Bushing Small Ends,need Some Advise

[opticaltrigger 52]

Hi guys,looking for a bit of advise here.

Just got our hands on some new Wossner pistons which use a 22mm pin and want to hang them on the standard rods which normally require sweating on.

 

I would really like to have them fully floating in the piston and the small end so I was wondering if this is something that has been done by anyone.

I dont have a rod in front of me at the moment to look at but I was thinking that perhaps if there is enough material there the small end could be bored and bushed to float on the new pin.This would make dismanteling things very much easier in the future.

 

But honestly I dont know,It crossed my mind so I thought I'd just put it out there and see either what you guys think or if anyones done it before.

 

Anyway all the best

O.T.

 

[welshpug 1,661]

if they're intended for a 143mm conrod then you could use XU9J4 rods if the piston is the correct width and bore.

[opticaltrigger 52]

Hi welshpug,thanks for coming back to me.

The rods are 143mm and the new Wossner pistons were originaly for an MI16 turbo but we are going to use them in the 8v turbo project.

 

The small end width on the standard rod is 24.2mm and I would need to take a mm off both sides to get them in the piston anyway as the pistons are meant for 22.4mm width MI16 rods.

But if I used the xu9j4 rods which should fit in the piston obviously the big ends will be 22.4 also.If I'm understanding you right that would mean that the rod would then be guided by the piston istead of the crank.Is that right?

 

O.T.

Edited May 17, 2015 by opticaltrigger

[petert 589]

That's correct. Mi16 rods are "piston centered" rather than "crank centered" like an 8V. I'd use 16V rods if the piston has been machined to control the end float. It's no issue bushing an 8V rod, but taking metal off the sides as well is starting to get unnecessarily expensive.

[opticaltrigger 52]

Hi Peter,

Thanks mate.I havent machined the pistons,they are right out of the box 83.5mm oversize ones from Wossner but if I'm hearing everybody right the MI16 (XU9J4) conrods should pop right in and give me a fully floating pin then.Great.

 

Ok,..I saw these conrods http://www.ebay.co.uk/itm/Conrod-for-Peugeot-Citroen-405-Mi16-309-1-9L-S16-XU9J4-Con-Rod-Pleuel-Bielle-RPF/131465705912?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140122125356%26meid%3D6c8c0da1f47c4ea281102c054f46b71a%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D251550657288&rt=nc on ebay and was wondering if anyone knows anything about them or has ever used them.Reason I ask is that they do seem very,very cheap compared to others and I've never heard of them either.But thats not to say they are terrible either,just wondered if anyone knew.If they are ok then they seem to be the answer really as far as I can tell.What do you guys think?

 

Thanks again Welshpug and Pete for the advise

All the best

O.T.

[welshpug 1,661]

I dont think peugeot rods are well known for being weak, quite the opposite, I know of plenty of high power budget engines using standard rods, I would get hold of standard ones for pure simplicity and knowing they will work.

[petert 589]

The rods on ebay are your average, cheap Chinese items. I run a set to 8000+ in my XU10J4 without any problems. I'm not sure I'd go much further, but they're excellent value for money when you consider the TOTAL cost of reconditioning a set of standard rods. So long as your pistons are machined to control the rod float they'll be fine. For example, here's a set of Iapel pistons which were advertised as a true XU9J4 piston but only had the draft from the forging process on the inside. The solution was to machine the inside parallel and make thrust washers.

[opticaltrigger 52]

Once again thanks very much Welshpug , Pete.

 

I know what you mean about the standard rod welshpug they are very Tonka,thats why we kept them in but the machining required is quite alot now.

That was a nice fix for the pistons Pete.

We will get a set of those ebay rods ordered then,8000 rpm is plenty for us.They sound like the ideal fix for the problem,just not so wide on the big end.

 

Whats important here I supose is what sort of clearence should I be looking for between the side of the small end and the inside of the piston ?

 

I'm hoping that the Wossner pistons will be accurate enough and the ebay rods just fit right but I will check now that you mentioned yours Pete.

And also would I be correct in thinking that I would need to get MI16 big end bearings also,as they must be also not be as wide as the 8 valve big ends.

 

Thanks again guys very helpfull of you

 

O.T.

Edited May 18, 2015 by opticaltrigger

[welshpug 1,661]

1.9 mi big ends are the same as 8v.

[opticaltrigger 52]

Thanks welshpug that clears that up.I will just order standard 1.9 8v big ends as normal.

Do you know what clearence there should be between the piston and side of the small end welshpug?

I thought it must be a fairly specific clearance as the piston guides the rod and you would'nt want it to tight either.

 

Anyway all the best and thanks for coming back to me on it

O.T.

[petert 589]

They're not quite the same. Mi16 rod bearings were copper backed. For your application I'd be looking for something a tad better than the standard 8V bearing. ACL for example, if you can get them, list three different rod bearings for XU engines - Aluglide, Duraglide and Race Series. Side clearance is approx. 0.010-0.012".

[opticaltrigger 52]

Thanks again Pete,

I will try to locate some ACL race series.

 

Is that 10 to 12 thou on either side of the small end or just one Pete?

 

Thanks very much again and all the best

O.T.

[petert 589]

In total.

[opticaltrigger 52]

Thanks very much once again Pete.

 

O.T.