Weak Links
Race Director
Joined: Nov 2000
Posts: 10,340
Likes: 664
From: Beverly Hills (Pine Ridge) Florida
If your asking what fails first (assuming good maintenance), then I would offer that internally, the cast iron (integral) valve stem guides are one of the first to go. Fixing that normally means installing bronze guide liners with new valves, and switching to roller tipped rockers (recommend the Comp Cam version) does wonders to alleviate that issue in the future. Also add PC seals to the intake valve guides. Note that when the guides go, oil floods down the stems, and cakes the backside of the intake valves (reducing air flow through the valve). Also the valve rocks on the seat, and therefore does not seal properly.
The bottom end is pretty good, unless wound to high RPMs on a regular basis. Then I would invest in some better rods. Flat camshafts/lifters are on the endangered list due to the change in motor oil, but switching to a good diesel oil that is rated CI-4 will solve that (at least while CI-4 is still available). Oil pumps can see an awful lot of wear from debris, and still pump enough oil. SBC bearings do fail, but normally only due to other faults that caused them in the first place.
Timing chains do stretch (which retards the cam and boosts high RPM output at the expense of the low end), and eventually slip/break.
Head gaskets and warped heads/block deck occur normally only if the engine is overheated, and then it is a sure bet.
Sometimes rocker studs pull out, but that is rare (but beware if you change the cam to a higher lift version with heavier springs - then switch to screw in studs, or at least pin the existing ones).
Water pumps last and last, but eventually they all begin to leak. Same with fuel pumps. Distributors fail slowly, but they all need a rebuild eventually. Carbs should last along time, but throttle shafts/plate wear, and Holley accel. pumps leak, etc.
Now I am sure I have forgotten some!
Plasticman
The bottom end is pretty good, unless wound to high RPMs on a regular basis. Then I would invest in some better rods. Flat camshafts/lifters are on the endangered list due to the change in motor oil, but switching to a good diesel oil that is rated CI-4 will solve that (at least while CI-4 is still available). Oil pumps can see an awful lot of wear from debris, and still pump enough oil. SBC bearings do fail, but normally only due to other faults that caused them in the first place.
Timing chains do stretch (which retards the cam and boosts high RPM output at the expense of the low end), and eventually slip/break.
Head gaskets and warped heads/block deck occur normally only if the engine is overheated, and then it is a sure bet.
Sometimes rocker studs pull out, but that is rare (but beware if you change the cam to a higher lift version with heavier springs - then switch to screw in studs, or at least pin the existing ones).
Water pumps last and last, but eventually they all begin to leak. Same with fuel pumps. Distributors fail slowly, but they all need a rebuild eventually. Carbs should last along time, but throttle shafts/plate wear, and Holley accel. pumps leak, etc.
Now I am sure I have forgotten some!
Plasticman
Last edited by Plasticman; Feb 23, 2007 at 07:49 PM.
Thread Starter
Safety Car
Joined: May 2003
Posts: 4,797
Likes: 239
From: Ocean Township NJ
Thanks John.
It's a 365 SHP, which I'd like to spin to 6000-6500 RPM, every once in a while. I'm seriously considering replacing the stock rods with a stronger set..........to protect the original block. While I've got it apart, I'd like to "optimize" the original design. What I'm looking for, is what components need to be improved upon, and in what order (or reasonable facsimile thereof)to boost rev range/peak output/torque. Some of these items might be mutually exclusive, but you can see where I'm going.
Engine is as built, all original components still in place.
It's a 365 SHP, which I'd like to spin to 6000-6500 RPM, every once in a while. I'm seriously considering replacing the stock rods with a stronger set..........to protect the original block. While I've got it apart, I'd like to "optimize" the original design. What I'm looking for, is what components need to be improved upon, and in what order (or reasonable facsimile thereof)to boost rev range/peak output/torque. Some of these items might be mutually exclusive, but you can see where I'm going.
Engine is as built, all original components still in place.
Le Mans Master
Joined: Apr 2001
Posts: 9,556
Likes: 288
From: Granbury Texas
I agree with John on the wear stuff, but when something BREAKS, it will be valvetrain or a rod. Change to better rods and upgrade your whole valvetrain together and you can run 7000 rpm for years. I do
