26 replies to this topic

[BaronVonchesto]

Just so we're clear on the nomenclature I'm using in this post:
front - the side of the engine that faces outwards and has the 3 core plugs visible.

no 1 piston - the one closest to the radiator side

no 4 piston, the one closest to the flywheel.

Got my block back from the machine shop and i'm at the stage of my rebuild where its time to put the crank and pistons back in, but i'm confused. Haynes shows which that each conrod goes in a specific place based on the direction of the angle on the bigend like so:

 haynes-pistons.jpg   40.67K   17 downloads

 

what's not clear however is whether the image in the book is looking at it from the front or the back of the engine. As I understand it, the bit with the little oil hole on the conrod big end should face the front, but i'm not too sure. I've taken a picture of my conrods with them lined up exactly as in the haynes manual, but could someone tell me going from left to right, which is for pistons 1,2,3 and 4? and also if looking from the front of the engine they go in as in the picture, or the other way round?

 pistons.jpg   56.46K   18 downloads

 

just to be clear these are for a 998 A+ engine.

 

[DeadSquare]

The way that you have shown your con rods, is as if you were sitting in your Mini and looking at them through the "body, exhaust pipe and block", with X ray eyes.

[nicklouse]

but as they are a mirrored assy. you could be looking from the front of the car.

[jeffster06]

The way I see it is regardless of which side you are looking at (grill side or firewall side) 1 and 4 have their non-angled side to the outside of the block and 2 and 3 have the non-angled side to each other. To put it another way none of the crank bearing caps will have a slant next to it. Hope I made some sense there, I also read somewhere that you won't be able to put it in the wrong way because the offset, but you could put the piston on the wrong way around though. 

Edited by jeffster06, 20 June 2019 - 08:14 PM.

[KTS]

number 1 piston is the one closest to the water pump end of the block  (i.e. the right hand end of the block as you look at it from the front)

[DeadSquare]

but as they are a mirrored assy. you could be looking from the front of the car.

 

No, surely not.

 

The bolts go through the cap into the rod (at an angle) from the exhaust side of the engine, not from the starter side

[DeadSquare]

The way I see it is regardless of which side you are looking at (grill side or firewall side) 1 and 4 have their non-angled side to the outside of the block and 2 and 3 have the non-angled side to each other. To put it another way none of the crank bearing caps will have a slant next to it. Hope I made some sense there, I also read somewhere that you won't be able to put it in the wrong way because the offset, but you could put the piston on the wrong way around though. 

 

I'm sorry, but your "Hope" that you have made sense is unfounded.

 

Your "slant" theory enables you to swap the 1 and 2 conrods round, but then they face the wrong way.

 

Looking at the engine as if you are about to be run over by a Morris Minor, the conrods are split from one "O" clock to seven "O" clock, not from eleven "O" clock to five "O" clock.

[jeffster06]

The way I see it is regardless of which side you are looking at (grill side or firewall side) 1 and 4 have their non-angled side to the outside of the block and 2 and 3 have the non-angled side to each other. To put it another way none of the crank bearing caps will have a slant next to it. Hope I made some sense there, I also read somewhere that you won't be able to put it in the wrong way because the offset, but you could put the piston on the wrong way around though.

I'm sorry, but your "Hope" that you have made sense is unfounded.

Your "slant" theory enables you to swap the 1 and 2 conrods round, but then they face the wrong way.

Made sense in my head lol... not sure how you could swap 1 and 2 conrods around if you know which cylinder they came out of though..

[DeadSquare]

 

 

The way I see it is regardless of which side you are looking at (grill side or firewall side) 1 and 4 have their non-angled side to the outside of the block and 2 and 3 have the non-angled side to each other. To put it another way none of the crank bearing caps will have a slant next to it. Hope I made some sense there, I also read somewhere that you won't be able to put it in the wrong way because the offset, but you could put the piston on the wrong way around though.

I'm sorry, but your "Hope" that you have made sense is unfounded.

Your "slant" theory enables you to swap the 1 and 2 conrods round, but then they face the wrong way.
 

Made sense in my head lol... not sure how you could swap 1 and 2 conrods around if you know which cylinder they came out of though..

 

 

If he knew from which cylinder the rods came, he wouldn't have needed to post.

[Spider]

I find the easiest way in regards to the off-set to simply look down the bores with the crank fitted. The off-set in the Big End on the crank when viewed this way is pretty obvious.

 

In regards to which way the split should face, maybe this diagram might help

 

[jeffster06]

 

 

 

The way I see it is regardless of which side you are looking at (grill side or firewall side) 1 and 4 have their non-angled side to the outside of the block and 2 and 3 have the non-angled side to each other. To put it another way none of the crank bearing caps will have a slant next to it. Hope I made some sense there, I also read somewhere that you won't be able to put it in the wrong way because the offset, but you could put the piston on the wrong way around though.

I'm sorry, but your "Hope" that you have made sense is unfounded.

Your "slant" theory enables you to swap the 1 and 2 conrods round, but then they face the wrong way.
 

Made sense in my head lol... not sure how you could swap 1 and 2 conrods around if you know which cylinder they came out of though..

 

 

If he knew from which cylinder the rods came, he wouldn't have needed to post.

 

Just reread his post and I see my error now, not sure what I was thinking there thought he was just stuck on the orientation. 

[ryomini]

For us amateur and infrequent engine assemblers it goes to show that taking a series of pix and labelling items front or back, left or right, 1-4 etc can save us soooooo much anxiety.  I remember when I disassembled, I was convinced my mental pictures would recall easily but now my brain is as rusty as my mini floor panels lol !

[BaronVonchesto]

okay from the many comments here i think i'm clear. the book is showing things looking from the rear of the engine. that makes a lot of sense.

[BaronVonchesto]

one other thing, my bigend bearings are the type with the tabs on them. does the bigend cap go on to the conrod such that the two tabs are close together or far apart? 

[DeadSquare]

one other thing, my bigend bearings are the type with the tabs on them. does the bigend cap go on to the conrod such that the two tabs are close together or far apart? 

 

Ouch !

 

I do hope that you know which cap came off which rod.