The continuing saga of my 6V92 that suddenly died without any codes or warning signs.
I think the camshaft is broken. I barred the engine over this morning, and the camshaft pulley (the pulley that rotates counter-clockwise) does not turn at all. When I turn the pulley, it rotates smoothly for about half a turn in both directions, then there's a hard resistance.
So, what's the next course of action? I've spent almost fourteen years, countless thousands of hours, and a significant chunk of money on converting it (even though it's not yet finished), installing all the house systems including solar, and have completely rebuilt the entire cooling system a few years ago and have rebuilt the Jakes. Apart from this mechanical snafu, it's otherwise in good condition. I could walk away from it now or have it towed to the nearest scrapper, but I don't want to spend money on something that may fail again in the future. This was going to be my retirement home, at least for a few years, but obviously I need to rethink that now.
How much do rebuilt/reman 6V92s go for? If I can, I would be happy to not have electronics in another engine, but finding good MUI engines is getting hard these days.
Any words of advice or suggestions? Life is not exactly rosy for me right now.
Thanks, John
Don't give up over a camshaft. A dirty job to repair but fairly simple if you have the tools and knowledge. An indoor place to work is a plus as well as the engine has to be removed.
I thought it was the cam or gear train on the rear, it's not a big job once you get the head off I pull the cam from the front so I don't need to pull the engine to remove the bell housing
The DDEC is the better engine of the 2 , if the engine was solid with no white smoke repair
it's not going to cost that much ,finding the DDEC cam.may take awhile
Sorry to hear this John, there is still hope yet. ;)
How do you know the camshaft is broken?
I thought you were dealing with a SRS sensor code?
Your best bet is to probably find a roving diesel mechanic who knows Detroit diesels to just come in and perform the repairs.
Not an earth shaking event especially if you can do some or all of the labor. Use the serial number and start looking for a cam now at all the usual places. In my 53 years of running 2 strokes I had one camshaft break, on an 8V71, but it can happen. Also had a cam follower break and destroy a 12V71.
John get a hold of Don Fairchild, I'm pretty sure he has contact info for the guy who inherited a little mom an pop Detroit shop in Scott City, MO. I used to buy a lot of "unobtainable" new Detroit 2 stroke parts from them back when we were running 2 strokes. The old guy that owned back then once told dad "If Detroit made it, and we don't have it, it's because my wife doesn't realize it exists!"
Don used to stop in there a lot on his trips to this part of the country and for a while the old man was trying hard to sell Don the business!
Last I remember the old man had left it to his grandson and things were up in the air as to what the grandson was going to do with it.
;D BK ;D
Even without labor,the price of parts is out of this world if you can get the parts.I am not a big fan of after market off shore parts but they are cheaper.
Do the California-certified 6V92TAC engines like mine have different camshafts than the regular 6V92TAs? What is the main difference between TAC and TA engines?
I'm seeing suspiciously cheap camshafts on eBay. I thought camshafts were $1000 or more. I have the 6V92 Parts Catalogs in the bus, so I'll look up the numbers today. If one camshaft failed, what's stopping the other one from also failing? Maybe I should also replace the other one at the same time, or at least get it Magnafluxed. The bad camshaft's seal is also leaking slightly, so I'll replace both seals as well. Anything else in there that I should also replace at the same time?
I should remove the other side's valve cover and make sure that camshaft turns when I bar over the engine. If both camshafts don't turn, I guess the problem is elsewhere. I should also check the hydraulic/PS pump that's driven off the bad camshaft, but I replaced it only a few years ago when I rebuilt my entire cooling system.
John
I know there was a bulletin on city bus engines broken camshaft issues with dn50 gear drive alt. They recommended to raise idle speed. I guess harmonics at idle was causing issues. May have been 6-92 or 71. Several years ago.
I reached out and texted Don, he thinks they are still in business. Try giving them a call.
Midwest Diesel 573-334-7707. He also said "If they don't have one have him talk to Clifford, he will know where to find one!" LOL! I told him Clifford was the one that said they'd be hard to find!
He said last time he was there they had several left hand DDEC 6V92's for buses in the warehouse! (yeah I know that won't help you, but might be of interest to some of the GM guys wanting to upgrade!)
;D BK ;D
Quote from: Busted Knuckle on October 21, 2022, 11:53:43 AM
I reached out and texted Don, he thinks they are still in business. Try giving them a call.
Midwest Diesel 573-334-7707. He also said "If they don't have one have him talk to Clifford, he will know where to find one!" LOL! I told him Clifford was the one that said they'd be hard to find!
He said last time he was there they had several left hand DDEC 6V92's for buses in the warehouse! (yeah I know that won't help you, but might be of interest to some of the GM guys wanting to upgrade!)
;D BK ;D
Thank you!
You could check with Leid Diesel in Newville, Pa.
Do they shear keys? I have no experience on this engine! Just wishful thinking for a fellow busnut....don,t forget marine industry for parts
Just curious why more owners do not stockpile or take a bet on a running salvaged motor. They are not cheap but seem a reasonable option to do an easy swap and back going in no time. Take your time sorting out the old one, maybe scrounge around for parts to rebuild for future use or sell off.
I'll second Leid Diesel, they have engines and parts a plenty. Even have 71 series Jake exhaust bridges.
You could do this to your engine just to be sure it's good to go.
Quote from: luvrbus on October 20, 2022, 01:56:52 PM
I thought it was the cam or gear train on the rear, it's not a big job once you get the head off I pull the cam from the front so I don't need to pull the engine to remove the bell housing
I spoke with the lead mechanic at the place I may use to fix it (they specialize in 2-stroke Detroits and buses, especially Crowns), and he said they'll have to pull the engine to separate the drive gear from the camshaft. How do you do remove the cam from the front without pulling the engine? He also said the idler/reversing gear may be the culprit. I took the valve cover off today and saw that the camshaft is intact along its length (both the rear and front cylinders' rockers move when I turn the pulley), so it's either broken at the drive end or the gears are broken. What would cause this to happen? Boomer says that in 53 years he's had only one camshaft failure, and it's evidently not a common failure.
Another problem is that some or all the valves on that side may have hit the pistons, so they're probably bent. I was going to check the other camshaft, but there's no point now: I'm in for some serious work one way or another. Plus, I'll have to spend a lot just to get the bus towed 55 miles to the repair place for them to give me an estimate.
Thanks, John
If that was my engine, I'd pull it out and tear it down. Camshaft not turning is going to allow valves to hit pistons. Plus maybe something got in gear train. This is not going to be a quick fix.
If it is the idler gear the engine doses have to come out,the idler gear has a bearing that goes bad.The cam will come out from the front. Yvan probably made a Utube video of it,I learn the trick many years to keep from removing the old Funk gear box with 4- 2 stage pumps mounted to it (that is the correct name Funk),machine work on the heads when a gear train goes is going to cost nowadays $2500 ea now for a 8v92 done right.the 8v92 would break the cam with the 50D a lot before DD upgrade a cam just for the 50D