Head specs,,,, again!
Discussion
Ive been looking at heads on another thread (Yella Terra) and I'm sure I've asked this question before but I'd like to try and understand the difference in the heads employed on my 450 as opposed to the ones fitted on the 5.0 l engines.
Reading a few things I'm of the understanding Rover fitted big valves 42 mm inlet 36 mm exhaust to all these heads,
Tvr may then have ported the 5.0 ones (or did they?) but I'm pretty sure the late 450 heads are standard Rover items with no work done ie porting.
I'm just wondering what I can do with my heads,,,
Are they stage 1 or 2 or 3 or what!
Are the 5.0 heads different from the late 4.6?/450 heads ?
It doesn't take a scientist to work out the ports are the weakest link, looking at throttle bodies, brilliant but you still end up with a restriction at the ports,,, for all the air induction mods etc, isn't it really about getting the biggest porting work you can which will give you the best increase in power output.
I'm thinking about gas flowing and opening things up,, other than doing clever things with the bottom end is this not the best tuning work I should consider to get the full power of the engine.
More air means more power so getting the inlet tract opened to its maximum and matched to ported inlets with what should already be big valves??? Should set me up for any future Yella Terra type mods,,,
Does this make sense, I've been thinking of plenum and trumpet upgrades but keep thinking the inlet ports are what I should be looking at!
Suggestions/advice/ piss take welcome.
As my driving slows down I feel the need for more power to compensate.
It's that bad I've cancelled doing Hethel until my cars as fast as Matthews Griff,,, trouble is he's also developing his car at a rate of knots,,,,
anyway what the heck should I do to my 450 heads to get them breathing in more!
Cheers Alun.
Reading a few things I'm of the understanding Rover fitted big valves 42 mm inlet 36 mm exhaust to all these heads,
Tvr may then have ported the 5.0 ones (or did they?) but I'm pretty sure the late 450 heads are standard Rover items with no work done ie porting.
I'm just wondering what I can do with my heads,,,
Are they stage 1 or 2 or 3 or what!
Are the 5.0 heads different from the late 4.6?/450 heads ?
It doesn't take a scientist to work out the ports are the weakest link, looking at throttle bodies, brilliant but you still end up with a restriction at the ports,,, for all the air induction mods etc, isn't it really about getting the biggest porting work you can which will give you the best increase in power output.
I'm thinking about gas flowing and opening things up,, other than doing clever things with the bottom end is this not the best tuning work I should consider to get the full power of the engine.
More air means more power so getting the inlet tract opened to its maximum and matched to ported inlets with what should already be big valves??? Should set me up for any future Yella Terra type mods,,,
Does this make sense, I've been thinking of plenum and trumpet upgrades but keep thinking the inlet ports are what I should be looking at!
Suggestions/advice/ piss take welcome.
As my driving slows down I feel the need for more power to compensate.
It's that bad I've cancelled doing Hethel until my cars as fast as Matthews Griff,,, trouble is he's also developing his car at a rate of knots,,,,
anyway what the heck should I do to my 450 heads to get them breathing in more!
Cheers Alun.
Until someone corrects me, I have stopped all attempts to improve the power output of my car.
I have in the past upgraded the AFM, plenum, inlet pipes, trumpets, cam, flywheel, etc.
But my heads are what V8D describe as "Stage 3", which I believe are standard 450 heads.
The standard 500 heads have bigger valves, and my only option to go further is to get heads with bigger valves.
In the mean time I have analysed what I want from the car, and the answer is a fun car that handles properly. I have that.
Now I need to sort out the chassis condition and cosmetic appearance.
I have in the past upgraded the AFM, plenum, inlet pipes, trumpets, cam, flywheel, etc.
But my heads are what V8D describe as "Stage 3", which I believe are standard 450 heads.
The standard 500 heads have bigger valves, and my only option to go further is to get heads with bigger valves.
In the mean time I have analysed what I want from the car, and the answer is a fun car that handles properly. I have that.
Now I need to sort out the chassis condition and cosmetic appearance.
There's a lot more to a good porting job than *just* the cross-sectional area of the ports.... whilst you want big enough to physically pass the gas volumes needed, you also want shape and profile to encourage flow. Floor shapes, bend-profiles, tapering through the port etc all impact on gas speed and turbulence... the aim is to keep speeds high and achieve swirl into the chamber. Big ports can slow speed and even cause fuel drop out from the charge, which is one of the reasons why low speed running can get lumpy. Different porters have different tricks and approaches but it's a well-trodden path with Rover heads and, ultimately, the castings' dimensions limit what can be achieved without breaking through into water galleries etc.
Afraid the reality is our heads are pretty poor for making power, a good porter will make them a lot less poor but they will never be good in the way LS3 heads (say) are.
Must be remembered it's but one part of an equation involving other elements that also need to be thought about...
Afraid the reality is our heads are pretty poor for making power, a good porter will make them a lot less poor but they will never be good in the way LS3 heads (say) are.
Must be remembered it's but one part of an equation involving other elements that also need to be thought about...
Thanks for the replies
I've also read the later 4.0 engines share the same heads as the 450.
But I can't find any reference to the size of the 450 valves being smaller than the 5.0
I often have your engine in mind when considering these things Anthony and I've thought maybe your heads are 4.6 spec
I didn't realise you've done trumpets and a lightened flywheel.
That's maybe why the figures ar'nt huge on your car but it accelerates very fast, less mass to rotate so it picks up quicker.
Lightened flywheel does interest me muchly.
When.i was a youngster I read a book about Ford X flows and porting,
Getting unrestricted swirl was what I understood from it,,
It's one of the reasons I've kept faith with the 38mm trumpets, my theory being at least the airs rushing in!
So if your vaguely serious you need a matched inlet port and the heads cleverly ported to make best use,, and the biggest valves you can get which I'm assuming is around 42-3 inlet 36-7 exhaust. I can't Es how you can get much bigger than that anyway, guide work to take out that restriction and ultimately a big old cam to make the best of it.
Still, do the standard 5.0 heads have bigger valves / combustion chamber from the late 4.6 heads.
I need to speak to Dom and actually write down what has been done to my engine for a start!
Thanks chaps
I've also read the later 4.0 engines share the same heads as the 450.
But I can't find any reference to the size of the 450 valves being smaller than the 5.0
I often have your engine in mind when considering these things Anthony and I've thought maybe your heads are 4.6 spec
I didn't realise you've done trumpets and a lightened flywheel.
That's maybe why the figures ar'nt huge on your car but it accelerates very fast, less mass to rotate so it picks up quicker.
Lightened flywheel does interest me muchly.
When.i was a youngster I read a book about Ford X flows and porting,
Getting unrestricted swirl was what I understood from it,,
It's one of the reasons I've kept faith with the 38mm trumpets, my theory being at least the airs rushing in!
So if your vaguely serious you need a matched inlet port and the heads cleverly ported to make best use,, and the biggest valves you can get which I'm assuming is around 42-3 inlet 36-7 exhaust. I can't Es how you can get much bigger than that anyway, guide work to take out that restriction and ultimately a big old cam to make the best of it.
Still, do the standard 5.0 heads have bigger valves / combustion chamber from the late 4.6 heads.
I need to speak to Dom and actually write down what has been done to my engine for a start!
Thanks chaps
Alun, 450 heads are just standard heads as they came from Rover. Non ported and standard size valves.
500 heads are fully ported and have the biggest valves you can get in them and on bigger seats plus bulleted guides. Same as Peters really.
IF !!! yours are still standard you probably stand to make a decent gain.
500 heads are fully ported and have the biggest valves you can get in them and on bigger seats plus bulleted guides. Same as Peters really.
IF !!! yours are still standard you probably stand to make a decent gain.
carsy said:
Alun, 450 heads are just standard heads as they came from Rover. Non ported and standard size valves.
500 heads are fully ported and have the biggest valves you can get in them and on bigger seats plus bulleted guides. Same as Peters really.
IF !!! yours are still standard you probably stand to make a decent gain.
Quantify, please 500 heads are fully ported and have the biggest valves you can get in them and on bigger seats plus bulleted guides. Same as Peters really.
IF !!! yours are still standard you probably stand to make a decent gain.
Some bed time reading Al.... 
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
ClassiChimi said:
It's that bad I've cancelled doing Hethel until my cars as fast as Matthews Griff,,, trouble is he's also developing his car at a rate of knots,,,,
LOL only very marginally on the straights and as we found out at hethal you can make up for it in the corners and have more talent than me so all it all evens out. If you want some bedtime reading then I can recommend this book, very interesting read.
As Anthony says the best thing you can do is get out there and drive it. Yours is more than fast enough as is. If you really want a quick car you may as well stop pissing around with a few BHP here and there which is expensive and just get Dom to turbo charge it. pound per BHP that is the most economical way to get more power.
Mr Haribo said:
I have a 4.5L I have been told the heads are the same from late 4 to 4.5
4.3 and 5 can be different
But if your looking for power stage 3 from V8 developments
from there it will only get worse ported inlet manifold 76mm plenum etc
I only wanted 300BHP ! I'm weak .........
yes, yes you are.. weakest willpower ive ever seen! 4.3 and 5 can be different
But if your looking for power stage 3 from V8 developments
from there it will only get worse ported inlet manifold 76mm plenum etc
I only wanted 300BHP ! I'm weak .........
Matthew is spot on. Before you go chasing 20-40 extra bhp, which won't really feel hugely different, consider the alternatives:
1. Any form of farcical induction.....adds 100-150 bhp at one go. It just needs you to start with a sound engine. And it looks so SHINEY!!
2. 6.2 litre LS3 conversion. A brand new crate engine, ancillaries, clutch and super smooth Tremec gearbox, plus exhaust pipe work and ECU etc, probably works out around £10,000, but look at what you have to sell? Your present TVR engine, gearbox and flywheel must be worth well over half of that.
1. Any form of farcical induction.....adds 100-150 bhp at one go. It just needs you to start with a sound engine. And it looks so SHINEY!!
2. 6.2 litre LS3 conversion. A brand new crate engine, ancillaries, clutch and super smooth Tremec gearbox, plus exhaust pipe work and ECU etc, probably works out around £10,000, but look at what you have to sell? Your present TVR engine, gearbox and flywheel must be worth well over half of that.
Stage 4 heads and crossover induction with 8 throttle bodies will set you back £5k plus fitting, and you still will be well short of 400 bhp.
Feast your eyes on this:
https://www.partsworldperformance.com/ls3-engines
Feast your eyes on this:
https://www.partsworldperformance.com/ls3-engines
Hi Rich
Well yes that's the ultimate and something for when I sell my motorbike
I've got no funds to start doing the work so it's just thinking aloud.
I was reading about a chap in the states who was proposing to deck his block and skim the heads to raise compression, that got me thinking mines been decked and skimmed, not to extremes but I'm sure that's where my powers derived, so if I just matched the inlet port to the heads and opened up the ports slightly a few induction mods on top and my engine should be at its peak for its level of tune.
I don't want to change plenum and trumpets if the problem is later in the inlet and if my heads could be opened up safely then any other changes later might just work better.
If I had 20 bhp more and a similar number in the torque curve I'm sure I'd notice it when trying to shave off a few tenths trying to unsettle Mathew,,
Cheers for the heads up on that book Matthew,
Thanks Richard I've read those threads and Robs first post answers most of my questions.
Your entirely right Anthony,, maybe I should get the flywheel lightened first and see what that weight saving can do for the engines spin up speed., regardless of peak figures if the engine pulls hard then it's going to travel across the ground faster so taking out that needles weight must be a good place to start.
Maybe I'm imagining a tuning list, an engine stand and 3 years of man funds and a lot of reading and back handers and I'll do a Peter and build one myself.
What you all laughing at now,,,,,,,
Well yes that's the ultimate and something for when I sell my motorbike
I've got no funds to start doing the work so it's just thinking aloud.
I was reading about a chap in the states who was proposing to deck his block and skim the heads to raise compression, that got me thinking mines been decked and skimmed, not to extremes but I'm sure that's where my powers derived, so if I just matched the inlet port to the heads and opened up the ports slightly a few induction mods on top and my engine should be at its peak for its level of tune.
I don't want to change plenum and trumpets if the problem is later in the inlet and if my heads could be opened up safely then any other changes later might just work better.
If I had 20 bhp more and a similar number in the torque curve I'm sure I'd notice it when trying to shave off a few tenths trying to unsettle Mathew,,
Cheers for the heads up on that book Matthew,
Thanks Richard I've read those threads and Robs first post answers most of my questions.
Your entirely right Anthony,, maybe I should get the flywheel lightened first and see what that weight saving can do for the engines spin up speed., regardless of peak figures if the engine pulls hard then it's going to travel across the ground faster so taking out that needles weight must be a good place to start.
Maybe I'm imagining a tuning list, an engine stand and 3 years of man funds and a lot of reading and back handers and I'll do a Peter and build one myself.
What you all laughing at now,,,,,,,
Edited by ClassiChimi on Sunday 7th August 20:48
Edited by ClassiChimi on Sunday 7th August 20:49
carsy said:
Alun, 450 heads are just standard heads as they came from Rover. Non ported and standard size valves.
500 heads are fully ported and have the biggest valves you can get in them and on bigger seats plus bulleted guides. Same as Peters really.
IF !!! yours are still standard you probably stand to make a decent gain.
Hi Ian, this is what I'm thinking, 500 heads are fully ported and have the biggest valves you can get in them and on bigger seats plus bulleted guides. Same as Peters really.
IF !!! yours are still standard you probably stand to make a decent gain.
At least I've cemented in my mind what my heads are now.
If my ports are standard then I've got more I can do to free up those last few ponies which is nice to know.
Peter your 4.6 was a beast and that had stage 4 heads I believe.
I've got this magnificent engine management system that cost the price of an engine so getting my heads upto the job will justify it even more
Thanks gents.
ETA because I think my heads are in fact standard I'm assuming my engine had about 275-280 bhp on the CUX after Dom re built it, sort of upto Taraka standard, it did have a chunkie chip in it
So the introduction of the Mbe appears to take that upto around 295-300 bhp,,
Would others agree with that assumption,
Would anyone else like to inform me /us of how an engine management system with a multi point trigger wheel can make an engine more powerful,, I'm doubting what I'm saying as I'm saying it,, surely the Ecu can't add upto 25 bhp,, I believe the torque curve is even bigger than that!
How does it do it?
I might be thick as a post but I know what I want
Edited by ClassiChimi on Sunday 7th August 23:37
Gassing Station | Chimaera | Top of Page | What's New | My Stuff