[03marauderman]

New member here..I own a 72 GTO bought new, & the original owner..survivor...It has 64k miles.. 400 w/A/T 400...my concern is the timing chain, seems quiet, but are the timing gears steel or that plastic composite? Thanks

[johnta1]

70 last year for the plastic coated gear I believe.

You should be good to go.



And welcome to PY!

[03marauderman]

Thanks...What year we're the plastic coated gears first used? - Wasn't it in Chevy's the most common?

[johnta1]

I think the 1967 engine used the plastic gear, probably for consumer comfort (quietness).

But they were a joke on longevity.
(most replaced with the T4 chain/gear)

Don't know about chevy stuff really.

[AJD1964]

Back in high school in the early 80's, my very first car was a '73 lemans sport coupe 350/350. It was a hand-me-down that my Aunt & Uncle bought brand new. It only had 75K miles on it when I got it (a rust bucket though!).

One of the timing gears had fiber/plastic or whatever teeth. It broke on me. So I can tell you that a '73 350 definitely had the "weak" gear teeth. So I would not assume '70 was the last year for one.

[03marauderman]

My friend has a 74 G/P SJ with a 455 & he tore his down for the same fear & discovered it had steel gears...Now my question was the 350 Pontiac the same as the 350 Chevy's? - I remember back in the day Malibu's & Monte Carlo's going through timing gears like Grant went through Richmond....

[b-man]

Originally Posted by 03marauderman

Thanks...What year we're the plastic coated gears first used? - Wasn't it in Chevy's the most common?

Pontiac started using the nylon cam sprocket in 1964.

[b-man]

Originally Posted by 03marauderman

My friend has a 74 G/P SJ with a 455 & he tore his down for the same fear & discovered it had steel gears...Now my question was the 350 Pontiac the same as the 350 Chevy's? - I remember back in the day Malibu's & Monte Carlo's going through timing gears like Grant went through Richmond....

Pontiac and Chevy 350 engine share no parts other than the distributor cap, they're completely different engines.

[03marauderman]

OK - Now that's established..any other input on theses gears?

[b-man]

Input?

Probably needs replacing about now even with the iron sprocket, so I would put a top-quality timing set in soon. The timing chain will stretch, retarding valve timing and causing the ignition timing to become a bit unstable as well.

Cloyes Tru-Roller timing set, my first choice.

[03marauderman]

Advise well taken...I will keep that brand in mind...Who would you recommend getting it from?

[b-man]

Summit Racing is a good outlet for quality parts and free shipping if you spend $99 or more.

[rexs73gto]

As far as having a plastic gear in your 73 LeMans , it probably got put in at a later date by someone who may have thought it would be quieter then the metal gears. No 73 came with a plastic gear for a timing chain, ever. In mid 70 the plastic gear was taken out of service because of concerns of engine damage when they would come apart & plug up the oil pump pick up. If you had a plastic gear in it when you took it apart it was a replacement set that was a left over from some old parts store or left over junk from a dealer who didn't know any better.

[Lloyd-TX]

Originally Posted by rexs73gto

As far as having a plastic gear in your 73 LeMans , it probably got put in at a later date by someone who may have thought it would be quieter then the metal gears. No 73 came with a plastic gear for a timing chain, ever. In mid 70 the plastic gear was taken out of service because of concerns of engine damage when they would come apart & plug up the oil pump pick up. If you had a plastic gear in it when you took it apart it was a replacement set that was a left over from some old parts store or left over junk from a dealer who didn't know any better.

Ditto. No nylon camshaft sprockets used on Pontiac V8s past the 1970 model year.were

[Lloyd-TX]

By the way, welcome aboard 03marauderman. How about a first name so we can address you properly?

Oh, and being the '72 GTO fan that I am, how about more details on your GTO, along with a few pics? We'd love to see and hear more.

[sonjaab]

My 72 350 HAD a plastic gear!
Replaced it/chain/gear/camshaft/lifters at 80k miles
with a steel gear.

STILL quiet and purrin' at 180k miles!

[necdb3]

I replaced several steel/nylon capped timing gears in Pontiacs from the early 70's. I couldn't tell you what engines they were (350,400,455, to long ago) but there's no doubt they still used them on engines beyond 1970.

Unless a bunch of cars had them installed after production. (I doubt it)

[03marauderman]

Lloyd-TX ..Hope not to bore others...I bought my 72 GTO new as a left over in 1973 from a 1 car showroom, Ma & Pa dealership Redner Pontiac, GMC in Central Valley NY. The owner/salesman/service mgr. sold it to me for invoice,as that was the time of the gas crises, & gas guzzlers were not in demand. I had just got out of the army & had a job driving a tractor trailer delivering gas...thus got free gas...Anyhow its a 400/400 A/T hardtop, buckets, console mounted shifter with factory 8 track player, gauges, P/S, No A/C or Pwr brakes, drums all around...(probably the same as a 6 cyl Chevelle, as it does not want to stop) What the hell was Pontiac thinking about? especially when disc brakes were getting popular...It had steel wheels with raised white letter tires & poverty caps, which I immediately replaced with Rally II - Fortunately I kept the wheels & caps...Its Wilderness Green with a green interior, green was not my favorite color but I got used to it..Its got 64k miles, never wrecked or rusted, always garaged. The one regret I have is, I never saved any of the paperwork... Prior to that I had a 65,& 66 GTO, then a 69 Charger, then the 72 Goat.....So there you have it....I'll try to get some pics posted....Thanks for your interest....