My V8S Engine is different because....!
Discussion
Well after a few of you had insisted that there might be some alterations to my V8 engine, as it revs higher, I called the previous owner last night as curiosity got the best of me! He didnt make any improvements, but said that about 10 years ago the car went back to the factory and had the engine rebuilt to the 'Big Valve' spec and a 'G' has been added to the Vin plate under the bonnet (supposedly denoting a Big Valve version as on the Grif) I cant see why this would affect the rev limit but dont know what other modifications were made to the car during this rebuild, I will try to find out more.
So it appears that mine might be slightly different, anyone know what sort of power hike the Big valves might give?? Harry? I suppose the rolling road with Mark Adams will answer this, cant wait!
Mike
So it appears that mine might be slightly different, anyone know what sort of power hike the Big valves might give?? Harry? I suppose the rolling road with Mark Adams will answer this, cant wait!
Mike
The big valves do rev higher, at least Dads 4.3 BV griff did. They will rev higher because they can get more air into the cylinders, at high rpm smaller valves limit the amount of air. It should be good for a few more bhp. Interesting if you get it on the dyno.
Z
Are there not a few 4L wedge's out there in BV guise, perhaps a comparison.
Z
Are there not a few 4L wedge's out there in BV guise, perhaps a comparison.
pies said:
anyone know what sort of power hike the Big valves might give?
Mike
IIRC From what i recall from "2 sheds" there is no powergains from BV over standard
Soz
Interesting....so whats the benefit of BV, I was told by an engineer last night it was definitely more power. Why are the Griff BV cars sought after if there are no advantages over the standard? Will have to check this out!
Mike
pies said:
IIRC From what i recall from "2 sheds" there is no powergains from BV over standard
Soz
Just did a search and found an article that says the 4.3 BV gave out 20bhp more than the normal 4.3!! heres part of the write up from http://driving.timesonline.co.uk/article/0,,12930-1073983,00.html
"The Grifith is powered by a high-performance Rover V8 the early 4 litre cars produced 240bhp, respectable in a car weighing just 2,340lb. But that was only the start: soon the engine grew to 4.3 litres and power leapt to 280bhp. Aware that owners craved still more power TVR offered a BV (big valve) version, squeezing 300bhp from the 4.3 litre. With small numbers of the BV version produced they have become highly sought after and represent an almost depreciation-proof investment"
So it would appear 15-20bhp is possibly the effect of Big Valves!
Mike
pies said:
Maybe but ill side with 2sheds and shpub
I only enquired about this as a couple of other V8S owners had mentioned that my car was faster than theirs and revs a lot higher (to 7000rpm). I went for a spin with a friend of mine who has a Chim 450 last Sunday and he could not keep up and have found out my car has a rebuilt Big Valve engine! If it doesnt make any difference to the Power can anyone shed some light on why my car seems faster and revs higher than other V8S's?? I am not complaining it would just be nice to know! It would appear the Big Valves are doing something to enhance the performance or it wouldnt have been pointed out to me by other owners
Mike
pies said:
There might be more to it like a lightened flywheel solid lifters etc
Nice to have though
Yeah like I said I dont know what other stuff was done, I am going to call TVR Power to see if they have a record! Like I said not complaining, but would just like to know. MrSheen said straight away that my car was much faster than his as he has driven it a few times, although that could be his is still being run in
Dave and Mat at the training day said it was faster and revs higher than any V8 they had seen! So got me thinking Mike
shnozz said:
I think I can hear HarryW crying...
All cried out now
. Good to hear, but be a little cautious. Mine was 'gas flowed' from new (on build spec sheet) with a 214 cam in it. When it was stripped last year for the re-build, it had standard late (28cc from the 4.6) heads and a 435 cam,
. You are right that breathing is really the secret to these beast, beleive me its pissed me off more times than I care to remember
. Have chat with Dom at TVR power as well, he normally has the records of each engine built, but may struggel with older ones but may have it if its 'different' like yours. Have the engine serial number to hand, the one on the engine block, not the one off the VIN plate, incase they are different. My block one had the HC suffix and was the test mule for the first HC, the VIN said nothing
. Mine was called GT/Speed 8 spec when it left TVR Power. Fitting 5 ltr heads will give you bigger valves btw, but they are not the best. However its the rest of it i.e. cam/trumpets/manifolds/exhaust/ECU mapping that goes in to actually release their potential.
Be very intersted to see what Mark thinks of it, are you booked in at Austec with him in the near future then, might pop up to have a nose
. Harry
Just had a thought, it is not beyond the realms of TVR's that it may even be 4.3 lump in it . Which may explain the increased performance if every thing else is standard. Whcih for one moment I do not believe, no standard ECU allows you to rev up to 7K, no standard engine would last 6 months if revved that hard , to be honest even a tweeked balanced and lightened one will not tolerate it, certainly the ancillaries won't AIMHO. Harry
Gassing Station | S Series | Top of Page | What's New | My Stuff