VH valve springs

Singles, twins and fours.
Mickypic
Posts: 71
Joined: Mon Dec 10, 2012 8:11 pm
Contact:

VH valve springs

Postby Mickypic » Mon Apr 10, 2017 12:09 pm

Does this spring look right for a 1949 VH iron head. Doing a top end overall and ordered some new springs from draganfly. One on right is old springs which is 3.8mm dia wire x 6 1/2 turns, left one is the new one which are 5mm dia wire x 7turns. Next picture is of new spring fitted. Is there enough space in coils for valve to open properly or is it coil bound ? Do not know history of bike so do not know if old spring was the correct one.
Attachments
IMG_0370.JPG
IMG_0369.JPG

User avatar
PeterW
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 331
Joined: Fri Oct 07, 2011 10:17 pm
Location: Oxfordshire
Contact:

Re: VH valve springs

Postby PeterW » Mon Apr 10, 2017 3:19 pm

If it helps, I've just replaced the exhaust spring on my 350 with a new one from Drags. Gauge was the same, it was a better length and not pitted...
Yours does look very thick and I wouldn't expect them to be a vastly different spec from the NH.
WP_20170326_17_19_40_Rich.jpg
350 springs

User avatar
Leejm
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1194
Joined: Thu Feb 05, 2015 1:17 pm
Location: Nuneaton, Warwickshire
Contact:

Re: VH valve springs

Postby Leejm » Mon Apr 10, 2017 3:28 pm

I think your old springs are the later vs422 spring. I just put a new set in my vha and they look like yours.
1948 NH, BSA D10 SPORTS. 1953 VHA, 1951 KH rigid project.

Mickypic
Posts: 71
Joined: Mon Dec 10, 2012 8:11 pm
Contact:

Re: VH valve springs

Postby Mickypic » Mon Apr 10, 2017 9:15 pm

Anyone got a pic of their VH valve spring fitted to compare with mine ?

david.anderson
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1423
Joined: Mon Mar 28, 2011 4:52 am
Location: south coast NSW Australia
Contact:

Re: VH valve springs

Postby david.anderson » Mon Apr 10, 2017 11:31 pm

The standard VH valve spring, VS20 which was used in the VH up to 1950 is a slightly larger diameter and larger wire than the VG or later VH spring VS422 and has a massive seat pressure, which only serves to overload the valve train. The seat pressure is over 300lbs, which greatly exceeds what is necessary. The VS 20 spring uses a larger bottom collar to accommodate the larger spring. The VS20 spring does not become coil bound with standard cams, but will be coil bound with any of the HS cams. If in doubt measure your fitted length, (should be about 1.7" depending on seat wear) then tighten a valve spring up in a vice and measure the coil bound length. A standard cam will lift the valve about .320"
David

Mickypic
Posts: 71
Joined: Mon Dec 10, 2012 8:11 pm
Contact:

Re: VH valve springs

Postby Mickypic » Tue Apr 11, 2017 1:38 pm

Thanks Dave
Which spring would you recommend I use ? I am using a standard single lobe cam with iron head.
Cheers Michael

User avatar
adrie.degraaff
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 3039
Joined: Sun Feb 27, 2011 10:07 am
Location: Holland
Contact:

Re: VH valve springs

Postby adrie.degraaff » Tue Apr 11, 2017 2:42 pm

Mickypic wrote:Which spring would you recommend I use ? I am using a standard single lobe cam with iron head.

I would say use the weaker left spring, the right one could weare your cam rapidly.

Mickypic
Posts: 71
Joined: Mon Dec 10, 2012 8:11 pm
Contact:

Re: VH valve springs

Postby Mickypic » Wed Apr 12, 2017 10:24 am

Found this on internet. http://archives.jampot.dk/technical/Pis ... 0_1960.pdf
It looks like my old spring was from a NH not a VH

User avatar
Eero.Korhonen
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1005
Joined: Tue Sep 04, 2012 10:02 am
Location: Oulu, Finland
Contact:

Re: VH valve springs

Postby Eero.Korhonen » Wed Apr 12, 2017 10:46 am

That is very useful, thanks. By the way, your springs looks right, I have same in my VH.
Br, Eero
Ariel VH 1954, IZH 350 1962, H-D Sportster Hugger 1992, AOMCC Member 133

david.anderson
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1423
Joined: Mon Mar 28, 2011 4:52 am
Location: south coast NSW Australia
Contact:

Re: VH valve springs

Postby david.anderson » Wed Apr 12, 2017 10:59 am

The springs in the photo are probably VS422 which were fitted to all VG models and to 1951-58 VH models. They look similar to the NH springs but are not the same or the same part number.The VS422 springs are suitable for normal road use. They will allow valves to bounce as revs exceed 6000rpm, particularly with older springs, or where the Hallite washer has not been fitted under the springs, which results in the spring being subject to excess heat and resultant strength loss. From memory the VS422 spring exerts a valve seat pressure of 90lbs when new, which is much less than the seat pressure of the VS20 springs that you have just fitted at over 300lbs. Most modern cars that are fitted with a 1.7" valve have a seat pressure of about 100lbs so why would you need such a strong spring.
My VH is fitted with a HS cam and valve springs from a GMH V6 which have a seat pressure of 110lbs. They do not bounce at 7500rpm
David


Return to “Four stroke”

Who is online

Users browsing this forum: No registered users and 16 guests

cron