Jump to content


Photo
- - - - -

Low Compression Across The Board

engine

  • Please log in to reply
6 replies to this topic

#1 Vinay-RS

Vinay-RS

    Put's foolish ideas in peoples heads

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,097 posts
  • Location: Cape Town

Posted 11 November 2024 - 05:27 PM

Hi all, 

 

It has been a while since I've posted here. 

 

I normally don't drive a lot and the Mini has had some electrical issues (gauges misreading for a while and some overheating issues (bigger concern since we're rolling into summer now). 

 

Anyway, storytime, I drove to Cape Town (~50 km away) on Saturday morning to get some spares to finally get around to the radiator update job. When driving home on Saturday evening, the car started bogging down when on the highway. Then well stopping at a set of lights the Mini decided to cut out. It struggled to get going and then was idling really rough and smoking badly from the engine bay and this smoke was coming into the cabin. This is SA, so you don't stop on the side of the road and especially at night. So I limped the Mini home (probably a bad idea for the car, but it makes sense for safety). I get home, park up, and then popped the bonnet. Everything was caked in oil. I opened the oil filler cap and it was smoking. So I left it alone to cool down. The next morning, I checked the oil again. There was no milky residue and it didn't smell. I checked the radiator and it was full (so that didn't cause the issue). Then I checked the dip stick and the engine had like 3 l of oil (basically it either spat out or burned the oil.) 

 

A friend suggested I check compression to see what is going on. 

 

Borrowed a pressure gauge and did compression tests this evening. The values are basically zero on 1 and 4. 

 

1 - 200 kPa

2 - 1000 kPa

3 - 800 kPa

4 - 180 kPa

 

I stopped at this point since the numbers were so so low. Figured there was no value in trying to do a leak test next. 

 

Guessing this means engine out and rebuild? :( 

 

 

 



#2 Spider

Spider

    Moved Into The Garage

  • Admin
  • PipPipPipPipPipPipPipPipPipPipPip
  • 14,458 posts
  • Location: NSW
  • Local Club: South Australian Moke Club

Posted 11 November 2024 - 05:40 PM

Hey mate - bumma !

 

By the sounds of it, the rings on 1 & 4 have ceased to seal. I'd guess here, especially as it's been parked up for a while, it's from stale fuel and low octane.

 

Might be worth taking the head off for a look, you never know, but with oil 'everywhere' and smoking from the oil filler cap, I'd say the piston ring lands have been 'hammered' and the rings pinched.



#3 Vinay-RS

Vinay-RS

    Put's foolish ideas in peoples heads

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,097 posts
  • Location: Cape Town

Posted 11 November 2024 - 05:55 PM

Hey mate - bumma !

 

By the sounds of it, the rings on 1 & 4 have ceased to seal. I'd guess here, especially as it's been parked up for a while, it's from stale fuel and low octane.

 

Might be worth taking the head off for a look, you never know, but with oil 'everywhere' and smoking from the oil filler cap, I'd say the piston ring lands have been 'hammered' and the rings pinched.

Thanks! The Mini did get driven (usually once a week) but not far ~10-20 km. 

 

I'll pull the head tomorrow and have a look and then see if I can borrow an engine hoist to pull the engine. 



#4 miniGTS

miniGTS

    Mini Mad

  • Members
  • PipPipPipPip
  • 192 posts
  • Location: Cape Town

Posted 11 November 2024 - 06:55 PM

If you don't get one to borrow, coastal hire should be able to assist with hiring, delivery and collection.

#5 Vinay-RS

Vinay-RS

    Put's foolish ideas in peoples heads

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,097 posts
  • Location: Cape Town

Posted 12 November 2024 - 03:07 AM

If you don't get one to borrow, coastal hire should be able to assist with hiring, delivery and collection.

Thanks, Nathan :) 



#6 sledgehammer

sledgehammer

    Up Into Fourth

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPip
  • 3,077 posts
  • Location: I'm sittin here besides my self

Posted 12 November 2024 - 09:45 AM

Sadly , I think Spider is right -
 

piston rings in 1 & 4 may have pinched up due to overheating / maybe broken ,

 

I would get the head off - before condemning it to recon 

Is the engine a 1100 cc (1098) ? , if so ...
 

I have in the past had clubman's 1100cc that smoked & low compression

 

They run hot & the rings stuck up with carbon & dropped compression with gas getting past

 

& blowing oil out breathers ,

I stripped it , found rings stuck tight to piston  groove & oil control return holes blocked right up

I drilled holes slightly bigger , cleaned the ring grooves up , so rings worked , cleaned oil control ring up

 

bores were good with only slight wear , reassembled with main + end shells & pump , head refresh - all was good

 

took a while to get oil burnt out of exhaust , but compression was up & no smoke .

engine was stripped & work done , but no rebore ect , this was on the 1100cc's , they do sometimes go like this .

Best of luck 



#7 Vinay-RS

Vinay-RS

    Put's foolish ideas in peoples heads

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,097 posts
  • Location: Cape Town

Posted 12 November 2024 - 03:20 PM

Sadly , I think Spider is right -
 

piston rings in 1 & 4 may have pinched up due to overheating / maybe broken ,

 

I would get the head off - before condemning it to recon 

Is the engine a 1100 cc (1098) ? , if so ...
 

I have in the past had clubman's 1100cc that smoked & low compression

 

They run hot & the rings stuck up with carbon & dropped compression with gas getting past

 

& blowing oil out breathers ,

I stripped it , found rings stuck tight to piston  groove & oil control return holes blocked right up

I drilled holes slightly bigger , cleaned the ring grooves up , so rings worked , cleaned oil control ring up

 

bores were good with only slight wear , reassembled with main + end shells & pump , head refresh - all was good

 

took a while to get oil burnt out of exhaust , but compression was up & no smoke .

engine was stripped & work done , but no rebore ect , this was on the 1100cc's , they do sometimes go like this .

Best of luck 

Thanks! It's a 1275 SA block. Hopefully something useful can be seen/determined when the head is off. 







Also tagged with one or more of these keywords: engine

2 user(s) are reading this topic

0 members, 2 guests, 0 anonymous users