Why did GM start using plastic timing gears?
Thread Starter
Race Director
Joined: Aug 1999
Posts: 11,123
Likes: 673
From: SE Pennsylvania
St. Jude Donor '03 thru '26
Oldtimer
Why did GM start using plastic timing gears?
I was just wondering why they used these setups and do they still use plastic gears in current engines? :eek:
Burning Brakes
Joined: Nov 2001
Posts: 787
Likes: 1
From: Toronto Ontario
Re: Why did GM start using plastic timing gears? (Wightnite)
For quiter running engine, most engines now use timming belts that must be replaced every 60,000 miles, If that belt breakes on some engines it will destroyes the engine. I just had my water pump sieze up on my intripid. The timming belt was also driving my water pump once the water pump siezed the timming belt jamed and destroyed my overhead cams the engine was tosted. Cost me $2500 for a rebuilt 3.5 liter. Give me back the good old timming chains.
Racer
Joined: Jul 2001
Posts: 363
Likes: 0
From: Winston-Salem NC
Re: Why did GM start using plastic timing gears? (killain)
Yeah, you gotta watch those plastic timing gears. They are quieter, but check out the gear that came out of my V6 Buick -
The amazing thing is that the car was still running! I had no idea anything was wrong until I changed the oil and found chunks of plastic in the old oil.
Jeff
The amazing thing is that the car was still running! I had no idea anything was wrong until I changed the oil and found chunks of plastic in the old oil.
Jeff
Advanced
Joined: Aug 2001
Posts: 64
Likes: 0
From: Newburgh IN
Re: Why did GM start using plastic timing gears? (jbroughton)
for the last 30yrs if i had a g.m. product withover 60k mi. i would check and replace if there were nylon "plastic.". Thay were soposed to be quiter but i could not tell the difference. :smash: :seeya
Le Mans Master
Joined: Mar 2002
Posts: 7,456
Likes: 2
From: Coming home from Luckenbach Texas
Re: Why did GM start using plastic timing gears? (killain)
I had one of those in my '69 Cougar. Actually, it was a steel gear with nylon teeth. They did it to keep the noise down. Naturally, I replaced it with steel gears.
Unlike many newer cars, these darn things will keep running even if you loose a tooth or two! :smash:
Unlike many newer cars, these darn things will keep running even if you loose a tooth or two! :smash:
Racer
Joined: Dec 2001
Posts: 498
Likes: 0
Re: Why did GM start using plastic timing gears? (killain)
I heard that it was to keep the engine quieter. However, with my 84 I put in a Cloyes tru-roller and didn't have any problems with my knock sensor. Also, I feel much safer!
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Burning Brakes
Joined: Sep 2001
Posts: 805
Likes: 0
From: College Station / Highland Village TX
Re: Why did GM start using plastic timing gears? (jbroughton)
Yeah, you gotta watch those plastic timing gears. They are quieter, but check out the gear that came out of my V6 Buick -
The amazing thing is that the car was still running! I had no idea anything was wrong until I changed the oil and found chunks of plastic in the old oil.
Jeff
The amazing thing is that the car was still running! I had no idea anything was wrong until I changed the oil and found chunks of plastic in the old oil.
Jeff
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: Why did GM start using plastic timing gears? (page62)
I think the term is an 'interfearance' engine will kiss the valves into the pistons if timing is off enough, and most older engines were not of the interfearance type....most newer engine are interfearance, especillly foreign made engines....to me there is NO reason for that type of design, just sloppy engineering, or give a crap attitude on company's part.....or planned obsolescence....take your pick, it's sh it.....
GENE
GENE
Team Owner
Joined: Jul 2001
Posts: 182,997
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Why did GM start using plastic timing gears? (73-454)
>>For quiter running engine, most engines now use timming belts that must
>>be replaced every 60,000 miles, If that belt breakes on some engines it will
>>destroyes the engine. I just had my water pump sieze up on my intripid.
Ooops!! I have a Intrepid with 62000 miles on it.... maybe I should have the timing belt replaced....
Olivier
>>be replaced every 60,000 miles, If that belt breakes on some engines it will
>>destroyes the engine. I just had my water pump sieze up on my intripid.
Ooops!! I have a Intrepid with 62000 miles on it.... maybe I should have the timing belt replaced....
Olivier
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Re: Why did GM start using plastic timing gears? (page62)
Actually, it was a steel gear with nylon teeth. They did it to keep the noise down.
Roller timing set rec.!
