flak monkey
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 posted on 18/3/10 at 07:06 PM |
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F**&ing thing
Well I still have idle problems.
Refitted everything again with no sealant or anything. Idle was a little rough to start with difficult to tell if it was hunting, if it was it was
small.
However I still have a 1300rpm or more idle
So I now either have one massive air leak across all cylinders or no air leak and a still high idle.
Spraying brake cleaner in the each barrel results in the idle speed slowing down. Spraying it around all joint has zero effect.
Thats with 4 deg ignition advance too.
I need of a little motivation now 
Sera
http://www.motosera.com
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eddie99
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| posted on 18/3/10 at 07:07 PM |
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quote:
Originally posted by flak monkey
I need of a little motivation now
Can't help im afraid David but think of how insane the car is going to be once done  That should be some inspiration
http://www.elitemotorsporteng.co.uk/
Twitter: @Elitemotoreng
Facebook: http://www.facebook.com/pages/Elite-Motorsport-Engineering/153409081394323
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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skinned knuckles
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| posted on 18/3/10 at 07:11 PM |
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I've got no advice on your dodgy idle, but hope you stick at it. if these things were easy to build, vevry other f@$ker would have done it.
the fact its hard puts you in to an exclusive club once you've cracked it. keep at it buddy.
A man isn't complete until he's married, then he's finished
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Ben_Copeland
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| posted on 18/3/10 at 07:16 PM |
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Didnt Nothampton Motorsport shed any light on it?
Ben
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Z20LET Astra Turbo, into a Haynes
Roadster
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http://www.facebook.com/EquinoxProducts for all your bodywork needs!
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big_wasa
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| posted on 18/3/10 at 07:23 PM |
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You could take a brake from yours and finish mine 
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boggle
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| posted on 18/3/10 at 07:26 PM |
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time to call the rolling road???
just because you are a character, doesnt mean you have character....
for all your bespoke parts, ali welding, waterjet, laser, folding, turning, milling, composite work, spraying, anodising and cad drawing....
u2u me for details
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Breaker
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| posted on 18/3/10 at 07:26 PM |
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Did you change compression ratio ?
Did you change camshafts ?
Did you balance the throttles ?
How much vacuum on the intake and are the sensors working OK (throttle position, intake manifold pressure, cooling temperature sensor) ?
Perhaps you can monitor whether your engine is running lean or rich with a lambda sensor to see there is something wrong with the fuel injection ?
[Edited on 18/3/10 by Breaker]
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MikeR
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| posted on 18/3/10 at 07:36 PM |
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could you put a bit of wood progressively and slowly covering all four trumpets?
Ie take the roller barrels out of the equation by slowly restricting the air to all four barrels - if you can get the idle down by manually
restricting air flow to all four you know its air past the rollers.
Then i'd play at restricting each barrel and combination of barrels to figure out if its an issue with all four or just one.
(i've never played with roller's but have you balanced them all so they all open at the same time now you've disturbed them taking
everything off?)
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omega0684
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| posted on 18/3/10 at 07:39 PM |
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you should have stuck with the pinto
sorry mate no help i know
chin up and keep smiling 
take a half hour break, have a coffee and a biccy and go back, start at step one and work logically
All the best! 
I love Pinto's, even if i did get mine from P&O!
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Bigheppy
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| posted on 18/3/10 at 07:41 PM |
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Please humour me for a while, on your last post you said the carb roller/barel was round on the inlet and oval in the outlet of the throttle body. If
the barrel were rotated 180 deg making the oval side the inlet to the throttle body due to the shape of the oval when the throttle was closed a
smaller amount of air could be drawn in so reducing the idle speed. This is how some model aeroplane engines were configured. I appreciate this might
not work in your situation but it might be worth investigating.
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r1_pete
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| posted on 18/3/10 at 07:45 PM |
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It looks like you've answered your own question David, if spraying the cleaner into the barrels slows the tickover, it is temporarily reducing
the clearences, and reducing the airflow.
I know you've tried just about everything else, but altering timing to reduce tickover is not the way to go, that is making the engine run
inefficiently by not full burning all the fuel and washing lubricant from the bores increasing engine wear.
The advantage of these bodies is only realised at WOT, how often are you up there on a road car? would the supplier swap them for butterfly bodies?
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flak monkey
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| posted on 18/3/10 at 07:48 PM |
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Rolling road isnt an option at the moment. The cars not even driveable as it is. Plus no one will touch a megasquirt car unless is running pretty much
spot on to start with.
Compression ratio was changed from 10.8:1 to 10:1
Cams are new but standard timed as per standard Ford procedure.
Throttles are roughly balanced - from experience if they are poorly balanced idle speed will decrease rather than increase. They are in pairs (like
webers) so there is only one balance to set and like I say, its very close as is.
Vac is about as good as I would expect, around 65-70KPa at 1300rpm.
Lambda sensor is already fitted and talking to megasquirt. AFR is around 13 at the moment, which is still too rich.
Turning the roller through 180deg is not possible and not correct so its a no go.
If its a big airleak causing the high idle I am f&$(ed if i can find it.
Sera
http://www.motosera.com
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r1_pete
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| posted on 18/3/10 at 07:50 PM |
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quote:
Originally posted by Bigheppy
Please humour me for a while, on your last post you said the carb roller/barel was round on the inlet and oval in the outlet of the throttle body. If
the barrel were rotated 180 deg making the oval side the inlet to the throttle body due to the shape of the oval when the throttle was closed a
smaller amount of air could be drawn in so reducing the idle speed. This is how some model aeroplane engines were configured. I appreciate this might
not work in your situation but it might be worth investigating.
That would just mean when the throttle is closed the oval would be opposite where it is now, as the inlet and outlet is symetrial top to bottom it
wouldn't make a difference.
Only on opening the throttle, you'd have an oval against circular and vice versa.
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flak monkey
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| posted on 18/3/10 at 07:50 PM |
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If i cant get it running with what I have then I have zero chance of making it to Stoneleigh. Theres too much time and effort involved in changing
from the roller throttles.
They wouldnt swap them anyway - I have drilled 4 MAP take offs in them to start with, and I also didnt buy them new - well they are new but not first
hand should I say!
PS also looking at the best part of £1k's worth of throttle bodies sitting on the side of the engine at the moment
[Edited on 18/3/10 by flak monkey]
Sera
http://www.motosera.com
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r1_pete
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| posted on 18/3/10 at 07:54 PM |
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Have you tried running them with the pairs disconnected? another long shot, but is one pair holding the other pair open? You'd only see that
with a gauge on each map take off.
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flak monkey
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| posted on 18/3/10 at 07:56 PM |
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The linkage is in the middle of the pairs and they interlock so there is no option of disconnecting the pairs sadly
Sera
http://www.motosera.com
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r1_pete
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| posted on 18/3/10 at 08:08 PM |
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OK, this might sound stupid, but to prove air is getting by the clearance in the barrels, could you temporarily seal all but the opening at the bottom
with plasticine?
You couldn't operate the throttle but if you get a decent tickover, the issue is identified if not rectified.
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flak monkey
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| posted on 18/3/10 at 08:11 PM |
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I could and thats something I can try tomorrow afternoon.
I am just stumped as to where else there could be air getting past in high enough quantities to give such a high idle.
Sera
http://www.motosera.com
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GeoffT
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| posted on 18/3/10 at 08:22 PM |
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Hi David, just one more suggestion, although you're probably into 'suggestion overload' by now...
The idle bleed screws you mention - you say they are screwed right in, but are they in fact fully closing the air bleed? Are they fitted with springs
behind the heads, if so are you sure they're not bottoming on the springs? Easily checked by temporarily removing the springs if fitted.....
As said by many others though, look for nothing else until you've fixed the air leak........
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flak monkey
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| posted on 18/3/10 at 08:26 PM |
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The bleed screws sit on tapered seats in each throttle body and simply have a lock nut, pretty simple really. They are all screwed down tight and
appear to seal.
Its at this point I wish I hadn't bothered with roller barrels and just fitted jenveys in the first place Or even just a plenum and
mahoosive single throttle body
[Edited on 18/3/10 by flak monkey]
Sera
http://www.motosera.com
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GeoffT
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| posted on 18/3/10 at 08:36 PM |
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Ok, how about this.
Pressure leaks are much easier to find than vacuum leaks, so rotate the engine till both valves are closed, then via an adapter of some sort in the
plug hole, pump some pressure in and use soapy water to see where it's coming out.....
Sorry, should of course have said rotate till the exhaust valve is shut, inlet valve is open..
[Edited on 18/3/10 by GeoffT]
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stevebubs
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| posted on 18/3/10 at 08:42 PM |
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quote:
Spraying brake cleaner in the each barrel results in the idle speed slowing down
Sounds like they're not fully closing to me...
[Edited on 18/3/10 by stevebubs]
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stevebubs
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| posted on 18/3/10 at 08:47 PM |
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David,
May I also suggest posting a message on se7ens.net.
There's a fair few caterham owners on there, and the technical expertise in that area is pretty high (several Caterham duratec owners + Caterham
dealer)
Stephen
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stevebubs
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| posted on 18/3/10 at 08:47 PM |
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Oh yes - and a lot of them live in Cambridgeshire...
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Dave Ashurst
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| posted on 18/3/10 at 09:01 PM |
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You tried pouring water over it I guess?
best
D
Edit: I see - you used brake cleaner...
[Edited on 18/3/10 by Dave Ashurst]
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