Big or ULTRA Big???
Discussion
As part my planned upgrades this winter to my 450, I'm looking to do some head work.
Now, as far I understand it, there's a likely chance my 450 engine is using TVR's big valve heads, but with nothing else done to them. Does that sound right? I've borroscoped the cylinders and I'm definitely running pocketed pistons, so I'm hoping they might go together?
So my question is, assuming that they are the Big valves, and I was striving to keep a lid on costs, am I likely to 'feel' much difference between a pair of gas flowed big and ULTRA big valves?
I'm planning on getting my bits from V8D, so running a Stealth cam along with a GEMS.
90% of my useage will be road.
Now, as far I understand it, there's a likely chance my 450 engine is using TVR's big valve heads, but with nothing else done to them. Does that sound right? I've borroscoped the cylinders and I'm definitely running pocketed pistons, so I'm hoping they might go together?
So my question is, assuming that they are the Big valves, and I was striving to keep a lid on costs, am I likely to 'feel' much difference between a pair of gas flowed big and ULTRA big valves?
I'm planning on getting my bits from V8D, so running a Stealth cam along with a GEMS.
90% of my useage will be road.
IF you have TVR BV's - and that's a reasonable size if (according to Robs lengthy & definitive post which I don't have time to find, only the "450 HC"'s got them) - then the size of the valves is not your issue, the lack of porting is the restriction.
Without adressing that first I don't believe you will see much gain (IMO).
I had a set of 450HC BV heads and managed 295bhp. Changing the heads for (very) well-ported set running the same size BV's netted an increase of 22bhp.
If considering only changing the valve size without doing any porting, keep the BV's and spend the money on porting instead - otherwise the main restriction will still be present.
HTH
Dom
Without adressing that first I don't believe you will see much gain (IMO).
I had a set of 450HC BV heads and managed 295bhp. Changing the heads for (very) well-ported set running the same size BV's netted an increase of 22bhp.
If considering only changing the valve size without doing any porting, keep the BV's and spend the money on porting instead - otherwise the main restriction will still be present.
HTH
Dom
It's either; if their bv heads, I'll get them ported, but if their standard on there, I could go the ULTRA size, so wondering how much difference they'd be on the road.
Also, I've never seen 450 bv's. Any 450 I seen on sale have no mention of it...i wonder was this just a TVR'ism, in the way that some 'might just have them, or was it a real factory option and model?
Also, I've never seen 450 bv's. Any 450 I seen on sale have no mention of it...i wonder was this just a TVR'ism, in the way that some 'might just have them, or was it a real factory option and model?
I have a 2000 year car so a late 4.6 engine.
Rover fitted big valves to these heads but not necessarily the very biggest.
My valves are standard as supplied via Rover but the engine was re built ( re freshed) via Powers.
38 mm trumpets and cat Y 65mm plenum so standard Rover Tvr inlet tract.
No blended base that I'm aware and no porting.
After going Mbe the car was then mapped.
300 Bhp 345ft lb
I then used a de cat Y and although not mapped car was faster and I estimate around 305-310 Bhp
Standard heads.
Sadly at this time I can't tell you if mine has pocketed pistons but I don't believe they are.
Some confusion can come from the early 4.5 engines that were different again and did have big big valve heads I think? Some porting may have been done so more akin to 5.0 heads on those early 4.5 rather than the later more common 4.6 engine as it's known.
I do believe with a blended inlet manifold and base plus 45 mm trumpets etc I could get nearer to 320 Bhp fully de cat.
Check your compression before deciding to much I'd say.
I enjoy these big valve threads
Rover fitted big valves to these heads but not necessarily the very biggest.
My valves are standard as supplied via Rover but the engine was re built ( re freshed) via Powers.
38 mm trumpets and cat Y 65mm plenum so standard Rover Tvr inlet tract.
No blended base that I'm aware and no porting.
After going Mbe the car was then mapped.
300 Bhp 345ft lb
I then used a de cat Y and although not mapped car was faster and I estimate around 305-310 Bhp
Standard heads.
Sadly at this time I can't tell you if mine has pocketed pistons but I don't believe they are.
Some confusion can come from the early 4.5 engines that were different again and did have big big valve heads I think? Some porting may have been done so more akin to 5.0 heads on those early 4.5 rather than the later more common 4.6 engine as it's known.
I do believe with a blended inlet manifold and base plus 45 mm trumpets etc I could get nearer to 320 Bhp fully de cat.
Check your compression before deciding to much I'd say.
I enjoy these big valve threads
I hoping to save some money then if they are bv, then I could just get them flowed. I was interested though how much I'd notice the ULTRA bv heads.
As part of my gems conversion I need to replace the flywheel, so an opportunity to lighten it and fit a new clutch - not that it strictly needs it, but it's probably the original, so makes sense.
Then, if I'm doing that......im thinking I should do a bottom end refresh, re balance everything and top hat it. This way i can safely up the compression in line with the heads/block and cam.
As part of my gems conversion I need to replace the flywheel, so an opportunity to lighten it and fit a new clutch - not that it strictly needs it, but it's probably the original, so makes sense.
Then, if I'm doing that......im thinking I should do a bottom end refresh, re balance everything and top hat it. This way i can safely up the compression in line with the heads/block and cam.
I know a man with a lot of engineering experience who has taken his 4 litre engine apart this last winter, ported the inlet manifold to within a wafer of its life, bored out and fitted the biggest valves he could get to the heads, and has managed 335 bhp from the finished result, with no other work than a careful rebuild of the standard 4 litre engine a couple of years ago.
So what you are asking is well possible, but you need to take every step to get as much air as possible into the combustion chambers. Heads and inlet manifold.
So what you are asking is well possible, but you need to take every step to get as much air as possible into the combustion chambers. Heads and inlet manifold.
Thats sounds very impressive, but it's absolute drivability I'm looking for. Highest bhp is attractive, but only if it's 'nicely' available on the road.....if that makes sense??
I'm I thinking is 'If' I I wouldn't really notice the UBV heads on the road with my set up, then I could saved laid!
I'm I thinking is 'If' I I wouldn't really notice the UBV heads on the road with my set up, then I could saved laid!
QBee said:
Torque is what makes for drivabiltiy.
So go for the best torquey cam you can.
Plenty of choices out there, but I certainly enjoyed my V8D stealth cam in my last engine.
So go for the best torquey cam you can.
Plenty of choices out there, but I certainly enjoyed my V8D stealth cam in my last engine.
I feel torque from low down is best on the road, combination of good manners at slow speeds coupled with a healthy feel of torque in any gear at any time allows speed without all the high revs.
I've started reading up about inlet and porting and keeping fuel and air mixed as it travels into the inlet port is half the battle. Smoothing out and increasing port size can increase flow but slow it down, fuel being heavier than air it can seperate and run along the walls especially as it goes around corners so a pourus surface helps keep the fuel suspended in the air. It's not just delivering the fuel it's spraying it to get the best explosion that really matters.
I often think of having my heads opened up but I'd so rarely go where the power would be that it seems slightly pointless,,
My narrow inlet tract is obviously helping me with low speed engine manners and is the reason I'm so happy with the car.
I've been told my heads are roughly the equivalent to Stage 3 heads. Standard 5.0 in essence
Dom once mentioned how Rover had listened to info supplied by the likes of John Eales and himself as John developed much of these later engines for Rover and in fact my standard 2000 year heads do have better worked ports.
I'd like to believe it anyway
Classic Chim said:
QBee said:
Torque is what makes for drivabiltiy.
So go for the best torquey cam you can.
Plenty of choices out there, but I certainly enjoyed my V8D stealth cam in my last engine.
So go for the best torquey cam you can.
Plenty of choices out there, but I certainly enjoyed my V8D stealth cam in my last engine.
I feel torque from low down is best on the road, combination of good manners at slow speeds coupled with a healthy feel of torque in any gear at any time allows speed without all the high revs.
I've started reading up about inlet and porting and keeping fuel and air mixed as it travels into the inlet port is half the battle. Smoothing out and increasing port size can increase flow but slow it down, fuel being heavier than air it can seperate and run along the walls especially as it goes around corners so a pourus surface helps keep the fuel suspended in the air. It's not just delivering the fuel it's spraying it to get the best explosion that really matters.
I often think of having my heads opened up but I'd so rarely go where the power would be that it seems slightly pointless,,
My narrow inlet tract is obviously helping me with low speed engine manners and is the reason I'm so happy with the car.
I've been told my heads are roughly the equivalent to Stage 3 heads. Standard 5.0 in essence
Dom once mentioned how Rover had listened to info supplied by the likes of John Eales and himself as John developed much of these later engines for Rover and in fact my standard 2000 year heads do have better worked ports.
I'd like to believe it anyway
the later serp heads have bigger exhaust ports but the restriction in the intakes abysmally small intake throats and large valve guide protrusion in this area 
opening out the exhaust ports on their own what a waste of time Rover 
with the numbers you have Alun your heads have been tickled IMO nice camshaft and an MBE dont equal your numbers you have 
Stepping off the willy waving step for a moment there's a good chance mine could be more like 290/5 335/40 depending on roads train loss calculations
It's slower than 5.0 cars I've been up against, mind you they ain't no normal 5.0 cars
Block decked and heads skimmed seem to be at the heart of it. That and new piston rings.
I know the heads were disassembled as valves re lapped and steel rockers used and I plagued Dom to make it fast but safe.
I'll take the inlet manifold off someday when I don't use the car so much and look see.
It's slower than 5.0 cars I've been up against, mind you they ain't no normal 5.0 cars
Block decked and heads skimmed seem to be at the heart of it. That and new piston rings.
I know the heads were disassembled as valves re lapped and steel rockers used and I plagued Dom to make it fast but safe.
I'll take the inlet manifold off someday when I don't use the car so much and look see.
OP what do you mean by Ultra Big Valves?
This term is often used in relation to non-TVR valves, and as I understand it they are not much different to TVR BV's.
Valve size info (see "Cylinder Heads" section)
FYI - here is the link to Robs post I couldn't find earlier...
Robs post on engine differences
HTH,
Dom
This term is often used in relation to non-TVR valves, and as I understand it they are not much different to TVR BV's.
Valve size info (see "Cylinder Heads" section)
FYI - here is the link to Robs post I couldn't find earlier...
Robs post on engine differences
HTH,
Dom
Edited by Dominic TVRetto on Wednesday 16th August 17:13
Yeah, it's all a bit unclear, but from what I can work out now, tvr Bv's are the same as V8D's ULTRA.
I've not long had a conversation with Rob at V8D. He said I should look for 'HC' on the engine bay plate which should signify bv engines, but looking I don't seem to have that stamp, but I so have the pocketed pistons which are apparently an indicator of a bv engine.....im lost and confused! Guess I won't truly know until I take the heads off!
I'm going to get the block top hatted and balanced at the same time, and any compression increase could be done then.
I've not long had a conversation with Rob at V8D. He said I should look for 'HC' on the engine bay plate which should signify bv engines, but looking I don't seem to have that stamp, but I so have the pocketed pistons which are apparently an indicator of a bv engine.....im lost and confused! Guess I won't truly know until I take the heads off!
I'm going to get the block top hatted and balanced at the same time, and any compression increase could be done then.
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