I drive my c5 daily, I have put on 30,000 miles in 2 years to the tune of 58,000 miles... I need a reliable motor for 100,000 miles...

I am comparing engine choices vs. mod types in a reliability test.

Criteria:
I want to know how an LS6 Crate engine with its finely engineered specs and perfectly combined metal tolerance to heat expansion will stand up against a custom built motor using aftermarket vendors and combined parts.

The test:
performance over a 100,000 mile period

Choose one:
1)New Custom NA motor with Stroke/Head/Cam package to produce 550 RWHP
2)New Stock short block with Turbo/Head/Cam package to produce 550 RWHP

Final questions:
-Does a custom built aftermarket motor perform trouble free for 100k Miles?
-Which setup will last longer with less issues on a test over 100k miles?

:confused:



[Modified by KEPRGHT, 8:16 PM 1/6/2003]

 

I vote for #1.

 

You drive daily, and have 58,000 miles on your current motor. You are looking to replace that motor and want the replacement motor to last 50% LONGER than you current motor (100,000 miles), AND at the same time, you want 60% more HP (350->550). If the replacement motor is treated the same as you current motor, and has 60% more HP, then It would be hard to believe that the replacement will last as long as your current motor.

Have I misread your question?

 

Neither one will last 100K. YOur are asking too much for a high performance engine. You would be lucky to get half of that.

 

This is an issue I used to bring up with the C3 crowd every now and then. My experience has been that a rebuilt engine, even without an aggressive H/C setup, will almost NEVER last 100,000 miles. In fact, I've never known a single person who has been able to go more than 100,000 miles with a rebuild.

On the other hand, I can recall reading an excellent article in Car Craft or Hot Rod magazine about factory crate engines. When they spoke of the Chevy ZZ3 engine (345HP and 392 lbs-ft torque), they mentioned an interview with one of the Chev. engineers involved with this engine. He told them that the engine can be pushed hard and yet STILL be a 100,000-mile engine without breaking a sweat.

Needless-to-say, I went with the ZZ3 and easily cranked out 290 RWHP. No, it doesn't generate the power you are looking for, but I tend to believe that factory crate engines are generally more durable than many rebuld jobs.

 

The above comments on longevity are spot on. Your two objectives are clearly in conflict with one another.

550 RWHP NA is a stretch whether you're looking for long life or not. Unless I'm mistaken, no one has posted dyno results showing that much power without spraying. As for the turbo option, you would have to drop the compression of the factory motor to 9:1 or less to allow a boost level on pump gas that will get you to 550. The most common way to do this: aftermarket, dished pistons, so goodbye to factory precision and the perceived reliability that goes with it.

 

to get 550rwHP NA it would have to be an extremely radical motor. :eek:
Aggressive solid roller cam, high CR, etc.

A motor like would require valve train refreshment every season I think, at a minimum.
Valve lash would need to be constantly adjusted, possibly more internal motor maintenance would be needed on regular basis.

 

Mitch,
My current motor is still pumping out the ponies. I dont need a replacement and probibly wont untill the 100k mark. I am thinking of going turbo, and am interested in getting info from Engine builders or people with built engines about how long their engines last without problems.

Charlie,
How long have you seen performance built (aftermarket) engines last?

Dave,
Yea, this is exactally what im thinking, but add a turbo with lowered compression heads (leaving the pistions alone) should run well for 80k miles im thinking...

Eug,
thanks for the input on HP/Mod in NA

Marco,
Im thinking lower compression heads (6.0L) what ya think

Anyone with info on the above topics is greatly apreciated.

I am currently thinking:
-New LS6 short block (or trade up to a 02 z06)
(leave it stock & and do a proper 5k mile break in)
-6.0 Heads with lowered compression
-FI Cam
-Cerra Turbo kit (after they work out the bugs)
-boost to about 500 RWHP



[Modified by KEPRGHT, 9:46 PM 1/6/2003]

 

Boost over 5-6 lbs. on a stock block might be OK for a while with a 9:1 C.R., but detonation can do a job on stock pistons. Forged, lower compression pistons would be good insurance. Then, 500 RWHP with a turbo, especially if you stay out of high boost conditions a majority of the time, might give you the life expectancy you're seeking.

 

Marco,
Have you heard of the 6.0L heads? Do those have a 9:1?

Could i get less compression from porting the CC of the head?


[Modified by KEPRGHT, 12:49 AM 1/7/2003]

 

Go with the aftermarket to be assured all clearances are correct. GM is not in the buss. of building high horsepower reliable engines. Simple things like rod bolts in a factory eng. are good enough for a honda maybe. Connecting rods are marginal at best the pistons are junk hyperjunk. Find a GOOD machine shop in your area and have them do the engine right the first time. I just completed mine what a nice peice engineering awsome. easiest engine Ive ever removed. Put in good rod and piston cam some head work and you will be one happy camper.

 

David,

How long will i be a happy camper?

20k miles?
60k Miles?

 

I don't think either type engine package will do what you ask. To get 500+ rwhp you will have to "push the envelope", and I don' t mean just with block, head or camshaft. If you plan on running the car hard (which is the only way you can get the HP you indicated with the packages you indicated) you will have valve spring issues at the least. I have a H/C package from Cartek (their Stage 2-X) and even with my A4 after 10,000 miles the valve springs "begin" to loose some strength. This was not enough to cause problems, but I am talking 10,000 miles and you are speaking of 100,000 so you can see the wear issues you will have. My engine has 80,000 miles on it but the H/C package has only 10,000 and my rwhp is only 424 with the A4, but a 6spd will be more, but I doubt it will achieve 500 rwhp. A friend has a 97 with 120,000 miles and has recently installed the Magnasun S/C on it, but he cannot achieve 500 rwhp even with that ! As a matter of fact his rwhp is just shy of mine, but that is with the stock boost they have (approx 5lbs he states). I would say if you want 100,000 uninterrupted miles then you better stay away from big rwhp #'s.

 

With good machine work proper clearances I expect 60k before any type of repairs. The stock junk went that long rebuild because of oil burning problem rings stuck to pistons. ANDTHE NEED FOR SPEED....

 

This is EXACTALLY the type of information i was looking for... numbers from real applications in use.
Thank You!!

 

It DEPENDS on how hard you drive the car. :lol:

But seriously though, why would a person want a Hi-HP car and not drive it hard?

 

Ive had a number of built cars in the past and what I've learned is that the more power you want over stock is directly proportonal to a shortened life expectancy. Even with a H/C set-up you start taxing the valvetrain which increases noise and shortened lifetime. I realize that aftermarket parts can be good and for a specific range/application they will out preform OEM but OEM was engineered with deeper pockets for longevity/noise/all round performance. For 100k expectancy and turn-key reliability/daily driver, stick with stock HP application(like Z06) and be happy. If you got to build more into it, expect to fix it and/or have quirks-it's reality.
BTW, I'm building an ATI D1 Z06 with expected 600RWHP but I'm not expecting even close to 100K and I know that I'll have to work on it and it'll have some driving sacrafices/quirks.