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Old 03-10-2011, 02:51 PM   #1
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Default Guys with "built" (forged) engines

How many of you guys with forged bottom ends just tossed the pistons and rods in with little to no machining?

i have been interested since i have been hearing from most here that they havent balanced the engine internals and have been using it for XX years.


i would love pistons and rods in the short term but the balancing and machining costs in my area cost more than the parts which breaks the budget. on the inverse im not going to toss some gang parts in and blow **** up in a week.

Matt
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Old 03-10-2011, 02:57 PM   #2
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Bad idea, unless you are in cuba, and have no choice. Gotta plan for the machine work as well.
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Old 03-10-2011, 02:58 PM   #3
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I consider this notion a complete waste of time. Do it once, do it right, do it white.
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Old 03-10-2011, 03:40 PM   #4
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the bore and balance is cheap compared to everything else
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Old 03-10-2011, 03:45 PM   #5
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I just threw SBC parts in my motor and it ran. I did not even bolt anything down.
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Old 03-10-2011, 04:04 PM   #6
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I remember there being a thread on what machining is reccomended, but i cant find it with the search.

if you have done machining what have you done, what is needed and what is gravy?

if you just do a bore/hone and a full balance thats not too bad... but the builders here are slinging all of this crap around about high boosted street builds.
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Old 03-10-2011, 04:19 PM   #7
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A simple crank balance and polish should cost $120-$150 up here in Canada. Then it's up to you how much further you take it. You can balance everything or match it as closely as possible by weighing everything. A bottom end done like that should spin to 8k without any problems.

Ignore what all the "builders" are saying. Just bore/hone, balance/polish the crank and balance your pistons, rods and rings as closely as you can my mixing and matching. You can tKe it one step further and take material off the underside of the piston in tiny amounts to match it perfectly. Anyone charging you more that $30/hole and $150 for the crank is charging too much n
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Old 03-10-2011, 04:31 PM   #8
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the balancing quotes i have been getting are in the area of $350 and bore/finish coming in at $45 per hole ($180 total)

polishing the crank is necessary, or is that gravy?

so if i essentially wanted pistons and rods so i can toss some real boost in it with a stock VVT head i would be looking at:

-pistons
-rods
-bearings
-head gasket

-balanced
-bore/hone

everyone here is trying to add line-hone @180$, knife edging at $250 (iirc) and some weird tempering and crap to the block.

-Matt
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Old 03-10-2011, 04:49 PM   #9
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I got bore/hone w/ torque plate and line bored for $325, was told knife edging was overkill for a street car.

Also, so long as you're doing all this get:
new water/oil pump (with fancy gears, of course)
full engine gasket set
arp head/main studs
belts/hoses
coolant re-rout

Then, once again while you're in there:
headwork
valve seals
fancy valves/springs (I'm trying to resist doing this)

And you'll be 4-5k in the hole with the rest of us!

Last edited by chokeasphyxia; 03-10-2011 at 04:55 PM. Reason: remembered more engine stuff
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Old 03-10-2011, 05:13 PM   #10
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the "while your in there" thing is the whole reason i made this thread.

headwork, fancy valves and random useless **** like that pushes most builds to the 4-5k range.

i want to take my GOOD VVT engine and just put basic pistons and rods in. keep costs low for other things that fail when im racing this summer.
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Old 03-10-2011, 05:31 PM   #11
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Quote:
Originally Posted by falcon View Post
A simple crank balance and polish should cost $120-$150 up here in Canada. Then it's up to you how much further you take it. You can balance everything or match it as closely as possible by weighing everything. A bottom end done like that should spin to 8k without any problems.

Ignore what all the "builders" are saying. Just bore/hone, balance/polish the crank and balance your pistons, rods and rings as closely as you can my mixing and matching. You can tKe it one step further and take material off the underside of the piston in tiny amounts to match it perfectly. Anyone charging you more that $30/hole and $150 for the crank is charging too much n
lol @ Canadia
lol @ spinning a Miata to 8000rpm. I'm just a layman, but I've seen my engine beat the turbo to death with vibration at <7k and would never go higher with this motor.
I agree with the cost/benefit ratio. Hit the big stuff that make the engine reliable and take that last $1000 you'd spend on removing material and porting to the suspension fund because I promise you'd get more bang for your buck out of half a set of Xidas over 10hp from a p&p.
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Old 03-10-2011, 05:47 PM   #12
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Quote:
Originally Posted by hustler View Post
lol @ Canadia
lol @ spinning a Miata to 8000rpm. I'm just a layman, but I've seen my engine beat the turbo to death with vibration at <7k and would never go higher with this motor.
Lol @ Hustler, I've been revving my engine to 7800 for 4 years straight, with no broken pumps, valves, throttle bodies, NOTHING. The VVT engine does in fact, like to rev.
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Old 03-10-2011, 07:00 PM   #13
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Just do a basic balance, matching things up with a decent scale as best as you can. For a street car, full balancing and blue printing is a little over kill. Get the cylinders bored and honed. Maybe polish the crank if it needs it. Take a dremel to the cylinder head. Just do a gasket match and knock as much of the casting marks out as you can, nothing serious. All that takes is time and a few cans of brake parts cleaner to get the shavings out. You don't even have to remove the valves to do that one.
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Old 03-10-2011, 07:13 PM   #14
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I'm going to get berated for admitting this, but I only put rods in my car. I blew a headgasket, decided to pull it, put a new gasket in and eagle rods. I reused my stock pistons, bearings, headstuds, etc and did no machine work at all. I just put it all back together and I've got probably 10k on that motor that's seen up to 18psi without any complaints so far.
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Old 03-10-2011, 07:15 PM   #15
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I actually have a few questions that are somewhat similar to this. I'm looking to do a budget build. (I.E. student budget) Ive got a torn down 94 block that im looking to build. What are your thoughts on forged rods, everything else stock and a complete rebuild?

I dont have a turbo as of yet. but I'm looking for a trackable 240 hp down the line. Thoughts, Suggestions? Should I hold out for some pistons while I am at it? will stock 94 pistons hold to 240 safely?

Edit: ^sort of to the extent of what hes done. Except with machinework and a homebrew balance job.
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Old 03-10-2011, 07:43 PM   #16
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Quote:
Originally Posted by Reverant View Post
Lol @ Hustler, I've been revving my engine to 7800 for 4 years straight, with no broken pumps, valves, throttle bodies, NOTHING. The VVT engine does in fact, like to rev.
Lol @ you, actually. There is a confirmed intake camshaft harmonic that will destroy the #1 intake valve seats if you run the motor at 7500+ for any sustained period of time. There's a local CSP car that destroyed 4 heads last year due to excessive sustained RPM - they dropped the rev limiter down and stopped hammering the intake seats out of #1 immediately.

My limiter is set at 7400 for a reason.

You must hone the motor, that's not optional. It is HIGHLY recommended that you bore the motor, unless you are having custom pistons specifically created to match your bore sizes with the proper wall clearances. Start with a running motor and nothing else is needed, IMO - neither of my built motors had any additional balancing done beyond matched pistons/rods.
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Old 03-10-2011, 08:09 PM   #17
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I have datalogged WOT sessions of 110 seconds. Literally WOT for 110 seconds on 5th gear. Several of those were at 7500-7600. Granted, only one such datalog. Do I stay at 7500+ for more than a few seconds each time? No, I shift. I first installed my MS in July of 2006. 5 years later and this engine is still here.

How many times have I gone above 7500? If only twice per day (way more), then in 5 years, and if only lasts 1 second every time, that's roughly sixty minutes spent above 7500rpm.

Maybe the USDM engine is different, maybe you track guys alter something but don't share, I don't know. My own engine has exactly Z E R O failures in the 5 years of being MSed and being pounded a little too much.
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Old 03-10-2011, 08:12 PM   #18
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Quote:
Originally Posted by Savington View Post
There's a local CSP car that destroyed 4 heads last year due to excessive sustained RPM - they dropped the rev limiter down and stopped hammering the intake seats out of #1 immediately.
We all know the story about Bill's car.

First, it was "overheating" each time.
Then it was the VVT that was switched on at the setpoint with the TEC2, rather than progressively retarded and destroyed the head.
The the Hydra was fitted and now its the sustained high-RPM operation that causes the failure.

So what is it?
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Old 03-10-2011, 08:59 PM   #19
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IF the bores are in very good condition you can get away with new rings and a HONE.
Said hone can be a DIY job using a brush hone. The hone is needed for the new rings to seat.

www.brushresearch.com

There is some technique to it...

Last edited by JasonC SBB; 03-10-2011 at 09:12 PM.
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Old 03-10-2011, 09:33 PM   #20
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You NEED to hone the engine at the least
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