Hey folks. I’m new here but not new to cars. I’ve been a mechanic for years but I’m kinda stumped on a Mini R53 I’m working on. Some background...

The car in question is a 2006 R53 with 160K. Car had no compression in cylinders 2 and 3 but had over 100 psi in cyl 1 and 4. I picked it up cheap because of this. Car is very clean otherwise.

Knowing all the possible causes, I bit the bullet and pulled the head. Found carbon’ed intake valves in cyl 2 and 3 that wouldn’t fully close. Seemed to be the problem. While taking the head apart I did notice the cam journals were worn more than I would like but the previous owner said this problem just happened so I was/am hoping that is irrelevant. Head had minimal warpage (.0015-.002”).

Cleaned and lapped ALL the valves and they looked great. Nice seat patterns and no signs of problems. Assembled head and installed. Along the way replaced all the seals and gaskets I touched and Installed a new T/stat, water pump, timing chain guides, tensioner, etc. New head bolts, torqued properly.

After a few weeks of after hours work, I went to fire it up and now I have no compression in any cylinders. None. The guys I work with insisted I must have screwed up the timing. Even though I followed the guide to a T. So I pulled the front timing cover/oil pump. Hadn’t done this yet so I guess it was conceivable it skipped a tooth at some point. Well the timing is dead on perfect. Chain is tight. And as I said, the guides and the tensioner are new.

So Mini peeps, what have I missed? What would cause loss of compression across the board? I’m quite confident the valves and head are good. And the timing is too. I’m racking my brain trying to think of something I overlooked that could account for the compression loss. I’m hoping maybe someone has run into this before.

thanks!
D

 

The only things -

1. Head is not seated on the block
2. No head gasket
3. No spark plugs
4. Cam to crankshaft timing is off
5. The timing chain is broken
6. The starter is not spinning the crankshaft
7. You forgot to unlock the door and get in the car

Not trying to be (too) funny, but there isn't too many things it could be..!
Have a friend go over the engine for you.
And what about the "front" timing cover ? Is there a rear...timing cover ?

Mike

 

Well I spent some more time working on this. As I said in my first, the timing was correct so that’s good. I rolled it over to TDC #1 and did a compression leak down test. Compression was going out the exhaust. Ok. Did the other cylinders and some had the loss from the intake valves, some from exhaust. Weird.

further investigation revealed the rockers on some of the valves were too tight when they should have been completely off the valves. Like they were holding them open when they should have been fully released.

Pulled the timing chain and pulled the rocker shafts. Performed leak down test again. Test passed with 10-15% leakage. Now I turned my attention to the rockers/lifters. Well several of them are fully expanded and will not compress. So basically they ARE holding the valves open all the time.

Does anybody know for sure if there is a way to bleed down the lifters? Not really keen on buying a set of new rockers for $40 each.

I also asked myself what caused this? Since I had the oil pump off, figured I give that a once over. Took it apart and the gears had some wear consistent with the mileage. Nothing to worry about. BUT when I went to take the pressure relief valve out, it was stuck in the bore!! Has to use pliers to pull it out. It was stuck in a mostly closed position and I think was allowing too much oil pressure. Perhaps enough to over pump up the lifters?? I cleaned the piston and the bore with some scotch brite and now it glides in and out with ease. Assembled the pump.

At this point, I think the problem was simply lifters/lash adjusters potentially because of excess oil pressure. I do need to figure out how to rectify the lifters if possible, and then reassemble the thing. Again.

If anybody has tips on the lifter thing I’d like to know. Otherwise I’ll update this when the car is running. 30 years of being a mechanic and I’ve never seen this happen before.

 

I have not tried, but I think it's possible for the cam timing to be set 180 degrees off.

 

I agree with MVPeters. I have not done a cylinder head replacement on any Mini but I have lots of experience with Volvo and Ford cylinder head jobs. Even on Volvo and Ford, I always pay very close attention to the orientation of the camshafts. Even being careful, I managed to install a camshaft 180 degrees off once. Luckily, with the special tools for the job, I managed to identify my mistake while it was (relatively) easy to correct.

 

Gauge you're using is proven correct? No faults, leaks?

Jus' scratching my head here...

Cheers,

Charlie

 

"I rolled it over to TDC #1 and did a compression leak down test. Compression was going out of the exhaust. "

Perhaps this is the key. Did you see 150 lbs psi & then a slow leak? or no pressure at all?

I'd be surprised if all the lifters stuck at once, but if you have them out, try soaking them in acetone, ATF, carb cleaner, or whatever, overnight. Then soak them in Marvel M oil for a while. In theory, they should stay in their original bores, but I don't think this is critical. They will clatter like crazy until they pump up when you first start the engine!

 

Agreed, somehow you got the timing 180° off.

​​​​​​

 

I was doing a leak down test where I feed compressed air into the cylinder and the guage measures leakage. Had 90% leakage. Valves are staying open.

I will pull the rockers off the shafts Monday after the holiday and try soaking the lifters. They aren’t all stuck but several are. It’s very strange.

 

Thats what I was convinced of myself. But it wasn’t. Marks lined up and the cam is keyed onto the sprocket properly.

I appreciate people’s input. I will absolutely update this when I get positive answers. May take
a short video too showing what I’m seeing now.

 

I didn't know you could put a cam 180 off???

 

not sure if the lifters are hydraulic or not (sounds like yes) but, yank them and soak them in ATF fluid for several days... there may be debris and or "stiction" in them preventing them from releasing.

Another thing you could do is heat them up some and see if they will release that way.

Also FWIW... the chain tensioner is also oil pumped... I'll bet doing the above would free a sticky tensioner as well. I use this stuff https://www.hotshotsecret.com/stiction-eliminator/ in the Ram where it reduced oil usage from 4qt over 10k OCI to approx 1 qt over 10K OCI. I suspected sticky rings. I have run it in the R53 motor prior to switching over to royal purple oil. I doubt it was in there long enough so I plan to top off with it once oil level drops some...


Please Please post back what your solution is... All to often fixes are found but no resolution is reported back to threads where the issue was discussed...

 

Just tossing this out there but I have a great condition stock head im getting rid of for dirt cheap..if you need it , 50$ + shipping you can have it, off my personal car so I know it had 0 issues
I would think a bad hg you'd have contaminated oil or coolant or leaks at the head to block.. i have a feeling your valve aren't fully closing or seating but just my guess.

 

Did you resolve this issue? I replaced all rockers - car won’t start. Wondering if I need to prime the lash adjusters …