double valve spring early heads are they any good
Moderator: phpBB2 - Administrators
-
- Newbie
- Posts: 21
- Joined: Thu Nov 23, 2006 7:51 am
- Location: wellingborough northants
double valve spring early heads are they any good
i have an early set of heads with the double valve springs
are these any good or are they fit only for paper weights?
i had heard that the drag racing boys like them for some reason
thanks mark
are these any good or are they fit only for paper weights?
i had heard that the drag racing boys like them for some reason
thanks mark
- ihatesissycars
- Forum Contributor
- Posts: 938
- Joined: Sat Nov 18, 2006 8:22 am
- Location: Aaaaaaampshire!
P6 heads maybe? Their the worst of them all if memory serves!
You can pick up some efi heads for peanuts off egay these days so you may aswell go for that. I think p6 heads aren't unleaded compatible so that could be another reason to change.
http://cgi.ebay.co.uk/Range-land-rover- ... dZViewItem
Or if you contact a seller on ebay called rangeroverheaven he usually has something available for a good price. You'll get a minor performance boost using efi heads too.
You can pick up some efi heads for peanuts off egay these days so you may aswell go for that. I think p6 heads aren't unleaded compatible so that could be another reason to change.
http://cgi.ebay.co.uk/Range-land-rover- ... dZViewItem
Or if you contact a seller on ebay called rangeroverheaven he usually has something available for a good price. You'll get a minor performance boost using efi heads too.
V8'less but a fountain of dorky knowledge ref v8's!
The double valve springs are preferred for racing. I have doubles on my heads that I have shimmed and set to suit the wilder cam. The are much stronger than the singles and ensure faster closing and a tight seal at higher rpm.
I'm using old pre SD1 heads with this setup and they seem very good for use with Nitrous. I have been using unleaded fuel and gas on these 31 year old heads for 4 years now with no problems.
I'm using old pre SD1 heads with this setup and they seem very good for use with Nitrous. I have been using unleaded fuel and gas on these 31 year old heads for 4 years now with no problems.
- HairbearTE
- Guru
- Posts: 870
- Joined: Sat Nov 18, 2006 12:27 am
- Location: Melton Mowbray
Various aftermarket double springs have been used in racing but if your gonna use old rover springs from a P6 for racing i'd seriously advise you check em over first. Many will have done umpteen miles and be knackered. They also dont leave much room for the extra lift of a big cam. The P6 heads themselves dont have hardened seats so must have them fitted before using unleaded. The ports are slightly smaller than later heads but can be modded easily enough to flow plenty. The quality of the castings is not as good as the later heads though, in fact rv8 head castings have consistently improved in quality over the years.
and dont they use a different size thread for the spark plugs?
Regards Tony C (COOPS)
MS2 V3.57 Ecu mapable efi and wasted spark ignition.
Procharger D1SC supercharger and Cossie RS500 Intercooler @ 14psi of Boost. 416 RWHP, (boost leak)
Forged 4.8 V8 kitted out with the dogs Cajones of parts.
Sponsored by: www.v8performanceparts.co.uk, www.interpart.biz, www.caprisport.com & www.baileyperformance.co.uk
MS2 V3.57 Ecu mapable efi and wasted spark ignition.
Procharger D1SC supercharger and Cossie RS500 Intercooler @ 14psi of Boost. 416 RWHP, (boost leak)
Forged 4.8 V8 kitted out with the dogs Cajones of parts.
Sponsored by: www.v8performanceparts.co.uk, www.interpart.biz, www.caprisport.com & www.baileyperformance.co.uk
They have same plug thread, only shorter reach.
As for the springs, they limit the valve lift so if you intend to use a non std cam beware of coil bind. Another thing, the OD of the springs is different so if you use old heads and wish to update your springs it may be difficult to find an uprated option. SD1 type will not be a straight swap. There are two otions for uprated single spring that can manage higher lift, Opel CIH engine range and Ford V6 springs. They just fit the pre SD1 head and hardware.
I had old Range Rover heads that I ported with SD1 valves, mainly because I had them and to buy a later heads would have cost money. I now have modified 4,6 heads and they require a lot less porting for same end results. So, unless you really enjoy porting it is better to use later heads.
As for the springs, they limit the valve lift so if you intend to use a non std cam beware of coil bind. Another thing, the OD of the springs is different so if you use old heads and wish to update your springs it may be difficult to find an uprated option. SD1 type will not be a straight swap. There are two otions for uprated single spring that can manage higher lift, Opel CIH engine range and Ford V6 springs. They just fit the pre SD1 head and hardware.
I had old Range Rover heads that I ported with SD1 valves, mainly because I had them and to buy a later heads would have cost money. I now have modified 4,6 heads and they require a lot less porting for same end results. So, unless you really enjoy porting it is better to use later heads.