BenB
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| posted on 19/3/10 at 08:34 AM |
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Very strange. Hope you get it sorted! It certainly sounds like the air is getting in there somewhere..... You're running NA at the moment I
assume? The TBs might not appreciate being force fed I suppose if you're hooked up the blower. But I suspect you'll be wanting to get it
working properly NA first!!
Is the timing right? It could have nothing to do with the roller bodies- something like a mix-up re timing could cause a high idle.
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MakeEverything
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| posted on 19/3/10 at 08:51 AM |
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Try fitting the filter and inlet plenum. The further flow restriction may reduce the air into the rollers.
Personally, it sounds like the inlet ports are too big for the engine, so restricting the inlet by use of a filter or restrictor makes sense.
What do you think?
I know that putting a filter onto the carb on the Dutton made one hell of a difference and it suddenly stopped running rough.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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sebastiaan
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| posted on 19/3/10 at 08:54 AM |
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The rollers are leaky. Everything points in that direction. Question: do you still have the MAP lines connected to all 4 barrels? If you do, then that
could be a cause for your higer (well, a bit higher) idle. Reasoning for this is as follows: the 4 cylinders do not draw air in at the same time;
roughly one of them is sucking at once (4 strokes, 4 cylinders...). By having the barrels connected, every cylinder is effectively (through the MAP
hoses!) sucking on 4 (slightly leaky) barrels, and thus sucking on 4 times the "leakage area". Plug up the MAP takeoffs and see what
happens with the motor running (for now) in alpha-N mode. If this helps and as an alternative to running speed-density, you could always use an
airflow meter to determine load.
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boggle
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| posted on 19/3/10 at 09:11 AM |
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surley your map feed line should come from one point on the manifold???
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....
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MikeRJ
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| posted on 19/3/10 at 10:21 AM |
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quote:
Originally posted by boggle
surley your map feed line should come from one point on the manifold???
If you only take the MAP feed from one cylinder when using individual throttle bodies then you get a very rough, pulsing signal that is of no use.
Sebastian makes a very good point with the MAP feeds though, what sort of diameter are the pipes you are using? I would definitely try his suggestion
of blocking them up and running under Alpha-N if you haven't already.
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flak monkey
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| posted on 19/3/10 at 10:39 AM |
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I am using 4mm vac hose for the MAP feeds. I have tried running under alpha_n and it made no difference.
As an update to this I have spoken to Raceline this morning and decided to order a set of DTH 45mm Jenvey throttle bodies. Conventional style. They
should be with me tomorrow morning. Their opinions on roller barrels seem to match with quite a lot of others and they have seen a few. All in all
very helpful people to talk to and they were very interested in my project.
David
Sera
http://www.motosera.com
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boggle
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| posted on 19/3/10 at 10:40 AM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by boggle
surley your map feed line should come from one point on the manifold???
If you only take the MAP feed from one cylinder when using individual throttle bodies then you get a very rough, pulsing signal that is of no use.
Sebastian makes a very good point with the MAP feeds though, what sort of diameter are the pipes you are using? I would definitely try his suggestion
of blocking them up and running under Alpha-N if you haven't already.
sorry....was thinking plenum thoughts, not individual ports....
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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sebastiaan
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| posted on 19/3/10 at 10:57 AM |
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quote:
Originally posted by flak monkey
I am using 4mm vac hose for the MAP feeds. I have tried running under alpha_n and it made no difference.
David,
Also with the 4mm MAP hoses disconnected and plugged per cylinder (by stuffing a 6mm bolt in each hose?). the problem is the amount of air entering
the engine, not the control strategy. So just switching to Alpha-N will change nothing if the engine hardware is not changed at the same time.
BTW, I think it's a good move to go for conventional TB's. Expensive experiment though.
[Edited on 19/3/10 by sebastiaan]
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flak monkey
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| posted on 19/3/10 at 11:00 AM |
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quote:
Originally posted by sebastiaan
Also with the 4mm MAP hoses disconnected and plugged per cylinder (by stuffing a 6mm bolt in each hose?)
BTW, I think it's a good move to go for conventional TB's. Expensive experiment though.
I have given up with the roller barrels. I have no more time for messing around with them. They may well work on another engine, but not on mine. As
long as the Jenverys arrive in the morning I will get those fitted. And yes its a VERY expensive experiment!
Knowing my luck I will have the same trouble with the Jenveys as its some other underlying problem somewhere! If there is I give up.
[Edited on 19/3/10 by flak monkey]
Sera
http://www.motosera.com
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stevebubs
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| posted on 19/3/10 at 11:12 AM |
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quote:
Originally posted by flak monkey
If i did go down the jenvey route I would leave the injectors in the head anyway and blank the ports in the throttle bodies and use them for MAP take
off.
I dont really want to smear loads of grease around the rollers, they are meant to be run as they are (I have a copy of the Cosworth Duratec engine
build manual and have followed it to the letter). All that would tell me is if there is air leaking past the barrels.
I did get some rough readings with the synchro when I first fired it up, and th readings were around 6-7 on the scale, which is high for idle, this is
also without a proper seal on the synchro. The pinto would normally have idled showing 3.5-4 on the scale, so there seems to be more air being pulled
in.
3-4 is what I'd be expecting so it looks like your excess air is definitely coming in the trumpets...
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Ivan
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| posted on 19/3/10 at 11:34 AM |
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Just to make you feel better - if the barrels where leaking that much what would happen if you where making full boost and came off the throttle -
would the leak under boost with a closed throttle just keep you going rather than slowing down...... Sort of the opposite of boost lag....boost
persistance. Not much fun entering a corner 
Maybe you are better off with throttle bodies.
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stevebubs
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| posted on 19/3/10 at 02:44 PM |
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quote:
Originally posted by flak monkey
If i did go down the jenvey route I would leave the injectors in the head anyway and blank the ports in the throttle bodies and use them for MAP take
off.
I dont really want to smear loads of grease around the rollers, they are meant to be run as they are (I have a copy of the Cosworth Duratec engine
build manual and have followed it to the letter). All that would tell me is if there is air leaking past the barrels.
I did get some rough readings with the synchro when I first fired it up, and th readings were around 6-7 on the scale, which is high for idle, this is
also without a proper seal on the synchro. The pinto would normally have idled showing 3.5-4 on the scale, so there seems to be more air being pulled
in.
Why not 2 sets of injectors? you can get better granularity at the low end then....
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goaty
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| posted on 19/3/10 at 09:09 PM |
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wow....missed this thread.
cant believe it david, didn't hink ti would beat you. Did you try greasing them up??? have cosworth had anything to say???
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flak monkey
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| posted on 19/3/10 at 09:19 PM |
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quote:
Originally posted by stevebubs
Why not 2 sets of injectors? you can get better granularity at the low end then....
Yep, thats also a great idea. Might look into that should I have idle issues with the current 630cc injectors. At the moment I will just run the
single set to keep things simple 
With regard to what Titan say, I dont know yet, I am waiting for the technical guy to get back to me as he was out of the office today.
Hoping to get the Jenveys tomorrow and after some minor fettling get them fitted and tested to see if it truely is where the problem lies. I damn well
hope it is!
David
Sera
http://www.motosera.com
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matt.c
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| posted on 19/3/10 at 09:32 PM |
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Flak, I dont have a clue what you are on about and cant answer any of your questions but hey mate whats new! 
I admire you with all your ideas and your great work. I wish i was as good as you.
Now get back in that dam garage and sort it as im getting bored waiting for my test drive!
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NS Dev
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| posted on 19/3/10 at 10:04 PM |
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Flak, can you just clarify, (only just seen this thread!) you say idle doesn't change until all the rollers are open by
6mm.....................
if that's the case, air is getting in AFTER the throttles!
6mm of opening should see it revving a LOT!
Are there any ways in for air downstream of the throttles?
I simply don't understand, 1400rpm doesn't need a lot of air (my experience is only with normal butterflies, but under 1mm of opening will
give more than that idle) but 6mm of opening is what you would be using when driving gently!!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Doofus
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| posted on 19/3/10 at 11:45 PM |
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quote:
Originally posted by NS Dev
Flak, can you just clarify, (only just seen this thread!) you say idle doesn't change until all the rollers are open by
6mm.....................
if that's the case, air is getting in AFTER the throttles!
6mm of opening should see it revving a LOT!
Are there any ways in for air downstream of the throttles?
I simply don't understand, 1400rpm doesn't need a lot of air (my experience is only with normal butterflies, but under 1mm of opening will
give more than that idle) but 6mm of opening is what you would be using when driving gently!!
As the roller is tapered, (widest on non engine side when fully open) the visible gap from the outside is 6mm before the engine side gap starts to
open.
Unlike a butterfly, the roller presents 2 restrictions as it closes, front and back of the roller.
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westy turbo
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| posted on 20/3/10 at 11:29 AM |
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could be air leak-vacum..
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flak monkey
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| posted on 20/3/10 at 02:46 PM |
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Definately no vac leaks anywhere.
Anyway, fixed the problem now. Fitted the set of DTH jenveys that arrived this morning. Runs sweet as a nut now, much smoother and 950 rpm idle. Will
post pics later, doing this off the phone
Sera
http://www.motosera.com
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goaty
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| posted on 20/3/10 at 03:46 PM |
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sounds good but would still be good to knwo what the problem was, expensive either way...lol.
At least you seem happy now
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westy turbo
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| posted on 20/3/10 at 03:52 PM |
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UP for sale then?
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eddie99
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| posted on 20/3/10 at 04:16 PM |
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quote:
Originally posted by flak monkey
Definately no vac leaks anywhere.
Anyway, fixed the problem now. Fitted the set of DTH jenveys that arrived this morning. Runs sweet as a nut now, much smoother and 950 rpm idle. Will
post pics later, doing this off the phone
Excellent, shame about the cost but at least your back on track for Stoneleigh
http://www.elitemotorsporteng.co.uk/
Twitter: @Elitemotoreng
Facebook: http://www.facebook.com/pages/Elite-Motorsport-Engineering/153409081394323
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Madinventions
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| posted on 20/3/10 at 04:57 PM |
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Great to hear you've got it sorted out at last, but a very expensive experiment!
If you're coming to Diss tomorrow, I'll buy you a pint if it'll help!
Ed.
Mojo build diary: http://www.madinventions.co.uk
Solo music project: Syrrenfor http://www.reverbnation.com/syrrenfor
View my band website:
http://www.shadowlight.org.uk
http://www.eastangliankitcars.co.uk/
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Stuart_B
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| posted on 20/3/10 at 05:19 PM |
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hi david, glad you sorted out the idle promblem, sham about the cost involed
stuart
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flak monkey
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| posted on 20/3/10 at 08:12 PM |
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Thanks guys, works much, much better now.
All I can say at the moment is that the high idle on the rollers is due to the clearance between the roller and barrel. I have spoken to a lot of
knowledgeable people in the last week and they say that this is a common problem on rollers and can be bigger problems on some engines than others -
even the same model engine. So whilst one duratec may run fine on them, some wont. It also depends on the spec of the engine and a whole host of other
things.
I am happy with it on the raceline DTH's and they looks pretty smart.
David
Sera
http://www.motosera.com
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