LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Scared to cam a high mileage motor

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Old 07-31-2006, 02:08 PM
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Scared to cam a high mileage motor

Well, I am to the point where I want to start heavily modifying my Z28. I just had the rear-end rebuilt (still has 3.23 gears though), and has a cat-back and CAI on it. My problem is is that the motor and trans have 145,xxx miles on them, and it is still my DD. I am wanting to go with a decent sized cam and good set of heads for it, but don't want to risk terminally breaking something in the motor or transmission. I will be doing a 700r4 build and buying a bare block for a 383 rotating assembly in the future but will consider a basic rebuild for what i have, but for now I just want to go ahead and do a H/C swap. Would you suggest this at such high-mileage or look into a rebuild first? Thanks.

- Also, I will need to do a higher stall speed torque converter for this cam, and need to know if that would be smart with the mileage as well.
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Old 07-31-2006, 02:52 PM
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Re: Scared to cam a high mileage motor

Cam would be okay, but heads AND cam is a fair amount of torque...the T56 will hold up for a while depending on how it's been abused. If you're thinking of H/C, make sure you have headers on order as well...have to get the fundamentals first. In your shoes, I'd save up for the bottom end/transmisison and do everything at once for peace of mind.

I cammed my T/A at 140k miles and it's doing pretty well...3rd gear has a synchro on the way out but she's still got probably 3-4k left, and it had that problem before the cam swap. Everything else is in tip-top shape.
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Old 07-31-2006, 03:29 PM
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Re: Scared to cam a high mileage motor

do a compression and leakdown test...see how the engine is.

beyond that...it's a crap shoot.

we've all seen spun bearings on engines with <50K miles...and engines that are like the energizer bunny with >100K miles.

don't be a *****...build it...when it blows up...rebuild it better
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Old 07-31-2006, 04:05 PM
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Re: Scared to cam a high mileage motor

mine went at 114k with hotcam spun bearings...definately do a leakdown or just save up and rebuild it.
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Old 07-31-2006, 04:08 PM
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Re: Scared to cam a high mileage motor

CC306 123kmiles and 2 spun rod bearings.
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Old 07-31-2006, 04:23 PM
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Re: Scared to cam a high mileage motor

i am scared of the same thing..........i have run out of mods and i want a cam, but am afraid of a spun bearing

<------------103k miles here



so afraid i am probably just going to leave it like this and sell it in a year or two and buy a vette or a ls1 camaro and a acura for a dd, lol
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Old 07-31-2006, 05:15 PM
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Re: Scared to cam a high mileage motor

I did a cam with 140k miles. The bearings lasted 3 days.
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Old 07-31-2006, 05:20 PM
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Re: Scared to cam a high mileage motor

did cam with 109k -

5k later and about 30 track passes.... still reving it to 6400 almost daily with absolutely no problems..


like said above... crapshoot. but if it breaks, just think of it as finding the weakness in your engine
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Old 07-31-2006, 05:24 PM
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Re: Scared to cam a high mileage motor

It's a crapshoot that I would not suggest if you cannot afford to be without your car and cannot afford to fix it right away.
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Old 07-31-2006, 05:31 PM
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Re: Scared to cam a high mileage motor

Originally Posted by 94v6a4
I did a cam with 140k miles. The bearings lasted 3 days.

Damn
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Old 07-31-2006, 05:35 PM
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Re: Scared to cam a high mileage motor

If this is your DD dont risk it man. It will get real expensive if you dont have the cash to fix it right away. Build you a motor on a engine stand and take your time. Install it over a weekend and people will wonder where you got the new 150hp from.
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Old 08-01-2006, 04:06 PM
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Re: Scared to cam a high mileage motor

That's the thing, the car is my DD and I'm in my last year of high school so I have to keep it running. With over 145k miles on it I dont want to risk too much. I really have just run out of mods though. Being in an emissions county I can't do too much with headers and that's about the only thing left. Guess I'll just save up and get a beater once I graduate.
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Old 08-01-2006, 04:49 PM
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Re: Scared to cam a high mileage motor

Originally Posted by 99 outlaw
That's the thing, the car is my DD and I'm in my last year of high school so I have to keep it running. With over 145k miles on it I dont want to risk too much. I really have just run out of mods though. Being in an emissions county I can't do too much with headers and that's about the only thing left. Guess I'll just save up and get a beater once I graduate.
just save up and do it right.........build a new motor

Victory Racing is offering full rotating assemblies for 1500

just buy that, find a block..........have it cleaned and go from there

besides a cam swap with all the RIGHT things replaced would have costed you the same thing.

Cam, Springs, Roller Rockers, Double-Roller, Electric Water-pump, Gaskets, and Dyno Tuning Time.............

Do it right the first time,

If you're on a bugdet, go forged internals now, and run your stock heads and cam.......then upgrade from there. Then you have unlimited possibilities (Depending on how strong you made the bottom end)

Whatever you do, GL
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Old 08-01-2006, 04:51 PM
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Re: Scared to cam a high mileage motor

Spray it with a 100 shot instead for now.

I also wouldn't do heads/cam w/o *some* kind of headers on there.
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Old 08-02-2006, 01:24 AM
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Re: Scared to cam a high mileage motor

Originally Posted by scottslt1z28
just save up and do it right.........build a new motor

Victory Racing is offering full rotating assemblies for 1500

just buy that, find a block..........have it cleaned and go from there

besides a cam swap with all the RIGHT things replaced would have costed you the same thing.

Cam, Springs, Roller Rockers, Double-Roller, Electric Water-pump, Gaskets, and Dyno Tuning Time.............

Do it right the first time,

If you're on a bugdet, go forged internals now, and run your stock heads and cam.......then upgrade from there. Then you have unlimited possibilities (Depending on how strong you made the bottom end)

Whatever you do, GL

Thanks for the nod Scott.

We can turn the rotating kit sale into a saving on the standard short block price. That has been a common option throughout the sale.

One thing is for sure its easier and cheaper to do it right the first time, than it ever is to do it twice

You have a PM Outlaw.
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