Evaluate my engine combo plz...

Reply Subscribe

Thread Tools

Search this Thread

07-21-2003, 10:16 PM

neat

Registered User

Thread Starter

Join Date: Jul 2001

Location: Raleigh, NC

Posts: 221

Evaluate my engine combo plz...

Ok, I have just purchased a 1992 Corvette with the following engine mods:

.030 over
Align honed, decked, and squared
Ported oil return passages
Cast steel SCAT 383 crank
4340 H beam forged rods
Forged Pistons (10:1, but final compression ratio comes to almost 11:1 with heads and block decked)
Jones competion cylinder heads, professionally ported. 2.00/1.54 valves.
LT4 hotcam with install kit (new lifters, pushrods, and springs)
Full roller rockers
Port matched LT1 intake
Misc. headers and borla catback

Other stuff-

New opti (Grrr, stupid Opti)
Newly surfaced Fly Wheel and new pressure plate
24 lb/hr fuel injectors
AFPR
750 CFM TB
Tuned with tuner cat

The engine builder said the motor was built for N20 so the pistons have an extra 5 thousandths of clearance. I've never heard of that before, what's that all about.

Thanks a bunch guys!

07-21-2003, 10:39 PM

Blue96z28

Registered User

Join Date: Jun 2003

Location: Oklahoma

Posts: 709

sounds mean to me

07-21-2003, 11:17 PM

neat

Registered User

Thread Starter

Join Date: Jul 2001

Location: Raleigh, NC

Posts: 221

Thanks, anyone else?

07-21-2003, 11:51 PM

HardcoreRM125

Registered User

Join Date: Apr 2003

Location: Pgh, PA

Posts: 2,628

The extra .005 clearence is because with N20 then egnine heats up more, and obviously as it heats it expands, So the extra clearence keeps the engine from wearing as hard as a regularly clearenced motor when spraying ... Sounds like a hard Vette

... I think if i was you id start with a 75, to make sure its all good , and work your way up to the 200ish range? Hehe spray is good ...

07-21-2003, 11:56 PM

WheelmanZ28

Registered User

Join Date: Sep 2002

Location: Chicagoland Area

Posts: 1,158

Damn, that sounds like a bullet proof engine to me

Spray away my good man

Please pardon the boldness of my question, If u don't mind me asking, how much did u pay for that ride?

07-22-2003, 12:01 AM

neat

Registered User

Thread Starter

Join Date: Jul 2001

Location: Raleigh, NC

Posts: 221

Quote:

Originally posted by WheelmanZ28

Please pardon the boldness of my question, If u don't mind me asking, how much did u pay for that ride?

Check your PM's...

07-22-2003, 06:47 PM

neat

Registered User

Thread Starter

Join Date: Jul 2001

Location: Raleigh, NC

Posts: 221

TTT

07-22-2003, 07:04 PM

chucks97ss

Registered User

Join Date: Jan 2002

Location: Houston, TX

Posts: 442

What length are the rods, and what is the deck height of the pistons? 6" rods give a 1.113 deck height, which isn't ideal for a lot of nitrous, so hopefully they used 5.7's. Also, what brand are the pistons? I assume at the very least they are forged since the words nitrous where used from this engine builders mouth.

Also, where is the extra .005 clearance? There are lots of details left out. It could be a decent motor, but you need to go more into detail with the blueprint specs. I raise a serious red flag with the extra ".005" piston clearance". You need to know where that clearance is. If that's piston to bore clearance, unless you have JE, Wiseco's, or even Ross, you are asking for piston skirts to break.

Later
Chuck

Last edited by chucks97ss; 07-22-2003 at 07:07 PM.

07-22-2003, 07:34 PM

wicked_95z

Registered User

Join Date: Jan 2002

Location: J-ville,NC

Posts: 1,469

I would assume (hope) that the extra .005" is the ring end gap. Of course we all know what happens when you assume

07-22-2003, 10:06 PM

#10

HardcoreRM125

Registered User

Join Date: Apr 2003

Location: Pgh, PA

Posts: 2,628

Ive heard of engines being built like that before. And from what i understood it was extra ring gap clearance ... However, i dont thnk it would break piston skirts if it was .005 would it? I mean i could see it breaking them if your spinning really fast like say over 7K ... but could .005 really break piston skirts ? Not trying to criticise , im jsut asking so dont take it the wrong way man lol

07-22-2003, 10:09 PM

#11

HardcoreRM125

Registered User

Join Date: Apr 2003

Location: Pgh, PA

Posts: 2,628

In the above post , when i started talking bout breaking skirts , i forgot to say that i meant Even if it was bore clearance ... and this thing wont let me edit my posts for some reason ???

07-22-2003, 10:11 PM

#12

chucks97ss

Registered User

Join Date: Jan 2002

Location: Houston, TX

Posts: 442

Quote:

Originally posted by HardcoreRM125
Ive heard of engines being built like that before. And from what i understood it was extra ring gap clearance ... However, i dont thnk it would break piston skirts if it was .005 would it? I mean i could see it breaking them if your spinning really fast like say over 7K ... but could .005 really break piston skirts ? Not trying to criticise , im jsut asking so dont take it the wrong way man lol

Standard piston to bore clearance on a normal forged piston is .004-.006 thousanths. Add another .005 on top of that, and yeah, you could have some issues unless you have really good pistons. It's called piston slap. Has nothing to do with piston rings. You are probably correct about the extra .005" being in the piston ring gap though, so what I'm talking about is totally unrelated. A person just needs much more info before they can go and tell this person that is a good motor.

Later
Chuck

07-22-2003, 10:31 PM

#13

treyZ28

Banned

Join Date: Aug 2001

Location: looking for a flow bench so Brook and I can race

Posts: 3,505

all that money for and a hot cam?

but thats just my personal opinion.

I've been "sold" on the high lift theory but thats just me.

6'' rods are a good thing in a nitrous IMHO.

new fuel pump is a good idea with nitrous. walpro 325 or something like that is like $130. easy install.