7 replies to this topic

[Racer_Pete]

Hi, I got my engine block bored out to 1061cc a couple months ago from a engine machinest along with various other things done to the block, I also got them to press the new +0.80 pistons onto the A+ floating rods (Mini spares flat top mega type). I started to put the new pistons into the block fitted with the rings, the correct way with the arrow pointing to the water pump and them facing the correct way as it says on the pistons. The piston went into the bore fine, i then fitted the ARP bolts and torqued them up. After finishing one completely i spun the engine over by hand but when i spun it the rod hitted the side of the block, At first i thought it was the wrong rod bolts so i changed them to the standard ones, but the rod still hits the side. So i looked at the piston again to make sure i put it in the way it says. (it was) By this time i was somewhat confused!! I had a closer look at all 4 of the pistons to see that there all the same with the arrow facing the water pump and facing front etc.... two of the four pistons have been fitted the wrong way! with them facing 180degrees the other way.
No. 1&4 have been fitted the wrong way, and so when you fit them as they should they hit the side of the block because of the offset of the rod. I rang them up and they said ''we havent seen mini pistons with arrows''. They also said to me ''they should be okay to fit because they are not offset pistons'' ??

My question is will they be okay to fit with two of them being the wrong way round or will i need to get them pressed off and put the correct way?

(when i say will they be okay i dont mean just put them both in as i have already and smashes the block lol. obiously i would turn the complete piston/conrod around) so two of the arrows would be facing the wrong way so they fit as they should.

I have probley made this look really confusing, hopefully i havent, thanks.

Edited by Racer_Pete, 17 November 2009 - 10:41 PM.

[bmcecosse]

The arrows are there for a reason - get them to turn them round! At NO extra cost of course!

Edited by bmcecosse, 17 November 2009 - 10:47 PM.

[HARBER07]

This is why i get annoyed with the machinists near me!! I just look at it this way - they are on there for a reason - so they all face the same way! Personally I would take them down there and get them to put them right FOC.

[01smartc]

They will find it very hard to press the pistons back off without damaging them, or bending the rod.

[Racer_Pete]

Thanks for the replys,

what could happen if i do fit them as i said above though?

[Wil_h]

What you are saying is that they fitted the pistons to the rods all the same, when because of the off-set rods two need to be one way and two the other.

998 pistons are offset and thus need to be fitted the correct way. They fitted them, thus they should correct the problem. I find it very difficult to believe that they have never fitted pistons with arrows on before, considering they seem to know about off-set pistons.

[Racer_Pete]

What you are saying is that they fitted the pistons to the rods all the same, when because of the off-set rods two need to be one way and two the other.

998 pistons are offset and thus need to be fitted the correct way. They fitted them, thus they should correct the problem. I find it very difficult to believe that they have never fitted pistons with arrows on before, considering they seem to know about off-set pistons.

Yeah thats exactly what I mean, I find it hard how they have 2 the wrong way, its not exactly rocket science!
I would get them to take them off but its quite a long drive there and back, good half a day, and I want to start building it up asap as the old engine is out and I need the mini.

So bascily I really shouldnt risk putting them in?

[Sprocket]

The pins are not press fit on floating rods :S

If you do have floating rods, then its a simple task to change things around.