Fitting Mi16 Xu9j4 Pistons To 8 Valve Xu Rods

[welshpug 1,626]

As above, simple really, I'd like to fit 8 valve conrods to my XU9J4 piston, the pin size and small end of conrod is the same as the piston, but locate differently (interference fit in the 8v, clearance fit and Circlips in the 16v)

 

The main issue is that the rod's small end is too wide by roughly 1.75mm, my thinking is to get the rods narrowed by say 1.73mm (allowing for some clearance)

 

So how and where and how much would this cost me?

 

 

Another question, do I need to heat up the 8v piston + rod assembly before pressing the gudgeon pin out? (and cool the gudgeon pin and heat the 8v rod when I go to fit them to the XU9J4 piston)

 

 

Thanks!

 

 

 

[welshpug 1,626]

Apologies for the multiple posts, I got an error after pressing the post topic button and pressed back so I wouldn't lose the info, and it happened twice!

[B1ack_Mi16 67]

You should only need to heat the rod / cool the pin, as the pin is a slip fit in the piston anyway.

I've never done this kind of work myself so no idea of how hard it is to separate them.

 

Are the 8v rods really wider at the small end than the 16v ones?

I always believed the 16v ones were widest because they were piston located. But should not cost much to get them machined down. 30£ each maybe?

[welshpug 1,626]

I think it is the 8 valve that is piston located as they have far less room to move side to side

 

I have just measured an RFY XU10J4 small end and they are 19.3mm wide, in a 22.45mm wide RFY xu10J4 piston, the XU9J4 piston I have is roughly 22.60mm wide, I haven't got XU9J4 conrods.

 

the XU 8v rod I have is 24.20mm wide with 0.02mm clearance.

 

(Figures are only rough ones from my £8.99 Vernier, I haven't got an internal Micrometer or disassembled the conrod from the piston to measure it accurately as yet)

[B1ack_Mi16 67]

The XU9J4 is 100% piston located and the small end of rod fits exactly into the piston.

[DamirGTI 327]

Well it's a bit dodgy business on a DIY basis without proper tool (we've been doing that on other engine types/brands , it's rather tricky operation , two man job mostly and this two persons had to be trained/quick )

 

You'll need to cool/freeze the guiding pins in the freezer and heat up the con rods up to say 250C , then , one must hold the conrod/piston assembly securely so that they do not move while other person press in the frozen guiding pin inside the piston/conrod .. but the tricky bit is that both of you must react quick as if done to slow you'll end up with guiding pin "semi pressed" in .. need to note the importance for the correct depth when pressing the guiding pin inside ..

 

I would ask someone in the Peugeot or Citroen service for help as they have special tool for this job which makes it much easier , this is how it looks like :

 

http://s27.photobucket.com/albums/c151/Pie...;current=1P.jpg

http://s27.photobucket.com/albums/c151/Pie...;current=2P.jpg

http://s27.photobucket.com/albums/c151/Pie...;current=3P.jpg

http://s27.photobucket.com/albums/c151/Pie...;current=4P.jpg

http://s27.photobucket.com/albums/c151/Pie...;current=5P.jpg

 

Damir

[welshpug 1,626]

many thanks Damir!

 

My earlier comment about heating up the piston and rod was for removal of the pin not for fitting, would be somewhat difficult to heat the conrod up without the piston in this situation

 

 

I very much Doubt that many dealers at all will have such specialist equipment, apart from not many doing work this involved, there aren't many established places in their original buildings, when they move to newer buildings old tools and stock often get skipped

 

My friend does have a wood/coal burning stove and a fridge in his workshop though

Edited February 10, 2009 by welshpug

[Anthony 1,000]

I'd imagine a good engine builder or machine shop should have the require tooling to do it?

[James_R 3]

I think bridgecraft eng could modify the pistons to fit suitably, then they're "just a press fit" apparnetly, ask nik he just did it on his Mi build?

[DrSarty 90 1 Cars]

My friend does have a wood/coal burning stove and a fridge in his workshop though

 

Oh that makes it OK Meirion.

 

Nothing like DIY.

 

I'd go somewhere they've done this before personally, rather than try and do it with a Clipper lighter, a mallet and a beer fridge.

[welshpug 1,626]

doh, you're right on the beer fridge Rich!!

 

we did however have a makeshift forge arrangement a few weeks ago and had a flame coming out of the top of a 12 foot chimney, the wonders of a load of coal and compressed air

 

Thanks everyone for your input, I shall do some enquiring

[DamirGTI 327]

My earlier comment about heating up the piston and rod was for removal of the pin not for fitting, would be somewhat difficult to heat the conrod up without the piston in this situation

 

.. did misread something , i can't offer reasonable info regarding separating the piston/conrods as we've (at the mechanic garage) been pressing the guiding pins out without heating/cooling process as the pistons where ment to be scrapped anyway and replaced with new ones .. sometimes we succeed to separate the rods/pistons without damaging the pistons itself but they where mostly "chipped" during the separating process ..

 

If i remember Graham (Pugtorque) did this conrod/piston separating successfully in a vice without damaging the pistons .. right ?

 

Damir

[welshpug 1,626]

ahh damaging the old pistons is not a worry, I have no need for them

[DamirGTI 327]

Ok. then , “die hard” procedure : do you have access to the hydraulic press ? first you'll need to cut an thick square piece of steel (a little bit bigger than the piston , and thick/high as the guiding pin if you intend to do it with hammering the pin out rather with the hydraulic press .. can make it from several layers say 4 or 5 layers of 2cm steel plates) with an gap/hole for the guiding pin trough which he'll drop out during the pressing/hammering - place the piston on the steel plate , center the guiding pin with the hole in the steel support plate , find an piece of steel tube (socket extension will do as well !) of similar dia. as the guiding pin (a little bit smaller of course) , place ti on top of the pin then apply pressure and the pin will pop out trough the piston/conrod and support plate .. or you can simply use heavier hammer to bang it out … (but you'll need a mate to help you out a bit by holding the piston in place ..)

 

 

 

Damir

 

EDIT : try to heat them (entire piston/conrod assembly) in the hot water first prior to pressing/hammering out the pins , i dunno it might be easier then ?!

Edited February 10, 2009 by DamirGTI

[welshpug 1,626]

I have access to a 20T press

[DamirGTI 327]

Nice one ! it'll be piece of cake with the press

 

Damir

[welshpug 1,626]

Got a gudgeon pin out of the donor conrod/piston assembly;

 

 

This is how the gudgeon pin sits in the XU9J4 piston when placed roughly central, quite a bit longer than the original one, but I'm not sure if XU9 ones would be suitable for use in the other conrods as they fit differently, i.e originally not bushed but an interference fit unlike the XU9J4 that just push in and are secured by circlips.

 

[nick 3]

Contact Martin (crf450) he did mine. It isn't really a diy job (as in, with a blow torch and a vice) Martin machined the 16v piston to give the same piston/rod clearance as the 8v and then made a boss that centralises the pin in the piston when it was pressed in. The pins are a VERY tight fit in the rod so make sure when you press them in everything is dead square.

 

Piston measurement have a look at this thread as well.

 

Nick

[welshpug 1,626]

I dropped Martin a PM as soon as I posted earlier, thanks for the link to your thread Nick, looks like the XU7JP4 pistons don't have as much float side to side at all compared to the 1.6+1.9 8v as the width inside them is only 24.40mm.