Cartel
Active Member
I had the pump out so I stuck the scope in there to have a look.
Is this a nylon gear?
Is this a nylon gear?
Timing chain...is it nylon?
- Thread starter Cartel
- Start date
Cartel
Active Member
Cartel
Active Member
I'm willing to bet it has this comp cams timing set in there
maybe this?
maybe this?
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Jerry Hall
New Member
Looks like a steel gear to me. The only nylon gear would have been an original part or OE replacement.
Worst pix ever lol. Nylon would only be the cam gear... nylon over aluminum, IIRC. If the chain isn't flopping around, why worry?? I would think most OEM cam gears would have surely self destructed from the heat/cool cycles by now???
57fury440
Well-Known Member
As said above that does not look like nylon. Most likely a steel replacement which is fine if it isn't sloppy.
Jerry Hall
New Member
Original cam gear on a 383 that I just rebuilt some months ago. The engine went back standard bore, and all stock except a upgraded cam. A little cleanup on that cam gear an timing chain and it would pass for almost NOS. The engine had 97K miles and only .002 wear on the worst cylinder. Absolutely no ridge was found. I had to replace one piston due to a cracked skirt. No one believes how clean this engine was for the miles shown on the odometer.
Gerald Morris
Senior Member
Save that engine for me! I had a pleasant surprise when opening the block I'm now running too. No ridges, pistons, while .060 over bore were also in XLNT condition. I had already removed a steel timing set from this engine, which was made originally no later than Nov., 1965, then rebuilt some time after, yet still long ago. Thanks for posting these pix. I've never seen the infamous nylon gear until now.
GOLDMYN
Senior Member
75K miles, no cracks or damage, BUT, I did replace it
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I would change that set if it were me. In photos #8 thru #12 I don't like the looks of the cam gear. It might just be the poor quality photo, but, to me, it looks like quite a bit of wear on it. What kind of slack is there in the chain? How many miles are on it? I would use at least a double roller chain instead of a stock looking single design.
Gerald Morris
Senior Member
I wonder how well modern plastics might do as cam gears, or if a cogged BELT with such would be best. Think of how much power one can deliver by reducing the mass of the timing chain! Racers think thus. I should liberate funds from the Oppressors and Exploiters to research this worthy notion, for The People of course.
Not for the feint of heart or budget build. CHRYSLER Jesel KBD-35000 Jesel 2-Piece Upper Pulley Belt Drive Systems | Summit Racing
Gerald Morris
Senior Member
Yes, racers think in terms of those crucial gains in efficiency and damn the expense. Reckon I'll stick with dual roller steel chain and sprocket stuff for humbler needs. Might be interesting to get the weight of the cam pulley and belt from Jesel, along with sundry metal pulleys and chains, then estimate the rotational inertia of each and how much power might be lost with each set. One can likely get a fair estimate of inertia from I = (MR^2)/2, then add in the Mchain to whatever portion of the pully circumference engages the chain or belt. We can then estimate our Tau and take w for a given rotational rate in rpm, allowing for 2pi radians et voila!
Then fun intensifies when we then opt for low mass pistons! Shall we try hypereutectic aluminized sand grenades, or forged aluminum discs? I'd go w the latter, but plenty folks like the former. What's the lowest mass we have off the shelf for pistons? Who makes the strongest connecting rod? How much moolah would a REAL racing engine go for in a B/RB block? If only I didn't have my little wriggling spawn to attend here, alas, but they're fun too! God-willing, I can teach them these simple concepts.
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