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308 Black motor help

Started by GMH-01X , Jun 29 2015 09:39 PM

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#26 _LS1 Taxi_

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Posted 05 July 2015 - 09:45 AM

In Red, Blue and Black V8 motor heads the valve configuration was [ IN - EX - IN - EX - EX - IN - EX - IN ] causing the infamous "hot spot" in the centre of the head.

In VL Group A & VN-onward V8 heads, the valve configuration was [ IN - EX - IN - EX - IN - EX - IN - EX ]

So the cams need to be a completely different design to suit to modified valve configuration, mix 'em up and the back four cylinders will be trying to breath in through the exhaust and out through the inlet manifold!

I understand the different firing sequence between the cams but that still doesn't change what I'm saying. The firing order of the dissy must match the camshaft. The rotating assembly is the same for both motors, it's only the cam that changes the firing order.

The only time this goes to pot is if you're running Efi. If running a carbed VN 5.0 I can't see why you can't retain the factory cam so long as you keep the firing order appropriate to the cam...

Edited by LS1 Taxi, 05 July 2015 - 09:47 AM.

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#27 yel327

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Posted 05 July 2015 - 12:45 PM

It isn't firing order Daz it is the location of the inlet and exhaust valves that changes hence the cam lobes have to move with the valve otherwise you'd be opening 4 x exhaust valves (2 per bank) on their respective intake strokes and opening 4 x inlet valves on the exhaust strokes.

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#28 _LS1 Taxi_

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Posted 05 July 2015 - 02:48 PM

No worries guys.

You are correct. Thanks!

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#29 rexy

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Name:Rexy
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Posted 05 July 2015 - 07:58 PM

There is no difference between a 165kW or a 185kW engine, just buy the best one you can. The power difference is in exhaust, cold air intake and tune (memcal).

It will work fine with a manifold, carb and dizzy but will lose heaps of power - far better off keeping the injection and they are a snack to make work. You'd need a different cam to get it all working and even then it will be less than 9:1 compression.

Not exactly the quick changeover he was looking for though. Will need extra budget for electrics and fuel system.
Also of course will need new exhaust to suit the VN heads.

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#30 GMH-01X

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Name:Aaron
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Posted 05 July 2015 - 09:12 PM

Not exactly the quick changeover he was looking for though. Will need extra budget for electrics and fuel system.
Also of course will need new exhaust to suit the VN heads.

G'day rexy
The Senator motor is just another option for me and I'm well aware of wiring, exhaust , fuel pumps and serge tank required for the efi motor - having this set up is a good reliable motor or I could always rebuild a red, blue or black mild streeter and spend twice as much as the efi motor would cost to do.

Cheers Aaron

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#31 yel327

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Posted 06 July 2015 - 11:54 AM

Not exactly the quick changeover he was looking for though. Will need extra budget for electrics and fuel system.
Also of course will need new exhaust to suit the VN heads.

Most of the conversion stuff is off the shelf today though, so if you wanted to you could buy it all and it is essentially a bolt and plug in with a few fiddles in mounting the EFI pump and surge tank. As you state the exhaust is the major expense/hassle though especially if running extractors plus if the gearbox is manual/trimatic pattern then there's that issue too.

When you factor in the expense of a Harrop dual plane manifold, new cam and lifters, gasket set, carby setup, etc., the cost of parts to fit the EFI engine as an EFI isn't that bad if it is a good running motor.