Detroit put plastic teeth inside v8 engines-here's why

Comments · 406

• CR

  @crustyoldoffroader7436 · 2 weeks ago

  In 1974 my 1968 GTO jumped time. I couldn’t believe there was plastic on that cam gear. I would have preferred the noise.

  75

• DO

  @dougsather2939 · 2 weeks ago

  I was a line mechanic at a Pontiac dealership in Orlando Fla and the Pontiac and small block Chevy got about 5 years out of the plastic timing gear set. I changed a set in a church parking lot on a Chevy for a friend once. That was gravy for pay under warranty. GM made the best engines ever in the 60's and 70's. Good times. 😇🙏

  54

• RW

  @RW4X4X3006 · 8 days ago

  We were replacing this nylon crap in our engines back in the 80's - one of the first things to upgrade.

  8

• WE

  @weseld1 · 8 days ago (edited)

  When my 1970 Firebird 350 started with a BANG and stopped running, I was pretty surprised, and got it towed to my fathers garage. &nbsp;After a little diagnosis, he said &quot;Timing belt. &nbsp;Have to tear it down.&quot; But when we got the timing cover off, and found the real problem we were even more surprised to see a &quot;PLASTIC GEAR?&quot;. &nbsp;I the few seconds it had run after the BANG nearly all of the nylon teeth had been stripped off of the hub and turned into white flecks in my oil pan! &nbsp;He was a diesel truck mechanic and had never seen a plastic timing gear, but quickly said, &quot;Those cheap bastards have saved a little on costs by using a plastic gear instead of a steel one!&quot; &nbsp;We got good all steel replacement parts , and the car ran fine after we got the timing set AND all the plastic debris out of my oil (which was a lot more work!). &nbsp;But thank you for telling me what GM was thinking when they put in the &quot;plastic&quot; gears into the new cars. &nbsp;<br><br>Ironically, we next had to tear the engine down again to replace the camshaft, after one of the hydraulic valve lifters wore down into a cutting head and rounded the egg-shaped cam down into cylinder. &nbsp;If we had only torn the engine down a little further when we were replacing the timing gear, we might have noticed that the valve was not lifting and fixed both problems with one week in the shop. &nbsp;As it was, our repeated tear-downs kept her going until 1996.

  5

• RA

  @RandyThompson-g5i · 12 days ago

  Jackson gear drives are noisy but hold absolute timing. I actually like the sound.

  13

• MI

  @michaelyounger4497 · 13 days ago (edited)

  In high school I had machine shop and auto shop classes. My big project was rebuilding the engine in my 68 pontiac. All the machine shop work and the mechanical work. My shop teacher threw me a challenge. I made a pair of oversized gears to replace the sprockets so there was no more chain. It wasn&apos;t that hard to do. I used an alloy nickel steel. They meshed beautifully and the engine was smooth and quiet. The hardest part was to make a bigger timing cover. I ended up cutting up and welding together parts of three timing covers then had to sand and buff it all smooth before electroplating it. After all that work I couldn&apos;t sell that car. Its still in my garage after 40+ years..and it still runs.

  38

• BR

  @BretButlerSr · 2 weeks ago

  I take those nylon timing gears replace them with double roller timing set .

  50

• CR

  @craigbosko2229 · 6 days ago

  My first car was a 1970 Pontiac Le Mans I bought it from my Aunt and paid $900 ,it had 63,000 miles on it and a 350 cu in engine but eventually adding alot more miles to it the top gear had nylon plastic over the gears and ended up wearing down but I replaced the top gear just with steel teeth only, the bottom gear was in excellent condition and the chain itself had about maybe 3/16 of an inch of play in it so I kept the original timing chain. Timing on that engine was 9° and when I put everything back together, checked the timing the engine ran perfect .The entire job took me a week and a half but I really learned alot about an engine and I&apos;m totally convinced that the heart of an engine is the Timing Macinisum not the Carberator and I was about 25 year&apos;s old and I wasn&apos;t afraid of my hand&apos;s all grease, in fact I was looking forward to it. Every vehicle I&apos;ve ever owned has had a timing chain, I WILL NOT EVER OWN A VEHICLE WITH A TIMING BELT IN IT JUST BECAUSE THESE AUTO MANUFACTURERS WANT TO MAKE EXTRA MONEY ON THE SIDE. The only way to go is having a Timing Chain or Timing Gears, period! If you&apos;re into Diesel you&apos;ll get Timing Gears in the engine. Even the Corvette engine&apos;s have Timing Gears in them. 😊

  1

• EA

  @earlatkins9559 · 7 days ago

  When I had my Chevelle&apos;s 283 rebuilt, &nbsp;it had a crank gear with nylon teeth. I had both gears changed to all metal. &nbsp;The engine actually ran better and sounded great.

  5

• PA

  @PatrickHarris-tc3dh · 9 days ago

  I remember changing the timing gears on a 4 year old Pontiac back in 1970, the plastic never lasted for decades if it was regularly driven.

  1

• UL

  @UlyssesConradFitt · 13 days ago

  I refreshed a 1973 440 with 117K miles . Replaced timing set with an HP dual roller . No noise . <br>The original chain was very loose , but the nylon cam gear was still in surprisingly good shape . <br>I just changed the timing set , oil pump , and valve seals . <br>It ran like new and still runs now , 20 years later .

  12

• DR

  @drwthmpsn7457 · 8 days ago

  I rebuilt a 1963 Chev 283 decades ago. It had nylon teeth on the timing sprokets. &nbsp;I reason I&apos;m told was to reduce noise.

  1