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Andy

Yet another XU9/10 engine build

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Andy

I hesitate to begin this thread, not quite sure where it will lead, or quite what the cost might turn out to be, but the fun is in the journey ( so I am advised)

 As avid readers of this forum may know, I have rebuilt my 205gti from a bare shell and fitted a similarly rebuilt XU9J4 engine which, apart from bodies, an  Emerald, and a Miles Horne exhaust  manifold , is standard. And it all works very nicely thank you . But I think I can do better , hence the start of a new build thread. 

Better start with the background. I have three xu10j4 blocks, one of which is an RS. I have rods and pistons for all three blocks, and an assortment of sumps, oil pumps, windage trays , 52 link chains and 26 tooth sprockets . I also have an XU9J4 block, one Mi16 88mm stroke crank ( but no 86mm ones ) and one S16 Head, the latter becoming the start of the story . 

I do not have an RS head, but do not want one . ............. Pause for shouts of ‘ why not’ Answer, in two parts ( a) my wonderful Miles Horne  SS manifold fits the Mi16/S16 head but not the RS one and (b) I have  the S16 head and ,Petert stage 2 hydraulic cams 

 Bottom end wise, the head will fit either block. Sense and cost suggest the iron block, heart says the alloy one. Two minor considerations  centring  on the installation. If I use the iron block, the manifold will need re-angling ( read cut and re weld) and I will have to do something with the pedalbox,/master cylinder to give cambox cover clearance . If I use the ally block, one engine out, the other in .

 Against that , an 88mm crank in the iron block, with a rebore  to 87mm gives the 2.1 litre formula which is a known, tried and tested  route to good, reliable power and torque .  If I use the alloy block, 85mm liners are available as a one off purchase, but needs block machining to fit . Upside of that one is that an interference fit is possible doing away with the liner seals  and locks the liners in place.

Anyway, back to the plot . I have started work on the head. Guides are out and I have been busy simply cleaning the ports, removing the casting lines, smoothing out the very slight lip on the short radius in the exhaust port but being careful not to enlarge the ports at all , nor leaving a polished surface. ( 60 grit emery tape on the end of a slotted rod was the weapon of choice for most of the work so far. ) . 

I am under no illusions however. The impact on engine performance so far is roughly zero. The more important stuff is to come. The inlet valves need unshrouding and the machine shop (Stanwoods in Bawtry) will have their work cut out to give me the required 3 angle cut on the  inlet seats ( exhaust will be easier ) . They are confident they can do that and retain a seat width on the inlet of 1.6mm  but it might be necessary to increase the valve size to get the seat to work properly .  

Anyway, I have started , not quite sure where I will go with it yet, but it is fun!

 

 

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petert

Some facts that will help with your decisions:

 

1. I've never seen an Mi16 or S16 head that can take a full 3 angle cut, with a 1.6mm seat and a standard size valve.

2. An oversize inlet valve requires "eye browing" of the liner to make it unshroud and flow correctly. This can only be achieved with a copper head gasket.

3. An Mi16 head flows a lot better on an 86mm bore than it does on an 83mm bore. Free horsepower.

 

I thought you were doing the head with Guy?

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Andy

  Morning Peter,

 Thanks for that very helpful input. Yep. Off to see Guy next week with what I have done so far. He will probably get cross with me, tell me that I have wasted my time and then proceed to show how it should be done properly. Like you, his view on this head is that the ports require little work at all; the issues are all in the valve seat and transition into the combustion chamber . Method in my madness!! Take your point on the 3 angle inlet valve seat. I do not see how there can be enough room on the o.e valve  seat, but Guy will inspect . As for the liners, agree on 83mm but the 85mm ones I had looked at might be less of a problem. Remarkably the cost of these from Westwood is almost the same as their 83mm ones, but they are still not cheap at nearly £500 for a set . It is ‘this bit that makes to alloy block route more expensive. All the other costs are similar for both routes ( full balance, pistons, rods etc) which is why I have started with the head ( though this could get expensive too if I go down the solid lifter route ) . 

Oh. Thanks for the email. . I have replied in my usual verbose manner

Andy

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Andy

A couple more fairly irrelevant pictures  . This is not going to be a quick build. I fished out thenone Mi16 crank I have and found that (a) it has been ground already and (b) therefore, unless the journals are within spec, I am going to be a crank short. I do have access to a turbo diesel one , but have an unsubstantiated prejudice against them .

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Andy

Next port of call ( no pun intended) is the thoughts about valves. As the guides are out, there is an opportunity to replace them with gti6 ones ( assumumimg that the o.d is the same as the Mi16 ones) . The advantage is that I can then use valves with 6mm stems that  are lighter. Now comes a plan so cunning you could stick a tail on it and call it a weasel . For the inlet, use the inlet from the EW engine that is in the 206gti180. It has an almost identical stem length to the Mi16 valve and a diameter of 35.00mm which is a small but useful  increase( useful in the sense that it will help with the 3 angle valve seat cut) . For the exhaust, the gti6 one has the correct stem length and a diameter of 30.6 mm . Given that I want a 30mm throat cut for the exhaust, that too should do the job. And it also leaves open a choice of hydraulic or solid lifters, although the latter are looking tempting ( I know Peter , a set of your hydraulic cams are on my shelf, but maybe they may be of help to someone else if I go the solid route )

Right. What can possibly go wrong ( ie what have I missed)

 

 

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welshpug

I love my turbo diesel crank :D

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petert

You didn't like any of those Supertech valves? I think you'll find that you need 35.5mm in order to get the seat work perfect. Will you notice the difference however?

 

The forged turbo diesel crank is 4Kg lighter than Mi16. I use them in my race engines :)

 

85mm sounds like a good compromise.

 

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Andy

Hi. The 206gti 180 and the gti6 ones I looked at were Supertech, but in those apeugeot sizes. I will look again as an extra 0.5mm would help.

 

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Andy

Just read the 4kg bit. The one I have is from the XU9D I am sure it was only 1kg lighter than the Mi16 one. However, my real concern, obviously unfounded , is that with only 4 webs, and pretty industrial ones at at, it might be quite hard to ensure that the centre of mass is actually exactly on the crank axis . There is a risk that , if off axis, then the centre of mass orbits around the centre line . At high rpm, that could be a problem. However, given that you race using one of these, perhaps I had better shut up , get my coat, and retrieve my diesel crank from a shed in Portsmouth or get one from the Forum that is available 

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Andy

Welshpug. Morning. Just out of curiosity, why do you love your diesel crank?

 

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welshpug

I have a 92mm one, more cubes :D

 

The XUD9TE crank is fine for well past 8k, Colin satchell has one in his very high 200's bhp 1998 cc engine,  it is a different crank to the non turbo engine.

 

downside of the longer stroke crank is that it needs custom rods.

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Andy

Ah. If it is the 92mm I can see the real attraction. As I am sticking with 88mm then my first choice was going to be the Mi16 crank I have, provided the journals are good. That has to be my next job, but as my micrometer only goes to 25mm, I will wait until I visit Guy Croft later this week or early next.

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Kane

Has anyone ever witnessed an mi16 crank fail? Reason I ask is that the 88mm diesel crank has been talked up a lot on here over the years and although it has been proven to work in competition engines does it warrant the cost/effort to move away from the mi crank? If that 4kg weight difference is correct Peter then I guess it's a clear cut choice given the benefit of lightening the rotating assembly but for strength alone I am not so sure it is really required. 

 

I'm going to be following this with interest Andy as I aim to build an XU9J4 headed engine (based on a 205 block due to regulations) but am also deliberating whether a rebored iron block or alloy block with custom liners is the better option. Keep up the updates 

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welshpug

there is no additional work or cost involved in using the 88mm TD crank over the XU9 or XU9J4 crank.

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Kane

There is if you don't have a diesel crank. Like Andy, I have an Mi crank here which is thankfully in good condition and usable so to source a diesel one would attribute some cost and then there's the possibility of having it checked/reground if required. 

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wicked
1 hour ago, welshpug said:

there is no additional work or cost involved in using the 88mm TD crank over the XU9 or XU9J4 crank.

And the later 2.0 HDI crank (88mm as well)?

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Andy

Recently I was building an XU9J4 engine for a friend. ( now complete ) He had a good Mi16 crank and an Xu9D crank which, initially, he was keen to use . Snag was that when dropped into the alloy block, some work was needed on the crank web to clear one end of the block, and the thrust washers were not playing ball, with an option of doing a bit of machining on the crank to get it all to work. In other words, to get the diesel crank to fit was not quite a drop in job. At this point, friend decided ( rightly in my view) to use the Mi16 crank. Hence my comment about having access to a diesel crank , albeit in Portsmouth and potentially costing me both postage and the crank itself. . 

Having just looked in detail at my Mi crank  and borrowing my neighbours 50mm micrometer, the big ends are all fine (49.7mm ) . I could not measure the mains but one of them has a light score mark running circumferentially for about 30mm . I think I need a crank . **gg** 

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Andy

Oh. Liner update. Westwood will make me a set of 85.00mm liners . Wait time is 6 weeks after order. Not asimple drop in as per o.e, so some engineering cost if I go this way. However, I could end up with bonded in liners, no liner seal issues , deck height and liner protrusion machined in situ and easier to build as no liner clamping to worry about. Downside is expense and iron block easier way to even more power, but I have already discussed that dilemma above 

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welshpug

thats odd, I have an XUD9TE crank in an alloy block awaiting an engine build and it spins nicely, I did even try the XUD11 crank and that only just rubbed, a little work and it would turn fine.

 

thrust washers werent a problem.

 

49.7mm means ita had one grind already, on the big ends at least.

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Andy

Evening Mei. Yep. Crank has already been ground. Hence my concern unless 0.5mm underside are available . The diesel crank was odd. The web nearest the water pump end just rubbed . As for thrust washers the diesel ones have tangs on them as they are for the iron block, and the xu9 ones were too thick. Easy to remedy with some machining on the thrust face of the crank, but a snag nevertheless . So what thrust washers have you used, he asked ? 

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welshpug

i think diesel big ends come in a 0.50 oversize buy you will need to check the location of the tang.

 

just standard thrust washers, theres a few variances.

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Andy

 

Phew. Just checked and it seems that 0.5 mm undersize bearing are available ( King) so if the mains do need a regrind it looks like I can get shellsI feel better already 

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Andy

Ah. Perhaps I did not try hard enough with the thrusts and the diesel crank then. The new set I had were a good0.5mm too thick. Absolutely fine when I used them on the mi crank though .

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Andy

 Next question. I would quite like, to fit an oil filler onto the Mi16 cam cover that I have on my bench. It says ‘magnesium ‘ on it and when I took it to two different places today to ask about tig welding the threaded oil filler tube that I have , both said that tig welding onto magnesium was not going to happen. I guess that the later s16 cover that is on the engine in my car is Aluminium so would not have the same issues , but wondered if anyone on here had managed to do such a mod on the Mi16 cover? I had thought about chemical metal as an option 

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