XU9 Mi16 Rebuild - 2 stages

[Fumanchu 2]

I'm looking to do a 2 stage rebuild on the 1.9 Mi16 unit fitted to my 205 as its currently showing low compression on cylinder 3 and the leakdown tests showing air escaping into the oil system. 

 

Due to other competing demands on my wallet, i'm looking to have the rebuild done in 2 stages:

Stage 1) Forged high comp bottom end + standard head 

Stage 2) Rebuilt head inc larger valves, machined for double valve springs and solid lifters

 

For stage 1 - I'm looking to get new liners as mine are ovalled. Hence, am looking at getting a set of Westwood ductile liners - are these in standard size only or can I go bigger for more displacement? For the forged pistons and rods, whats the recommendation for a set that will handle track/rally use in the future? For the head, what's the highest duration I can go without having to change the springs/lifters? Any recommendations on cam, e.g PeterT would be welcome. I'll be running an aftermarket ECU (ECUMaster black) with 48mm Jenveys (to accommodate the stage 2 build).

 

Stage 2 - In the UK, where's the best place to do the headwork inc larger valves and the machining work? With headwork done, what are the recommended cams?

 

Thanks in advance.

Edited 12 hours ago by Fumanchu

[welshpug 1,649]

for the "stage1" build you are quite limited by the valvetrain, grinds on a standard cam blank would be suitable for this, Peter could no doubt answer a few of your questions.

 

but you can use standard rods and pistons for this, you wont need high compression and standard rods are more than strong enough,  you may well have issues trying to run enough compression for stage 2 with such a mild cam, dynamic compression figures would be through the roof.

 

48mm bodies would be too big for this, 45 would be far better, the air speed at lower rpm from too large a port will plummet and hurt drivability,   I was told 45mm was enough for around 240 bhp so my 2.2 is on 45's.

 

 

a friend has a head with solid tappets valve springs and cams that he may part with , they're pretty wild Piper cams, so would suit your stage 2, does need a set of valves as someone bolted it on top of a standard piston

 

 

liners don't need to be anything fancy, Goetze still make them in 8v shape and are pretty reasonable,  under £150.

you can go to 83.5mm on these easily

 

anything over that needs block machining as the lower skirt of the liner gets too thin and need taking out for an oversized liner from the likes of Westwood, that adds up to about 2k from memory  (a friend recently asked an engine builder about going 84/85mm)

 

peugeot valves are pretty big already, I'm not sure where this "big valve" thing has come from other than really old 2 valve heads from other manufacturers!

[Fumanchu 2]

28 minutes ago, welshpug said:

a friend has a head with solid tappets valve springs and cams that he may part with , they're pretty wild Piper cams, so would suit your stage 2, does need a set of valves as someone bolted it on top of a standard piston

 

let me know if your friend wants to sell the head. 

 

Re. the bottom end - I was looking at westwood ductile liners and robinson forged rods but apart from Wossner's, i'm struggling to find any other forged pistons that are available.

[welshpug 1,649]

Loads of pistons available,  I use Robson rods with a modified omega piston, originally for a vauxhall xe at 87mm.

 

A honda B series is available in 83mm, I'm looking to use something based on those to give a longer rod and lighter piston.

 

 

Or of course, just ask someone like  CP Carillo to make you a set.

[petert 581]

Stage 1

what you need to understand, is that Mi16 rods are piston centred and 8V rods are big end centred. 99% of forged pistons sold are big end centred. If you use a standard Mi16 rod on a big end centred forged piston, there will be excessive rod thrust and you'll end up with cracked piston pin bosses.

 

All is not lost though. There are Mi16 specific forged pistons on the market. Perhaps Aries or JE? Martin from PR Developments was trying to sell some recently.

 

Wossner sell a rod which is 8V width on the big end and Mi16 pin on the top. However, Wossner do silly things with pin sizes. The std, XU9J4 pin is Ø22. You'd need to check the Wossner specs.

 

Attached is a pic of an Mi16 Iapel piston which I machined internally to remove the draft and then made thrust washers, for use with an standard Mi16 rod.

 

Getting custom rods made is certainly a good option.

 

You don't need new liners. You can bore the oem liner to Ø84. Beware, that they need to be torque plate in the block, ideally. Otherwise they will be oval.

 

Edited 2 hours ago by petert

[petert 581]

Here's a fun fact I just learned. The XU9J4 Wossner rod with the wider 24.2mm big end is G0066. Pug1off sell a piston & rod kit with a PEC rod of the same part number but incorrect BE width.

 

https://www.peugeot-tuning-parts.co.uk/peugeot-405-mi16-1.9-wossner-high-comp-forged-pistons-pec-rods

 

Beware that this is entry level stuff.

[welshpug 1,649]

got a 2nd fun fact for you, PEC dissolved in January 2020..

 

 

 

one of the directors was appointed to Wossner uk late 2019..

[welshpug 1,649]

and if you were ever considering PEC stuff, here it is almost straight from the source, they're 22.45mm small and big end width, 22mm pin.

 

https://www.maxpeedingrods.co.uk/product/high-performance-peugeot-405-mi16-309-1-9-gti-16v-xu9j4-4340-en24-chrome-moly-forged-h-beam-connecting-rods-conrod-with-arp-bolts-x4pcs.html

[petert 581]

I've used Wossner G0066. They're definitely 24.2 wide.

 

"Hi peter, Dominik has asked me to speak to you about this.

 

I think in essence your asking about the OE piston being “rod guided” while the big end has plenty of side to side movement. 

 

On these rods and pistons, we switch it around a bit so the piston/rod then becomes guided by the crank. The Big End width is actually 24.2mm wide (typo in the catalogue) which controls the side to side float when using K9042 & G0066.

 

Hopefully this answers your question?

 

David Wheeler

Unit 26 Allshots Enterprise Park

Woodhouse Lane

Kelvedon, Essex 

C05 9DF

+44 01376 583030

www.wossnerpistons.co.uk"