TBI 454 Engines / Want to know about timing chain gears......

[Klink K5]

I am just curious how many members have had their 87-95 454 TBI timing chain covers off to verify if they are FACTORY all metal gear & chain OR have you seen the aluminum/ plastic teeth upper gear with metal chain and lower gear.........

My 1995 454 engine I believe has a timing chain issue but just want to see how many people have seen what types of TIMING CHAIN SETUPS in their factory BBC engines

Thanks

 

[USSkoval]

I've got a '91 454 with 90k on it, iirc, the original cam sprocket was pot metal with nylon teeth. It's hanging on the garage wall, but I'm not home to go double check it.

 

[1-ton]

I would be willing to bet that the gears are steel. The only time I have seen nylon gears on a big block was back in the Mark IV big block days when there were factory big blocks in coups and sedan cars. Big blocks only come in trucks now days, and they would be equipped with a heavy duty use steel chain and sprocket.

 

[diesel4me]

I replaced two nylon coated cam gears ,one was in a '74 GMC C-10
I had with a factory 454/TH400,and another 454 one that came out of a '74 Chevelle ,that was in my '77 GMC K2500..both had sloppy chains and some missing nylon teeth off the cam sprocket,which I found lodged in the oil pump screen and the sludge at the bottom of the oil pan..

I replaced quite a few nylon cam gears in small blocks--one engine had lost almost all the nylon off the cam gear and at least one nylon tooth made it past the oil pump screen and got mashed into the pump gears..engine still ran great with normal oil pressure though..

I had a GMC Cabalero that had a 229 Chevy V6 that needed a timing chain so bad it had worn a hole in the timing cover..

I happened to have a box of free GM parts a friend gave me when he was cleaning out his garage..one of the items was a new in the box Cloyes S-390T cam gear that had the nylon coating..there was a new timing chain loose in the box too,that turned out to be for a SBC..

Being low on funds at the time,I used the nylon cam gear & the chain..figured if they last 100,000 miles,the truck would be long gone before it ever needed another one..but all the other engines I put timing chains and gears in got at least metal gears,vehicles I was planning to use to commute to work in long distances got a double roller Cloyes setup...

 

[USSkoval]

Here's the original timing set from a '91 454. This would be a genV engine, pot metal sprocket with nylon teeth.