Minimum PV clearance on a 3V 4.6L

• May 12, 2010

• #1

C

circusboy

Senior Member

Joined

Jul 31, 2009

Posts

1,112

Reaction score

8

What is the minimum pv clearance needed on a 3V motor?

I'm getting ready for the motor swap and just wanted to make sure I'm ok.

I put a stock 3V head on the new short block last night. I got .145" on the intake valves and .260" on the exhaust.

I also wanted to make sure that the lift on a stock cam is .432"

My new cams have .492" lift on intake and exhaust.

THat would leave .085" on the intake valves and .200" on the exhaust valve.

 

• May 12, 2010

• #2

C

circusboy

Senior Member

Joined

Jul 31, 2009

Posts

1,112

Reaction score

8

is there somewhere i can go or look to find this info

 

• May 12, 2010

• #3

C

circusboy

Senior Member

Joined

Jul 31, 2009

Posts

1,112

Reaction score

8

thanks anyway fellers. I guess i'll be the test mule again, wish me luck lol

 

• May 12, 2010

• #4

Chris06GT

Dragging LS A..

Joined

Sep 16, 2008

Posts

4,667

Reaction score

24

Location

Alabama

Dude, man, you in a hurry?....lol

Most these guys don't get settled down and a chance to get on a computer till later in the evening and have time to read the threads....

Give it a bit...someone will chime in...

 

• May 13, 2010

• #5

US-1

Banned

Joined

Apr 8, 2007

Posts

12,808

Reaction score

183

Location

The ShadowLands

You're fine. Let it eat.

 

• May 13, 2010

• #6

spyder7724

Senior Member

Joined

Apr 21, 2007

Posts

854

Reaction score

10

Location

Maryland

US-1 said:

You're fine. Let it eat.

Click to expand...

agreed, even though mine is a 5.4 (which actually makes it worse) i'm running .560"+ cams with flat tops no valve reliefs and i have zero PV issues...although i did lock out the VCT but those cams will still be fine using the VCT if you choose as long as you haven't gotten silly with duration or valve timing events.
take SD's word for it though he's got more experience.

 

• May 13, 2010

• #7

C

circusboy

Senior Member

Joined

Jul 31, 2009

Posts

1,112

Reaction score

8

vct is going to be locked out. 241/251 duration.

96 teskid block with 04 cobra rotating assem.

 

• May 13, 2010

• #8

US-1

Banned

Joined

Apr 8, 2007

Posts

12,808

Reaction score

183

Location

The ShadowLands

At the risk of repeating myself................

 

• May 14, 2010

• #9

C

circusboy

Senior Member

Joined

Jul 31, 2009

Posts

1,112

Reaction score

8

I'm there dude, chill lol

 

• Oct 29, 2016

• #10

46addict

13726548

Joined

Aug 25, 2016

Posts

1,832

Reaction score

56

Location

Lawrenceville, GA

circusboy said:

vct is going to be locked out. 241/251 duration.

96 teskid block with 04 cobra rotating assem.

Click to expand...

Bringing this back from the dead..
Has anyone ran this combo on their car? Can you use 4v pistons with 3v heads?

 

• Oct 29, 2016

• #11

BruceH

BBB Big Bore Boss 322

Joined

Sep 13, 2009

Posts

13,810

Reaction score

21

Location

Pacific Northwest

46addict said:

Bringing this back from the dead..
Has anyone ran this combo on their car? Can you use 4v pistons with 3v heads?

Click to expand...

You can. It doesn't make a whole lot of sense unless you are getting a bargain on pistons that will make the compression ratio you are looking for. Most 5.4 pistons also have the same compression height as 4.6.

If using 4v pistons with a higher lift cam you would want to have an exhaust valve relief cut into the pistons. By the time you do that it would of been better to start with 3v specific pistons.