Paul Davenport
2 posts
Joined: 08/02/2009 18:05:40
Location: Darwen United Kingdom (Excluding channel Islands)
Dash pot oil
Just reading this thread - Use proper SU dashpot oil - 3 in 1 is to thin and lets the piston up to fast causing a weak mixture, engine oil doesnt work as its a mutigrade and changes viscosity - SU made the carbs to work with a specific oil grade - why change things???
Posted: Jul 12, 2009 01:08 AM
michael
79 posts
Joined: 02/03/2007 23:58:38
Location: Carpi Italy
dashpot oil
i use 15/40 oil to top up, just 2 3 cm to the brim, i did use for a while burlen su carb oil. i think 20 /50 is a bit thick they say you should yose a light oil.
Posted: Aug 16, 2009 09:45 AM
a. mericanminifreak
183 posts
Joined: 02/11/2007 23:17:14
Location: rosbach v.d.hohe Germany
Which carb should i buy?? stage 2 998cc
Webers are great when they work right, i find them to sensitive, but if you want the extra umpf i would a twin HS4 SU setup im sure you would be happy with that, su's always seem to take a god beating with dirt and crapy fuel , and definitly K&N for filters they alow the most air--clean air into your carbs because of the oils that are used in K&N's the can be cleaned and used over and over again some have 10 OR 15 year warranty, you wont find that on other air filters.
Posted: Jan 05, 2008 07:59 PM
pickme
672 posts
Joined: 08/09/2004 23:10:14
Location: Chippenham United Kingdom (Excluding channel Islands)
What Dashpot Oil?
As far as I know, 3 in 1 oil is supposed to be good. Most engine oils are too heavy particularly for cold starts. I think the proper SU stuff is basically 3 in 1 anyway. I use Manitou suspension fork oil, but thats what I have around so....
Posted: Feb 07, 2005 06:22 PM
David
28 posts
Joined: 07/10/2004 14:28:33
Location: Inverness United Kingdom (Excluding channel Islands)
Try the carb
Have you checked the oil in the carb? Im not an SU expert, but I think if there is not enough oil in, it may cause this problem. Worth a shot?
Posted: Jul 29, 2005 02:03 PM
Tom
13 posts
Joined: 14/09/2004 13:06:54
Location: Maplewood United States
.
the reason for said borewashing is due to petrol washing oil away from the bores - it acts like a thinner to oil, so the piston rises back up the bore with no oil between the rings and bore walls resulting in metal on metal contact - extreme wear! a properly calibrated su will also match your cam choice well on this engine, ie an HIF44 will be very street driveable with a good low end - pulls away with good torque = acceleration.
Posted: Mar 02, 2005 01:16 AM
Matthew
1 posts
Joined: 24/03/2005 15:30:47
Location: Hassocks United Kingdom (Excluding channel Islands)
cooling
I reckon i need to fit a oil cooler to my car, it is 1.3 italian job, but i dont know how to loop one in, which one would be best, and which hoses and bits and bobs i will need. i recently put on a set of twin SUs, and thats all the upgrades the engine has. As i was coming up the M6 on a hot sunny day, the car was cooking its spuds off! Although the car wasnt over heating badly it was still running hotter than it normally would on the motorway, and i was having to open the air vents to help cool it down, which was like sitting in hell! There is plenty of water in it and the pump is working well. The secondary fan is also working well. Will a oil cooler be the answer to my cooking problems. Cheers.
Posted: Jul 10, 2005 01:18 PM
John
1948 posts
Joined: 28/05/2006 16:49:46
Location: cambridge United Kingdom (Excluding channel Islands)
998 Metro Block...
if its just the block casting that you are using from metro then there may not be any differnce. as for your setup big bore manifold and exhaust system wont work well on a 998 people have tryied it and it just kills the power at normal revs. 1.75" system doesnt really loose much power over larger bores til you get over 110+bhp which your engine wont have. secondly oilcooler wont really be nessary if you do fit one make sure its thermostate controled or it will overcool oil and increase wear. metro turbo carb is designed to be used on a turbo seals float chamber ect are designed to work under boost, while it will work it wont work as well as a hif su for a normally aspirated engine, for that hif38 or hif44 or even twin hs4 should all work ok on a highly tuned 998. around 65bhp is when hif44 starts to hav advantage over its smaller brother but you wont loose alot on a 998 with a hif4 and twin will give best power with good manifold.
Posted: Nov 26, 2007 08:52 AM
J. Clarke
judder
could be out of dashpot oil (damper) so will lean out on acceleration, remove top of su and top up with engine oil. when it does it next time pull choke out 1/4 see if it causes it to recover will indicate its due to lean mixture rather than ignition. yeah if still no solved service ignition, leads plugs dystribitor cap points and condenser if applicable (pre 1990). also it could be pinking/knocking due to fuel octane being too low try filling up with premium to see if its resoved, the head could be coaked up with carbon causing it to reqire higher octane. also it could be carb is just out of tune if uv modifyied the engine without ajjusting the mixture.
Posted: Jun 10, 2008 08:02 AM
mark1275GT
3 posts
Joined: 04/02/2006 20:40:26
Location: fulhamu/london United Kingdom (Excluding channel Islands)
Carb Issue ?
After a rebuild on the carb Got it back on once again today. Started ok, but run crap. spent ages messing with the mixture and idle, but just couldn't it right at all. I was using SU carb oil from. so thought i'd try 2 in 1 oil, to see if it would make it any better. so i empty the SU oil, then used the 2 in 1. ran 10 times better for some reason ? But after i rev the engine, the exhaust goes pop pop pop, then does some kind of release of air from the carb alot of the times when i put my foot down. Tried that colour tune, but dont seem to change colour to me lol The ign timings seems ok etc. Anyone got any ideas ? I know most will say rolling road, which i'll get round to sometime. But just want to get her running ok ish for monday morning :)
Cheers
Posted: Aug 31, 2008 12:36 PM
unusual problem
su dashpot oil? headgasget failing? engine cold? i think it more likly to be the third, u run it around for 20 min and it was ok?
Posted: Apr 08, 2007 10:11 PM
Pirate_copy
35 posts
Joined: 31/01/2005 18:08:36
Location: United Kingdom (Excluding channel Islands)
Hello Does anyone know the best oil to use in my SU dashpot? I have been told that it needs to be very thin and i should use 3 in 1. Is this correct?
Posted: Feb 04, 2005 04:23 PM
Andy McDonnell
Joined: 01/07/2019 12:55:09
Location: Naivasha Kenya
Slowly over heating Mini
Hi, I am having an over heating problem with my mini, it’s a 1275cc pre A+, built for classic rallying so has rally cam, high lift rockers, runs twin 1.5”SU LCB etc. I set the timing static as run with old school points and condenser. The radiator is the special 4 core from Mini spares, new water pump and hoses and 5 blade hot climate fan, it has the bypass hose fitted but I run with no thermostat, the climate I am in is 30 to 35oc during the day so hot anyway, if I run at idle or just above for 30 mins or so it wont go over 90oc (I run a electric TIMs gauge) but when I drive fast it slowly creeps over 100oc when it gets to 110oc the cap starts letting fluid past (It opens) if I continue to run fast the head gasket just burns between 2 and 3 (I have been through 2 head gaskets but the head and block have been faced and are straight), if I slow down and drive gently it slowly returns to 100oc, I run with coolant and the brakes are not binding. I do not run a heater and this is just blanked off, I do run with an oil cooler too, is there something I have missed? Should the bypass be blanked off if no thermostat is fitted? I’m thinking to run the heater matrix but in the front to give additional cooling as am at a loss right now? Any advice?
Posted: May 04, 2024 02:03 PM
webbie
15 posts
Joined: 17/03/2008 11:55:14
Wont Run
hi ya mate black smoke means over fueling. adjust the fuel/air ratio screw on the carb, what carb u using? if u have a 1 3/4 su then running slightly rich will cause black smoke same as if u was using a webber. i dont think its the dizzy timing but by all means try it but try this first.
its just a thought but i might work my mate was having the same problem. once he topped up the oil in the carb it stopped
Posted: Mar 21, 2008 09:46 PM
Alex
129 posts
Joined: 20/10/2004 23:06:00
Location: York United Kingdom (Excluding channel Islands)
I just Can Get Her To FIre!!?!? Someone Please Help!!
Hi, I have got a 1991 mini cooper 1275 carb and just had the engine out so i could have some bodywork repairs done to the front end, while it was out i thought i would renew the gearbox as third was almost impossible to get into without soundling like u forgot to use the clutch. While in Bits i fitted a new road rally cam, and unpgraded all the valves and vale spring, new oil pump and water pump. Thougth i would renew as much as possible while it was out. Its all gone back together a cham. I have never been a fan of the SU carbs the calibatation used to drirft out making them fail mots on emmisions. As i planed to use the car on track day and performace driving alot i thought i would fit a 45 weber. I managed to get my hands on a resonably price used module the seem in good condition, the only down side is it is jetted for a 1380 and i am only running a 1275. I have been told that i should be able to atleast start it on therse jets. Planning on get it running rich on the 1380 jets and have it put on a rolling road and jetted and tuned propoerly. So everythting is asembled and i have estimated the timing at 5 degrees advanced. And it wont fire.I have grandully advance the time degree at a time al the way to +20. But i nothing. I have taken a can of easy start to it and it caughts but still doesn;t fire. I have checked that i have a spark at all the plugs and i have whiped fuel pipe off to make sure fuel was geting threw. I also removed the carb and inlet and cranked it to see if there was any evidence of fuel in the inlet - there is! So what the hell could be wrong. 1. WIll it actuially start on thw 1380 jets 2. Can anyone estimate what the timing should be (bar in mind that it did run at +25 before i took it to bits) 3. Anything else im misisng????
Posted: Jun 12, 2005 04:05 PM
163 posts
Joined: 09/09/2004 09:32:06
Location: DK-2000 Frederiksberg Denmark
Dashpot Oil
Are you using the correct needle? I assume that youve re-used the needle from your old engine, which was the same as the new engine - or youve gotten a new needle which is suitable for the new engine. Well, which oil to recommend can be a bit of a can of worms, so Ill refer you to the following article: http://www.minispares.com/Article.aspx?aid=201 If your engine is completely stock, including air filter and exhaust, then genuine SU oil will probably be your best bet. Now, Ill suggest trying a bit of engine oil, just enough to cover the dashpot dampers one-way brass valve (about 1½ of oil in the hole). If this is causing the engine to run too rich on accelleration, try a thinner oil until you get the results that you like/need. Personally, Im using 20W fully synthetic oil (Castrol motorcycle fork oil) for my warmed-over 998. Motorcycle fork oils are especially nice, as you can get them as thin as 5W, also 10W, 15W etc. - and, when fully synthetic, are extremely stable in varying temperatures. This is not the case with old-type solutions, like 3-in-1 oil, which varies wildly in heat and cold. Another benefit of fork oil is that if you buy a liter, its not going to cost a fortune for a lifetime supply.
Posted: Feb 23, 2005 10:23 PM
colin49
26 posts
Joined: 30/08/2005 22:05:27
Location: Glasgow United Kingdom (Excluding channel Islands)
Rough Idle
The damper is filled with the specific SU oil and the spring was replaced at reconditioning.
Anyone got any ideas about the fuel return or leak off pipe. Also i have removed all the emissions gathering equipment from under the wing, so where should i connect the tank return pipe( is it a return pipe???) to. currently its venting into the wheel arch.
Any ideas??? Thanks
Posted: Apr 15, 2008 11:54 AM
spluttering engine.....
sounds like piston might be sticking in carb. id be tempted to strip top of carb down clean in in spirit then lighly oil and reasemble.
to do this remove airfilter housing, unscrew u bend at back of carb, remove damper, insert finger where u bend was lift piston up inside carb. remove c clamp/ring from of damper cylinder, remove 3 screws holding su dome housing on then lift asembily away becarful not to damage or drop piston. make sure there are no notches in piston groove where piston may stick in open position.
only other thing i can think of is possibly grit in float bowl causing needle valve to stick.
Posted: May 14, 2008 08:56 PM
azzmazz87
Joined: 11/10/2005 17:16:27
Location: Nr Nuneaton United Kingdom (Excluding channel Islands)
My New Mini Engine
Hey everybody, I have spent the last 6 months constructing a new engine for my 998cc 1987 Mini city E. I have not quite finished putting it back together and just wondered how quick it would be when finished and what horsepower it will have... Spec.. Based on a 998cc block, bored out to +60 and pocketed (also Skimmed to minimum) JP Flat-top pistons- Lightened and balanced conrods 12G940 Head - Double Valve springs and standard rockers Reground crankshaft and balanced 276 Kent Cam Standard Gearbox with centre oil pickup Lightened Flywheel 1.5 inch single SU Carb Mainflow 3 branch manifold- straight through pipe and twin dtm stile exhaust I have been reliably informed that this engine will have a compression ratio of 11:1, anyway i wud like to hear what you guys and girls think! Thanx
Posted: Dec 18, 2005 11:31 AM
C. Barron
332 posts
Joined: 04/05/2006 21:28:31
Location: Mid Calder United Kingdom (Excluding channel Islands)
coughing carb
I have a 1.5" su with pipercross filter on a 998 with minisport fast road cam, stage 1 kit, and mildy modded head.
The problem i have is that when the engine is cold it needs choke to run on idle (as you'd expect), but then as soon as i try to pull away it tries to die. but when i put the choke in once moving it instantly runs better, but as soon as i stop i have to dive for the choke to stop it stalling again. James
What about the dashpot oil, is there enough ? without enough oil the dashpot lifts instantly and leans the mixture right off, you would need the choke to help you to accelrate but then the mixture would be too rich to maintain a constant speed......worth a look maybe
Posted: Oct 26, 2006 09:16 PM