I need to adjust the ignition advance of the Fury V8 I just bought.

I would like to know where to find the different degree figures for my engine, spec as follows:

"
Fitted with as new 4.6ltr Cross Bolted Rover V8 (700 miles with all receipts).
Vulcan Maxiflow gas flowed big valve heads
Piper 285 Cam
High Rev lifters
Steel timing gear
Mallory Distributor
Webber 500
Port matched Offenhauser inlet
Edelbrock full engine dress kit
"

I don't know which engine bit determines the optimum degree figures (cam maybe?) and so I don't know where to start searching for these figures. A friend of mine has a Small Block Chevy and he suggested 8 deg idle and about 32 deg at 3000 rpm.

In case the settings are given by the cam used, Piper cams are as follows:

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BP255 (Approx 255 ° duration) Very mild road cam where low end improvements are needed

BP270 (Approx 270 ° duration) Fast road cam for use in otherwise unmodified engines

BP285 (Approx 285 ° duration) Top fast road cam for use in hot hatch and modified road engines

BP300 (Approx 300 ° duration) First stage competition cam, ideal rally cars, short circuit where some mid range is required

BP320 Top race profiles
"

There's a thin vacuum tube going from the Weber carburettor to the Mallory distributor. In my car, this is disconnected because connecting it makes the engine go very wrong. A mechanic told me that the engine was running way too advanced. That would explain why it's heating up too much as well.

Where would you look for the relevant degree figures needed?

Cheers,

Alex

Personally running.

11 at tickover to arround 28 not fully RR tunned yet but seems ok.

My spec 4.2 EFI typhoon cam waisted spark ign.

Running hot could be a lot of things but in my personal experiece running lean caused a lot of heat issues.#

REgards

Agriv8

From what I've read in one of the RV8 tuning manuals you should aim for maximum advance just short of pinking (pre-ignition) under load. This might sound obvious but apparently the standard timings are quite conservative and you can aim for more advance if you want optimum performance.

Also, I'd recommend you use as much fuel octane as you can get your hands on. I'm using Shell V-Power (99 Octane) in both my road car (SEAT Cupra R) and my Locost RV8. I'm also using Castrol Lead replacement additive in my Locost.

HTH,
Craig.

It depends when your maximum advance occurs, you should be looking for around 36 degrees @ 5000 as you have no control on the advance curve the rest will just fall where it does.

The vacumn pipe will add further advance, with a hot cam you would probally look to bin this and block the holes anyway.

If its running hot then the most lightly cause is air in the system, this will rise to the highest point, the inlet manifold.

As you have a weber carb, is the inlet a modified RV* carb one, ie someone has sawn off the top triangle and welded on a plate, if so does it have a small water pipe at the top.

If not you may need to add one at the highest water point (drill a small hole and epoxy a bit of brake pipe) and take this to the header tank. RV8's really struggle with any air here. You rad must be below this point making it hard to bleed.

You could also try putting in some water wetter, if the system is marginal this will improve things.

Regards Mark

You want between 14 and 16deg at idle. Idle advance is solely determined by the duration of the cam.

And you want 36-38deg all in advance (just happens to be the same as a pinto for the RV8). This is usually at anywhere between 3000 and 4000rpm.

You have an aftermarket dizzy, so the curve should be set up right for the engine.

David

Thank you all very much for the info and tips.

Special thanks to David, who replied a previous post which I deleted by mistake without even being able to read his post

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The vacumn pipe will add further advance, with a hot cam you would probally look to bin this and block the holes anyway.

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You have an aftermarket dizzy, so the curve should be set up right for the engine.

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The vacuum pipe either needs leaving disconnected and being permanently blocked off - if you leave it open you will suck air in the wrong side of the inlet (the vacuum advance it just gives you greater fuel economy whilst cruising). Or you can try to work out whats wrong with it.

The mallory dizzy will (read should) have a different advance curve for your modified engine. And so will be completely different to a std one modded ones also usually have less total advance as otherwise you end up with too much all in and lots of pinking and broken pistons.

All you need to do is set the advance at idle, at say 14deg for a start using a strobe - or tell the garage what you want if you dont have a strobe (they are cheap enough to buy). Then check its not pinking under load, either on a rolling road or whilst driving. You can then check with a strobe how much total advance you are getting, and make adjustments to suit.

The amount of total advance you need depends on the geometry of the combustion chamber, the position of the spark plug in the chamber and the duration of the cam.

David

Have a look here: http://hometown.aol.com/dvandrews/timing.htm

[Edited on 14/5/07 by flak monkey]

[Edited on 14/5/07 by flak monkey]

could have sworn i posted a reply to this yesterday? from my own experience the weber 500 is a good match for a 3.9 with a mild cam but may be a bit lean on a 4.6 without re jetting,if your temps go over 80c then power will suffer quite a bit and i would suggest a maximum advance of 28 degrees and around 10 at idle. i dont know which mallory dizzy you have but they can be set to limit advance fairly simply . heat is a big issue with the rover engine as i got a lot better results when i sorted the cooling out on my car after a dyno session which saw temps of around 95c . the 4.6 had to run much hotter in the range rover to comply with emmisions and the power really suffered because of it ,i think that a lot of the liner problems that plagued the later engines was down to the fact that they got so bleeding hot!

Dave,

Excellent post and excellent read on the link provided, cheers. I should make sure that the garage doing the work are happy with the degree figures provided.

Froggy,

I'm terribly sorry to hear you had replied to my post already. I deleted all that by mistake. A little software glitch made my post appear twice and, as I deleted what I thought was a duplicate, the whole thread dissapeared, including a post by Flak Monkey and you one as well and I couldn't read them

Thanks for the post, then definitely very important for me to keep the temperature as low as I'm being able.

Thanks a lot everyone!

BTW I've been searching through the invoices for further details of the Weber carb and Mallory distributor I'm running but haven't found anything, so:

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the weber 500 is a good match for a 3.9 with a mild cam but may be a bit lean on a 4.6 without re jetting

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i dont know which mallory dizzy you have but they can be set to limit advance fairly simply

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