The Diesel Garage banner

1 - 11 of 11 Posts

·
Junior Member
Joined
·
255 Posts
Discussion Starter #1
Got a funny vibration along with noise coming from front of engine on my 1lw.
Everything is pointing me in the direction that it is something under the front cover. Put on new dampner and checked everthing under the covers, including installing new double valve springs.
Can anyone give me a heads up on what to look out for once i get the cover off the front. What normally fails or wears out in the gear train??

Thanks :bang
 

·
The other guy
Joined
·
3,936 Posts
Got a funny vibration along with noise coming from front of engine on my 1lw.
Everything is pointing me in the direction that it is something under the front cover. Put on new dampner and checked everthing under the covers, including installing new double valve springs.
Can anyone give me a heads up on what to look out for once i get the cover off the front. What normally fails or wears out in the gear train??

Thanks :bang
Big one used to be the main idler bushing. It has since been revamped to brass and has very little wear. There are also TSB's on the cam gear damper wearing out the rotate balls too fast, hence a new gear set available (for not too cheap). Main thing is checking gear lash after head removal. All done under the peanut cover.

Remove front "peanut" cover, remove covers and jakes (only). Lock the accy1 idler with screwdriver between 1 and 2, then check lash between accy2 and cam gear by moving cam gear back and forth with a 9/16" on the four cap retainers on the cam gear. We like .005" to .007". Spec goes all the way up to .012", but we don't like it that loose. It adjusts by removing the accy gear #2 three 5/16" bolt retainer, then loosen the 3/8" nuts and bolts to move idler hub (in is tight, out is loose). Get the bolts real tight, nuts don't matter much. If you don't have a dial indicator, just go by feel. If it's too tight to move, your eating the front cam bushing. :thumbsup
 

·
Junior Member
Joined
·
255 Posts
Discussion Starter #3
Thanks for the reply ynot,
Can you tell by looking at the rotate balls in the cam gear if they are worn out or not? also what gear are we talkin about, is it the main cluster gear that has the bushing problem??
 

·
The other guy
Joined
·
3,936 Posts
Thanks for the reply ynot,
Can you tell by looking at the rotate balls in the cam gear if they are worn out or not? also what gear are we talkin about, is it the main cluster gear that has the bushing problem??
Nope, can't tell, and actaully never even had to replace one. Just a Cat TSB I'm quoting. I say it's BS for incorrectly adjusted lash.

Not the main idler, the top accessory idler, as in the one you see when you pull the peanut cover that drives the cam... :happymugs
 

·
Junior Member
Joined
·
281 Posts
I just had a 1LW come in last weak with intermittant throttle response,sometimes it was fine and might run 1000 miles without issues then it would not even start or die the next time,then suddenle would not start at all! ended up finding that the cam gear had broken and was missing about 10 teeth where the engine speed sensor pick up was,replaced gear with new[about 1000 bucks,WOW] running fine now! only 1 of cats horrible designs in my book,GOOD LUCK:thumbdown
 

·
The other guy
Joined
·
3,936 Posts
I just had a 1LW come in last weak with intermittant throttle response,sometimes it was fine and might run 1000 miles without issues then it would not even start or die the next time,then suddenle would not start at all! ended up finding that the cam gear had broken and was missing about 10 teeth where the engine speed sensor pick up was,replaced gear with new[about 1000 bucks,WOW] running fine now! only 1 of cats horrible designs in my book,GOOD LUCK:thumbdown
Never seen a Cat gear break unless something was dropped in there (or it's a mechanical without the 131-7123 idler bushing). Sht does happen tho :(
 

·
Junior Member
Joined
·
255 Posts
Discussion Starter #7
Well when we did the valve springs and checked everything on the top end i took the peanut cover off to check the timing. We found our problem as to why we could not get the timing to calbrate. With the flywheel pined, the cam was a little more then a full tooth out. I pulled idler gear off and moved cam full tooth to correct this, it calabrated fine after this also. But i still think something is wrong elseware in the gear train, as i did a timing cal two years ago with out any problems and nothing has been touched under there since????? . Leads me to think somthing is wearing in there . It does run better now, but it still viberates and is a bit noisy under high power/boost situations.
Oh ya, when i had that gear under the cam gear off it looked like a normal shell type bearing in there, definatly not brass! Is this the one that should be updated. We also used a tapered feeler gauge to check lash , it had 10 thou so we left it alone. Do you think i should tighten that up a little more?
 

·
The other guy
Joined
·
3,936 Posts
Well when we did the valve springs and checked everything on the top end i took the peanut cover off to check the timing. We found our problem as to why we could not get the timing to calbrate. With the flywheel pined, the cam was a little more then a full tooth out. I pulled idler gear off and moved cam full tooth to correct this, it calabrated fine after this also. But i still think something is wrong elseware in the gear train, as i did a timing cal two years ago with out any problems and nothing has been touched under there since????? . Leads me to think somthing is wearing in there . It does run better now, but it still viberates and is a bit noisy under high power/boost situations.
Oh ya, when i had that gear under the cam gear off it looked like a normal shell type bearing in there, definatly not brass! Is this the one that should be updated. We also used a tapered feeler gauge to check lash , it had 10 thou so we left it alone. Do you think i should tighten that up a little more?
The brass one only goes in the big main idler you can't see. Moving the accy idler to calibrate timing is kinda wierd. I'd be inclined to move it back and back up the accy idler, then set it by feel and re-calibrate timing. Bet the noise goes away. Remember the mark and the gear don't have to be exact. Half tooth off is normal on a .030" shaved head, and timing will calibrate :D
 

·
Junior Member
Joined
·
255 Posts
Discussion Starter #9
Okay, gotcha on the big main idler. Don;t you think its posible that the bushing has worn so much over time that it made it not want to calabrate??
I find it hard to believe that i had to move the cam one tooth to get it to calabrate, when 100,000 miles ago it calabrated fine, and i changed nothing since then. Maybe it has the old style bushing in there and its calling it quits. I guess i should just take the front cover off and see whats going on in there! Thanks for the help!!:thumbsup
 

·
The other guy
Joined
·
3,936 Posts
Okay, gotcha on the big main idler. Don;t you think its posible that the bushing has worn so much over time that it made it not want to calabrate??
I find it hard to believe that i had to move the cam one tooth to get it to calabrate, when 100,000 miles ago it calabrated fine, and i changed nothing since then. Maybe it has the old style bushing in there and its calling it quits. I guess i should just take the front cover off and see whats going on in there! Thanks for the help!!:thumbsup
Those bushings don't wear enough to make a timing change. I'd just try the back up thing mentioned earlier. Think you'll be suprised!! :happymugs
 

·
Registered
Joined
·
2 Posts
Swan, did you ever figure this out fully? I have the same vibration and noise in mine too. However, my backlash was really really tight. I think it has worn something out as a result of being so tight, for who knows how long. Any advice would help. Thanks
 
1 - 11 of 11 Posts
Top