Xu9j4 Rebuild With 8v Crank And Rods

[unariciflocos 49 1 Cars]

I think a better approach would be to machine the liner seats, but that would make honing the liner a must as the lip would move down and upset the new rings. I chose not to hone my liners because the lip is barely noticeable and I don't want to risk ruining the liners. (I may have ruined them by not decking them properly, but I'm hoping for the best)

Edited June 10, 2010 by unariciflocos

[petert 607]

My friend who did liner decking for me, Owen Wuillemin, passed away recently, after loosing a battle with cancer. He made a mandrel which held a liner on axis in the lathe, then faced the liners to length, after decking the block first. The length is determined after decking block. This is done by my head guru on a Bridgeport mill with a large. multi-tip facing cutter, as you'd face a cylinder head. I noticed in your picture that you'd used a relatively small diameter milling cutter. This is fine provided the machine is rigid and the cutter doesn't leave a mark.

 

Once the block is decked you need to establish the amount to be removed from the liners. I ALWAYS grit blast the liner seat areas first to ensure the liners seat properly. There can be half to one thou variation in the liner seat axis (is that the word?), as the seats "sink" over time. So it pays to check the liner protrusion on BOTH sides to ensure the liner top is parallel with the block.

 

It's a fiddly job to do correctly but definitely worth the results. Even when fitting new forged pistons, I still deck the liners/block to obtain zero deck height, then remove unwanted material from the dome.

[matthewm 1]

Started on this yesterday, have machined the 16v pistons to match the size of 8v ones, and what I'm wondering is the reasoning of using the 16v pins opposed to the 8v pins?

The 16v are obviously lighter, although when they 'float' the surface contact with the piston is minimised, where as using the longer 8v pin makes it more like the standard design.

 

Also just realised I didn't mark the rod to piston orientation, is the correct way as in 'unarcifolocs' diagram with 'a' being the tag?

 

One more thing, does anyone know the reason why the arrow and the letters 'DIST' point towards the belt end? Is it that the word distributor has been lost in translation?

[welshpug 1,675]

dist = distribution, = timing belt side.

[unariciflocos 49 1 Cars]

IIRC I used the 16v pins, because the 8v ones were fubar. I'm sure I mentioned it somewhere here in the thread but can't be bothered to search now.

 

Pic I posted of the piston is from the xu9j4 rebuild manual in M@tts' signature so I would assume it's correct.

 

The tags of the rods are to the back of the block and the arrow on the piston points to the timing belt side.

 

Does anyone know where I can find shells? They are no longer available in Romania... well I can find King shells but at 10 quid a set I have zero faith in their quality.

[matthewm 1]

Smashing - guessed it went something along those lines welshpug - caused me a little head scratching mind!

 

I'll pm you tomorrow with the price and make of what shells I get mate, then can sort out posting a set over if your interested...

[unariciflocos 49 1 Cars]

Would be forever in your debt

[mmt 15]

Hi,

 

Very nice work. Hope you will get it running and be able to abuse it without surge problems.

 

Why do yoy deck the block and liners?

 

Is the mi16 and the 8v rods not the same length?

[unariciflocos 49 1 Cars]

The block and liners are decked to increase the static compression ratio as per Peters' instructions http://www.taylor-eng.com/xu9j4/16v_compression.htm I've calculated the compression now to be 11:1, but my calculations may be flawed... The Mi16 head can't be skimmed to increase compression because the valve seats are very close to the surface.

 

16v and 8v rods are the same length, yes.

 

It's very difficult to source parts because I can't get ANY of them from where I live and paying 20 30 quid shipping for the most insignificant bits and bobs adds up. Car is being sprayed and I'm also working on finishing the house so that I can move before winter starts, so it looks like it will be a while before I race it again.

Edited July 18, 2010 by unariciflocos

[mmt 15]

Sounds like you chasing POWER!

 

How much horse power you expect the higher compression ration will make?

 

I´ve got a similar engine with the same kind of rod set up. Pure racecar on sticky Yokohama slicks. ...no surge so far.

Very much worth the effort.

 

Keep posting pictures.

[welshpug 1,675]

you will have surge, it just hasn't caused any issues yet.

[unariciflocos 49 1 Cars]

I want to build a strong healthy and reliable engine. I use the car for hillclimb rallying, but I also drive it to the office from time to time. I usually find myself getting out of the car with my feet numb, adrenaline pumping and walking around the office with a Cheshire cat grin on my face for a good 30 minutes and my coworkers asking me if I'm ok. Damn I miss driving it .

 

I have a set of GSXR 750 bodies that will be welded to a cut down Mi manifold and will be purchasing a Vems ECU with wideband lambda. A lot of people will frown on both of these, but Sandy uses bike bodies for his race engines and Eric Yellow uses Vems on his 466bhp S16 turbo so I'm confident that with enough attention to detail these will work.

 

I expect to have the engine running by October, but will keep everyone posted. I also have a pts style baffle in the post that in addition to the 8v rods, extended pickup, 26tooth sprocket and chain I expect to help with the surge.

 

But then again, this being my first engine build, I may c*ck everything up.

Edited July 19, 2010 by unariciflocos