Well after 13 years and 365,000 miles I think it may be time to rebuild my MINI. I started noticing a large loss of power going up grades, and temperatures rising pretty quick. My water pump gears started making a bit of noise, so I swapped in my old supercharger last week. It fixed the noise, but of course not the lack of power. Today I did a compression test, which turned out low, very low, all the way across (105-120psi). I then did added a bit of oil to the one of the 105psi cylinders and it bumped it up to 165psi. So it looks like the rings need replacing. I can't say that I am really surprised with this many miles, and have been expecting it for sometime. So now a question for you guys who build/ rebuild engines. I am planning on replacing rings pistons, bearings, and re-building the head. What I am wondering is, should the connecting rods be replaced? I have not dig into the engine yet, when I do it may become obvious, but since I haven't build an engine since high school (in my 40's now) I figured it wouldn't hurt to ask some who have done one more recently. Also, since I'll be in that deep, what else should I look for?

Nik

 

modded mini with 365K miles on the clock is amazing and true testament that the R53 Tritec engine is good and more bullet proof than newer gen Mini. you can add new valves and guides and valve springs in your list. How about new supercharger unit?
Good luck in your project.

 

That's really awesome that you got 365K miles with those performance mods! Really makes me proud. The connecting rods are forged steel with floating pins (bushed on the rod), unlike the R50 base engine, so you shouldn't need to replace them, although you may want to check the piston pin to bushing clearance as that may be worn with so many miles. I don't remember what the max piston pin to rod clearance should be, but hopefully you can find this in one of the repair manuals. If the clearance is too high, you're very likely to experience piston pin ticking at idle and just off idle when no-load revving the engine. Rod bolts should probably be replaced though when you re-do the bearings, as they are "torque to yield."

 

Unbreakable -

Thanks for the input. I been reading your tritec posts, great story. You should be proud they are great engines. I cant wait to get into it and bring it back.

Nik

 

I would call one of the vendors that post on this forum for advice. Way , Detroit tuned, Sneed, all do engine rebuilds. Or call Jan from rmw, he's banned on this forum but I'm sure you can easily find him on the other (also banned lol) mini forum

 

365,000, nice. the guy with the 380K MINI in Wisconsin , needed some engine work done around 350K last time I talked to him. Spun bearing or something. Rebuild or getting a new engine ?

Until you tear apart the engine , you will not see the whole picture of what needs replaced.

 

XSMINI, We have a short block at the machine shop right now being assembled, and we also have rebuilt heads sitting on the shelf. If you need anything throughout the rebuild chances are we have it IN-STOCK and ready to ship, we also carry full gasket kits that will provide every gasket required to do a rebuild even valve guide seals.

If you wanted to save some time, but spend some extra money and have a rebuilt engine with a warranty we would be more than happy to help you out.

Either way, we would be glad to help in anyway throughout the rebuild process.

Nick
Detroit Tuned
586-792-6464

 

Thanks Nick - I was actually looking at your site last night and noticed you had quite a bit there. I will give you a call when I dig into the engine more. I know I can do the rebuild myself, and have actually have kinda been looking forward to it. If however I scare myself out of it I'll call you and discuss options.

Thanks,

Nik

 

Okay, let us know how we can help and we will get you everything you need to get the job done.

There is something rather serene about being able to slowly do these jobs over a month or so, makes for a great hobby. Makes me wish my cars would break a bit more often.

 

My wife had a classic Mini as a daily driver for about 8 years, it kind of cured me of wishing my cars would break more. The thing was a blast, but I really got tired of working on it every weekend. I always wanted to take the time and re-build it properly, but never had the time. (Kids will do that)

 

Started the tear down this afternoon. got most of the big stuff out of the way. Wont be able to work on it again until the weekend.

Nik

 

Pretty clean so many miles, looks like some major progress, wonder what the internals look like with all those miles. Post up for sure.

 

Go ahead and throw a $4 crank sensor seal at it while you are in there looks like that one is done.

 

Ya Think???

 

Yeah, that one is done

 

365,000 miles not too shabby! I guess my 2005 is a spring chicken with 118,000.

 

If i can get to 365K that would be awesome, just at 256K here on 05'

 

Mother Nature didn't like my plans to work on the mini this weekend. Got in two days of snowboarding instead

Nik

 

Oh no.... snow problems. Mother nature did not think it was time for the MINI project to be done. She thought you needed time off

 

Made a bit of progress today, getting very excited. So far everything is looking pretty good. Oh, and I ordered a the Mega camshaft from Detroit Tuned.
Now for some pics:




Engine Out!





Engine Bay





All the way out





clutch plate





365000 mile clutch





flywheel





head





pistons





hone marks still





crank

For an engine with over 365,000 miles and having always followed the OBC recommended oil change interval (usually around 22,000 miles) I think it looks really good. All the bearings looked great and the original hone marks are still visible on the cylinder walls.

Nik

 

Very cool! You got some great mileage of that motor.

 

Dug in a little more today:thumbs:

Pistons out!


Valves


Some Deposits on the valves


Valve train


Cam


Some cam wear


Some more cam wear, only two lobes


Pretty clean after 365000 miles and following the OBC oil changes (~22,000 miles between changes.


All in all it looks pretty good. glad I bought a cam

Nik

 

That's amazing. The piston skirts and cam lobes are not too happy, but that whole clutch assembly is remarkable! It seems to be that you drive with mechanical sympathy.

Charlie

 

The clutch and the flywheel look in pretty good shape. Bottom looks great, yea i can see that cam wear.

Looking good.

 

Really cool for me to see these pictures from such a high mileage engine. Hard to believe you only changed oil about every 22K miles! Pistons look incredibly fresh to my eye. I don't detect any headland "nibbling" from knock and it looks like the skirt coating hasn't worn much. The carbon deposits are very normal and really less than I expected.


Would love some direct close-ups of the skirts to see if the grafal coating is worn through or not. Cam wear isn't too surprising given the mileage and infrequent oil changes. In my discussions with the cam Engineers over the years, they always explained that "over the nose" contact stresses at idle are very high, worse than in high speed operation and this is the when cam lobe spalling can be initiated. We used to talk about running a couple thousand hour idle test but never did. This is one reason I've always been leery of running aftermarket cams and high load springs. The OE's use some pretty sophisticated design programs that calculate the accelerations, jerk and even the 3rd, 4th and 5th derivatives (known as "snap," "crackle" and "pop" - not kidding!) of velocity as well as contact stress, to make sure that the lobe designs are safe and reliable for the life of the engine. I spent a lot of time with the cam engineer on this engine to ensure that the performance requirements were met while still making it reliable. If I only had a < 30,000 mile lifetime expectation I probably wouldn't hesitate to go aftermarket, although I've heard of problems with regrinds not lasting long.


Keep the pictures coming! Love this thread and can't wait to see you get 'er back on the road as strong as new!