4v Valves in 2v Heads - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars
Ford Forum Ford Forum

» Auto Insurance
» Featured Product
ยป Wheel & Tire Center

Go Back   Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > The Garage - Tech Forums > Engine Specific Tech > Cleveland Tech
Register Home Forum Active Topics Photo Gallery Auto Loans Garage Mark Forums Read Auto EscrowInsurance

FordForums.com is the premier Ford Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 11-16-2005, 02:40   #1 (permalink)
Registered User
 
Join Date: Dec 2004
Location: Melbourne
Age: 28
Posts: 47
Question 4v Valves in 2v Heads

I know people put 4v exhaust valves in 2v closed chambers heads, Is it benificial to also put them in the intake side? Or does this decrease performance?
Sorry If this is a bit of a stupid question.
F399 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 11-16-2005, 02:43   #2 (permalink)
old B - new B
 
351cid's Avatar
 
Join Date: Jul 2005
Location: sunshine coast QLD
Age: 49
Posts: 890
Re: 4v Valves in 2v Heads

my heads are fitted with the bigger valves on both sides. originaly 302 - 2v closed chambers.

get it in fast , let it out fast .
__________________
dave
`75 XB FAIRMONT SEDAN injected 351, toplaoder, disc brake 9", factory paint+ vinyl roof.
`03 BA XLS ute - lpg, auto, lsd, acid rush paint,
WWW.sunshield.biz
351cid is offline   Reply With Quote
Old 11-16-2005, 02:55   #3 (permalink)
Southern Coupe
 
CJR09's Avatar
 
Join Date: Sep 2005
Location: New Zealand
Age: 36
Posts: 215
Re: 4v Valves in 2v Heads

Quote:
Originally Posted by 351cid
my heads are fitted with the bigger valves on both sides. originaly 302 - 2v closed chambers.

get it in fast , let it out fast .

I emailed Terry Parker a week ago regarding engine build and he recommended not using 4V on the intake side as he said it restricts flow with the 2V unless the 2V's are extensively ported and big revs are intended.

Small pipe (2V) + large valve = reduced flow
CJR09 is offline   Reply With Quote
Old 11-16-2005, 03:03   #4 (permalink)
old B - new B
 
351cid's Avatar
 
Join Date: Jul 2005
Location: sunshine coast QLD
Age: 49
Posts: 890
Re: 4v Valves in 2v Heads

Quote:
Originally Posted by CJR09
I emailed Terry Parker a week ago regarding engine build and he recommended not using 4V on the intake side as he said it restricts flow with the 2V unless the 2V's are extensively ported and big revs are intended.

Small pipe (2V) + large valve = reduced flow
mine will pull hard till it hits the rev limiter at 7000 rpm

has not had a lot of work done to the ports , was intended but i run out of money,( injection cost double what i was expecting ).

tops of my pistons were machined to get the compression right and shaped for better burn

i guess it all depends on the total package really , there are basic principles but one size does not fit all.
__________________
dave
`75 XB FAIRMONT SEDAN injected 351, toplaoder, disc brake 9", factory paint+ vinyl roof.
`03 BA XLS ute - lpg, auto, lsd, acid rush paint,
WWW.sunshield.biz
351cid is offline   Reply With Quote
Old 11-16-2005, 03:20   #5 (permalink)
Registered User
 
xdclevo's Avatar
 
Join Date: Mar 2004
Location: Cairns
Posts: 1,946
Re: 4v Valves in 2v Heads

Quote:
Originally Posted by 351cid
mine will pull hard till it hits the rev limiter at 7000 rpm
Anything will pull hard to 7000rpm, no matter how the flow is, if it is cammed correctly. As stated, the best flow figures are achieved with std or slightly bigger at 2.10 intakes and 4v exhaust valves.
xdclevo is offline   Reply With Quote
Old 11-16-2005, 05:09   #6 (permalink)
Registered User
 
Join Date: Oct 2005
Posts: 181
Re: 4v Valves in 2v Heads

Quote:
Originally Posted by F399
I know people put 4v exhaust valves in 2v closed chambers heads, Is it benificial to also put them in the intake side? Or does this decrease performance?
Sorry If this is a bit of a stupid question.
XDCLEVO IS RIGHT. 2Vs ARE BEST BUT WITH THE AGE OF THESE HEADS YOU JUST GO ONE SIZE BIGGER TO GET THE RIGHT VALVE HIGHT.
WHEN YOU PORT THESE HEADS YOU CANT TAKE TOO MUCH MEAT OFF AROUND THE SHORT TURN, SO IF 4Vs WERE FITTED THE AIR WOULD HAVE TO TURN HARDER TO ENTER THE CYLINDER. NOT GOOD FOR HIGH FLOW. I GET 4Vs AND TURN THEM DOWN TO 1.25mm OVER STANDARD 2V SIZE. IN DOING THIS WITH CLOSED CHAMBER HEADS, IT ALSO DOESNT SHROUD THE VALVE AS MUCH AS 4Vs WOULD, RESULT, MORE FLOW.
xrglen is offline   Reply With Quote
Old 11-16-2005, 06:26   #7 (permalink)
Registered User
 
Ohio XB's Avatar
 
Join Date: Oct 2005
Location: Northeast Ohio, USA
Posts: 267
Re: 4v Valves in 2v Heads

I've been discussing with a 351C group about putting 460 sized intake valves into 2V 351C heads. That would be the same as a 4V valve turned to 1.25 mm over stock (about .050" + stock 2.050" = 2.100"). I hear the 460 valve is about 2.090".

Here is a link to a head flow chart showing this modification in a 2V head in the Ford Cleveland section....

http://users.erols.com/srweiss/tablehdc.htm#Ford

In this chart, compared to a 2V head with 4V valves, the 2V head with a 2.080" valve actually flowed more than with the 4V valve. I would suspect this is due to velocity being lost with the 4V valve. Just too big of a hole for the intake runner to dump through. Especially consider the gain in flow at .300" of lift, and consider that the valve will pass that position twice in it's cycle. I would say the 2V head with approximately 2.080" valve shows a significant superiority, on the street at least, advantage over 4V intake valves in a 2V head.


Steve
Ohio XB is offline   Reply With Quote
Old 11-16-2005, 18:51   #8 (permalink)
Registered User
 
grey_esp's Avatar
 
Join Date: Sep 2004
Location: W.A.
Posts: 337
Re: 4v Valves in 2v Heads

The other problem with putting both 4v valves in is it doesnt leave much meat between the 2 valves and they generally will crack across the seats.

Also porting to fit a 4V intake gets you too close to the water gallery in the head, which will ofter crack as well.

I bough a full set of stainless 4V valves and had them turned down to a fraction smaller than a 4V on exhaust and a bit bigger than 2V on the inlet. the inlet was just blended to suit new seat and the exhaust was opend right up to suit the big valve. Not sure what the flow tho. And I dont have them running yet but I was told this is standard practise and they have had great results using this method.
__________________
Pics are post on www.fordespghia.com
grey_esp is offline   Reply With Quote
Old 11-18-2005, 00:48   #9 (permalink)
351 XE on LPG
 
Join Date: Jul 2003
Location: Perth, Western Australia
Posts: 742
Re: 4v Valves in 2v Heads

4V valves are also heavier, which mean the springs have a harder job of keeping all that mass under control. It may only be a little bit of extra weight, but I've heard that at revs it does make a difference.
Rhett is offline   Reply With Quote
Old 11-18-2005, 17:32   #10 (permalink)
JG33
 
YellowFireXAGT's Avatar
 
Join Date: Oct 2004
Location: Melbourne, VIC
Posts: 83
Re: 4v Valves in 2v Heads

I run a std size 4V exhaust and custom made inlet which is halfway between a 2V and 4V which works a treat. BTW the heads are 302 relieved and heavily port/polished
YellowFireXAGT is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

  Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > The Garage - Tech Forums > Engine Specific Tech > Cleveland Tech



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

Posting Rules
You may not post new threads
You may not 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


Powered by vBadvanced CMPS v3.2.2

All times are GMT -7. The time now is 15:19.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.6.0
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.