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 October 7, 2024 by Fumanchu

[welshpug 1,666]

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 1,666]

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 601]

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 Omega 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 honed in the block, ideally. Otherwise they will be oval.

 

Edited October 8, 2024 by petert

[petert 601]

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 1,666]

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

 

 

 

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

[welshpug 1,666]

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 601]

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"

[welshpug 1,666]

I do wonder if one of their typos led to the gti6 piston having such a large intruder

[petert 601]

Stage 2

this is such an open ended question and depends on how deep your pockets are.

 

Valves: the main reason for fitting oversize valves is to remove the gap/ridge from casting core shift, under the valve seat. The standard head does flow very well out of the box, but when you want more that's what's needed. Another issue with the oem valves is the multi-groove collets. The grooves wear over time, especially if thrashed and expand. If you try to remove a worn valve you'll destroy the valve guide. If the valves grooves are trashed, then the valve guides probably are too. A single collet groove is preferred. So then you need to find suitable valves. ie Ø35-36.5mm, 7mm x 104.5 long with a single collet groove for the inlet and Ø29.7-30mm, 7mm x 103 long with a single collet groove for the exhaust. In Australia, they don't exist. The easiest way forward is to use 4.6L DOHC Ford V8 valves, cut to length, reduce diameter of inlet,  machine a collet groove and re-harden the tip.

 

An alternative is to use RS500 Cosworth "long d*ck" valves with an open bucket. This is a lot better as you increase the bucket from Ø32 to Ø33, which repairs wear in the bucket bore.

 

Springs: only go to doubles if absolutely necessary. The cost involved of machining the spring base area for doubles will be substantial. It's far easier to stay with single Catcams PAC-S10011 springs and 99333 titanium retainers.

 

Cams: this is the least of your issues, as you need to sort out above first. You also need to make it all works together as a package. Cam choice will be based on compression ratio too, but ideally 11.5-12:1. An inlet profile of around 250º @ 0.050" and 0.430" of lift and 10º less on the exhaust is where you need to be. eg Catcams 4901552.

 

Ø48mm throttle bodies are fine on 2L. That's what I use. Make sure you add a cam sensor for improved low end response via sequential injection. Easiest way is to use an XU10J4 thermostat housing.

Edited October 8, 2024 by petert

[petert 601]

When researching for a place to build your head, ask if they have a "single point cnc seat cutting machine". Whilst expensive, these machines are vastly more accurate and faster in cutting seats and throat profiles, compared to old profile cutters.

 

 

[Fumanchu 2]

22 hours ago, petert said:

Springs: only go to doubles if absolutely necessary. The cost involved of machining the spring base area for doubles will be substantial. It's far easier to stay with single Catcams PAC-S10011 springs and 99333 titanium retainers.

 

Cams: this is the least of your issues, as you need to sort out above first. You also need to make it all works together as a package. Cam choice will be based on compression ratio too, but ideally 11.5-12:1. An inlet profile of around 250º @ 0.050" and 0.430" of lift and 10º less on the exhaust is where you need to be. eg Catcams 4901552.

@PeterT:

 

A few more questions:

1) What are the max rpm that the above Catcam springs can safely manage?

2) Do they fit in place of the std items, without machining

3) Can they handle Catcams 4901552 with the addition of solid lifters? 

Edited October 8, 2024 by Fumanchu

[petert 601]

4 hours ago, Fumanchu said:

@PeterT:

 

A few more questions:

1) What are the max rpm that the above Catcam springs can safely manage?

2) Do they fit in place of the std items, without machining

3) Can they handle Catcams 4901552 with the addition of solid lifters? 

1. 8000 with their titanium retainers

2. Yes. The 99333 retainers are really mandatory, otherwise you'll need too much shim to get the seat pressure correct. ie the PAC-S10011springs, whilst they do drop straight in, shouldn't be used with oem retainers unless you know what you're doing.

3. As per their website, pic attached

[Fumanchu 2]

Thanks everyone. 

 

Current engine build spec list:

 

Catcam Valve Springs (S10011)
Catcam Valve Spring Retainers (99333)
298° / 290° Catcam cams - 4901552
Catcam Vernier Pulleys - CTPE007
Solid Lifters
Westwood ductile steel liners - 83.5mm
Robson Engineering forged Connecting rods
Wossner 83.5mm forged pistons
Jenvey 45mm throttle bodies
ECUMaster Black ECU

No headwork apart from checking core head, valves and guides, renewing/refreshing where necessary.

 

How does the above look - overkill or underspecced? Any gotchas or gaps?

Edited October 18, 2024 by Fumanchu

[petert 601]

Perfect. Similar to Pug1off's build. Being a 2L with a bigger bore, it's always going to breathe better than an 83.5.

 

https://www.facebook.com/hashtag/205gti6

 

Don't forget to add the cam sensor. That's to improve driveability, not total hp.

 

You'll need new injectors.

[Fumanchu 2]

On the topic of a 2L engine, I was led to believe that the 85mm liners were inherently weaker due to less material. Has there been any reported failures of  engines with 85mm liners?

 

Also, which injectors would you recommend?

[petert 601]

I’ve only ever done 84mm with a standard liner. You’d need to speak with Westwood. I think the block needs modifying for there 85mm liner. When you start doing stuff like that, you may as well use a 2L block and go to 87mm.

 

In regards to injectors, there’s a few variables. E85 compatible? Full height or half height? What connector? Best talk with Jenvey about heights to begin with.

[welshpug 1,666]

we don't have E85 in the uk, Super unleaded 98/99 is E5  (at the most, some is zero),  boggo 95 is up to E10

[petert 601]

That's a shame. I guess not much of a sugar cane industry! The norm for a street legal turbos in Aus is now 800hp for a K24 and 1000hp for an R32/33, thanks to E85.

[petert 601]

You'll probably also need some 1mm spring shims, in order to get the seat pressure correct. Part number is 0951 31. I'd order them now. Standard is 0.5mm, so that will give you options of 0.5, 1.0 or 1.5mm.