Alez
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| posted on 13/5/07 at 10:17 PM |
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Rover V8 ignition advance??
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:
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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
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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
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Agriv8
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| posted on 13/5/07 at 10:38 PM |
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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
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
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craig1410
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| posted on 13/5/07 at 10:58 PM |
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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.
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mark chandler
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| posted on 13/5/07 at 11:45 PM |
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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
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flak monkey
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| posted on 14/5/07 at 07:14 AM |
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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
Sera
http://www.motosera.com
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Alez
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 posted on 14/5/07 at 08:31 PM |
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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 
quote:
The vacumn pipe will add further advance, with a hot cam you would probally look to bin this and block the holes anyway.
Maybe the guy who installed the distributor wasn't wrong after all!
quote:
You have an aftermarket dizzy, so the curve should be set up right for the engine.
Same curve as for a standard engine? Then any garage that services Range Rovers will do, which is good news here.
Cheers,
Alez
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flak monkey
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| posted on 14/5/07 at 08:38 PM |
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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]
Sera
http://www.motosera.com
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froggy
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| posted on 14/5/07 at 08:56 PM |
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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!
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Alez
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| posted on 16/5/07 at 09:30 PM |
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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!
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Alez
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| posted on 16/5/07 at 11:54 PM |
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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:
quote:
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
This pushes my English a bit too much, but the guy showed me how the low rev mixture were adjusted with two little screws whilst the high rev mixture
was fixed by two small needles fitted to the carb, which were aftermarket, not Webber. I'm not sure if that means re-jet and I can't find
a receipt for those needles (don't know English name for them).
quote:
i dont know which mallory dizzy you have but they can be set to limit advance fairly simply
I don't know myself but will try to take a few pics of it tomorrow and see if I can match them to the ones on the Mallory website..
Cheers,
Alex
[Edited on 17/5/07 by Alez]
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