3.6L or 4.0L

[minkybob]

Hi, From the Chim side.
What if any are the performace and reliabilty difference's from the two engines?

P.S should I take the leap into the unknow or keep my sorted 1999 450?

Cheers

[bholleran]

Hi,

when I was looking to buy mine I drove both the 4.0 and 3.6 and if I am honest there was very little difference between them in my opinion. If anything the 3.6 felt better mid range.

I think it was also said that the 3.6 was a bit more reliable.


In the end I went for a 3.6, but I would have been quite happy with a 4.0.

[Zippee]

The above post is pretty accurate. The 4.0 has a little more low down torque but to be honest theres nothing in it in the real world. I've never had any trouble staying with 4.0 Tuscans.

[dpd3047]

The 3.6 is more reliable as ive said elsewhere on this forum

Edited by dpd3047 on Monday 18th October 16:20

[Robertjp]

I have yet to see any evidence that shows one to be more reliable than another. Typical speed 6 issues are completely unrelated to cc. As for the torque I drove both a 3.6 and on a single test drive couldn't feel much difference.

The more important thing is its year and whether it has had any engine rectification wk, when and who by.

As for the swapping, it makes sense in lots of ways but just do your homework, they can be moneypits! My tuscan has consumed a lot of cash in the first 18 months!
Rob

Edited by Robertjp on Monday 18th October 16:53

[Pacman1972]

Robertjp said:

I have yet to see any evidence that shows one to be more reliable than another. Typical speed 6 issues are completely unrelated to cc. I drove both a 3.6 and on a single test drive couldn't feel much difference.

The more important thing is its year and whether it has had any engine rectification wk, when and who by.

As for the swapping, it makes sense in lots of ways but just do your homework, they can be moneypits! My tuscan has consumed a lot of cash in the first 18 months!
Rob

Don't be so sure - A while back when I was looking at Tuscan's I monitored the cars for sale in Piston Head classifieds over a period of about 6 months I found something in the region of 70% 4.0's (pre 2003) to have had the engine rebuild whereas only 1 of the 3.6's had had one and if I recall that was for a different reason.
Not very scientific granted, but when you have ratio of 67 - 1 surely more than a coincidence?

[Allandwf]

Always wondered what is the ratio of 4.0's to 3.6's made?

[alphaone]

Interesting post pacman, I wouldnt have thought that the cc made any difference, but now you have pointed your findings out it makes the 3.6 an option that I never thought about before - cheers

[truck71]

I drove and/or was driven in 4 MK2 Tuscans and 2 Tamoras before buying my Tuscan, the Tuscans were all 4 litres (one S) except the one I settled for, 3.6. Performance wise I couldn't tell any of them apart except that the Tuscan S had slightly longer gearing. I saved a few £k by buying a 3.6 v a 4.0 at the time which will probably repeat itself come sale time (I preferred the drive of the Tamoras in many ways but couldn't turn down the Tuscan on it's looks/presence). Never felt shortchanged by it's oomph even after 10 months although I wouldn't turn down some more. No idea about the reliability bit.

[dvs_dave]

There's more 4.0's around than 3.6's .

With regards reliability, the 3.6 shares exactly the same head and valvegear so by default has the same wear related failure modes.

Where the 3.6 is "possibly" less prone to failure is at very high revs, 7500+ rpm. Some say that the 4.0 may have close to critical forces on conrod 6 at 7500+ rpm which "may" lead to it failing. But as the rev limiter cuts in at 7300, shouldn't be a problem and certainly not a common or well known one.

[dpd3047]

As ive said before the 3.6 is a more reliable for the following reasons,
the shorter stroke less torsional vibration, piston speeds are lower for given rpm, conrods are correctly balanced the longer rod gives less side loading on the pistons.the head on both engines are the same as are the camshafts. Note Red Rose and S camshafts are also the same the valve timing is different for these engines also compression ratio is higher.

[bobcuth]

The 3.6 engine was, I'm reliably informed via ex factory people, better developed and less stressed than the 4.0 - which stacks exactly with the above post.
The downside to a 3.6 - if you come to sell on, which I guess happens, most red-blooded males would tend to seek out the biggest bhp engine. A point to ponder.
Saying that - I pondered, and have a 3.6 Tuscan, and it goes like @@@@!

[dpd3047]

Thanks for that. The original design was for a 3 litre and a 3.5 litre engine. The 3 litre was dropped in favour of the 4 litre. And the rest as they say is history.

Edited by dpd3047 on Tuesday 19th October 22:19

[Tuscanuwe]

But displacement increases the power.
Why does TVR power develops a 4.5 liter engine with
100.000 miles warranty?

So the niggles are quality and some areas with bad design of the engines.

If they are sorted a 4.0 or 4.5 is just as good as a 3.6 liter engine.
Better we ask Dom, he can answer better as we try to do.

Uwe

[Robertjp]

dpd3047 said:

As ive said before the 3.6 is a more reliable for the following reasons,
the shorter stroke less torsional vibration, piston speeds are lower for given rpm, conrods are correctly balanced the longer rod gives less side loading on the pistons.the head on both engines are the same as are the camshafts. Note Red Rose and S camshafts are also the same the valve timing is different for these engines also compression ratio is higher.

I have no doubt all of the above is correct, tho there is a danger of misleading the op isn't there? The failures and issues associated with the sp6 are around finger followers, camshafts, valve guides, oilways etc. Whilst the differences between the 3.6 and 4.0 may have been intended to give better reliability, the overriding, far more significant issues are unrelated to the differences. The material and quality issues, the ones the op should be worried about are the same across all sp6 variants. As for the perception that more 4.0l have failed, well as has been said, there were far less 3.6's and they were generally in later cars, which goes a long way to explaining the difference.
Not trying to be picky but the op should focus on the bits that have shown themselves in the past to be the primary issues
Rob

[dvs_dave]

^^^^^^
Indeed, any differences in reliability being talked about are at best theoretical. In practice (which is much more relevant) there is no difference. Plenty of evidence around to back that up too.

[G20RG B]

I agree with the last 2 post, quality of the parts used was the issue with reliability NOT the size of the engine.

[car crazy]

Would be interested to know the answer to the op's original question ie performance figures for 3.6 and 4.0:
0-60, 0-100, top speed and bhp.
I used to own a 4.2 cerbera are Tuscans quicker or slower or wouldn't i notice the difference.

[G20RG B]

car crazy said:

Would be interested to know the answer to the op's original question ie performance figures for 3.6 and 4.0:
0-60, 0-100, top speed and bhp.
I used to own a 4.2 cerbera are Tuscans quicker or slower or wouldn't i notice the difference.

I don't think you would notice the difference, the 4.2 should be just about able to keep up with a tuscan............

[Robertjp]

G20RG B said:

car crazy said:

Would be interested to know the answer to the op's original question ie performance figures for 3.6 and 4.0:
0-60, 0-100, top speed and bhp.
I used to own a 4.2 cerbera are Tuscans quicker or slower or wouldn't i notice the difference.

I don't think you would notice the difference, the 4.2 should be just about able to keep up with a tuscan............

I used to own a 4.5 cerby, I genuinely don't know which was quicker, the tuscan is like a scalded rat off the line, but I drove my cerby quicker above 60 baecause it felt so planted, I rarely have the throttle wide open on the tuscan at more than 100 leptons!
But, I haven't driven the tuscan much since I had new shocks, geo etc, so difficult to tell
Outright performance is very, very similar!

Edited by Robertjp on Friday 22 October 09:16