150K LS6 winter refresh, what would you do?
 

I have a 150k mile 2002 z06 as a track day / HDPE car. The season is over and I've got 4 months on my hands. The engine is stock and after suffering a broken valve spring a few months ago I decided I might want to do some preventative maintenance since I've been beating on it pretty good. I replaced the valve springs and valve seals and have good compression (200-205 PSI on all cylinders) and it runs strong but I probably ought to pull the heads and check on things.

I haven't done anything else to the engine besides improved racing oil pan baffles and a catch can set up.

It's long overdue for a water pump. I think it's original, probably everything is. What else would you do for reliability at the track? Timing chain / set?, oil pump, crank damper?

If I pull the heads, any recommendation for where to send them? New lifters I imagine?

Dare I swap the cam "while I'm in there?" It makes 354 hp to the wheels right now, but I wouldn't say no to a little more.

If it were me: C5R chain, chain damper, harmonic balancer, trunion bearings.

I don't think the oil pump really wears out (gerator), but they're inexpensive if you want to do it while you've got the cover off. Consider porting it and putting in a small shim.

Long may she run!

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if you are pulling the engine, I'd put fresh bearings in. If you are just servicing in place, I agree with GCZ. 125/150 thousandths oil pump shim is very easy upgrade....literally just a washer that fits in the cap

With the many miles I would be tempted to pull it and do bearings anyway. If you have the time and budget to go over it, new rings, bearings, hone the cylinder walls, timing chain, balancer, shim the oil pump.

I would not hone unless the block needs it you'll likely loose power.

that's one reason why I was asking for opinions, not losing power per se (although that is ) but just making things worse by messing with it. Trying to balance preventative maintenance vs "ain't broke don't fix it!"

The busted valve spring was a close call and something I should have dealt with proactively - those springs were yellow which I gather likely means original - in retrospect probably ill advised to be tracking a 20 year old 150k mile car for the past three years on original valve springs.

I also have a bad habit of doing things piecemeal and having to do it over again. Partly ignorance, partly being a cheap-skate. I've probably had my rear suspension apart 4 times in the past year, once for hubs, once for tie rod ends, then for balljoints and bushings, and then again to put in X-tracker hubs because I already trashed the standard SKFs. Probably should have just done it right once the first time. So if it's a good idea to do the timing chain @ 150k, I'd like to know what else makes sense to do at the same time. I haven't messed with engines all that much but I'm confident I could do a lot of what is being suggested so far. Pulling an engine would be a first for me and replacing bearings seems a little daunting, but if the consensus it should be done I've got all winter to figure it out. This car isn't a show piece by any means and it's not my daily, just so long as I get it back together by next season!

Thanks for your thoughts

My only concern would be a tapered wall with that amount of mileage.

With the heads off, it's pretty easy to check the bores....

do not send the heads to advanced induction in north carolina.