Julian B
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 posted on 3/9/06 at 02:31 PM |
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rover v8 engine running probs
Hi all
I have a rover v8 that im trying to setup
I have got it to the stage where it runs for about 10 mins without any problems. As the temperature gets to about 80deg the engine becomes lumpier and
eventually stalls. Trying to restart is difficult. Let it cool down and its all ok again. This only happens at tick over and you can get round it by
blipping the throttle when it starts to get lumpy.
Any ideas
PS its running a webber 500
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Guinness
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| posted on 3/9/06 at 02:35 PM |
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Sounds like the fuel is evaporating?
You've probably got sufficent heat build up in the ten minutes to do it. Would account for the difficult to start again too.
Darren W had this problem on his pintosaurous for a while.
(Sorry if this turns out to be rubbish, I'm a 1.1 litre BEC boy, not a 4 ltr CEC man!)
Cheers
Mike
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Andy S
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| posted on 3/9/06 at 02:58 PM |
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What colour are the plugs ?
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froggy
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| posted on 3/9/06 at 03:21 PM |
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is the carb new? if so then you will need to set the idle screws up to suit your engine as the weber is really a yank carb for 5litre v8,s have a
look on rpi or dje sites for the basic settings, mine took a bit of tweaking to idle right but its soooo much better then the holley
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Paul (Notts)
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| posted on 3/9/06 at 03:28 PM |
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havent reached the stage of starting mine yey ( ) but some people have recomended that I fit a thermal spacer between the carb and the manifold to
prevent fuel evaporation...
Paul
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Julian B
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| posted on 3/9/06 at 03:53 PM |
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Thanks for all the info guys
I have in fact got a thermal spacer which raises the carb off the manifold by about an inch. The idle is set for abot 800 rpm and i have the timing
set to 6 deg btdc.
I have just checked the colour of the plugs and they are quite carboned up (black) . Does this suggest its runnung to rich? How can i set the mixture
without a hydrocarbon meter?
Thanks again
Julian B
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Andy S
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| posted on 3/9/06 at 05:28 PM |
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From you described it sounds to me like the idle is running far too rich I asked about the plugs first just to satify this - its a bit like leaving
the choke out - Warms up then cuts out - becasue its not a choke, when you blip the throttle the plugs clear a bit and the process of sooting up the
plugs starts again.
I dont know enough about how the Weber 500 is set for idle but it sounds to me like you need to drop down a size on the jet if the idle mixture screw/
screws (again assuming ) are/is wound in enough.
Also check the timing is at the correct advance that you are getting a good fat spark
I guess thats its nice and easy to start from cold which is another indication that its too rich.
edit - The plugs are actually a very good -if basic - indicator for the way an engine is running - Its how it was done in the old days LOL hence the
old film of racing mechanics twirling braces with a plug socket and paying close scrutiny to the look of the plug
Andrew
[Edited on 3/9/06 by Andy S]
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moggybloke
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| posted on 3/9/06 at 07:11 PM |
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change the jets is the first thing these are available from rpi speak to them and they will give you the base setting for the mixture from what i can
remember its right in and then 2 1/2 out
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moggybloke
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| posted on 3/9/06 at 07:13 PM |
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also what rad are you using for the v8
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mark chandler
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| posted on 3/9/06 at 07:18 PM |
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If using carbs then they should already have bimetallic strips which richen the mixture as the fuel bowl warms.
Assuming it was jetted okay previously then I suspect its a case of the manifold getting overly hot, this would be due to the water outlet between the
carbs (8mm pipe to rad) being blocked.
Simply pull the pipe off if water flows then its okay, if not start exploring with a bit of welding rod or small drill bit. When blocked the water
evaporates and boils within the heads and maniold so everything get far to hot.
Regards Mark
[Edited on 3/9/06 by mark chandler]
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moggybloke
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| posted on 3/9/06 at 07:50 PM |
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what carbs use a bimetallic strip ive never seens this before on a weber
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02GF74
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| posted on 3/9/06 at 08:47 PM |
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quote:
Originally posted by moggybloke
what carbs use a bimetallic strip
SU HIF.
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froggy
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| posted on 4/9/06 at 10:38 AM |
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ive ran the weber on a 3.5 which is on the small side for the carb didnt need to touch the jets but wound both idle screws 3 1/2 turns to get the idle
about right . if the car will sit stationary without going over 80 degrees then your cooling system is up to the job, if your on a 3.5 lump then you
might want to move the accel pump linkeage to the lowest setting to avoid bogging too mine ran best at 4% co at 900rpm but it is easy to overfuel
as the weber seems more suited to the 3.9 and 4.6 lumps
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MikeRJ
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| posted on 4/9/06 at 11:04 AM |
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quote:
Originally posted by Andy S
edit - The plugs are actually a very good -if basic - indicator for the way an engine is running -
But only if the engine is being driven at normal speeds and temperatures. Having it idling from cold for ten minutes will almost certainly make the
plugs show a rich mixture.
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Andy S
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| posted on 4/9/06 at 05:16 PM |
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Doesnt really matter what the engine temperture or the running state - the plug will tell you what is happening if you know what you are looking
at.
At idle it will indeed indicate a richer running mixture - this is what is required - However it will also tell you if this mixture is to rich or too
weak. If you know what colour a 5:1 looks like in comparison to a 10:1
And all the better if you combine this with and understanding of heat range.
It takes a bit of effort thats all - like reading a map instead of just lumping a code in the GPS 
Andrew
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