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mrmarcos

1600 MI16

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mrmarcos

Hi guys,

 

I know this subject has been talked about a few times but hear me out please. My 205 1.6gti drives like a dream. However I have a few 1.6 gti engines and a mi16 head laying around. I have build other engines in the past ranging from forf essex, essex turbo, K series, mini engines etc. I like a challenge. 

 

I want to retain my xu5 1.6 block as I really like short stroke oversquare engines. 

 

I found a few topics about it mainly the one from "Renault 17" was good info. I know I need an extra cambelt roller which I am not seeing any trouble. The things I didn't find exact data on where the pistons, rods and head combo. The pistons on an 1.6 8V only have a very small reases and are straight with the liners at tdc. I read stories about skimming blocks and liners to get the correct compression.

 

who can tell me more? And please don't start in s16 engines or 1.9 mi16's. I know it is noy easy but thats no issue. 

 

Many thanks already! 

066A639E-96FC-45B1-98DE-BF5A9E71C613.jpeg

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Tom Fenton

I’ve pondered this occasionally but never really looked into it. I think you’d definitely need to use the mi16 piston for the necessary valve reliefs. To then get the compression high enough due to the shorter stroke you would need to see how much could come off the head and how much you could deck the liners and block. There would also I think be work to do to the 1600 rods to accept the mi16 pistons.

Look forward to how you get on. However I will say that it would have to be a labour of love for a road car, for motorsport to fit into a class I get how you could justify the spend. For a road car just for fun you could be into a lot of money on machining to make probably less power than a standard mi16 will.

Having said all that I liked my 1600 engine too so I turbocharged mine, just over 200bhp.

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welshpug

the 1.6 rods would need to be narrowed and bushed on the small end, Mi pistons will give ok compression for a mild road engine but like Tom said due to the smaller capacity its harder to bump it up with standard parts.

 

a later xu head would make it easier, smaller chamber, better oil returns/less holding capacity breathing etc, if you use the xu7 block then theres off the shelf timing belt kits, standard timing covers fit etc, and a higher chance the block isnt rotten and cracks when you tighten the head bolts

 

the crank seems good for the revs needed, I know sandy has built an Ew5 engine that went to 8k, though that bottom end is much much stiffer.

 

I've probably got almost all the base parts myself to build one of these too :lol:

 

realistically you need some rods and pistons made to suit or at least adapted to get a decent compression figure, also going this was whilst costly in parts means if you get it right a lot less machine time

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petert

The large XU9J4 chamber and flat top Mi16 piston doesn't give enough CR. Just do the maths using an on-line calculator, pockets -4cc, chamber 41cc. I like the idea of using an XU10J4R or RS head, with its smaller chamber. Some quick calcs suggest around 10.4:1. You could improve that with a thinner Cometic gasket. If that works with an Mi16 piston, you'll still need a custom rod.

Edited by petert

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mrmarcos

Thanks for all the replies now. Machining block etc is no issue. At work the guys in the shop could easily do this for me. Custom rods I will need to buy and pistons as well. If the pistons need to be made from scratch why not go for a D-top type piston which ups the compression. Is it strictly necessarily to start from scratch with the rods? What mods are needed to accept mi16 pistons if they would be used? Making the rod a little smaller so the pistons becomes centered on the rod is no issue. On the other hands if I opt for fully custom pistons there won't be any custom rods needed. Will try to put the head on this week and take some measurement. The block itself does not have any corrosion issues. 

 

But the 10.4:1 compression ratio is no issue for me as it is a road engine. It does not need to produce huge numbers. I want to get easier power by have a better breathing head. As I have the head, blocks, cranks etc I will put a dry build together to see how it all goes. All data is welcome on this subject. 

 

As Tom says, it is indeed a labour of love but I like a challenge. I also have a few 1.6 heads and a 1.9 head laying around if it really does not work. I have another car (not peugeot) which has a 310 duration cam in it. Really nice to drive fast but not so practical. To have the 8v head produce some extra power you are looking into quite a wild came. I love driving the 205 and if I can hold on to the rev happy 1.6 combined with a better breathing head it would for me be the ultimate engine in my 205. 

 

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welshpug

10.4 is not high, thats standard mi16, given the standard of fuel is pretty decent in the uk you can easily run a bit more which will only benefit you.

 

you can use the xu5/7 rods with the small end narrowed, they do need bushing as well for an Mi16 piston as they are circlipped in place, not a shrink fit like xu5/7.

Edited by welshpug

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Biggles

This is actually where my EW5 started - a friend of a friend built a 1600 Mi16 and I thought that's what I was looking for (it was for competition and I was aiming at the up to 1600 class).  It evolved into using the EW as a base rather than the Mi16.  And a truly awesome engine it is too.

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petert

I doubt there's enough "meat" on the pin end of an XU5 rod to bush it to Ø22 full floating. Thus why you need a custom rod, with a 1.6 big end and an Mi16 little end. Whether you make them piston or crank centred, doesn't really matter.

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Thijs_Rallye
15 hours ago, mrmarcos said:

The block itself does not have any corrosion issues

  

That you only know for sure as soon as the cylinder liners are out ;).

 

Peter Vingerhoets has driven RX for many years with a 1.6 XU engine and Mi16 head. (Super1600 class)

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welshpug

DSC_1062.jpg

 

afraid Peter might be right, thats an xu5/7 rod i have.

 

so you'll need a rod around 150mm that is bushed and to suit a 45mm big end, I think ive found one that is close

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mrmarcos
On 2/10/2020 at 7:29 AM, Thijs_Rallye said:

 

On 2/9/2020 at 4:14 PM, mrmarcos said:

The block itself does not have any corrosion issues

  

That you only know for sure as soon as the cylinder liners are out ;).

 

The block is complete bare for weeks. No corrosion whatsoever ;).

 

Would he have details from what he has done to get it to work? 

 

On 2/10/2020 at 5:21 PM, welshpug said:

o you'll need a rod around 150mm that is bushed and to suit a 45mm big end, I think ive found one that is close

Could you please share what you have found? 

 

Custom rode with mi pustons is not a bad idea. Or custom pistons to go on the xu rods. This opens the option to design a D top piston which ups the compression. Pocketing 8v pistons does no work I think as they are thin to begin with. 

 

I have an mi head now so that is a start. 

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welshpug

I did a few quick calculations and even for a mild road engine the positive dome needs to be a fair size especially with the mi16 head, personally I'd be inclined to use the later head as the chamber is smaller.

 

also use a longer rod to push the piston up further if you start with an mi16 piston, as a standard mi16 one will sit 0.88mm under deck, giving about 8.6-1.

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SRDT

The XU7JP4 and XU10J4R use the same valves (34.6 in, 29.6 ex) and even with a 10.4:1 CR the XU7JP4 pistons are dished not flat. It may not be as good as a Mi16 or RS head but you can probably find a cheap one.

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petert

An XU10J4R head is identical to an Mi16 head, in terms of valve diameter and ports. They’re a good thing, except for the valve springs and cams.

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