[PAUL K]

I took apart a completely original 71 400 and it used the nylon timing gears. I've taken apart what appeared to be original 72 engines and they used the steel gears. I'd agree with the other post 71-72 was the changeover period.

[Ben M.]

Originally Posted by Sirrotica

It's been hashed over a few times on this forum, and right around 71-72 is as near as I've seen documented of when Pontiac made the switch back to steel upper gears.

Yup. I've taken apart a half dozen '72 and later 400-455 engines that were factory unopened and none of them have a nylon timing chain. I know they were using them through 1970 at least (Pontiac's 1970 factory literature shows one on the cover), the changeover was likely the '71 model year sometime.

[track73]

Back in '72 while teaching auto mechanics in New Mexico a fellow teacher brought in his '68 Catalina with about 50,000 on it. The timing chain was all chewed up and ready to go. I had a '67 Catalina and was afraid that mine would be the same, since my Pontiac had a few more mile on it. When I looked at the TC on my car. it was pristine. It looked like it just came out of the factory.

[ponyakr]

"...Double roller chain & gears is a must in a Pontiac..."


That's just one man's opinion.

I disagree. I tried one DR set. After I discovered that the chain stretched just as quick as a stock type chain, I went back to stock type sets, in TRW boxes. Don't know who made 'em. Never had any problems with 'em street or strip. I always kept some extra chains & swapped 'em out any time I had the timing cover off. They were dirt cheap back then. Nowadays, a stock type Cloyes set is almost as cheap as just the chain.

https://www.rockauto.com/en/parts/cl...iming+set,5756

https://www.oreillyauto.com/detail/b...c3007k/2625477

I think I remember Cliff saying that he uses the Melling stock type replacement set, even in his race engines.

https://www.rockauto.com/en/parts/me...iming+set,5756

https://www.ebay.com/p/Engine-Timing...-350S/75561005

[PunchT37]

I know it's an Olds but, I took down a ,73 Olds 350 from a Delta 88 and it was nylon. My dad had a ,79 Olds 350. It sheared all the teeth off and into the pan. Plastic.

[Half-Inch Stud]

Pontiacs ate the nylon Timng gear quickest because Pontiacs made a ton more torque, from a bunch more stroke then those other GM engines. The instantaneous torques ran the Timing chain ragged.

[android 211]

Cadillac used them too. Their valve spring pressure was very low. Maybe the gears didn't have to work as hard.

[Chief of the 60's]

Originally Posted by ponyakr

"...Double roller chain & gears is a must in a Pontiac..."


That's just one man's opinion.

I disagree. I tried one DR set. After I discovered that the chain stretched just as quick as a stock type chain, I went back to stock type sets, in TRW boxes. Don't know who made 'em. Never had any problems with 'em street or strip. I always kept some extra chains & swapped 'em out any time I had the timing cover off. They were dirt cheap back then. Nowadays, a stock type Cloyes set is almost as cheap as just the chain.

https://www.rockauto.com/en/parts/cl...iming+set,5756

https://www.oreillyauto.com/detail/b...c3007k/2625477

I think I remember Cliff saying that he uses the Melling stock type replacement set, even in his race engines.

https://www.rockauto.com/en/parts/me...iming+set,5756

https://www.ebay.com/p/Engine-Timing...-350S/75561005

That is not "1" man's opinion. That is many experienced mechanics professional advise.

Not that I have anything at all against Cliff, but doesn't he run like 12's?

[Poncho60]

The regular old std cloyes set is just fine w me as I have pretty much zero interest in all these mega hp engines for the "street?". Too old to care anymore....stock works just fine for me.....as long as no nylon is involved!

[Goatracer1]

In 1969 took the nylon gear out of my new 428 at 468 miles. I wasn't taking any chances.

[Greg Reid]

Originally Posted by 77 TRASHCAN

Jeff, see if you can find the quote from the movie, "1941" Dialogue is from John Belushi...

Yes Germans!!!

It was 'Animal House' guys...
https://www.youtube.com/watch?v=V8lT1o0sDwI

[ponyakr]

"...Not that I have anything at all against Cliff, but doesn't he run like 12's?.."


Actually, I think his car can run low 11's.

http://forums.maxperformanceinc.com/...2&postcount=11

You can run whatever you want. But, to state that a DR is a "must in a Pontiac" is ridiculous, since there have been probably thousands of Pontiac powered cars run high 11's & quicker without having a DR set.

Guessing that there have been lots of stock type sets go 100k miles & more, including in some of the stronger 400, 428, & 455 engines. Not saying that a stock type set is stronger than one of the high dollar billet DR sets. Just saying that they are not all junk either, and won't break, just because the engine makes enuff power to go 11's on the track. And besides that, this thread is in the street section, anyhow.

Just for kicks, for all who read this post, if you have have run 11's or quicker, or know somebody who has, with a stock type set, please post that info in this thread.

11.82 was our quickest time. So, to some, that may not be quick enuff to count.

[Cliff R]

What type of timing set used would have NOTHING to do with engine power or how fast the car would be.

The stock type sets and used and preferred here, they are very strong parts. I actually prefer the older sets as pictured below and have a few sets in spare parts purchased off Ebay. The good sets show up on their from time to time and usually quite reasonable.

Even the very best double roller sets with the seamless chains and billet sprockets will experience chain stretch. I tried a Rollmaster set once in my first 455 and it ended up needing a chain after a few years of hard use and several thousand street miles. Up until that time I had used wide link plate sets exclusively in my own engines and went back with one in the current engine and it's fine now since 2009.

Far as nylon sets go they are excellent for full race set-ups and lots of "old timers" used them as they will provide constant tooth contact between the sprockets and absorb harmonics as well which reduces spark scatter and provides slightly smoother timing across the RPM range. I've never been comfortable enough with the plastic sets to try one for a street or street/strip car, but a good link plate set will last the life of the engine without much trouble........Cliff

Put a few pics below, notice the steel gears and heat treated on the teeth as well, these will be the best sets and an excellent choice for one of these engines. It's a little bit of a PITA to move the cam around since Mopar discontinued their 6 offset keyway set, but I stock up on those as well so good to go here for quite a while.

[steve25]

SB chevys had far less valve spring pressure then Pontiacs yet in terms of factory Cams and lifters they still had managed to fail Cam lobe in a 2 to 1 rate over Pontiacs from the work that I have done to them over the years.
You can also tie it into there owners who other then the retiree's who have nothing better to do but change there oil every 250 miles , all the other SB chevys guys using them as 50 mile a day commuter cars use to come into the repair shop for a oil change once every year!

[77 TRASHCAN]

Originally Posted by Greg Reid

It was 'Animal House' guys...
https://www.youtube.com/watch?v=V8lT1o0sDwI

OK, OK, at least I got the Belushi part right...LOL

[shaker455]

Originally Posted by 77 TRASHCAN

Jeff, see if you can find the quote from the movie, "1941" Dialogue is from John Belushi...

Yes Germans!!!

I watched the whole movie last night...lol.. crazy!...lol...no line like that..sorry

I can tell you Dianne Kay was (girl from eight is enough) quite the eye candy!

[shaker455]

Originally Posted by Half-Inch Stud

Pontiacs ate the nylon Timng gear quickest because Pontiacs made a ton more torque, from a bunch more stroke then those other GM engines. The instantaneous torques ran the Timing chain ragged.

I would tend to agree.

I found many old SBC's with them fairly intact.

[track73]

Grumpy Jenkins used the nylon gears in his real fast Chevies. He said the cam would slightiy retard at high RPM.

[Sirrotica]

Originally Posted by track73

Grumpy Jenkins used the nylon gears in his real fast Chevies. He said the cam would slightiy retard at high RPM.

Funny thing is that at that time here was a couple companies called Varicam and also Cam A Go, that built timing sets that would advance and retard camshaft timing based on how you set the thing up and at what RPMs you wanted the timing to change. Just throwing that out there that he could have used that setup., but I'm sure he had his reasons.

Of course the newest technology is able to advance and retard cam timing with use of hydraulics electronically controlled by the ECM.

[Formulajones]

Originally Posted by Sirrotica

Of course the newest technology is able to advance and retard cam timing with use of hydraulics electronically controlled by the ECM.

Can do it on older engines too with an ignition system and timing retard feature