The camshaft and lifters we...
The camshaft and lifters we removed were in excellent condition, and could certainly be used in a future project. Many builders recommend when installing a used cam and lifter set that each lifter be returned to its original lobe, or failure is possible. If original lifter order is unknown, new lifters are certainly an option. In either case, treat the installation as if using new components, and closely follow the supplier's suggested break-in, and you should have no troubles reusing a cam.
Conclusion
Few will argue that some modern oils have contributed to a number of flat-tappet camshaft failures, but we have to wonder, too, if improper break-in was a factor. We're finding now that even experienced hobbyists who've followed the same break-in procedures for years without incident are slightly revising their practice to ensure proper lobe and lifter polishing, and are making a bottle of oil additive a requirement at normal oil change intervals.
While some may feel that a flat-tappet camshaft is antiquated, and that roller technology has taken its place, we cannot forget the large number of hobbyists who don't have the budget or a combination that might benefit from a roller set-up-especially the young enthusiasts whose first brush with a flat-tappet is in a vintage Pontiac. So if you're considering a flat-tappet cam swap, closely follow the supplier's suggestions for break-in and long-term use, and your low-buck investment will likely reward you with thousands of miles of issue-free performance.
| Torque Specs |
| Item | Spec (ft lbs.) |
| Thrust plate | 20 |
| Timing chain sprocket | 40 |
| Timing chain cover bolts | 30 |
| Timing chain cover studs | 15 |
| Oil pan to timing chain cover | 12 |
| Harmonic balancer | 160 |
| Fuel pump | 25 |
| Fan and pulley assembly |
| to water pump hub | 30 |
| Valley pan | 3.5 |
| Valve covers | 8 |
| Distributor | 30 |
| Spark plugs | 25 |
| Coolant crossover to timing cover | 15 |
| Intake manifold | 40 |
| (25 if aluminum) |
| Carburetor | 4 |
If the cam gear was at 6:00,...
If the cam gear was at 6:00, the engine would be in No. 6 firing, and we'd have to rotate the distributor so its rotor points towards the No. 6 terminal on the cap.
A trip to our local parts...
A trip to our local parts store supplied us with the Fel-Pro gasket kits required to complete the camshaft swap-these include No. 2705 R.A.C.E. (Remainder to Assemble Complete Engine) and MS90205 Intake Manifold, which retail for around $25 each. After pre-fitting the timing cover alignment sleeves by slightly straightening and expanding them to snugly fit the block, scraping all gasket surfaces, and installing the new gaskets, we bolted the timing cover assembly to the block. We soaked the lifters in oil prior to installation, and coated the lobe contact surfaces with break-in lube during installation. We then installed the pushrods and rocker arms.
Hydraulic lifters utilize...
Hydraulic lifters utilize pressurized oil and a controlled bleed rate to continually maintain minimal valve lash. Factory lifter preload uses an ingenious set-up that incorporates a rocker stud with a precision-machined shoulder, a jamb nut, and 20 lb-ft of torque that's virtually maintenance free. We previously converted our engine's valvetrain to manual lash, which better controls preload, preventing lifter pump-up, and allows the use of roller rocker arms. Our preferred method of adjustment includes rotating the engine so one pair of lifters is on the camshaft's base lobe. We gently tightened the rocker nuts by hand until the pushrods made solid contact with the lifter cups, then used a wrench to tighten them 1/2 turn past zero lash, and locked the set screw.
Veteran engine builder Nunzi...
Veteran engine builder Nunzi Romano suggests using high-quality conventional diesel oil, a high-quality oil filter, and a bottle of GM Engine Oil Supplement (E.O.S, PN 1052367) for initial flat-tappet camshaft break-in and normal operation. Containing a highly concentrated amount of the desirable, high-pressure anti-wear additives, Romano says he prefers E.O.S. to others currently on the market, and highly recommends adding a bottle at every oil change.
A process similar to removal...
A process similar to removal can be used to install the harmonic balancer. We had our helper crawl under the car and secure the flywheel while we applied 160 lb-ft of torque on the retaining bolt. We then reinstalled the valley pan, coolant crossover, intake manifold, accessories and fan. The freshly gapped spark plugs were installed next, and then we dropped the distributor into place, aligned the aforementioned marks, and secured all its electrical connections. Before installing the carburetor, we filled its float bowl with gasoline and connected all the vacuum hoses. We then installed the radiator, filled it with coolant and water, and filled the crankcase with oil.
Quick start-up without prolonged...
Quick start-up without prolonged cranking is essential to proper break-in. With everything assembled and the engine ready to fire, we connected the battery and manually pumped the carburetor to provide the engine with a couple shots of initial fuel. We then hit the starter and were rewarded with an engine that fired almost instantly, and the break-in process began immediately thereafter. Romano's suggestions were to run the engine between 2,000 and 2,500 rpm for 20 to 30 minutes. During that time, we used a timing light to check spark lead, and we closely monitored engine vitals, also listening intently for abnormal noises.