Noisy timing gears?

[arveetek]

As some of you may know, I've been fighting a slight engine stumble at idle, along with a really annoying noise that I know doesn't belong with the engine....it just sounds funny. This weekend, Tim Wagner sent me a new injector to replace the one that leaked upon initial installation. That fixed the stumble problem, but it didn't change the noise.

I've finally decided that the noise is coming from the DSG gear drive. It's hard to describe the noise in writing, but it's more of a "chink-chink" or "chug-chug" sound that's in tune with the engine pulses at idle. What I believe the problem to be is excessive clearance between the idler gears and cam/crank gears, causing the gears to load up and release every time the engine fires.

The gear noise is masking the typical diesel rattle, and it really annoys me. The engine runs extremely awesome, but it sounds like a worn out engine at idle, and it's driving me nuts. I'm considering removing the gear drive and replacing it with a standard chain set.

Any thoughts?

Casey

p.s....I found out that Tim Wagner does not rebuild the injectors himself...he buys them from a third party. He does do the pump rebuilds....if I had it to do over again, I would probably purchase injectors from JK or other reputable supplier, and have the pump work done by Tim.

[BobND]

Did you verify the amount of play in the "reverse idler gear" as shown in the installtion instructions?

http://www.dieselservices.com/pdf/dualidler.pdf

When I did mine, it was in "spec", and outside of a little gear noise, it's not bad. Actually, the sound is "SWEET" compared to the noisy, worn timing chain I replaced!

I see where they have custom parts available if the gear lash is not within "specs".

[john8662]

Listen to a clip I recorded of my engine with the gears, I thought they sounded really really loud, got louder the longer the engine had run, and the thinner the oil would get.

62dslgears.mp3 (http://members.cox.net/acmdsl/www/62dslgears.mp3)

When tearing down the engine I found that the gears were starting to pit on the mating surfaces, I'll be starting with a new gearset, I didn't get any instructions with mine.

I agree with you on the injectors, I'd buy from Diesel Injectio Service any day when it comes to injectors, because they've been top quality, maybe not the cheapest. They've never given me any trouble with testing them either if I thought something wasn't right.

[BobND]

John,

How many miles on the set that were beginning to "pit"?

[john8662]

Well, I bought the set used, and it was in good condition when I installed it. The gears were not in the engine more than 3k miles..

My engine may have been a bit different in some ways. Like that I had to press my crank gear on the crankshaft, where others have reported that it went on relatively easily. As far as clearance within the gears, it was good. I don't know what was wrong. I still have them if you guys want pictures.

[Lightyear]

Have you used a stethoscope to pinpoint your 'chug-chug' noise? My '88 sounds bad at idle, a chugging type noise. I tracked it down to the left cylinder bank, posibly a bad lifter on #3. I got my stethscope from Sears, between $10 and $20. It'll really help find your phantom noise. Wish I had more help to offer; noises that shouldn't be there drive you nuts.

Buzz

[arveetek]

Bob,

I checked the clearances when I installed it according to the instructions that came with the set. There's a pretty wide range from 'tight' to 'loose' in my opnion. I don't remember now what I had, probably on the loose end.

John,

Yeah, that sound clip reminds me of my engine...I can hear the sound I'm hearing on mine over the diesel rattle, like on yours. Must be the same thing.

I'm not too keen on tearing down the front of the engine, checking it out, making adjustments, and then putting it back together to find out that the noise is still there. I'd almost rather just put a chain back in place and be done with it the first time....

Casey

[john8662]

Casey,

If you can wait for another month, I should be assembling the new engine and I'll get a second chance to check things out.

Yeah, I'm with you on the noise, I don't know what the deal is, I sent the same clip to a fellow at DSG, but haven't gotten a reply. I'll be contacting him again this week, I'll post the results on what I find.

The good thing about your gearset is that at least yours can still be covered under warranty.

Maybe we need a poll on the gearsets, like a rate your noise in the new engine.. Something we could do, I have a feeling that this is either a problem or could be normal.

I feel that I'll know more for comparison when I get the 6.5 in my 95 burb running because it's also equipped with a gearset.

[arveetek]

John,

I've listened to your audio clip several times, and our two engines sound very much the same, with the same noise that annoys me.

I'm in no hurry, so I think I'll wait 'til you get your engine back together.

Unfortunately, there's probably no warranty on mine. I bought mine from another DP member. The box was opened, but the plastic bags that contained the separate gears were unopened. I doubt DSG would honor a second party warranty.

Casey

[5.7L oldsdiesel]

I posted before about the governor weight cage in the injection pump as being the cause of many rough idle conditions.For curiosity,you might want to remove the governor cover on the injection pump to check for any signs of a loose governor cage.If you have play in either direction,its definately a cause for your rough idle.I came across a rebuilt pump with a bad governor cage before.It ran terrible at idle.I also had the updated steel governor cage fail that gave a bad idle on a 6.2 diesel.Replaced the cage and problem solved.

Sorry to hear about the possible gear drive noise your experiencing.Good luck in whatever you decide to do next.

[arveetek]

Thanks!

As I stated above, it looks like my rough idle is gone, after replacing one injector. It's really quite smooth now. Now all I have is the annoying noise issue.

Casey

p.s....I picked up a sweet '95 2 door 6.5LTD Tahoe 4WD last night! Look for more details later.... :D

[Dieselboy]

That's wierd. On my truck, there's a faint tick and tack if I'm standing right in front of the radiator, but I can't hear them clearly unless I pull the oil fill cap.

The gear noise in audio file is significantly louder than what I'm used to.