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 8 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!