Holley 600

[chrissugden]

Hi there,

I have a 4.2 V8 in my 110 CSW, Which since March I have completely rebuilt the engine and since then I have been having elecrical problems with the efi. So far I have replaced the stepper motor, air flow meter, dizzy cap, rotor arm, electronic ignition module, coil, leads, plugs 4 times. All of the parts have been replaced with high spec ones at a considerable cost but i am still having problems. I have also had the dizzy tested on a bench by a specialist and he says it is fine. I have run checks on the ecu with a multimeter and a test sheet and all the readings are well within the correct tollereneces. So as you may by now have appreciated I am pulling out hair.

So my plan now is to take off all the efi system and use it as a door stop and put on a Holley 600. My question is has anyone done this. I used to run a Weber 500 on an old 3.5 of mine and I loved it but it was very thirsty. I can only imagine that the 600 will be more so. I just don't want to go to all the trouble of swapping the thing over and be disappointed with performance.

Any views would be greatly appreciated.

Chris

[Boosted LS1]

Use the webber again, it's a good carb. If you use a holley go for vac secondaries. Don't get a double pumper carb, it will be very thirsty.

Boosted.

[stevieturbo]

Getting someone to properly diagnose the problem would be better than just repalcing parts at random.

I'd have though a 600 a tad large for a 4.2 depending on manifold used ?
The 500 properly jetted should be an excellent all rounder.

[Boosted LS1]

I had a 4.5 and originally used a 390 carb with the choke plate removed so it was maybe a 420 cfm/ish. According to charts available at the time it should have been adequate. When I switched to a 600 the bottom end pick up was transformed and the car was much smoother. I reckon the 390/420 wasn't big enough.

Boosted.

[chrissugden]

Thanks guys,

I should have written in the first post that 3 'specialists' have looked at the car and still no luck. I plan to run with carbs for a while and bench the EFI stuff and check each component individually. The reason also for a 600 is that I have a friend with a second hand one that I can basically have if I want it. And although I had a Weber 500 before I was just wondering what the general thought on the 600 was. A tad worried about fuel economy but as the car does not travel far I shall just live with it for now. Thanks for your views. I'll let you know what the outcome is.

Chris

[eliot]

I would say the 600 is too big. Weber 500 is a good fit, usually they need jetting down a stage or two to get mid range economy though. Fuel sloshes around a bit when off-roading in them though causing stumbles.

Why not learn all about EFI for yourself and convert it to megasquirt? One of the great things about them is the Megastim, which emulates the entire car on the bench - you can test and learn all about it before even turning a spanner.

[chrissugden]

I do love the idea of the megasquirt ecu but at present I live in Cape Town SA and to import one will be more than double the cost of buying one. So if I did manage to get hold of a MS ecu will I be able to get rid of my standard ecu altogether...?? The ecu at present only manages the engine.

[eliot]

yep, I assume yours is a hot wire setup. The only difference with the hot wire, is the idle control - or rather lack of a stepper motor driver on the megasquirt. But living in SA, i don't suppose thats an issue.
Surley you can get someone to bring one 'home' with them from the UK?

[chrisj]

The Weber 500 should be fine for the 4.2, a friend runs a tweaked 4.6 with one and it more than copes.

[chrissugden]

Against all advice I have fitted the 600, as it was free, and it works a treat. It has a vacuum operated secondary and when this kicks in all hell breaks loose. Very cool but also very thirsty.

It has got me mobile again though and I will now bench the EFI system and start getting bits tested.

Many thanks for all your replies.

Chris

[Boosted LS1]

chrissugden said:

Against all advice I have fitted the 600, as it was free, and it works a treat. It has a vacuum operated secondary and when this kicks in all hell breaks loose. Very cool but also very thirsty. Chris

If you can feel the secondary chokes kicking in then the carbs not set up correctly. Transistion should be smooth. Usually it means the primary jets are a tad small or you have the wrong spring on the vac diaphragm. You may also want to check the accelerator pump jets aren't dribbling or they may be to large. This would waste a lot of fuel.

Boosted.