Big Valve Heads
Discussion
.
Are you trying to DIY your heads to BV std? Proper BV heads use 1.69/1.5" valves which require new seats putting in the heads. Machining, interference fit & gluing seats and guides is best left to specialists IMHO. Its probably better to let someone like Jamie at CRE do this work - IIRC he has CNC data to do much of the work.
Many of the TVR BV heads seem to be hand finished, if you look closely at them they can appear quite different - which ones do you copy?
I am not really sure it would be worth the effort on a 4 litre of going to the extent / risks of converting to UBV's, you'd likely need to have a built a 8000rpm race motor to justify the need. Over-heading could be similar to over-camming in the outcome - capacity seems to affect these things considerably? IYSWIM. It would seem more sensible to use heads similar to Quinnys that deploy 1.63/1.4" valves that fit the existing seats and just do a guide & porting to that spec. It probably works better at all but extreme requirements for massive airflow (ie the 300bhp + top end..).
Many of the TVR BV heads seem to be hand finished, if you look closely at them they can appear quite different - which ones do you copy?
I am not really sure it would be worth the effort on a 4 litre of going to the extent / risks of converting to UBV's, you'd likely need to have a built a 8000rpm race motor to justify the need. Over-heading could be similar to over-camming in the outcome - capacity seems to affect these things considerably? IYSWIM. It would seem more sensible to use heads similar to Quinnys that deploy 1.63/1.4" valves that fit the existing seats and just do a guide & porting to that spec. It probably works better at all but extreme requirements for massive airflow (ie the 300bhp + top end..).
New heads are on the way from TA Performance in the States based on the Buick V6 design I think, but they could be pricey (rumoured to cost somewhere half way between Merlins and Wildcats).
Or you could try and source some Buick 300 alloy heads which are relatively cheap to buy although not always easy to find. They sometimes come up for sale on the Buick forums. They will outperform any of the Rover/TVR heads.
I got mine off via the local speed shop here in Aus (who will source any US part, new or second hand, and bring it over in their regular containers filled with GM, Ford, Chrysler V8 stuff). They came of a 64 Buick 300 located in a wrecking yard in the Arizona desert.
Head Stud in Melbourne did all the flow bench and porting wortk. Much bigger ports than Rover heads. 1.75 inlets/1.5 exh, flowed to support up to 410 hp.
300 heads had 54cc chambers - I welded these up to bring them down to 37 cc and used Buick 300 tin head gaskets. Work great on a 4.6.
Or you could try and source some Buick 300 alloy heads which are relatively cheap to buy although not always easy to find. They sometimes come up for sale on the Buick forums. They will outperform any of the Rover/TVR heads.
I got mine off via the local speed shop here in Aus (who will source any US part, new or second hand, and bring it over in their regular containers filled with GM, Ford, Chrysler V8 stuff). They came of a 64 Buick 300 located in a wrecking yard in the Arizona desert.
Head Stud in Melbourne did all the flow bench and porting wortk. Much bigger ports than Rover heads. 1.75 inlets/1.5 exh, flowed to support up to 410 hp.
300 heads had 54cc chambers - I welded these up to bring them down to 37 cc and used Buick 300 tin head gaskets. Work great on a 4.6.
Gassing Station | Griffith | Top of Page | What's New | My Stuff