got the mk1 out today to take it for a tank of optimax,its a good drive to get there. anyway on the way back i wound it up pulling on to the motorway,in 3rd gear just about to change and it really banged loud out of exhaust i think ive never ever over revved before ,there was sh1t loads of *black smoke* behind . the oil pressures dropped from 20(psi i think)to nearly nothing on tickover.when warm [:^(] what have i done? it still pulled well and isnt smoking or anything. [:^(] Edited by: riley
mine banged and spewed out alot of black smoke one time while going a little too fast around a roundabout (damn breather hose ) don't know if it affected oil pressure tho as my VDO gauges are lying in the boot still to be connected
Sure you didnt just hit the rev limiter?? If you really have no oil pressure the oil light & possibly buzzer will be getting your attention, along with a nasty death rattle from the engine.. [:^(]
it wont get death rattle with low oil pressure as it doesn't have hydraulic tappets, worth checking the oil pressure some other more reliable way if you can, i think. The oil pressure will drop if the oil temp is very high, ie after hard driving, though. how is it when it's cold now? With the k-jet, if your fuel system has any prob's, then it will run rich under full load conditions. that could mean you got a bit of extra fuel in the exhaust which exploded, de-coking you exhast at the same time. M.
you do get the death rattle without hydrualic tappets, the big end bearings will run short of pressure and the jeornals (sp?) touch the bearing surface creating friction and destrying the bearing very quickly - Death rattle, the tappets is no where near death, just unpleasant. I mechanicaly over reveed an 8v sticking it in the wrong gear (2nd not 4th) and it poured smoke and clattered so I scrapped the block. Edited by: jake
Riley, do you have any sort of rev-limiter with you running the carbs? If you have a contrifugally mounted switch in the rotor arm then you might have hit that. This would cause the petrol to be pushed into the exhaust without igniting. This would then ignite in the exhaust and backfire, definately causing a bang and could also cause the smoke from carbon being blown out the back. Dont know about the oil pressure, check it again, your pump could have cavitated while at high rpm. If the pressure stays low then change the pump ASAP.
cheers 4 the replies,maybe should have said what im running 4 people who dont know. kr 16 valve on 45s,replaced all the rings and oil scrapers about 2k ago!! @ jettin,i dont have a centrifugal type rotor arm as for the oil pressure,the gauge i have is incremented as 20,40,60,80,100,120.on cold start up it normally sits at 100(tickover) then when warm at 20(tickover). but straight after this happened the gauge dropped to just above nothing. i havent tried starting from cold yet since,,,, dont know whats happened?cheers. [:^(]
Gotta be a good chance that the oil pump is dying and not giving full pressure - standard ones aren't built for masses of revs.
Well its a guess, but your running carbs, so it could be a backfire if your hitting the rev limter on the ECU ( if your still running the 16v ECU). And you say it was black smoke. If it was blue smoke i would be more worried ,Worth checking it over for oil in the coolant etc and have a look at the oil in the dipstick. WOrth starting it up and checking the pressure, did the oil buzzer on the dash come on and the red light also ?? Fingers crossed its ok
cheers,i am running the 16v ecu with the mk1 tci unit,didnt know it had a rev limiter. yep it was black smoke/so this is just carbon in the exhaust?,the buzzer/light dont work as i killed em after the original lumps bottom end went so are we thinking its the pump? is there an uprated 1 i can get? 2.0 etc...if it is that cheers. Edited by: riley
Jake, i think the big ends, etc make more of a knock, than a rattle. The death rattle is normally used to descible the niose the hyd' tappets make when they are knackered or in need of more oil pressure. M.
is that hot? should be high on startup and then drop as it gets hotted, 2.5 bar at 2.o00 revs i think it should be when hot
I disagree with that, Jake is right Mark! The big ends do knock rather than rattle, but this is known as a death rattle as it signals the impending failure of the bottom end if it is caused by a lack of oil pressure! If the hyd tappets get a bit noisy & or lose oil pressure, this by itself isnt enough to blow the motor. Edited by: chrismc
on tickover when warm it normally registers at 20(psi i think) but its not showing anything. when cold it normally registers at 100 but its showing 80,on tickover.
QUOTE FROM: VW motoring, April 1996, "off with its head" pp57-60. "The dreaded 'death rattle' of worn-out hydraulic tappets is heard every morning all over the country....." M.
When i seized up the big end on my carb engine it started with a slight ticking that turned into a noise like sandpaper rubbing then into a heavy knocking until it seized & expanded the bigend in the bearings (i think) . My oil pressure is normally right up by 100 when cold & slowlly drops to about half whan walm (cant remember tick over temp as it's never ticking over ). Having no buzzer working is asking for trouble mind as you dont always get a chance to keep an eye on the dials (especially if down in the centre console). Mine pops sometimes when i hit the limiter depending on the engine temp (i dont change gear until i hit the limiter @ 6250 which is way off the red). Edited by: fthaimike
