GM VORTEC 7400 Timing Gear & Chain Set

[overlander64]

I just returned from the Chevrolet garage, and my Suburban now has a new timing chain and gear set. Based on the visual of a timing chain that had more than 3" of deflection and several chipped teeth in the gears, I was running on borrowed time with the original chain and gears. I can't really fault the Suburban as the original lasted 183,500 miles with the cost for replacement being about three times the cost of replacing the timing belt in my old Toyota once -- and in 180,000 miles of driving, it (the Toyota) required three timing belts.

The difference in the Suburban's road manners is remarkable -- silky smooth acceleration with no hint of rough/noisy idle that I had been experiencing for more than six or seven months. If possible, it seems to be running smoother than it has since it was new in April of 1998.

Kevin

[Silvertwinkie]

Great to hear Kevin. I'm still floored that you needed a new timing chain and that it was that deflected and chipped teeth. I owned a GM that had 167k on it and ran like a top. I always thought that the timing chains were good for the life of the vehicle.

[59toaster]

Originally Posted by overlander64

The estaimate to replace the timing chain and gear set with GM factory components is between $900 and $1,100. The water pump was replaced with a new GM pump at 122,000 miles when it began leaking. The pully and tensioners were replaced when the truck was prepared for last summer's journey. The truck has been serviced by either one of two long-time GM dealers -- Pioneer Motors in Lancaster, WI or COAD Chevrolet-Cadillac-Pontiac-Buick in Anna, IL every 3,000 miles utilizing the severe service maintenance schedule. There is no evidence of oil burning, and compression and leak-down tests return well within the normal ranges for this engine. I am not opposed to replacing the timing chain in advance of failure as only my Oldsmobile escaped without related motor damage when the timing chain failed.

Kevin

$900-1100 for a TIMING CHAIN?!?!?!?!?!?!?!?!?!
I'm in the wrong buisness

You do know you can buy a brand new 350 engine for $1800 don't you?


I'll do the job for $500 including the the basic parts. Bring it on over.

Seriously...yes it is a pain in the butt job but it is not a $900 in labor pain in the butt job. Even with Chevy's ridiculous mark up you should be able to buy the chain for less the $100. The Cloyes aftermarket is $30 at Autozone. Feldpro front gasket set it about $30. Gallon of Anti Freeze $6 Gallon of Distilled water $1.25.

[overlander64]

Greetings Eric!

From what the service manager at the Chevrolet dealership told me, anything much over 150,000 miles on a 7.4 Liter and the timing chain/gear-set is a candidate for replacement -- particularly if the unit has seen much use towing. We have basically found this to be true with both our small-block V8s as well as the big block V8s -- my first '75 Cadillac had to have a timing gear and chain set at 155,000 miles, the '84 Oldsmobile 5.0 Liter made to in excess of 100,000 before its timing chain snapped while driving on the highway (I don't know how it happened, but there was no other damage to the motor -- just needed a new timing chain and gear set as well as a new timing chain cover).

I can't complain about the cost of operating the Suburban (other than the pesky automatic transfer case electronic module). In nine years and 183,500 miles I have only had a very few repair expenses beyond the timing gear and chain set -- one new water pump, one new fuel pump, one idler arm, one set tie rod ends, resurfacing front rotors three times, one new blower motor for front heat and air.

Kevin

[Silvertwinkie]

Wow...I just retired my 1980 Olds Delta, which was the one with 167k on it.

We also had a 1985 7.4L in our Suburban w/130k on it.

Maybe ours were flukes. I've never heard that about timing chains, but I am glad you got yours fixed before it left you stranded!

I've seen your truck a few times and know it's in great shape...well worth saving!