I'm not going to jumble this thread up any more, I'll just add that, your lifters did have a pattern that you couldn't see with the naked eye. And I promise it will shorten the lifespan of your cam and lifters at this point. It has been well proven to be a fact.
Gee, maybe they'll wear out at 180,000 instead of 220,000 miles
. I'm not worried in the least bit. The fact is that cam manufacurers like Crane et al want to sell you lifters and want to minimize any potential liability.
As or being common to change cams without changing lifters, yeah people do it all the time. With roller lifters.
I'm not talking about roller lifter cams. Most OEM service manuals I've owned or read on flat-tappet applications don't say anything about replacing lifters with the cam. Nor do the OEM's generally include lifters with a service replacement cam. What do they know that the general public doesn't?
Also, how were you able to inspect your lifters for a wear pattern if they were still in the motor? How have you been able to inspect them and the cam now? Thats all I have to say about it.
I was able to look at the old cam - if there was anything unusual going on with a specific lobe or lifter, it would have been obvious on the cam. What I did see was a nice polished wear mark around the circumference of each lobe that was consistent with other properly worn cams I have seen.
Here's the bottom line: Without giving any names since it's not fair to them, the people I consulted with on this include:
- A powertrain engineer from a major OEM with probably upwards of 20 years of experience, especially in root-cause analysis of design and engineering issues specifically on gasoline engines.
- 2 experienced engine test technicians who work for a major OEM. One of them has around 20 years of experience and was involved in analyzing and solving issues on every major engine launch his OEM has made in those last 20 years. The other test technician has at least 35 years experience and especially familiar with flat-tappet engines and has personally performed various performance and durability studies involving cam changes where lifters were not changed - the specific purpose of most of these studies was not to gauge cam/lifter wear, cam swaps were made with various lobe profiles, but all using the same lifters to evaluate the cam's impact on performance and emissions.
The consensus of all of these experienced folks was that I was worrying for nothing and that in their experience there is nothing to support the whole mismatched cam/lifters hysteria. Furthermore, none of them even endorsed or recommend a specific break-in procedure upon initial restart based on their experiences, although I did bring the engine RPM up and vary it for roughly 15-20 minutes.
Lastly, I did use a flexible camera inserted through the OPDA hole to inspect what I could after the engine had a reasonable number of hours on it. While I couldn't see each and every lifter/lobe, the ones I could see looked good - the cam lobes had nice polished spots on them where the lifter feet were making contact, and the lifter feet themselves looked good.
Again, you are welcome to believe what you want. I have personally discussed the issue with the experts and performed a successful repair. I'm in a small group of people who have actually done something to solve the issue rather than apply what are ultimately temporary fixes (no offense to the fine folks on this thread and all their hard work). Once the gear teeth on the cam are worn beyond the hardened outer layer, it is only a matter of time before the vehicle sets a cam/crank sync fault (even with a new OPDA gear) and goes into limp-in, rendering it undriveable.
My only purpose in this thread is to share my experiences and the knowledge imparted to me by my experts. I'm not really expressing opinions - I am passing along the experiences of experts in the field and providing details of my personal project and the results thus far. I leave the decision of what to do with their vehicles up to each person reading this thread, I just want them to be aware of the information and first-hand experience I have acquired before they chart their own path.