76er Swallowtail K-Jet turbo build

[Peter Jones]

Remember the clutch spins at double engine speed (ie double the tacho reading), so if it was to let go, it would let go in a BIG way!

I'm having trouble seeing how a friction disc could rotate twice as fast as the crankshaft it's clamped to. Care to explain?

Pete

[Oneofthegreats]

I'm having trouble seeing how a friction disc could rotate twice as fast as the crankshaft it's clamped to. Care to explain?

Pete

I'll try & make it as simple as I can


A Crankshaft rotates at twice the speed of the Camshaft (& intermediate shaft in these engines)

The Crankshaft rotates twice in a full ignition cycle in a 4 stroke engine



May have got our wires crossed.

I meant that the clutch incl. the crankshaft, flywheel, crankshaft pulley, gearbox input shaft etc spins at double "indicated" engine speed off the tacho ie if the engine is indicating revving at 5000rpm on the tacho, the crank & all components attatched directly to it are spinning at 10000rpm.

[Peter Jones]

I'm pretty sure Tachos are measuring crankshaft RPM.

I just built one. For each "revolution" it's expecting 2 Ignition pulses which would equate to 1 Crankshaft revolution and 1/2 a camshaft revolution.

Is engine RPM not equal to Crankshaft RPM?

Pete

[Oneofthegreats]

I'm pretty sure Tachos are measuring crankshaft RPM.

I just built one. For each "revolution" it's expecting 2 Ignition pulses which would equate to 1 Crankshaft revolution and 1/2 a camshaft revolution.

Is engine RPM not equal to Crankshaft RPM?

Pete

Well, for every time the dizzy rotates around one full cycle, the crank turns twice. So when your using a timing light the crank is effectively rotating twice for every time the timing light flashes from the ignition pulse.

[Oneofthegreats]

Now you've got me all confused Pete! hahaha.

[Peter Jones]

Well, for every time the dizzy rotates around one full cycle, the crank turns twice. So when your using a timing light the crank is effectively rotating twice for every time the timing light flashes from the ignition pulse.

Yes, that's right but a timing light is sensing off 1 cylinder which fires only once for every two crankshaft revolutions. A tacho is sensing off the coil which fires twice per crankshaft revolution (4 cyl).

[Peter Jones]

Now you've got me all confused Pete! hahaha.

Me too

Nighty Night!

Pete

[Oneofthegreats]

I think somewhere down the line, I've had a momentary lapse in concentration knowing that the crank spins at twice the speed of the camshaft, intermediate shaft & distributor.

Been looking & measuring to many gear sets, gear ratios, diff ratios & tyres sizes! doh!

But forgot the the tacho reads off the ignition coil & recognizes that for every rotation of the crank, the coil fires twice (4 cyl. 4 stroke engine) which is identified as one revolution of the crankshaft by the tacho.

[Preen59]

Nice work there, Timmy boy!

Sorry i didn't reply to the picture message last night. I was at a wedding, phone on silent and was quite drunk. Haha.

[Oneofthegreats]

Well I finally drew up enough motivation to fit a new clutch (thanks to Doms dad Nick) & fit another gearbox.

Its just a stock replacement 210mm clutch for now, but refitted my HD clutch pressure plate for alittle more bite.

Hopefully the stock old diesel 4psd box can cope.


Time will tell!