2003 R50
I've had this code for quite a while and the car seems to be losing power more and more.
Cleared code, swapped the wires and it still reads #2.
Injector getting power and resistance is correct.
Did a compression check for all 4. #1 is 190, #2 is 70, #3 is 140 and #4 is 140. Obvious problem in 2 but 3 and 4 are not very good either.
I don't see any foam in the oil but ordered a kit to test the coolant for combustion contaminants and also a little endoscope.
I wouldn't mind doing the head gasket just for the puzzle of it and rebuild the head but want to see for sure.
any other easy checks i should do first?

 

Did you do a "Leak Down Test (Dry and Wet)" when you did the compression test?


Motor On!

 

No, I thought of it but only have a compression gauge and no air compressor. i thought it would be cheaper and easier to get camera and the exhaust gas detector kit. and the coolant looks kinda too dark and greyish color, not blue

 

Leak Down Test makes it clear quickly if you have compression rings that are no longer holding pressure ... unless there is damaged to a valve seat.

Motor On!

 

lacking an air compressor and leak down tester i did the blue fluid exhaust-gas-in-the-coolant test. negative result there. i wonder if there is anything i could see by pulling the valve cover

 

now the head is off. i never got shop air or a leak down tester to do a leak down test but i will test for bubbles with my tire inflator blowing into the intake and exhaust. interestingly cylinder number 2 is super clean. i dont think it was firing at all. there is no gunk on top of the piston like the other 3. another problem i see is one of the rocker's lash clip is broken on cylinder 1 intake rocker. it's just a little plastic piece that holds the little cap on. i saw the other thread but it's old. does anyone know where i can find one? or do i have to buy a new rocker?


2 on the left and 3 on the right. 1 and 4 are like 3

 

Where did you put the tester in, the expansion tank or thermostat housing?

In my experience the expansion tank won't work because there needs to be a lot of pressure in the system before the thermostat cap spring is pushed up to open to the expansion tank.

It could well be that you have misfires because of coolant leaking into the cylinder, washing it clean over time.

At this point I would highly recommend to get the head pressure tested. Also look closely at the block, is the surface nice and flat or badly pitted around the coolant passages?

I had a failure once because of corrosion eating away toways the cylinder:

 

i put the tester on both the tank and on the filler neck above the thermostat both results negative... the passages look good to me but i will look closer. waiting for some parts now so i have a little time to inspect things. i will take some close ups and also ordered a machine edge and feelers. im thinking i have to get a new lifter for the one with the broken clip.

 

Sounds like you're doing a good job. I would replace that broken lifter.

My intention was not to be a "know it all" as I definitely don't. Just wanted to prevent someone else from making my mistake.

For the car in the picture above I made mistake after mistake; I slapped a new headgasket on it hoping it would fix the burning of coolant. It didn't so I concluded the head must have been faulty. So I got a new head, got it skimmed and slapped it back on. Still burning coolant... Ended up buying a secondhand engine. Cost me a lot of money and time but I've learned my lesson.

 

thanks. you dont come across that way. i am definitely not a know it all. i know almost nothing but like puzzles and have a hanes manual and youtube to help the car runs but is almost worthless with the misfire and i dont need the car. it's handy in the city though and i enjoy driving the stick. it just takes space in the garage when im working on it, (thanks DW for giving up the space for a while) and i get to use my tools but if i have to put a lot of money in, aka machine shop, then it's going to go for organ donation.
i just looked at the gasket and closer at the head and see no sign of infiltration but voila! a cracked intake valve on #2! is it worth replacing all the valves? they seem to be pretty cheap. when my machine edge arrives i will do clean up and make sure the head and block are ok

 

another pic of the broken clip. if i replace this rocker does the stamp have to match? i see a replacement for the 302AA but not the r41

 

I don't know much but I do recall that there was a discussion, a while back here on NAM with the very same issue regarding missing or broken rocker clips. I think I remember reading that the end result was that a certain Chrysler Neon(?) model rocker clip also fit a 1st Gen Mini.
Sorry I can't seem to find that thread and I'm not much help.
Just curious; Would it be more prudent to replace that entire rocker or perhaps pull/replace the little plastic clip from a salvage (if new clips are NA)?
EDIT: I believe this is the discussion I remember reading.

 

yeah thanks i see that thread. those engine tech clips apparently fit but you have to buy four and pay for shipping. i found an oem rocker for twice that on ebay and think that's ok but don't know how to read the stamp. my rocker's all have different "r" numbers. the one in question is R41. the replacement part on ebay is R35

 

Are those the brass ones (retaining clips) from Bucharest?
I wasn't sure if those were still available?

 

no they are plastic and come with the lifter part too. kind of overkill

 

so I ordered a whole new set of exhaust rockers because they were $65 and had the 302AA on there. i dont know what that means but it matches mine. mine reads R 41 302AA. the new ones have a different number after the R.
cleaning the block and head surface has me a bit confused. I am trying to be super careful. i bought a machine edge and after initial cleaning it's within .004 everywhere on both surfaces but it's not shiny. there is still some residue that i am afraid if i take it off there will be more than .004 space there. i can see a lot of people use sandpaper but i am afraid to mess it up and make all my other efforts futile. is it ok to leave some of the old residue on there to keep it level?
the history here is that, known to me it has overheated once when i had a local shop do the clutch they gave me the car back without refilling the coolant and i ended up driving it for a few blocks overheated back to the shop. that was the only time i know of.
i also ordered a new set of valves and a spring compressor that had the lapping tool with it. ive done this before many years ago on a pair of mopar 360 heads. it used to be coarse then fine but now it seems the lapping compound just comes in one grit.

 

The discoloration on the block is nothing to worry about in my opinion, as long as its flat. If look at your new gasket you will see it has a raised edge around the pistons and oil and coolant passages. These are the areas you want to double check for clean and flatness.

The head seems to be a bit different in terms of gasket stuff being left behind. The issue is that you can't really scrub it as its aluminium.

Obviously it's very hard to judge from photos but when in doubt take it to a machine shop.

 

DON"T go scrubbing the head with 3M Green Pads, you can really mess up the Flat Surface by doing that.


Motor On!

 

i did use a red (fine) pad on it but wouldn't say i scrubbed it and was careful to apply very even, light pressure with a block over the entire surface. that's why there is still some discoloration. the block looks worse to me and there are a lot of scratches you can see in the photo. i was struggling keeping debris out of the cylinders. i thought there might be some kind of protectors you could put in there other than just rags. i see where an air gun would be very helpful here. maybe ill get one of those cans of compressed air to blow out anything that went down in the rings

 

next steps:
remove old valves and clean passages
lap new valves, install and check for good seating
reattach head using new bolts and proper procedure
reinstall cam & rockers etc with assembly lube
reattach everything and use new spark plugs and thermostat double checking hoses and connections. carefully double & triple check everything
fill with cheap oil, new filter and refill (bleed-in) coolant system with distilled water
run engine for a few minutes with heater on
drain water and refill with silicate based coolant 50/50 with distilled water if not premixed
change oil again after several drives
check compression again. if everything looks good and it runs good fine check exhaust back pressure with comp tester and adapter in the upstream o2 sensor bung
look into replacing cat

 

One more tip; get some oil pumping before starting it up. What I usually do is to remove the fuel pump fuse (#38? In the footwell) and disconnect the coil pack plug. Then use the starter to get some oil pumping.

This because the head is entirely dry when you have it off for a couple of days.

 

thanks Lucas. this is all very interesting. i really hope i can get this thing purring again. i don't drive much but love the 5 speed. i learned to drive many years ago in a Datsun 610 4 speed and have fond memories of that car. one reason i love the mini is the short wheel base feels more like those old rear wheel drive light cars even when it's frontwd.
something else i have pieced together...i think. i found a big hole in the pcv air line that goes from the throttle, under the intake to the valve cover. it was in a hidden spot and i never saw it until i was moving the intake out of the way. this should have caused her to run too rich, which is quite obvious from the condition of the valves and head. so much buildup on the valve and seat must have cause it to crack and i bet the cat is no good by now either. i could have done a smoke test but it wouldn't have mattered, or worse could have sent me trying to plug leaks when the valve was cracked and needed that anyway.
still waiting for my ebay order of valves and rockers. gonna lap the new ones by hand if i can get the suction cups to work. i see some people use a drill but i grind my coffee beans by hand too!

 

update: the new rockers came from ebay but the valves never arrived. message from the shipping company uniuni says: "delivery failure, wrong address. returned to warehouse". how hard can it be to find an address these days? i used to do deliveries when all we had were paper maps and our brains! anyway i re-ordered from the same company but via amazon. i know they can find my house.

 

finally got my valves and lapped them, reassembled the head and it's back on with no obvious issues. i should have taken more photos though esp for where wires are routed. i found this one little connector that i can't figure out where it goes. It emerges from the harness that goes from the firewall to the ECU. does anyone know where this little guy goes?

 

aaanyway...i got everything else buttoned up and did the crank-over no fuel spark for a few rotations and then plugged the fuse and the coil back in (it's fuse #20 on my R50) started it and it runs but terribly and i have to keep giving it gas to keep running. it's not throwng a code though. does it take a while to burn off any extra oil that was in the cylinders? when i had put the tensioner back in i wasn't able to get it to pop back out but thought it would after it first starts up. perhaps that is it...? maybe the tensioner is stuck now?