zx2ner25

ok, Im currently in the process of building a (somewhat) budgeted lm7 motor for an s10 im restoring. It will probably see anywhere from 5-10 pounds of boost.

my question is, will it hold up?

so far i have planned:
lm7 bottom end
lq9 heads
ls6 intake
ARP rod and head bolts
hardened push rods
Yella Terra Roller Rockers
SLP Heavy duty oil pump
SLP Double Roller timing chain
Texas Speed Custom Grind Cam
PRC Double Springs w/titanium Retainers

also for street use, which cam would you recommend? I want the turbo to spool up quick so its actually usable power

also, truck is 4l60e automatic, with 3.73 gears

HydroStream6

iTrader: (16)

Should hold up fine with decent tuning. Use GM MLS head gaskets. Lots of decent cams out there to choose from. Even the stock cam or an LS6 cam would be an alright choice.

southpaw0314

iTrader: (5)

id run the stock heads the 317 will lower the compression to much. it will run like a dog until you hit boost

zx2ner25

In your opinion, do you think someone like texas speed will be able to make me a cam that hs somewhat good manners but helps me get the turbo spooling quickly when I get on it?

zx2ner25

What about ls6 heads? I need something bigger, the lm7 is 10 to 1 I believe

HydroStream6

iTrader: (16)

I think the LM7 with 317s yields about 8.6:1

Stock LM7 is lower than 10:1 if I recall. If you want it to spool quickly, keep the comp up. With only 5-10lbs of boost, you shouldn't have to worry.

LS1NOVA

iTrader: (12)

Id use the stock 5.3 heads. The LM7 has 9.5 compression. Dropping 317's on will drop the compression too much unless your going for big boost which you are not.

I just put together a stock longblock 5.3 (stock cam, valvesprings, everything) with a Master Power T70 .96 that runs really really good on 8 psi. It lays over at 5500 due to the stock cam but the boost comes in fast, has great response, and is great street setup.

What turbo are you planning?

zx2ner25

IM using a single on3performance 76mm .96 ball bearing turbo

killernoodle

Let me know how that turbo works out for you. I contacted the sales rep about it asking if he has proof that it uses ceramic ball bearings, he said he couldn't take one apart without having to get it rebalanced. He did assure me that he has face-to-face contact with his supplier and that there is a very noticeable difference in shaft drag between the same size turbos in ball bearing vs sleeve bearing. He said the difference was audible as well (bearings make a unique noise).

Still, it is kinda strange behavior for a seller. If I was selling turbos and components I'd disassemble one of each product to show potential buyers that they are getting exactly what they pay for; especially if there was some doubt about their construction. I even mentioned to him that I bought a turbo once only to disassemble it and discover that it was sleeve bearing instead of ball bearing as advertised. There is no doubt that the oil requirements are different for ball bearings and I could have potentally ruined the turbo by putting a restrictor on it.

There is no doubt too that a single person who discovers that the seller is a liar can easily ruin the sellers reputation with just a couple posts and pictures on a forum.

Then again, maybe the seller is telling the truth, the turbo is awesome, and all of my fears are irrational

I'll be using one for my build if I hear enough good press, but right now it seems like an untested path. Don't let me dissuade you, I'm just pointing out concerns about an untested path

skinnies

iTrader: (33)

Leave the rod bolts alone, go with arp head studs, ls9 gaskets, use the stock heads, use an ls1 intake(no reason to spend the extra on an ls6 at this point), stock timing chain, stock oil pump, and stock rockers.

Good fuel and a GOOD TUNE is what will keep it together!

robbyredneck

iTrader: (1)

listen to skinnies. those engines are big time durable

zx2ner25

well ill do my best to post some type of review on it when i get it installed...

call me a newb, but what were you talking about with ball bearings needing different oil setup

would the other things hurt me at all? i've already bought some things, so im just curious what i should keep

killernoodle

Ball bearings generally need less oil than journal bearings. So I would be in the mindset that this is a ball bearing turbo and therefore I should install a restrictor onto the oil feed. This would have certainly caused damage because the journal bearings that are actually installed in the turbo would be starved of oil and fail.

The reason for this is that journal bearings need good oil pressure to float the shaft inside the bearings. Metal to metal contact between the bearings and the shaft is avoided in this way. Technically, the metal should never touch. In ball bearings, the oil only serves to cool and lubricate the ***** and races. The oil demands are less because you are not trying to float the shaft with oil pressure. Too much oil in a ball bearing turbo actually increases parasitic drag because the bearings would have to churn through oil.

If it has ball bearings you should be ok adding a restrictor (maybe ask on3performance what kind of feed it needs or if it has a built in restrictor), if it has journal bearings and you add a restrictor, it will probably fail.

zx2ner25

alright thanks, id never heard that before, but ill definitely take that into consideration

killernoodle

Before you install the turbo, would you mind posting some pictures? Maybe a video of you spinning it by hand? This might be a great turbo for the budget guys if it is what he says it is.

zx2ner25

not a problem... maybe a while before i get the turbo, Im still trying to do the wiring harness... 4 hours and counting

killernoodle

Cool deal, I was going to pick up a turbo in the next couple weeks. If I get around to it before you, I'll post a review of it

zx2ner25

Alright, sounds good, thanks

pwrtrip75

iTrader: (8)

only 5-10 lbs of boost definately leave the stock heads on it. like above mentioned.....317's will be a dog.

mgrm

So how did this turn out?