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Potent engine build - Crank, piston, rod choices


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#1 ceejaay

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Posted 02 February 2012 - 07:01 PM

HI all,

I have been asked to build a TR4 engine for a customer.

The car will be driven on occasionally on week ends mostly around town in traffic. No motorway use so no long periods spent at high RPM.

Low and mid power and torque is needed for rapid overtaking of slower moving traffic.... Occasionaly dragging another car at the lights etc will take place.

General outline of the proposed engine... 89mm, suitable cam, light flywheel, twin webers, headers, suitably worked head.

Now the choices...

Crank - Stick to the stock crank or go for a new billet steel unit ? - if the latter, why ?

Pistons - Forged pistons yes but standard compression height or "slipper" pistons which require a 7" rod ?

Rods - If the decision is to stick with standard compression height pistons, should I stick with stock rods or use billet ?

Thanks in advance
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#2 john.r.davies

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Posted 02 February 2012 - 10:14 PM

I'm no TR4 expert, but if "The car will be driven on occasionally on week ends mostly around town in traffic" the last thing it needs is a steel crank, slipper pistons, billet conrods etc. etc.
But I suspect you are either looking to rip off your customer, or havin' a laff, CJ.

JOhn

Edited by john.r.davies, 02 February 2012 - 10:15 PM.

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#3 Motorsport Mickey

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Posted 03 February 2012 - 01:48 AM

+1
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#4 ceejaay

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Posted 03 February 2012 - 12:59 PM

The customer is very clear on what he wants.... he wants to have the "most powerful" TR4 among his pals who also have some hot TRs.

He actually wants a 92mm bore engine. I managed to kind of talk him out of it and bring it down to 89mm but today he sent in a spare block and asked that I attempt to do the 92mm bore liners on that and if that fails to go with the 89mm on the complete engine.

Those are the specs he wants... ideally 92 or 89mm bore, suitably modified head (this will be bespoke done in UK and imported), a suitable cam, light flywheel, headers and twin webers... This is what he wants.
He wants something close to 200BHP

The rest of the car is already set up with all the steering and suspension mods, servo assisted disc brakes front and rear etc.
He kept building up the rest of the car to take the power and now finally he wants the engine built so ...

I would appreciate your input on the question in my original post
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#5 ntc

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Posted 03 February 2012 - 03:56 PM

If you are being paid to build such an engine you should not be asking here or anywhere come to that
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Regards
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#6 john.r.davies

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Posted 03 February 2012 - 04:25 PM

Good luck, CJ!
You'll need it.

John
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#7 MadMarx

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Posted 03 February 2012 - 05:01 PM

if he asks for, give him the full programm... :D
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#8 Tr4Tony

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Posted 03 February 2012 - 09:33 PM

200 bhp out of a four cylinder does not come easy or cheap, Nor is such an engine built from off the shelf bits ...... If he doesntbwant to compete with the car I humbly suggest that your customer takes a long hard look at what he's asked you for. You'll be spending an awful lot of his money and the roads are littered with unreliable expensive 'big power' wet liner engines.

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#9 kevin bryant

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Posted 04 February 2012 - 09:25 AM

Guys,

surely this is being a little harsh on Ceejay? In a world where the customer is meant to be king, if the customer wants something inappropriate surely the customer can have it? Have you never bought something inappropriate just because you wanted it?

I suspect a lead weight in the customers right boot would do the trick.

regards kev
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#10 ceejaay

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Posted 04 February 2012 - 04:17 PM

Thanks kev,

I built him a TR4 engine for his TR2 some years back.
It was 86mm but i opened up the combustion chambers to lower the comp ratio to around 8:1 then supercharged it.

He still uses that engine but wants more power for the TR4.

The man has pleanty money and pleanty of spare engines and parts.... So he doesnt mind experimenting, spending bags of money and blowing up his expensive engines.

He enjoys eccessive power and doesnt mind spending anything to get it. (i have built him a 350 bhp supercharged engine for his mk2 jag)

I told him it was not advisable to build such a potent engine for a road going TR and reminded him about the weak cranks on them but he was insistant on those specs.

I figured this would be the place to get some help and advice with choice of parts for this build but now im begining to doubt that thought.

ceejaay
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#11 Alec Pringle

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Posted 04 February 2012 - 10:06 PM

Hi ceejay,

your request is more than a little out of the ordinary, hardly surprising if it's greeted with some bemused responses.

200bhp from a wetliner 4 isn't impossible, but the end result will be more of a competition than a road engine, and it'll need some serious revs applying to strut its stuff.

There aren't many cars around with that sort of grunt, and TR4 Tony probably knows more than most about competing with a 200bhp 4 . . . .

Your suggestion of "Low and mid power and torque is needed for rapid overtaking of slower moving traffic.... Occasionaly dragging another car at the lights etc will take place" isn't really compatible with a 200 horse screamer.

Forced induction is probably nearer the mark, so I'd reckon you are back to the supercharger - and a billet steel crank and top notch rods and pistons would seem mandatory. TR Enterprises or Racetorations might have some useful experience to offer.

Cheers,

Alec
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#12 MichaelH

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Posted 05 February 2012 - 12:02 AM

Surely if he has a TR already with supercharging and he has a 350 BHP Jag and lots of money then he has a reasonably understanding of what he is requesting - get the Cambridge Motorsport catalogue and order the bits and let him have whatever modern technology can supply him
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#13 marvmul

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Posted 05 February 2012 - 01:56 PM

About 3 years ago, I had made a stroked (96mm) billet crankshaft by a Mr. C.Nuyts, Antwerp. Sadly a stroked crank was not allowed in the german Triumph Competition&British GT. I'm reluctant to sell it though.
Steve Chapman, competing in the UK with a TR4 in the UK, has bought then an identical crankshaft. I met him some months ago and he told me that his cranshaft has not been built into an engine yet, perhaps he's willing to sell it? These cranks are billet steel, with dummy main bearings : it has 8 counterweights,so every cylinder is balanced on it's own. The big ends are smaller than standard : Mercedes W116 bearing shells do fit.
This same Mr Nuyts has built for me a rather special TR3 engine block : it has steel liners, pressed in the machined block and welded(!) at the top, so there are no wet liners, the top of the engine block is flat. After fitting, the liners are reamed to size, 92mm and coated with nikasil. Nikasil is very slippery and has excellent lubrication properties. Honda, Porsche, Rover... have used nikasil in the eighties, but problems occured, because of the high sulfur content in the fuel then. Now the sulfur content is drastically lowered, so that problem must have gone. Sadly the Triumph Competition lowered the maximal bore to 89mm. I've used that block in 2 races of another competition, once with a cast iron cylinder head and once with a lightweight one : no problem occured with the engine block or the head gasket. 92mm bore x 96 mm stroke is 2.550 cc. 92 mm bore does great things for the torque, because of the better flow (less inlet valve shrouding). Is this a way to get lots of torque and about 200 bhp?
MarcelV. M., Belgium.
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#14 Motorsport Mickey

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Posted 05 February 2012 - 07:38 PM

No but 89mm pistons a 3mm head offset with MGB valves (bigger heads and waisted valves I think !) and top hat machined valve guide inserts bored into the water jacket to take them is and presumably would meet with the regulations stated ?

PS
89mm + 3mm off set gives the same amount of valve unshrouding as 92mm pistons,... well it did when I used it in 1996. It didn't give 200HP but the engine was faster than those that did. !

Mick Richards
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#15 Tony Millward

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Posted 06 February 2012 - 11:13 AM

Out of interest CJ, what upgrades has he (you) planned for the rest of the car..ie. Chassis, brakes, suspension, ignition and fuel delivery?. If these haven't been considered then it's pointless having 200BHP....just a thought.

Cheers

Tony
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#16 Peter Cobbold

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Posted 28 February 2012 - 06:46 PM

I'm with Alec - supercharge it. His other cars are blown -he'll really notice the lack of low down torque with n/a engine.

If he's got access to E85 fuel 200hp would be achievable with normal CR and normal rpm limit, but double normal mbep.
If he has no access to E85 but runs a business he should look at this as an alternative:
http://customs.hmrc....ment#P178_18889
( section 3.5 bioethanol, specifically TSDA11).
Dual fuel it - 97RON up until it risks detonation, then switch to ethanol. Easily 200hp that way.
But dont expect TRR scheme to insure it.
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#17 Ashley James

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Posted 01 March 2012 - 05:09 PM

The car would be utterly useless for anything except the track if it was tuned to 200 BHP and potentially unreliable and temperamental with some sort of forced induction.

If it was me I'd stick another engine and gearbox in it, for example a Ford Zetec or even a 3 litre V6.

Is the rear end up to it?

Ash
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#18 Peter Cobbold

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Posted 01 March 2012 - 08:59 PM

I dont find the old Wade blower unreliable, and an AFR sensor can nowadays ensure leaning out and detonation are avoided. Even on 97RON I get 100hp at 2600rpm and torque to match. A blower wins out on the road - smooooothe power delivery , no waiting to come on cam. On the track is another matter ( heat, MSA penalties etc). Great shame that E85 went as 97RON is a little restrictive of top-end boost.
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#19 jellison

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Posted 02 March 2012 - 02:36 PM

Deleted - double posted!

Edited by jellison, 02 March 2012 - 03:08 PM.

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#20 jellison

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Posted 02 March 2012 - 02:47 PM

Strange mix of what this guys want - but basically if he want it to be able to beat others stuff up at the lights and maybe some track work he will need some serious bits in the motor. As someone said 200bhp is very hard to do on a 4 pot TR (not impossible) unless alot of trick stuff is put in it and BIG Money.
I would not stroke one as they already have a fairly long stroke (Pete Cox did this years back and had just about the fastest TR 4 pot cars and engine combo's), but we are talking full race to get to 200bhp and to be up over 185 you will need 92mm bore and some very trick head work.

Steel crank is no different to a std one in terms of making it more complex - just means it will pull higher revs and free up the power at those revs - but pointless unless you have a very serious head that can flow the power high up (Marvmul knows this ;)).

It is really how much he wants to spend.

A full race TR4 is easier to run on the road than a 6 pot TR race lump (they need revs) as much bigger bore and can pull frorm lower revs (piston area), more of a torquey motor, but with a cam and head (+bottom end to hand those 2) it will not make any where near 200bhp AND pull from lower to mid rpm with no fuss - you just can't have everything in these old engines (need trick Fi).

You can't have the low end grunt and top end power, if you what as close to having the ultimate 4 pot TR it will Really cost. You will not get 200bhp from a 4 pot TR without it being "Full Race" and bigger bore that and fia (87mm) engine, and it will need a fantastic head and induction setup (Marvmul know this ;)).

Here's my 4 with a no limits engine (but nothing in this engine off the shelf) - http://blip.tv/jrell...te-2006-3573639 (pity about the big fly!). But this is beyond what anyone would really ever build for a regular road car.

This lump is going back in on Sunday after a freshen up, then on the rollers and the road for some summer fun :)
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