TVR engines. What do we expect?

[350matt]

The thing is it's entirely possible with the skills and materials available today to achieve the 100K miles and 8KRpm we all seem to want. The evidence is in the showrooms, and while we may argue that TVR don't have the resources of the big boys, these guys are building down to a price. I very much doubt it costs Honda the 7-8K the TVR engine is rumoured to cost for a similar specific output.

I'm looking foward to Mr Mellings talk as I've got a few ideas on why the SP6 engine is as unreliable as it is but would like to hear what he's got to say.
My feeling is that TVR subsituted some cheaper more readily available parts which sort of fitted with some mods, to replace the expensive bespoke designed parts which had no compromise.

We'll see

Matt

[rev-erend]

Could I just throw a fly in the ointment of the LS1 fans..

Whilst an LS1 engine offers much :

cheap reliable power

It's down sides in the modern world are emissions..

It's pretty well proven the 4 valve heads & high comp are the way forward...

Let's face it the AJP V8 was a good shot at what an LS1 could be but it's was still too dirty ..

The S6 is the future and I'm really looking forward to Al Mellings talk - as this engine does not seem to have had just the one kind of failure but manybe they are linked..

[the pits]

I agree with boss cerbera, why not just buy a vette?

[dinkel]

bosscerbera said:

The problem with building a TVR around an LS1 is that the donor car is already a mass-produced fibreglass 2-seater. It screams 'kit car' to just re-body someone else's running gear.

Point made . . .

S7 7 litre Nah, too big. Imagine what that or the LS would do to those slim TVR bodies . . .

[350matt]

ummm the LS1 and the latest LS7 are about as big the old rover V8, a smidgen longer a few inches shorter in height and only 1/2 wider , so it'd probably just fit as the RV8 wasn't exactly large. Also any engine can be cleaned up emissions wise, its making the requisite power 'and' being clean usually takes four valves etc

Matt

[Bitter'n'twisted]

the pits said:

I agree with boss cerbera, why not just buy a vette?

Seconded (or thirded).

The best bit about driving my Tuscan is the engine. It is fantastic!!!

I remember all the kit car comments I used to get when I had my Griffiths. It was always 'It's a kit with a Rover engine isn't it?'

[dvpeace]

GreenV8S said:

For a small production volume relatively high power output engine, I would have thought a scheduled strip down and rebuild at 25k would be acceptable. I guess this would represent about five years of motoring life for a typical car? As a potential buyer, I would be greatly reassured if the engine could be relied on to last this long, even if it did mean there was an expensive bill coming up at least I would know where I stood. People doing the rebuilds would also know where they stood and hopefully be able to organise a quick turnaround, this eliminates the other big issue of potentially having the car off the road for an extended time as well as a kick-in-the-teeth bill at the end of it.

If the engine needs a rebuild at 25k miles then it should be listed on the service schedule and there is then no myth about how long it should last. As you say if you know wthat it will cost £5k every 25k miles then you can make an informed decision.

Personally I do about 15k miles a year in mine and would be happy if all I had to pay for was basic servicing cerca £1k a time and an adition £5k at 25k miles. The problem for me is not the engine but every other part on the car that wears prematurly like springs & shocks at 16k miles. Suspention bushes at 10k miles. Clutch hydrawlics at 16k miles etc etc etc.

It's not just the engine that's a problem. Infact I think the current engine comming out of the factory is quite strong. I have done nearly 12k miles this year since mine was rebuilt and the car does not miss a beat.

[MOD500]

Very interesting thread.

Out of interest, was the S6 derived from another engine, or designed from scratch?

Thanks


Martyn.

[Tam Lin]

bosscerbera said:

Specific output (bhp per litre) is a key to reliability / performance / cost trade-offs. So, last question: 4. should there be an optional 'cooking' 300bhp motor, maybe a de-tuned Speed Six or some Euro/Jap V8?

That's the bit of the whole saga that I don't get. Why force a highly stressed engine on your production workforce, when the specs are up to you? I.e. why were the AJP8 and Speed 6 built with high specific ouputs/on top of which, in some cases, with no rev limiter?

I understand why Porsche & Ferrari have to do it: "Tradition" makes demands (hence a beetle with a flat 6 is 20 years on twice the price of a better balanced, faster 944T ), and they also have homologation issues to contend with: A GT3 or 360Strad with a 6L motor would be a tad restricted as to the series it could compete in.

You're running around with a 5L, there are rumours of a productionalised 5.5L AJP V8. If it lasts 50K miles, guaranteed (yes, I warm up engines as best as I can, and don't care if a datalogger is there to prove it), and give 360 BHP/360 Ft Lb. I'll take it. Don't wrap it up.

But, could the TVR Cerbera 2 pretty please
1) pass emissions without PFM,
2) have some thought given to understated downforce?

[Simonsparrow]

The AJP V8 seems to last quite well, a number of cars are in the 50k plus bracket. Steve Heaths was 90k plus miles when it went pop on the dyno, ACT developed their induction kit on a 4.5 with 90k plus miles. My own 4.2 has over 110k miles on it, no rebuild.

I'd say as a specailist low volume engine, a lot of the reliabilty is down to how it was built, how it's been looked after since and what its used for. A race engine will have a much harder life than a road car engine and will be required to be at peak performance at all times.

I'm sure my car is producing less power than when it was new, but its more than fast enough for me, so no problems!

My background is old cars, so I'm used to the concept of warming up and engine before caning it and it probably gives me a high degree of mechanical sympathy.

I have to say that on the road, in the south east of England, I rarely use more than 4-5k revs even when warmed up. That seems to get me going faster than all the traffic I want to pass, so maybe 'real-world' performance (low-ish revs) is also helping with longevity.

However, I still do track days and we saw just over 160 on the clock in france this year before a bonnet pin broke

I'd be very interested to hear Al Mellings thoughts on longevity regarding his engines.

[rev-erend]

I see no reason why a speed 6 should not see 80K without problems in the rebuild department..

In common with out 6 cyl engines it will ultimately have similar issues.. like cracking of the block between cylinder bores (BMW & Jag have this)..

The issues that I understand this engine suffers from are :

Cause : Cam to follower Misalignment (for what ever reason) - leading to sideways (lateral) thrust on valve stem

Effect :

1) Premature Follower & Camshaft wear

2) Valve guide wear & possible value seating issues

3) Values possibly bent due to over reving with worn followers/guide wear

4) Engine bearing/ring damage due to swarf from above effects


That's just my take on it..

Really looking forward to Al's views. It all sounds pretty straight forward to me to remedy

[bosscerbera]

Tam Lin said:

Why force a highly stressed engine on your production workforce, when the specs are up to you? I.e. why were the AJP8 and Speed 6 built with high specific ouputs/on top of which, in some cases, with no rev limiter?

A high specific output NA motor is the ultimate for response, performance, efficiency etc. etc.. Turbos have lag, superchargers have substantial parasitic losses.

Just as McLaren had no choice but to get a ground up engine, so too did TVR. Before I get flamed with a pantomime "Oh yes they did", cast minds back to mid-90s. Detroit iron was all there was, the only alloy option being a Corvette motor. TVR did play with other V8s (eg White Elephant).

The course to "ultimate headbanger TVR" was set with the evolution of the wedge from torquey 350i through to berserk SEAC. The high torque/low mass Blackpool ballistics arms race started here. The headbanger cars ALWAYS got the headlines which, IMHO, led TVR to believe its own PR - it became, or felt it became, synonymous with mad cars. Intoxicating stuff. Fact was though that Chimaeras - never the quickest, but quick enough - accounted for the most sales. Market misread methinks.

To the point: the only place from a 60bhp/litre 5.0 RV8 was up. (Answer to question: Why force...?) But you can't do that with a RV8. 60bhp/litre RV8s were pretty well on the limit of what you can call "reliable". Specific output and reliability have an inverse relationship - as you crank up the power, the reliability goes in the opposite direction. Accept that and you'll enjoy a TVR.

The petrol on the fire was TVR trying to cut costs out of the engine components .... compounded by classic Blackpool "skill variance" assembling said components .... and, worst of all, further compounded by wall-of-silence. It's the last bit that REALLY pissed people off. Shit happens but companies are judged by management of said shit rather than the shit itself. Good management could lick the contents of this paragraph.

I was curious about expectations to see how many people felt theirs were met. Quite a few by the looks of the thread. The remainder would surrender some "Top Trumps stats" for more reliability.

If you think of specific output and reliability as two graphs, the last time the graphs were close enough to bridge what I think are two camps was the 5.0 RV8. The divergence of the graphs says to me that there is a need for a choice of engines.
- One development programme should deliver a reliable engine ...and proceed to make it a little bit more pokey a bit at a time.
- Another development programme should deliver a stormer ...and proceed to make it a little bit more reliable a bit at a time.

The latter of the two is in place I believe, but it's too little too late to get "Chimaera Man" back in the fold. It's what to do about the former that IMHO will determine TVR's survival. Bomb-proof c.300bhp 4.0 S6 or Hemi V8 (with auto option) would be my choices.if I were a manager.

[chris watton]

Thank you for your thoughts Bosscerbera, I have thouroughly enjoyed soaking up the info you (and others) have put on this thread, very interesting.

Oh yes, I for one would find it a very retrograde step going back to an 'older' V8 car after sampling (on many, many occasions) the power of my very on song (for the past year and a half) S6 car!

[dinkel]

Exactly. TVR should move up and carry on setting trends other than be an epigone. That doesn't fit their tradition! So we'll be waiting for the next trendsetting engine. The S6 was . . . although a bit unreliable.

Still no comments on my S5000 idea. Or is it really that stupid?

[tommyLeone]

bosscerbera said:

A high specific output NA motor is the ultimate for response, performance, efficiency etc. etc.. Turbos have lag, superchargers have substantial parasitic losses.

i disagree with this statement! this is no longer the 60's phil.

why dont you look at the porkas of today, why dont you look at the LeMans dominating car the Audi R8
www.seriouswheels.com/top-2004-Audi-R8.htm

you make some good points, but generally speaking, i think you are out of touch with what the market segment which tvr fitted in at one point in time now wants, you are also very wrong about turbos/supers - today with chargecoolers and highly-efficient garret chargers and centrifugal blowers you get a LOT back for the minor losses and efficiency is up there with the best of NA motors - not forgetting way better combustion meaning friendlier on the emissions side (ie. look at the extreme amounts of wild-timing an NA motor has to run and overfueling to achieve high-power output, and then the rebuild intervals, perfect example would be a nascar NA engine producing in excess of REAL 700hp, i've seen the damage which takes place due to living on the edge of detonation hell personally in a high-output NA engine and its not a pretty sight)

to top it off, with todays current technological advances - aspirated motors have been proven to run longer than similar output high-compression NA configs

[bosscerbera]

TommyLeone said:

With todays current technological advances - aspirated motors have been proven to run longer than similar output high-compression NA configs

Good point. Would your suggestion be that TVR supercharges the Six in a bid for a reliability/power balance? Quite a lot of extra stuff needs to find a home under the bonnet, I've seen the Typhon set up. Would shift TVR's price point too.

Recent turbo cars I've driven, Noble M400 and FQ320. Last supercharged car was Koenigsegg CC8 (mind boggling). I race a Cobra with a NA +100bhp/litre 7 litre (tall deck) SB Chevy.

Turbos feel ultra-quick at peak but flat either side and lack the linear "Boeing feeling" of real NA power/torque - one of the best features of the S6. Modern superchargers can be fabulous but Gordon Murray told me SLR blower takes 180bhp (22% loss) so motor is generating about 800bhp gross (over 500kW, serious heat) to make the net 626bhp. Bonnet has special paint.

The initial plan for my Cerbera was a supercharged 4.5 (hoping for 600bhp) but heat and space for charge coolers were problems hence the NA 5.0 which has turned out to be a real gem. Done 8,000 miles in 4 months with it too.

[wizzpig]

chris watton said:

Thank you for your thoughts Bosscerbera, I have thouroughly enjoyed soaking up the info you (and others) have put on this thread, very interesting.

Seconded Chris. Excellent thread.

[ATG]

(surely the main difference btwn other 100bhp per litre engines and those made by TVR is that everyone else uses variable valve timing?)

[Chuggaboom]

ATG said:

(surely the main difference btwn other 100bhp per litre engines and those made by TVR is that everyone else uses variable valve timing?)

They also do hrs upon hrs of engine testing b4 letting the product get anywhere near a car that will be in the showrooms.

The AJP8 had its problems despite being put through a couple of seasons worth of Tuscan racing b4 being sold in Cerberas.

The Sp6 didn't.

[jsr]

I did read earlier in the year- in Sprint i think - that the Speed 6 under the Smolenski regime is now supposed to be as reliable as the Rover V8. It's still too early for customers to confirm if this is true, but that would be an acceptable level of reliability if it is true. Especially with the 3 years warranty too - i would like to think TVR can offer the warranty due to the increase reliability of the engine.

If you think back to the Speed 6 engine reliability poll/thread that was done last year (?), it seemed that the more recently built engines, suffered far fewer rebuilds over the same mileage.

It would be interesting to see the results of a similar poll if carried out in a year's time.