I have some questions about my engine I was hoping someone could provide some insight into.

2002 Acura RSX, base model (K20A3), 111,000 miles today.

About 14K miles ago (97K on the clock), I switched to Amsoil Signature Series 0W-30 oil and an Amsoil ea filter. I replaced the filter at 10K, after receiving a TSB from Amsoil that said to not run that particular model for > manufacturer's recommended interval. (5 or 10K, severe vs. normal conditions) Replaced it with a Wix and topped off with more Sig Series. I had also had a UOA done at 8K miles by Blackstone Laboratories that gave me the green light to continue using the oil. At 110K, I popped the top to check valve lash. While turning the crank, I noticed that two of the intake lobes were pitted. The car had been driving fine, save for the low-end hesitation that I attribute to a high-flow catalytic converter (reduced backpressure that the ECU can't accommodate.)

Once I saw the pitting, I screamed and ran around the house about ten times, then calmed down and put it back together. I found a used camshaft for $40 shipped that was in like-new condition. 130K miles on it. (It pays sometimes to have the "low-performance" engine - few people are interested in used parts, so they can be had cheaply!)

The owner always used 5W-30. Until roughly 80 or 90K miles, I used Mobil 1 5W-20, changed every 5-10K, per Honda's recommendation. The jury is still out on this issue (K20A3 intake camshaft lobe pitting is semi-common problem) as to whether the pitting is caused by thin (20 weight) oil or extended OCI's or poor quality camshafts.

A friend and I installed the new camshaft according to the Helms shop manual, and he adjusted the valves. I don't trust myself to know what constitutes "some drag" and "too much drag". The car ran fine, but more noisily than prior to the install.

Incidentally, I had another UOA performed by Blackstone at 13K. They said the oil was fine and to send another sample in 3K more miles.

So this week I took it to a local grease monkey, who adjusted the valves for $60. Car runs smoother and quieter. Unfortunately, one of the camshaft holder/cylinder head cover holder bolts snapped, apparently from over-torqueing the nut that holds the cylinder head cover on.

So, the party begins anew.

I spoke with the guy that did the work, and he agreed to fix the problem. I have ordered the parts.

My question is - is it OK to pull the head cover and simply remove and replace that one bolt - or is it necessary to loosen all the camshaft holder bolts and re-torque per the tightening sequence in the service manual? If all the bolts are loosened, then I would imagine all the valve clearances would need to be re-checked. Ugh.

Also - the man that checked/adjusted the valve lash mentioned that one exhaust lobe had a "discoloration, but was smooth, no pitting or scratches or anything". Does that sound like something to be concerned about?

Finally - is 10K + too long to run an oil even as good as Amsoil's finest? I believe that the intake cam lobe pitting took place before I switched to 0W-30. But I don't know for certain. And I wonder what caused the "discoloration" on the exhaust cam lobe.

I changed the oil and filter last night (Wix, Amsoil Sig Series 0W-30) primarily because of the recent camshaft install but also partly out of fear that my lobes are wearing because I have been running the oil too long.

Thanks in advance for any insight you can provide.

I would replace the bolt and be done with it.

As much as I love synthetic lubricants, I'd recommend that you only use SAE 5W-30 (e.g. Amsoil ASL) and change the oil and filter every 6,000 miles or 6 months, whichever comes first. I'm not a fan of SAE 5W-20 and especially SAE 0W-30 oils.

Discoloration likely came from the exhaust valve being adjusted too tight on the previous engine. Just make sure you don't adjust your valves to tight--it's better to have a little bit of noise.

Thanks, TX! I thought that would be adequate (just replacing the bolt), but at least one guy told me to loosen them all and re-tighten, so I wanted some more opinions. Of course the mechanic that broke it wants only to replace (and not do it the long way), so I didn't want to go by his recommendation without another opinion.

What is it about 0W-30 that you don't like?

Too much VI Improver to compensate for the 0W. NOACK Volitility tends to be higher also. They tend to have lower HT/HS Viscosity, which is important for OHC engines. The highest pressure points in an engine are on the cam lobes. They are last on the oil train and the first to go, if there's an oil problem. Focus on European oil standards and try to buy a SAE 5W-30 full synthetic engine oil that is ACEA A3 rated and MB 229.3 or MB 229.5. rated. Europen oil specs are much tougher--they are set by the auto industry, not the oil industry.

Damn it! I just loaded up with fresh 0W-30! Should I dump it out, or is it safe to run for short OCI! Lot of $ to flush down the drain, but so are new camshafts.

I was running Mobil 1 0W-30 previously; maybe it contributed to the camshaft pits. :>(

I wouldn't get rid of it. Instead, shorten the OCI. OW oils tend to shear down faster.

3K, 5K, 6K, 10K..

What about adding some zinc to the 0W-30?

Some BITOGERs are blenders, I'm not--too much can go wrong.

Check out full synthetic SAE 5W-30 Pennzoil Ultra European.