Stage 1 Heads for a 350i

[dellyend1]

Hi All, wanting to pick the brains of the collective knowledge if I may.

I'm contemplating buying a pair of second hand Stage 1 Heads to put on the 3.5 TVR engine. They look in good condition, fully working and have been skimmed etc

First Question is ' am I wasting my money and did TVR do some magic wizardry on the heads that I have so no power gain will be obtained ?'

Second question on the basis that it would be an enhancement is 'will any stage 1 heads off of a 3.5 work ? The ones I am looking at were used on a 3.5 l SD1 engine fitted with composite gaskets ? I've read somewhere that composite gaskets lower compression and thus power so would i be negating my existing horses for less by fitting composite gaskets ?

He is claiming that his 3.5 heads produced 220 bhp for him, I have no reason to disbelieve him but is this realistic. It all comes down to horses for pound notes for me I'm afraid. Happy to spend a few hundred quid for some second hand heads in good condition for 30 horse power, but not if I a) don't get any improvement on the standard output I have now and b) worse if I reduce the power !!!!

Any conmments / pointers really appreciated as always

Cheers All

Jeremy

[adam quantrill]

True you'll have to pipette the heads and the cylinders to work out the CR. However if the original seller had them running with composite gaskets which are thicker, he would have also skimmed the heads to get the CR back up again. If you then went to tin gaskets the CR would rise further and get too high.

[dellyend1]

Wow ! Thanks for the very detailed and comprehensive answers

So had a google search on what cam would be best for a 350i and as you can imagine there is a wealth of info and lots of past PH threads with very complex discussion.

This has made me realise pretty quickly that messing around with the engine to gain more power is beyond my skill set so if I want some more horses I must leave it to an expert.

This then makes my tiny mind ponder - what is the most cost effective solution to more bhp ?

1. Pay an expert to recommend, source and install a new cam and heads and sort timing etc

2. Source a bigger V8 and get it fitted professionally ?

Does anyone have knowledge of indicative costs for each option. I've seen a TVR 400 engine on ebay for £1800 ! Can a standard 3.9 be fitted from a range rover ? Would the standard ecu work ?

I know a lot will be reading this and thinking, just sell your existing wedge and upgrade accordingly. My answer is a) My Wedge has a good history file that shows it has been well maintained and is sorted. b) I'd have to sell my wedge and then wait until a suitable wedge came up if at all. C)Most importantly I like the colour, interior and condition of my wedge and want to stick with what I have got.

I'd just be greatful for any info on peoples experiences of engine output upgrades or transplants, what was the all in costs and who did the work and overall experience etc Would you do it again the same, with that wonderful thing hindsight ?

Cheers All.

Jeremy

[Wedg1e]

dellyend1 said:

Can a standard 3.9 be fitted from a range rover ? Would the standard ecu work ?

Yes (more or less) to the first part and no but sort of, to the second. The 3.9 Rangey engine in its early form (ie before they started with the Serpentine drive front end) is an almost straight swap, though you'd need to retain the TVR exhaust manifolds and engine mounts. If the Rangey was an automatic then you'd need the TVRs flywheel as well, and you'd have to change the spigot bearing in the back end of the crank.
You'd need the Rangey's ECU to match (a 3.9 need more fuel, obviously). It is feasible to modify a 3.5L ECU to suit a 3.9L engine but there are very few people who know enough about it to do the job.

The biggest issue would be that the camshaft on the R-R was profiled for torque rather than high-rev power and if you could live with that sort of delivery (and probably a built-in rev limit of about 5500rpm) then it'd be a reasonably straightforward job.
However what you wouldn't end up with is 390SE power on the cheap, unfortunately. Potentially you could, if you went for a later hotwire engine and had the cam and fuelling adjusted to suit, but there are so many variables that it's hard to be specific.
Your best option is probably an ex-TVR V8, perhaps from a Chimaera, Griffith or 400SE - but you need to see some proof that it actually is one of those and not just some scrapyard Landrover engine being touted as 'from a TVR'.

[mrzigazaga]

Good advice and knowledge being given there...This type of question can have very different answers..You could throw "loads a money" at trying to squeeze more from your existing engine..Or you could source a good genuine 5.0ltr griff lump...but all of this is not cheap..When i was looking at getting more power out of my V6 i looked into a 3.7 rebore with long stroke crank..Alloy cam gear..Port matching & polishing...Big valves..Inlet manifold re-worked..lightened and balanced flywheel........BUT...It was going to cost around 3-4K and i would be only gaining 15-20bhp and around 30-40lbs/ft torque...Not much as far as pound for lb goes..I even looked at a race prepared 240bhp N/A rebuild by a reputable V6 engine builder....And the cost was considerably less and very appealing...BUT...In the end i have settled for a supercharger as this will give me 250bhp and 280lbs/ft of torque running 4-6psi..(Low boost) on a standard set up engine...I have the option later with a change of pulley and bigger injectors and aftermarket ECU's to up it to well over 300bhp and over 300lbs/ft of torque..Although it will be a bloody nightmare to drive but i have that option...So i would say maybe look into the supercharged route..There are loads of different types but rotrex make some of the more compact blowers...Again not cheap but in comparison to the other options it might just come out on top...And thats just where the best place is for a blower...Ziga

[Wedg1e]

Hey Mark, you do realise that most of your rear suspension and drivetrain components are going to become consumables...?

[mrzigazaga]

Wedg1e said:

Hey Mark, you do realise that most of your rear suspension and drivetrain components are going to become consumables...?

...............................Mmmm...There is that!!

[smash]

Before you spend 1.5 to 2k on a TVR 400 engine have a look at the dyno results kicking around on PH.

They seem to generally make around 240 out of the box (ignore TVR figures) - a Rangie P38 4.6 will give 220 out of the box and match the TVRs 270lb/ft torque figure @ a cost of around 600 quid for a complete cut out engine including ecu. (there's been a few going through ebay and all less than £600).

A much cheaper route for very similar performance albeit different characteristics...This is assuming a 4.6 will fit of course!

Edited by smash on Tuesday 23 April 10:14

[dellyend1]

AAARRRGGGHHH, My head hurts but in a good way

Thanks for all the great advice. I need to sit in a dark room with a towel on my head and really think about what I want.

I think I would like to keep originality so am leaning towards new heads and cam and ported inlet manifold or the Super Charger which does seem the rather exciting option

Cheers All

[Danny Hoffman]

Interesting looking supercharger on fleebay for the rover V8

Closing the bonnet maybe an issue