1.94 vs 2.02 - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 02-02-2007, 02:08 PM
fbodyfreak's Avatar
Who loves burnt rubber
 
Join Date: Dec 2005
Location: TN
Posts: 30
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
1.94 vs 2.02

can any one give me an estimate on power to be gained by putting a set of 2.02 heads vs 1.94

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 02-02-2007, 02:10 PM
MI2600's Avatar
Member# 3287
 

Last journal entry: Vortec Heads
Last photo:
Join Date: Jul 2002
Location: N. Muskegon, MI
Posts: 2,632
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
My machinist claims you won't know the difference in the seat of your pants.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 02-02-2007, 02:33 PM
fbodyfreak's Avatar
Who loves burnt rubber
 
Join Date: Dec 2005
Location: TN
Posts: 30
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have read the other posts that say you get better torque in the low end with the smaller i am running a stock tune port with a small cam and headers is it worth the trouble to change the heads. both sets are 76cc chambers and i have 2,5cc domes on the pistons if it makes a difference
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 02-02-2007, 02:43 PM
327NUT's Avatar
Registered User
 
Last photo:
Join Date: Dec 2004
Location: So. Utah
Age: 68
Posts: 3,300
Wiki Edits: 0

Thanks: 0
Thanked 98 Times in 87 Posts
If you have a daily driver you'll never see the difference. Not worth the money or time involved.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 02-02-2007, 02:43 PM
poncho62's Avatar
Out of the Loop Moderator
 
Last wiki edit: Streetbeasts links
Last journal entry: at car show
Last photo:
Join Date: Oct 2003
Location: Hanover, Ontario, Canada
Age: 62
Posts: 17,031
Wiki Edits: 5

Thanks: 24
Thanked 332 Times in 258 Posts
I've been told that on a street car, its not worth the cost to go from 1.94s to 2.02s.........Maybe, with open headers, it might make a bit of difference.
__________________
Ontario Rodders
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 02-02-2007, 05:57 PM
Steve karch's Avatar
Member
 
Last photo:
Join Date: Feb 2002
Location: Regina, Saskatchewan
Age: 55
Posts: 414
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
In a mild street engine 1.94 are fine. If your running a high horse power engine at high rpm then 2.02 are good.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 02-02-2007, 08:57 PM
Registered User
 
Join Date: Jan 2007
Location: york. pa
Age: 57
Posts: 71
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
the bigger valves are only a benefit on a large cube small block or a smaller small block at very high rpm. you can make 400+ HP with 1.94 heads easily. several years ago i built a 350 with the keith black mini dome pistons. .110 dome if i remember right. 1.94 truck heads 76cc chambers. very mild port job. rpm intake. this motor i put into a 77 camaro with 4:10 gears and a 3500 converter. it ran in the 11.30's in very good air, 11.50's in summer. so it made good power. ive put together similar engines with 2.02 valves with similar results. remember that unless you have a larger bore, you reach a point where the valves are beginning to be shrouded. so the benefit of the larger valves is diminished. on a 400 plus cube small block intended for racing, larger valves are the way to go, even larger than 2.02. but for a 400 hp or so 350 or 383 thats a street or street strip motor, spend your money somewhere else. as someone else mentioned the smaller valves will also give you a more responsive motor down low. but since you say you have both sets of heads already, try the smaller valve heads, if you arent satisfied, try the 2'02's. and dont forget to post the results. try to get a few dragstrip runs in hopefully similar conditions if possible.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 02-03-2007, 02:42 PM
xntrik's Avatar
Save a horse, Ride a Cowboy.
 
Last photo:
Join Date: Jul 2005
Location: Arkansas
Posts: 5,131
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
JMO
We're talking performance here, not grandma rebuild.

Let's say installing a bigger valve into the same head, so we have a level playing field, ok. Just gouging it out and putting in a bigger valve is not worth the trouble. So I sort of agree.

The valve is not shrouded all the way around.
and it depends on the chamber shape.

Shrouding is irrelavent at lower power demand since the open valve flows way more than the engine demands anyway.

.040 more valve is not that much more to ruin shrouding. Gains come by the usual throat cut under the valve and the deshrouding in the chamber which should always done when any new valves are installed. Even if they are the original size (most machine shops are afraid to ask for $40 more to do it right.) Hand blending is recommended on intake and exhaust bowls, more $.

Adding a bigger valve is like "A bigger door lets in more wind." A 4% larger diameter valve is a significant amount of opening increase, which is in effect as soon as the valve moves off the seat. 4% larger circumference on a valve that is only open .100 is a large increase. .200 is less, etc, at .500 is not all that much. You are increasing the total flow area, percentage wise, a lot more at lower lifts.

Remember air is elastic and has momentum. Starting more air moving sooner with a bigger valve allows more air into the cylinder all the way through the intake stroke.

Yes they will make more power. Maybe 4% at lower rpm, apples to apples. With a proper throat cut, deshrouding, and blending maybe 8%. On the average 350 cubes, probably 20 torque and 20 hp.

Will you notice it in normal driving?

I would only do it if I needed new valves anyway. I would not go out of my way to do it unless I intended to do it correctly with a mild bowl porting also.

All that extra money is probably better spent towards buying better heads in the first place, if you are performance minded.

JMO

This site will not enlarge pictures.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 02-03-2007, 03:29 PM
Member
 
Last photo:
Join Date: Nov 2006
Location: pacific NW
Posts: 74
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
1:94s

I agree that 2:02s will not gain much if anything because of shrouding, how about considering a larger exhaust valve like 1:6, which will gain you more than a 2:02 intake valve...
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
1.94 heads or 2.02 jeff germano Engine 10 05-23-2013 06:38 PM
2.02 vs. 1.94 valves stfinney Engine 14 07-03-2005 01:25 PM
1.94 vs 2.02 NXS Engine 13 12-28-2004 12:09 PM
2.02 or 1.94 valves?? stfinney Engine 13 04-16-2003 08:38 PM
2.02 valves on stock 302 pistons mustang66maniac Engine 3 08-06-2002 12:30 PM


All times are GMT -6. The time now is 05:57 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.