[Mr Anonymous]

My dad, a diehard Pontiac guy, bought a new 68 wagon with I believe a 400. The timing set failed on the way home from the dealer. I didn't ask for details, any time it was brought up he would be furious all over again. 40 years was a long time to hold a grudge against a timing chain and some gears. He worked for a Chevy/Pontiac dealer from 59-63 and would tell me stories of stuff the factory would dump on the dealers. Stuff like one car that pulled REALLY hard to one side because they didn't put brakes shoes on one rear side, and wrapped heavy wire around the wheel cylinder to keep the pistons from coming out. Trying to find a rattle, pulling beer cans out of the insides of the doors. So when the failure happened in 68, it was just another ....

[mgarblik]

During the time period these were used, the factory warranty was 50K miles on drivetrain. There were timing sets failing under warranty, more than other brands? The Pontiac dealer I worked at as a line technician sold 50-60 new cars a month, so a medium sized dealer for this area. We were replacing about 1 timing set a week under warranty as I remember. I remember distinctly that GM WOULD NOT pay for an oil change during this warranty repair and WOULD NOT PAY for removal of the oil pan to clean out the plastic teeth. We would spray 2-3 containers of solvent from a pressurized spray container into the front gap of the oil pan with the timing cover removed and oil drain plug out to "flush" the plastic teeth out the drain plug hole. Of course if the oil was slugged up, it wouldn't work very well. Many customers would NOT PAY for an oil change during this repair. They were already pissed the engine had failed. The dealer attitude was if the customer wasn't going to pay, and GM was not going to pay, they sure as hell were not going to pay. So we left the oil filter on the engine and ran the drained oil through a paint strainer paper cone, and put it back in. We had several of these jobs come back with all the bearings spun and knocking or not running. On disassembly, the oil pick-ups were found to be packed tight with timing teeth. If they were over 50K miles when this happened, that's when the fireworks began between customer, dealer and GM. Generally, they worked out some sort of cost sharing for a new short block. So if you ever wondered why so many Pontiac's had service replacement blocks installed, now you have part of the answer. It was a different world in the 1970's. Customers were NOT king, and GM had 50% of the entire new car market. Customer care and concern were way down the list once the car left the showroom. Expectations were the car would be traded-in for a replacement every 3-4 years.

[Tom Vaught]

Originally Posted by mgarblik

During the time period these were used, the factory warranty was 50K miles on drivetrain. There were timing sets failing under warranty, more than other brands? The Pontiac dealer I worked at as a line technician sold 50-60 new cars a month, so a medium sized dealer for this area. We were replacing about 1 timing set a week under warranty as I remember. I remember distinctly that GM WOULD NOT pay for an oil change during this warranty repair and WOULD NOT PAY for removal of the oil pan to clean out the plastic teeth. We would spray 2-3 containers of solvent from a pressurized spray container into the front gap of the oil pan with the timing cover removed and oil drain plug out to "flush" the plastic teeth out the drain plug hole. Of course if the oil was slugged up, it wouldn't work very well. Many customers would NOT PAY for an oil change during this repair. They were already pissed the engine had failed. The dealer attitude was if the customer wasn't going to pay, and GM was not going to pay, they sure as hell were not going to pay. So we left the oil filter on the engine and ran the drained oil through a paint strainer paper cone, and put it back in. We had several of these jobs come back with all the bearings spun and knocking or not running. On disassembly, the oil pick-ups were found to be packed tight with timing teeth. If they were over 50K miles when this happened, that's when the fireworks began between customer, dealer and GM. Generally, they worked out some sort of cost sharing for a new short block. So if you ever wondered why so many Pontiac's had service replacement blocks installed, now you have part of the answer. It was a different world in the 1970's. Customers were NOT king, and GM had 50% of the entire new car market. Customer care and concern were way down the list once the car left the showroom. Expectations were the car would be traded-in for a replacement every 3-4 years.

I believe every word that you have posted Mike. I changed a lot of them too in the 71-73 timeframe on the week-ends when I would work cheap and my Uncle the Pontiac Dealer was fixing these issues for his customers. My aunt, the Head Accountant for the firm, used to be unhappy with GM about not paying for some of the work but she lived with it as I was saving them some money on the deal. We did the flush out of the oil pan but we also had the Kent Moore Tool to raise the engine and drop the pan (using a two post -Front/Rear hydraulic lift) and tall safety stands on the frame at work height. I could get the engine just right on the "B-Body and F-Body" cars and get the pan off but the "A-Body" cars were almost impossible without pulling the engines. One of my earlier experiences with "GM Engineers are not perfect". Others errors were Heater Core failures on GTOs and replacing 8.2" Rear Axle assemblies. My Uncle "Ate" a lot of those repairs (indirectly) but he was feeding me Porter House Steaks on the weekends and giving me a nice bed to sleep in, and some cash on the side. I paid taxes on that cash for the "on the side" work. My Aunt said "you have to do it".

So not every Pontiac Dealer walked away from their customers and had them eat the repairs.

Tom V.

[sdbob]

I thought to 50k and the gear was gone. I had a 70 Fbody-350 that had red light on,car body is actually the one I still have,I pulled pan yep clogged screen .pulled bearings all ok. Put on another pump,fired ran well. Sold it.Got lucky.

[george kujanski]

One memorable occasion on this topic..stop me if you heard it before.....

My wife and i were visiting my sister in San Diego, winter of '73....They had a trip set up to Yosemite with another couple, so we all went with them (6 of us total) up to Yosemite in the other couple's 70 Lemans.

On the way back, outside of Sun City Ca, the dash goes all red and the driver pulls over. He cranks the engine and it has the typical sound I've heard before, timing gear failure. I asked him what was the mileage....about 50K, second clue.
To close the story, A CHP officer picked us up, then pulled over a Firebird that was weaving over the road. Turned out he was a Navy guy sleepily heading back to San Diego. The officer convinced him to take us all back to keep him awake. A bit crowded in the gen 1 Bird with 7 of us there..

George

[thepontiacman]

I found another original timing set in a 68,000 mile 326 from a 67 Lemans yesterday. All the teeth still there. Another one to hang on the wall.
Still some low mileage engines around after all these years.

[camerjeff]

I had a conversation years ago with a retired Pontiac Dealership parts manager concerning the Plastic coated timing gears. He was convinced the reason some failed early was due to overheating during the bonding process when they were made. He said when he needed a timing set he would order at least 5 from the warehouse. Before putting them on the shelf he would inspect the gears for the color of the plastic. He said they would range from a creamy white to a dark tan almost brown.

He would return any sets that were not creamy white. He claims that they never had one fail that started out that color. Seems like a reasonable conclusion. But I only have his word for it. I did remove a Plastic coated gear from a low mileage 78 Buick 350 a couple of years ago. Still in perfect shape with 36,000 miles on it.

[Half-Inch Stud]

"Detonator 8" was the PMD nickname given by mechanics in the early 80's due to the nylon gear, and cast rods.

[SRR]

The only thing worse than these nylon time bombs were timing belts in interference engines. Great idea! Not.

[b-man]

Have kept this one around for whatever reason I’m not quite sure, found it today while trying to clean and organize my garage. Thought I’d share a couple pictures before it gets tossed, the nylon gear teeth are still very nice on it.

[Jack Gifford]

Anybody here old enough (or well-schooled enough) to tell me if I'm remembering correctly that the cam gear on a '36 Chevy (my first car) was all fiber except the hub?

[Sirrotica]

Yes Jack, I remember working with my dad on a I-6 216 that was originally a chevy truck chassis that someone had converted to a stationary power plant for a ski tow. I remember asking him about the fiber upper timing gear when he was doing the fall startup at she ski resort, and had pulled the head (valve job), and timing cover to inspect the timing gears. Since all that was left was the chassis and driveline, there was no way to determine what year this engine was.

From what I was able to look up on the web the 216 production began in 1937 though 1953 so it wouldn't have been the exact same engine you had in a 1936 chevy. Further research show the 1936 was 207 CI. It took a 7/8 inch wide fiber timing gear that fits 1933-1936 chevy I-6 engines. Link to NOS fiber timing gear on E Bay: https://www.ebay.com/p/1227924023

Chevy/GM continued using that same design of timing gear until at least the mid 80s. I had a 1988 Fiero that stripped the teeth off the gear of the 4 cylinder that was patterned off of the chevy 6 that was a new design in 1963, to replace the 235 older design that began in the 30s. It also had a knurled steel sleeve for the hub, with resin and fiber mold cast over the sleeve, so they used that design for over 50 years on the I-6 and I-4 engines.

[Jack Gifford]

Thanks for the answer Brad!
I honestly can't remember whether I needed to change the timing gear, or I just opened it up out of curiosity.

[242177P]

S305. Aren't these like service replacements? I have an
original, but it says GM 9794243. On the S305s there's a
logo, perhaps the manufacturer?