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Over the last few weeks my PV's engine has been sounding more and more 'off'. As usual, I kept blaming it all on the last change I did, kept tinkering with the Weber DCOE's, and blaming the occasional snorts and pops on the slightly cool weather. It still idled well, the fuel/air meter didn't seem to indicate anything too wrong, yet it got gradually rougher and weaker. So finally last night I took off the valve cover to check for a flat cam lobe. I had a ruler, but didn't need it. 7 of them went down nearly 1/2 inch at the valve, #1 (exhaust on cyl 1) went down only about 1/8th of an inch. Sure explains the snorting and backfiring - if you can't get all the exhaust out the exhaust valve some of it will still be around to ignite the incoming intake charge!
I had planned on putting a modified head on with the R cam and steel gears I'd aleady rounded up, but finances aren't allowing me to spend ~$1k on a new head so at this point I guess the stock F head will go back on as is.
I'm a bit puzzled at this cam lobe wipeout. It's the second one I've had it happen in this engine. The first was with an IPD street perf cam and IPD lifters that the engine was originally put together with during the big-bore rebuild about 10+ years and 40k miles ago. I had a different lobe go flat, and put in a new set of IPD lifters and a new 'D' grind cam, which has flatted again in only about 15k miles. I just wonder what I'm doing wrong. I tend to drive the car moderately hard, but I don't rev past 6500. I use synthetic Mobil 1 and Mann filters and change every 5000 miles. I adjust the valves roughly every 5000 miles as well. I did put 1.6:1 roller rockers on the engine about 2000 miles ago which probably put a little more stress on the lifters.
Any ideas on how to avoid another cam replacement?
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