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Rotating assembly and cam swap on 50K motor...what to replace?

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Old 01-31-2006, 12:06 AM
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Default Rotating assembly and cam swap on 50K motor...what to replace?

Ok I already have a rotating assy from an LQ9 in the garage, found a good deal on another member's complete LQ4 that I would like to buy and swap the rotating assy and cam out. For a 50K mile motor, what would you replace? Gaskets? Bearings? Or just swap and go?
Old 01-31-2006, 12:15 AM
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Main bearings, rod bearings, gaskets, cam bearings will be fine as long as there isnt excessive wear, hone the cylinder walls, put a ported LS6 oil pump in there, and call it good IMO.
Old 01-31-2006, 12:35 AM
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**** that's a lot of stuff. I was hoping for less than that.

Here's my dilemma....let me know what you guys think.

1st option: buy a motor in pieces and assemble, re-use as much as possible from the 5.3. Requires new heads ($350), rotating assy (200), lifters (250-ish), block (400), gaskets and bearing (400-ish?), crank pulley (35 - mine is chipped). The I can part out what's left of the 5.3 and probably get about $300 back. Total cost $1335.

2nd option: buy a running LQ4. Swap in the rotating assembly from the LQ9. Requires running LQ4 (1500), LQ9 rotating assy (250), misc gaskets (hoping for small cost - something insignificant). Then I can part out the complete 5.3 (500-ish), sell the LQ4 rotating assy (125-ish), LQ4 cam (25), intake manifold, injectors, etc (100-ish). Total cost $1000, not including gaskets and bearings. If the LQ4 is gonna require a lot in the way of gaskets and bearings it's probably a wash, but if I could get away with most of the stuff that is already in there, I could probably save a couple hundred $$.

Opinions? (Prices are best guesses....)

Last edited by thunder550; 01-31-2006 at 12:45 AM.
Old 01-31-2006, 12:51 AM
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Up the limit on your credit card!

You want a LQ9, or could you just slap the running LQ4 until you can build it the way you want it? I just don't see a LQ9 worth 1000+ bucks more than a LQ4. But maybe I'm not seeing the whole picture.
Old 01-31-2006, 12:54 AM
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What I'm trying to do is get an LQ9 for a lot cheaper than I could buy a complete one for. I think I can do it for the prices listed above, but I have not built a motor before and I know that with some project there are a ton of small parts that you normally don't think about that add up significantly. I already have spent $550 for an LQ9 rotating assembly and 317 heads. I am going to reuse my cam, rockers, springs, and pushrods that I currently have on the 5.3. Basically looking for the cheapest way to end up with an LQ9. I already have the hard part down, the LQ9 rotating assy. Just trying to figure out the cheapest way to get it inside a block and running.
Old 01-31-2006, 12:58 AM
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Originally Posted by Wilde Racing
I just don't see a LQ9 worth 1000+ bucks more than a LQ4. But maybe I'm not seeing the whole picture.
Just realized what you meant by this too. I am not talking $1000 on top of the $1500 for the motor, I am talking $1000 total after I sell off the extra parts at the end.
Old 01-31-2006, 01:30 AM
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****....the voice of reason is starting to kick in now. I should just take my time and do it right, replace everything that might be questionable. Thanks for the replies guys, I think I am just going to continue to buy small pieces one at a time, since money is tight right now anyway. Don't need to add $1500 to the credit card right now.
Old 01-31-2006, 07:44 AM
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Originally Posted by thunder550
Just realized what you meant by this too. I am not talking $1000 on top of the $1500 for the motor, I am talking $1000 total after I sell off the extra parts at the end.
O- now I'm picking up what you are laying down. Ya a running LQ9 at 1000 bucks invested is a great deal!

Originally Posted by thunder550
Don't need to add $1500 to the credit card right now.
O come on its fun
I'd start looking for a cheap 6.0 block, Do your first plan, it's cheaper to get started.
Old 01-31-2006, 10:48 AM
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Hey Thunder, I would definately take my time and build it right the first time. You mentioned using the old 5.3 cam. I know alot of people reuse cams, usually with new lifters or with same old lifters but on same cam lobe as before, I would not recommend that route on a vehicle that I personally had to rely on. The difference in valve spring tension (new/different heads) alone could ruin a tired cams lobe or several in short order. While it may not happen, its not worth the xtra labor/headache if it does.
It has happened to me on two seperate occassions, once with an old perfect circle brand cam and the other with a comp brand. I bought both cams new myself but reused them once each on a second buildup and both developed flat lobe(s) in a few thousand miles. Both had new lifters each time. People will tell you that with roller lifters and/or rockers that the cam will last longer. This could be possible if the rollers bearings didn't get sloppy due to wear which then creates all kinds of valvetrain issues.
Whatever happened with your transmission? I'm the one that recommended you talk to Mark B. @ Hughes Performance before you decided on tranny build.
I believe I talked to you last year in April at AS&M when you were dropping off your truck for headers install. I was driving the Red RCSB P/U and had just stopped in to talk to Ben.
Old 01-31-2006, 12:34 PM
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Thanks for the input. I do remember you from AS&M....haha come a long way since then. How's your truck doing?

The cam in the 5.3 has baout 15K miles on it right now, but it's interesting you bring that up. I have never heard of that before....what about all of the people on the board who are selling used cams and such? Is there a good chance that some of them would run into the same problem? My roller rockers were brand new and went in at the same time as the cam, and I would be looking at a brand new set of GM roller lifters for the new motor as well. I was considering going from the Ultra Toqrue to the Trucker cam from Vinci when I did the swap, I may just go ahead and do that from the beginning.

The tranny has been trouble...I have posted a couple other threads about it but if you haven't seen them here's a brief summary...

I decided to have my old tranny guy (Ken) rebuild it again. He found a broken parking gear and rear planet. First rebuild (he took it up to a 4L65E, had my stock converter rebuilt and restalled) a bearing in the converter went out and let the clutches scrape their friction material off, clogged up the lines and toasted everything. Second rebuild I don't think he had it cleaned up all the way and I lost the 2-4 band within a day. He has it again for the 3rd rebuild, I should have it back today I'm hoping. I already told him that if he doesn't get it right this time I'm taking it somewhere else, and he seemed ok with that. He even refunded my money until the truck is working correctly. Hindsight is 20/20 right? If I had it to do over again I would either take it to Hughes (actually stopped in to talk to Mark and have him diagnose the 2-4 problem before I took it back to Ken, just as a second opinion) or get an 80E and do the conversion. I may go ahead and do the 80E conversion as soon as I have the money for it anyway, just so I don't have to worry about it again.


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