Author | Topic |
john-saab Administrator
United Kingdom 2679 Posts | Posted - 05 Jun 2014 : 22:27:14
| Not quite there Si,the height issue can only be sorted by a radical chop to the filter housing, i'm trying to do it without totally butchering the housing or alteration to the carb, not sure if trimming 10mm off the carb top will affect the way it works?
'72 95 (The Flying Banana),'72 96(Bridget),'72 96 (green one)'73 96 (Vernon),'74 95 (Veronica) | |
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pchristy V4 Guru
United Kingdom 1790 Posts | Posted - 10 Jul 2014 : 17:24:19
| Having recently re-acquired my old 95, during the drive home from London, I noticed it "fluffing" a bit at full throttle. It also seemed to be struggling a bit on the steeper hills, though it was well laden....!
It felt like weak mixture, though I don't recall it doing that when I had it before. Mind you, back then it was on a standard exhaust and a CD ignition system. Put 400 volts through the coil, and ANY mixture will fire!!!
Now it has a Jetex, and a modern breakerless ignition, so I decided to try a richer main jet. Rummaging through my box of carb bits, I found both a 160 and a 165 jet (standard is 155). I've fitted the 160, and on a test run, the car is running much better. The "fluffing" has gone, and it now pulls strongly up hills without feeling as if its running out of breath!
I'll run a tankful through it like this, to get an idea of the mpg, and then maybe try the 165. I'm not expecting that to make a significant difference, but you never know!
My conclusions? a 155 main jet may be fine on an otherwise standard engine, but with a sports exhaust, you probably need a 160 minimum.
-- Pete "Duct tape is like the Force: It has a light side and a dark side, and it binds the Universe together!" | Edited by - pchristy on 10 Jul 2014 17:24:57 | |
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Doive V4 Fan
United Kingdom 160 Posts | Posted - 30 Jan 2015 : 15:13:08
| This thread has been a good read, as we are now the proud owners of Tommygoldy's car. He's done a lovely job fitting the 34ICH, the car runs sweetly, starts easily when cold with a spot of choke, and pulls like a train when it's warm. There is a small problem when it's hot though, and the engine is switched off to get fuel etc. It's impossible to start. I noticed today with the engine hot and the air filter removed, the fuel is spitting and boiling up into the carb throat. Tommy has fitted the thick spacer - is there much else that can be done to heat shield the carb? The exhausts could be wrapped I suppose?
1973 95 V4 - Toreador Red, Grey Primer and Red Oxide. | |
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Derek V4 Guru
United Kingdom 2192 Posts | Posted - 30 Jan 2015 : 18:12:18
| How close is the rubber hose to the exhaust? The metal pipe from the tank is shaped to route the hose to the mechanical pump but it can be given a bit of a tweak to route the hose you have now away from the hot downpipe. Old routing shown here. You also don't have the heat shield but I doubt if that would make a difference. Your hose to carb is also running on top of the radiator hose which is pretty hot. A bit of hose rerouting might solve the problem. They are both pretty long.
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pchristy V4 Guru
United Kingdom 1790 Posts | Posted - 30 Jan 2015 : 18:24:36
| Fuel vapourisation in the carb is a common problem on any V engine. In addition to the heat coming off the block / manifold, all the hot air tends to gather at the highest point - which isn't far from the carb! Its not uncommon to have to crank a bit when its hot, in my experience anyway. However, it usually only happens in hot weather - not the arctic conditions we've had of late!
When the engine is running, the carb is getting a constant supply of fresh, cool fuel. An electric fuel pump can help, but the under-bonnet one I used also tended to suffer from vapour locks on hot days, so I reverted to the mechanical one.
Its probably worth bleeding the cooling system, just in case you've got an air-lock in there, making the top of the engine hotter than usual. Does the Temp gauge read normal? Does the engine feel like its running hot? Any pinking?
-- Pete "Duct tape is like the Force: It has a light side and a dark side, and it binds the Universe together!" | |
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melle V4 Guru
United Kingdom 3833 Posts | Posted - 30 Jan 2015 : 19:02:17
| Do you follow the instructions when attempting a hot start?
1970 96V4 "The Devil's Own V4" 1977 95V4 van conversion project 1988 900i 8V | |
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tommygoldy V4 Fan
146 Posts | Posted - 31 Jan 2015 : 00:16:43
| quote: Tommy has fitted the thick spacer
Hello!
No I haven't (unless I'm losing it)! I originally had it mounted on a DIY wooden spacer. It ran perfectly on that. Nick Senecal converted it to the later cooling arrangement and I removed the spacer so that it would be "right" before I sold it. He reckoned it would run better with more heat! Seems that may have been a mistake - it did seem to be running richer following the change, but I didn't drive it much, so didn't experience the issues you are having.
If you check now it's sat on the original metal gaskets, so no insulation. I have a cardboard spacer gasket here if you want it which should help. Mail me your address and I'll post it to you. | Edited by - tommygoldy on 31 Jan 2015 00:25:32 | |
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john-saab Administrator
United Kingdom 2679 Posts | Posted - 31 Jan 2015 : 18:25:29
| I am still long term testing a "nylon" spacer..it seems to be brilliant at solving this issue but I have yet to try it on a really hot day. Only down side so far is that it makes the 34ICH stand a little high and I have noticed that the air filter housing has been rubbing on the underside of the bonnet. I'm found a sheet that is thinner and has a foil backing so will try that when (IF) I finally get a sample from the manufacturers.
'73 96 (Vernon),'74 95 (Veronica)plus 4 other 95's and 2 96's | |
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Derek V4 Guru
United Kingdom 2192 Posts | |
pchristy V4 Guru
United Kingdom 1790 Posts | Posted - 01 Feb 2015 : 16:36:07
| You could try one of these:
http://www.speedograph-richfield.com/html/vacuum_pipelines.html
which is intended as a take-off for a vacuum gauge - but it will also double up as a thermal insulator! Simply plug up the vacuum take-off....
-- Pete "Duct tape is like the Force: It has a light side and a dark side, and it binds the Universe together!" | |
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john-saab Administrator
United Kingdom 2679 Posts | Posted - 01 Feb 2015 : 19:12:57
| Derek..it's not nylon, it's PTFE which is OK up to 260oC alone but the "foil" is supposed to allow an even higher temperature range.
'73 96 (Vernon),'74 95 (Veronica)plus 4 other 95's and 2 96's | |
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Doive V4 Fan
United Kingdom 160 Posts | Posted - 15 Feb 2015 : 22:26:32
| quote: Originally posted by pchristy You could try one of these:
http://www.speedograph-richfield.com/html/vacuum_pipelines.html
which is intended as a take-off for a vacuum gauge - but it will also double up as a thermal insulator! Simply plug up the vacuum take-off....
Thanks for that Pete... sorry for being an idiot, but which one do I need? I'm guessing the MFA136 for the Zenith and Ford fitment?
1973 95 V4 - Toreador Red, Grey Primer and Red Oxide. | |
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chrisring Starting Member
United Kingdom 7 Posts | Posted - 02 Jul 2015 : 19:25:41
| I'm new to V4's and have recently got a 1974. I want to upgrade the carb and exhaust for a little better performance and economy. Can you recommend suppliers for the Webber 34 ICH and performance exhausts.
thanks Chris | |
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Doive V4 Fan
United Kingdom 160 Posts | Posted - 11 Jul 2015 : 01:26:26
| One thing I've noticed about our Weber - when the electric fuel pump is pumping, and with throttle closed, fuel is running out of the float chamber and down onto the back of the throttle butterfly, which in turn is filling the inlet manifold with neat fuel. Surely this can't be right? I would expect fuel only to be drawn when the manifold is under vacuum from the engine, and then only in atomised form? I think this may be the cause of our hot starting issue! The float is set correctly to 7mm closed, and the needle is seating properly.
1973 95 V4 - Toreador Red, Grey Primer and Red Oxide. | |
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Derek V4 Guru
United Kingdom 2192 Posts | Posted - 11 Jul 2015 : 11:34:52
| Yes that sounds wrong. Did the car come with the electric pump? Going back to the normal mechanical one might fix the problem. Where is the E pump, should be at the back near the tank if its one of the Facet 4.5psi type but can be under the bonnet if one of the low pressure (1.5psi)Huco ones. Electric pump should have internal valves that open/close when they get back pressure from the needle valve closing. Sounds like that isn't happening. If you go back to a mechanical pump you can keep the electric one in the system and have a switch to allow you to use it for a few seconds to prime the carb before starting. Saves the churning you often need if the car has been sat for a while. | |
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