Noble M500 Upgrades & Overhaul

[Peter Gidden]

Clue:

I also noticed at TDC piston was about 2mm short of block deck...

Another clue:

Old pistons were flat top CP forged pistons. New Cosworth pistons are dished...

[ashley]

[Peter Gidden]

I had a suspicion of what the problem was, but had never investigated the detail as it wasn't something that had ever affected me. Until now.

So, a couple of calls to Noble tuning guru at Roush and Arrow Precision and all was revealed...:

The original Duratec V6 was N/A. To turbocharge, Noble had to reduce compression ratio.

They chose to use flat top pistons and custom Arrow Precision rods that were approx. 2mm shorter than Ford OEM, thus reducing compression by not having the piston reach deck height at TDC. Essentially a cheap and dirty way of achieving the goal.

The big downside to a shorter rod is poor squish. Squish is an effect where the gases are suddenly "squished" out from between the piston and cylinder head within the combustion chamber, creating turbulence which promotes thorough fuel/air mixing, which is beneficial for efficient combustion. The gap between cylinder head and piston at TDC is typically less than 1mm or even less.

Around the time the M400 was released, Noble changed to a dished piston and Ford OEM length forged rod. Thus improving the squish effect.

What i had was dished-style pistons, but short rods.

Solution, buy long rods to match pistons.

So, another few calls to Roush and Arrow Precison and although i was about £1500 lighter, i had these:





Next job - fit pistons and rods. Again.



First piston and new rod fitted. Crankshaft fully rotates and pistons reaches deck height. Hooray!

[Peter Gidden]

Fact - ARP or similar rod bolts should never be tightened with a torque wrench.

Any decent engine builder will know that and use a rod bolt stretch gauge:



As it happens, and Ashley will confirm, one of his first questions when discussing me build his engine was "have you got a rod bolt stretch gauge?"

The bolt manufacturer will if you ask, specify a length that the bolt will stretch by when correctly tightened. The spec. sheet that came with the Arrow Precision rods specify ONLY a stretch length, not a torque figure.

Take a look at any ARP rod bolt and you'll find it has a dimple in each end. Those dimples are to locate the stretch gauge, not for artistic merit.

To use, the gauge is fitted over the bolt, remembering first to fit a suitable box spanner:



Bolt is tightened until gauge shows specified stretch, in this case 0.006" to 0.007".



So, do i know to what torque my bolts are tightened? No, i have no idea. But i do know they have been tightened to precisely ARP's specification.

All pistons and rods installed. Semi-stressed windage tray, oil pump and oil pick up fitted.



Bottom end done. Build time so far, 14 hours.

Heads needed no work except a deep clean, so ARP head studs refitted, new MLS head gaskets dropped in place, and heads torqued down.



Tomorrow evening camshafts, chains and tensioners.

[craig]

Looking real nice there Pete. Looking forward to further developments, and ultimately, seeing it finished.

Shame you won't have the new front clam on and burns silencers on for Lemans, but something to look forward to!

[gerbil1028]

Very nice son jealous.

[Gullzter]

Brilliant, glad it wasnt a major issue

Im looking forward to seeing it when im down

[Magic Beans]

Getting close now, Peter

What's left to do?

[DB Mr2]

I come here for the learning.

The cars alright too.....

[Peter Gidden]

Roush developed, Piper ground cams:



I already have uprated valve springs that i fitted when i installed this engine a few years ago.

Cleaning and inspection revealed a dodgy ratchet in one of the tensioners, so a new one was bought at £138. And people think Toyota parts are expensive! (A full gasket set and block bolts were £550!)

So, cams and chains fitted, timed in, and tensioners bolted in to lock everything in place:



A generous does of cam lube was rubbed on to all of the valvetrain. Cam and chain covers fitted:



Sump is last job for a complete longblock assembly.

[pistol pete]

looking good there peter
be a beast when done,
will you get run in time before Le'mans, need mapping or anything?

[Peter Gidden]

looking good there peter
be a beast when done,
will you get run in time before Le'mans, need mapping or anything?

Thanks Pete.

Will not need remapping before we go away. I'll get it remapped when i get back.

[Peter Gidden]

M400s came with 9 litre track day sump as standard. Original baffles have been known to cause issues, so a modified baffle kit was bought from a USA Noble specialist.

Old baffle kit:



New baffle kit:



Sump now fitted.

Next are flywheel, clutch and gearbox.

[gerbil1028]

[Draven]

Amazing work pete

[Peter Gidden]

Cam covers, lower inlet manifold c/w injectors and fuel rail fitted with new gaskets. Water pump bolted onto back of cylinder head.



Lightweight flywheel fitted. Then clutch. Clutch is made by Helix Autosport. Billet aluminium cover plate with 6 puck ceramatalic driven plate. Good for 500ftlbs.



6 speed gearbox with Quaife LSD fitted. I had the gearbox uprated by CTS about 3 years ago. Completely stripped, all gears shot peened and polished, OEM bearings replaced with metal caged bearings, and all shimmed up at operating temperature. Casing drilled and tapped ready for gearbox cooler lines to be fitted later this year. Good for 500ftlbs.

Cost around same as nice Rev3 turbo - complete car!



Engine is now ready to lift into car. Chassis design means all ancilleries have to be bolted on with engine fitted. Oh joy...

[Peter Gidden]

Another mad 13 hour day working on Craig's car, and two customer engines.

Before i can fit my engine, i need to plumb in my extinguisher. I opted for same as GB, but electrical version.

So first, after lots of measuring, i mounted the base.



Then, after lots of messing confirming there was access and space on the blind side, i drilled and fitted the (optional) bulkhead union.



Finally, extinguisher fitted, short piece of discharge tube cut, shaped and fitted.

[Gullzter]

Lovely Jubbly! Coming along very quick now
Hoping all fired up when im down

[craig]

Engine and fire extinguisher install looking very smart Pete. Will have look when I pick my car up.

[pistol pete]