So, Ive been into LS motors for less than a year and this question is just so I can explore my options. First off, my 98 has 127,xxx miles on it. It doesnt smoke or knock at all. Im accumulating parts now, that I originally planned on puttin on a fresh short block (which I was goin to put togather later). As I look around all the LS forums I can find, I see more and more motors with miles equal to, or higher than mine doin head/cam swaps, full bolt on's and nitrous. My question is, assuming my compression check turns out good, if I was to put a FAST 90 combo, Patriot stage II's, an MS3, and full exhaust on my car, how much longer could I expect the motor to last on a solid tune with occasional beating?

 

You're rolling the dice, just as you would with a new engine. Do some shortblock upgrades while you're at it. You'll sleep better at night knowing your engine has forged guts, or at least some better rod bolts in it.

 

Ya Ill prally do the rod bolts if I carry on with this motor. If the general mood is to go with internals, then Ill just wait and put a short block togather outa the car. I wanna minimize down time and not have the stress of havin one shot, so to speak, to have it run or not.

 

I hear you. I'm in the process of doing one slowly but surely. I like to do it once and KNOW its going to live, rather than risk some pricey power parts bolted to some weak *** stock components.

 

i have 127k on mine and have about 500 miles on my cam setup and heads are going on in the next week or two, crossing my fingers

 

^ See thats what Im sayin. There seems to be a lot of ppl doin stuff like this at high miles. Im just curious as to how long I can expect it to live before I need bearings, rings, a hone, etc. Assuming that the rods and pistons hold up to the task without trouble.

Like you said, deadhorse, its a roll of the dice with any motor, but Im not sure how the odds are on my end of the deal lol.

 

I'm about to swap in a 100k mile LQ9 and swap on H/C/I, while I build my 408 on the side, now that my H/C LS1 went at 65k miles due to oil pump failure. Sometimes it's luck/or unluck of the draw on a motor's demise coupled with upgrades, but the biggest factor is how the motor's been maintained during those 120k miles. If you've owned it for it's majority and know that it's been taken care of, I say go for it. Anything else is a crap shoot.

 

Well, I havent owned the car most of its life, but I am only the second owner. Lookin at the different aspects of the cars history it looks like it was DD'd locally all its life. I can vouch that everything else on the car was taken care of greatly. I still need to run a compression check to see where I stand. As we all know, theres no lies on that test.

 

I believe if you have about 130,000 miles and you put h/c on the car. Take it easy for the first few hundred miles. Slowly wean the new parts into the internal ones. They have to mate together. AS time goes on then give it a little more gas etc etc. I think it will work fine granite you complete the supporting mods too.

 

^ that doesnt really make any sense because there is virtually no break in on a fully hydraulic valvetrain...

 

mine has 141,4xx and is getting h/c/i swap as soon as my timing set and ported oil pump arrive.(within a week). if you do a camswap make sure you do the lifters. im pretty sure my car was maintained pretty well, ive put 12k on it since i bought it and havent had to replace anything besides the fuelpump. now granted, im not expecting my stock bottom to last forever...i really just want it to last until winter, then ill be building a 408 stroker or similar.

buddy of mine has 110k on a PRC 215 headed, MS4 cammed 02 TA, shifting at 7k rpm's...also sprays a 150 shot, and he has no problems at all. his car is a ******* beast.

IMO, with higher miles i would go with a smaller cam. my stock block will definetely never see 7k rpm's.

 

Talkin about the 7K shifting reminds me of one more thing. I personally wont be goin with a ***** to the wall tune, for the sake of saving some strain on the internals. Ill be lookin more for stock like driveability. Even with a nice conservative tune I really shouldnt be too short on power lol.