12 replies to this topic

[AdamVester]

Model: Metro 1275 Manual
Year: Not to sure early i think tho.
Description of problem (please be as in depth as possible): Um well when i got the mini it was fine bar the breaks what i sorted out. but now when i deaccselerate i get this popping noise comming from ware the carb is. dont no if it is the carb or manifold unsure as of yet as i have taken the engine out of car and its not running very well at the moment its in a friends unit.

i had a problem with the alternator at first (belt slipping so it took ages to start) fixed that problem then this one started.
i have taken the head off had it skimmed the pistons and valves looked alright.
the head has been put back on the car but now it seams to be lacking all its power i checked the vacume advanced and carb they seam fine. manifold seams fine without cracks and so does the gasket on the inlet (tryed the wd40 trick nothing...) so i think think its a leak.

dizzy cap and leads and arm are all fine been checked over. not sure about spark plugs i havent got around to checking them yet as friends working on mini in his unit for me since im working loads lately.

just wondering if anyone had this problem befor?

say i get into second gear accsel to 5k and take foot off all i hear it pop pop pop pop pop pop pop crackle pop pop pop... and then it stops.. when i accsel it doesnt pop iver. so if its poping and i put foot down again it will stop poping and start again when foot taken off. seams to happen more in the lower gears but it could just be cause i dont built the revs that high in the higher gears :S

i have read up on it being a leaky manifold gasket or cracked manifold or duff carb but carb was changed (could be reason for loss of power thinking about it) but poping is still there!!!

it doesnt pop out from the back just under the bonet it does smoke a bit underthere aswell at times and is loosing some oil but i think this is a leak from the gear selector seal :S

does anyone no any quick easy tests i can do or no what it could be? buggerd valve guide? duff plugs?

thanks all



Any non-standard parts that might be involved with the problem? Metro 1275 manual engine, Mini alternator, not sure on fule pump or filter havent had car that long, carb was from a 1.0L i did have the proper carb aswell but same problem with that and it sticks.

[AdamVester]

forgot to add if the engine does turn out to be screwed some how does anyone have a spare 1275 hanging around with a manual box they getting rid of? im looking for something under £300 if possible have not had much look searching in that price bracket anyware else.. everyone seams to be selling turbo and auto blocks.

[Ethel]

What carb is on it? Some have a little valve on the throttle plate that is supposed to eliminate this, it could be stuck. If it's an early MG Metro engine they have a high compression ratio that makes them prone to issues like this and running on. Also check the vac advance is working, sucking on the pipe will generate just enough vacuum to prove the diaphragm is still intact - you can just see it try to move the dizzy baseplate .

[bebbinator]

it could be that the exhaust manifold gasket is leaking

[AdamVester]

ill check them out when i get the car back tommrrow hopfully the carb was a random one i found on a 1l mini from scrappy think it was an xreg could be wrong tho it looks like a standard su carb but i am not sure.. it looks like this http://www.visn2.com...rbs_hs61(2).jpg if that helps? i no its not a 1.3 carb can i just swap the jets around? sorry for being so dumb never actually worked on a car with a carb befor but i have done lots of work with engines and stuff so i no some basics about them.

im sure the vacume is working tho as it was when i got the car my mate kinda hanged up on me for insulting him when i asked to check lol so i think that its fine but yeah i cant be sure he knows more about these engines than me. im used to dealing with pug/citron XU engines not these A series things

thanks for reply i will check this out asap tho

[bebbinator]

the carb cannot acually BE popping and banging but it could be the carb that is causing the problem but your best bet is that it will be the exhaust gasket

[bebbinator]

carb*

[AdamVester]

i thought the gasket myself to be honest when i started it up a while ago when i first noticed it. there was smoke comming from manifold when i reved it via the throttol on front i just figured it was oil on the manifold or something since there a leak at back of engine from someware (as i said i think its the selector seal) so it could well be that.. everytime it made the popping sound there was more smoke it seamed surly it couldnt be that simple tho. it did run at what seamed full power when it was running and making the sound still tho so it had no loss or flat spots. my friends mini with the same engine as mine seamed slower than mine even tho mine was making the noise. so yep could be that simple ill be sure to check it out. fingers crossed. does anyone no what the part number is for a new gasket?

[big matt]

jst had to re-new my manifold gasket because of exactly the same problem cold air leak on the inlet manifold, and shes running sweet as a nut now

[Surfbluegarage]

you can get popping throuhgt the carb its carb backfire had it on my twin hs2's when the mixture was very lean it pops back throught to the filter when the throttle is blipped.

[AdamVester]

you can get popping throuhgt the carb its carb backfire had it on my twin hs2's when the mixture was very lean it pops back throught to the filter when the throttle is blipped.

it did run really lean for a while befor the popping happend but it went away i cant remember if popping happend right after or not but it with within the same week. reason for it being lean was the choke was stuck on all the time (the old carb kept sticking it on or off) ended up just loosening choke cable and turning it off all the time..

but yeah it only does the popping once i loose off the accsel and stops when foots back on it again. it does it worse in second gear when i rev above 3k and take foot off. 9 normaly rev engine to around 5k then change if im in a hurry whats not very oftern i normaly drive the mini fairly slow and relaxed and always take it easy when cold.

[AdamVester]

got the car running its still low on power tho but this has to be down to the carb.. still making that noise ill get it back to my gurage on friday and i have weekend off work to try sort it out.. im hoping its the manifold cracked or gasket gone.. cant see it being gasket tho as it was changed when i done the head.. hopfully they didnt skim to much off the head i didnt find out details of how much was skimmed off ooops..

just a quick question if it is the carb loosing the power (ill find out by putting old one on) what carbs best for the engine? i heard a hif44 or something good to go for? i dont have much spare cash so need something cheap..

also if anyone has a carb spare laying around and wants to sell it let us no ill be interested.

[AdamVester]

well i got mini back been told there is some serious compression loss tho . not sure what this is down to as of yet.. its running at less than 50% of its power tho... break caliper on nearside is leaking from seals aswell i think so something small to sort out.. mini is running and drivable tho once breaks are fixed.

its running with the 1L carb alright sounds smooth on tickover and seams to start fine but once i turn engine off after a longish run it splutters for a few seconds. smells a bit of fule when starting up aswell. any ideas? carb not right?

i wasnt there to see compression test so i dont no the results but i been told it was bad but forgot to ask how bad might get it tested again at some point...

so anyone have a spare 1275 metro engine laying around they want to sell? looking for something <£300 if possible.

forgot to add its not longer poping and making unwanted sounds.

Edited by AdamVester, 19 December 2008 - 11:31 PM.