engine.

I know this is a long post and I can add pictures in a few days if they will help clarify the above.

man that sucks.. a leakdown test would be ideal.. could buy a leak down tester from summit and make a adapter with a injector nut.. I have spare I could sent ya. im in folsom about a hour 15 min from you. I could mail one if you like. I even have a used tappet but don't think that would be a good idea. as far as the pump those are easy. let me know if you need help I will be in reno next weekend.. sounds like you will will need atleast the gasket set and front bushing. also buy the upgraded cam springs there only like 30 bucks.. I have a bucket of used parts.if you want I could do the pump or show you how, trust me there easy as hell..:c:

Thanks for the reply and suggestions. I do need a spare injector, injector nut, etc. to make a leak-down tester. I'll PM you for details about that, your bucket of parts and your trip to Reno.

About the injection pump, I'm tempted to put a new cam in (I think I found one but it probably won't be here until next week) and spin the engine with the timing cover plate off and see what it looks like. I have disassembled a bad VE pump from my VW but never did put it back together so I'm somewhat familiar with the process.

I would be curious to see what bc847 has to say.. kinda curious myself if he thinks a valve got bent... I have never been in your spot on the cam deal breaking from the kdp.. im kind of kicking myself when I rebuilt my engine to see how the clearances would be if it did happen... did you go with a stock cam?? I myself went with a Hamilton cam..24 valve tappets..$$$ tho:c:

I'll send a PM to bc847 to see what he can add to this.

I purchased a good used stock cam (pn 3914639) and it's on the way from an eBay guy in Arkansas. I'm not much of a "monster power" mechanic, I just like my equipment to run strong and get good mileage, and I'm definitely on a tight budget.

honestly the Hamilton cam was not worth the money.. you get more from pump mods and fuel pin, timing advance.:c:

I've had my 6BT for 3 years but have only had to do regular maintenance on it so I'm new to determining what rebuild parts are available and/or correct. There's so much data on these forums it takes a while to decipher what's what. I hadn't even heard of "Hamilton" cams :humm:

Ask me a question about the 1980's era VW's and I know what to do or where to look. I'll catch on to this site soon!!!

As I understand things, the valves are pretty-much straight up relative to the piston, so there shouldn't be direct damage associated with the piston kissing an angled valve. That doesn't mean it didn't bend the valve(s) though. I've read where folks believe the push-rod is the weaker link in the valve-train and with that, we'd like to think the push-rod bent before the valve(s) were/are damaged.

That being said, your initial assessment of the valves by way of comparing the closed valve's stems being equal to one another seems sound.

I suppose I'd install a new cam with new lifters (it's NOT that difficult to do as per that shown in my cam swap thread).

EDIT: I see you've already got a used cam on the way. IMO, it'll be a toss-up as to whether it mates well with your original lifters (or new lifters for that matter).

Personally, I'd be reluctant at best, to NOT pull the head and do a full check out.

How lucky do you feel? :pca1:



- I'm rather well versed in the mid '60s beetles myself. My first car was a '65 40HP Beetle convertible, originally sold in Canada. Had the Karman logo on the driver's front quarter-panel section. Complete with an OEM auxiliary Gasoline-fired heater over the passenger's knees.

I wish I still had that thing.

bc. so if he got the matched lifters with the cam he would be okay.. correct?? even tho its in a different block? myself I always buy new or if I do go used I keep them matched. maybe iv just been luck!!! as for doing the lifters without pulling the pan my hats off to you.. I would never have the patients..

Camshaft details
 

Thanks for the input David. I am getting the lifters with the camshaft. I don't know if they're numbered but I'll see when they arrive early next week. I hadn't even thought about tappets matching the cam, I figured it was more important the tappets matched the block, so like novapat I figured it would just work.

Two years ago I put a used piston into my 85 TD Jetta and had to hand file the cutout for the piston oil squirter into the skirt of the piston. I had friends tell me it would never work and I've now got over 50,000 miles on it and I'm getting over 40mpg. The head is basically worn out and the bores were out of spec but with new rings it's running pretty good. I have a good spare engine ready to put in but it's hard to not keep running the one in there.

I don't mind pushing things a bit if I think it will work.

I'll figure out a way to do a leakdown test before I pull the head for inspection. I may just put the cam in and do the test then. The two bent pushrods were in cylinders 4 and 6. The worst one, with the broken tappet, was in #6.

That sounds like a desirable beetle, one with a working heater! And 40 HP!!!!

I would think so.

Me being me, I'd take it to the point of ensuring the lifters were paired with their original mating cam lobe, . . . . . . . but I'm funny that way.

yes a agree I don't like to change the wear pattern either... btw I asked you a long time ago about a knock that came and then went away and I found later that one of those good ddp injectors were poping at 1200lbs and burt my piston. I wish I was smart enough to post pics it was bad... I will never run ddp injectors again!!!:c:

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I found a old injector today with a nut if you need it sent to you.. just weld a quick disconnect and put air in the cyl.. if you need it let me know I will mail it before I leave town.. also not sure if you have a welder to weld it?? I can do it if not.:c:

Thanks novapat, I'll definitely take the old injector, I'll PM you with my address, and I do have a welder. That's a good idea to weld a quick disconnect on it!

Its on my counter for the mailman to pick up tommaro.. not sure if it will make it to reno Saturday. if not Monday. I sent 2 inj. nuts and one injector. I think I would gut the injector and just weld a quick disconnect so you could just bolt the injector in and hook air to it..:c: off to go camping.. back sunday night!! going to be a lot of quad riding and :c: going on!!:jump:

That's my plan for the injector, we thinking alike here. Thanks for sending it. My cam doesn't arrive until next week so I've got time this weekend to get everything ready. Enjoy your off-road time.

Crank timing gear turned on crankshaft
 

More damage found!!!

While prepping everything for the arrival of my cam I noticed the main crankshaft timing gear sheared off the pin/key that aligns the timing gear to the crank.

Is there a way to pull the timing gear with the crank in the block, and of course the engine in the vehicle? There's about a 1/8 to 3/16" space between the face of the block and the timing gear. Am I going to have to fab another tool to get this off?

Should I just leave it in position and re-time the engine with the crank gear in its "new" position?

I really don't want to pull this engine. I'm a backyard mechanic, literally! My Dodge doesn't fit in my garage.

New engine found
 

So.........................I'm going to pull the engine and work on it when I can. I'll either fab a tool to pull the crankshaft timing gear or remove the crank and have a shop pull the gear.

I found a GOOD 1991 6BT with 240,000 miles and no oil leaks. The FIRST thing I'm going to do is remove the timing cover, tighten all the case bolts and put a tab over the killer dowel pin.

The replacement engine doesn't have an intercooler so do I need to change the injectors (swap them from the old engine) to match the intercooler?

intercooled and non intercooled injectors are different. the non intercooled heads are known for cracking. intercooled are 7mm and non 9mm.:c:

Oh man! I'm still learning about these engines.

So maybe I'll just put the non-intercooled engine in and run it as is. I plan on getting the engine this weekend but I have to pull it from the truck it's in and persuade the guy I'm buying it from to haul it back to my house.

And thanks novapat for the injector, it arrived today. I will still use it when I start working on the KDP killed engine.

Photo's of KDP damage
 

So here's what I've found so far!!!! I'm going to pull this engine over the next few weeks and replace it with a non-intercooler engine I found for $1,500. Once this one is pulled I'll get further into it and see what else needs to be done. I'm also going to start a new thread on how to pull the crank gear without removing the crank.

Here's the crankshaft timing gear that's spun on the crankshaft and sheared the crank gear location pin.

Attachment 34665

The broken tappet caused by the bent pushrod.
Attachment 34666

The two bent pushrods from cylinder's 4 and 6.
Attachment 34667

The KDP with a nice bite taken out of it and the camshaft gear. There was no damage to the cam gear.
Attachment 34668

The KDP and the snapped camshaft.
Attachment 34669

wow man..that sucks. honestly I would check the valves for leakage with the injector and fix what you have... that gear should pull off! I would put the 1500 in the engine you have.jmo:c:

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spin that gear back to the pin and pull it off.

I just don't know how to get the gear off or how to spin it back to its original position. Look at my new thread where I'm looking for an answer to that question.

I will definitely test the #4 and #6 cylinders (I'll check them all.) for valve sealing before I do anything.

I'm going to install the "new" engine because I need the truck. I'll work on the KDP killed engine and put it back in if I'm not happy with the non-intercooled engine.

I like to have a spare engine. I have a spare for my 1.6TD VW and my '57 180D. I just work on them when I have the time and money.