16v Heads

[jackherer 543]

Which Mi16 engine is in the citroes BX19? Assuming the 19 means 1.9? If that's so where was the 2.0 version used?

 

1.9 was the largest engine in the BX.

[petert 550]

XU10J4 compression height - 39.1mm

[Pug_101 0]

XU10J4 compression height - 39.1mm

 

 

Thanks peter.

Is this centre of pin to crown? If so the pistons I have got are about 28mm.

[petert 550]

Is this centre of pin to crown?

 

Yes. As I said earlier, I'd opt. for the std. pistons. They're a bit heavier than the 1.9L piston, but they wear extremely well. The set I measured have done 160000Km and they're in excellent condition.

[B1ack_Mi16 67]

If so the pistons I have got are about 28mm.

 

Center of pin to crown is correct, and my XU10J4R (136bhp) pistons had pin height about 28-30mm somewhere, and used 160mm long rods compared to the std. 152mm usually found in the XU10 engines.

 

Maybe your's from an J4R too as the valve pockets looked a little bit small for a Gti6, at least compared to a Mi16.

 

My XU10J4R pistons looked different again, but my engine was a very early version and had oil-squirters, different from the newer J4R engines that doesn't have it.

[Pug_101 0]

Center of pin to crown is correct, and my XU10J4R (136bhp) pistons had pin height about 28-30mm somewhere, and used 160mm long rods compared to the std. 152mm usually found in the XU10 engines.

 

Maybe your's from an J4R too as the valve pockets looked a little bit small for a Gti6, at least compared to a Mi16.

 

My XU10J4R pistons looked different again, but my engine was a very early version and had oil-squirters, different from the newer J4R engines that doesn't have it.

 

 

The pistons above are found in V 8's, Mahle made.

Haven't got the car yet so not sure what spec the engine is, oil sqirters, con rods etc, but it's a 94 model so I may get lucky with the squirters.

Cheers

[24seven 104]

As a general rule post 1993 year cars are 2.0L as this is when catalysts were fitted.

I don't know what year the BX stopped production, but the 405 is fitted with both engines, pre 93=1.9L, post 93=2.0L. It should be the same for Citroens. I've got a 94 2.0L ZX and they were available with the 1.9L as well and I think the ZX replaced the BX so all 16V BX's should be 1.9L if original.

Cheers

 

 

Ahh gotcha. so was that meant to compensate for the power loss by the cat?

[Pug_101 0]

Ahh gotcha. so was that meant to compensate for the power loss by the cat?

 

Don't know. Maybe, but alot of money designing a new engine just for that.

 

 

I been thinking on my 16V project (bad idea ). I am getting the later engine management system (no dizzy or AFM) to use on the 8V I currently have. Will this work on the 16V engine??

I think it would as the 1.9L can be converted to 16V with a head and piston swap therefore the firing order, timing and fuel injection must be the same. I am not sure if the 2.0L would be quite the same but my thinking was that the 16V could be put into the car with this later management system. At least untill I fit a Megasquirt.

What do you think.

[Pug_101 0]

Found out about using Motronic 3.1 with a 16V engine and it would need remapping as the ignition curve is too far advanced. Thought I'd post that for future reference/search.

 

The Head I posted pictures on earlier in this thread does not seem compatable with a XU block. If it's the 1.8 16V found in 406's would this be correct, or could it be from a 206 GTi engine which is not the XU engine.

 

Intake and exhaust on correct sides of engine for a XU.

Head has a 10 cast into it on the dizzy end

Bore is around 83mm

 

So has anyone got any ideas on what it could be from.

Thanks

[petert 550]

It's definitely an XU head. Either an early XU10J4R (because of the veniers) or an XU10J4RS. How can you tell what bore it is? The gasket line looks like its a few mm outside the chamber. Take a look down the inlet ports. If it has wasted stem valves it's an XU10J4RS. The XU10J4R was fitted to 2L 306 and early 2L 406 models.

[Sandy 189]

It's not an RS head, there's no orifice for the vacuum pump on the "dizzy end" or spray bars as mentioned before. 83mm bore would be consistent with it being an XU7J4 head. I've had a couple of these recently, one of which I had reworked to a very nice inlet port shape, it's going on a 2.1 iron block pretty soon, so hopefully have some interesting results.

[Pug_101 0]

The 1.9 and 2.0 heads are very similar. 7mm valve stems, 34.6mm inlet valves and 29.6mm exhaust ones.

 

The Gti-6 is quite different with 6mm valve stems, 34.1mm inlets and 30.6mm exhausts. I prefer the larger inlet and smaller exhaust valves of the other heads.

 

 

It's definitely an XU head. Either an early XU10J4R (because of the veniers) or an XU10J4RS. How can you tell what bore it is? The gasket line looks like its a few mm outside the chamber. Take a look down the inlet ports. If it has wasted stem valves it's an XU10J4RS. The XU10J4R was fitted to 2L 306 and early 2L 406 models.

 

 

It's not an RS head, there's no orifice for the vacuum pump on the "dizzy end" or spray bars as mentioned before. 83mm bore would be consistent with it being an XU7J4 head. I've had a couple of these recently, one of which I had reworked to a very nice inlet port shape, it's going on a 2.1 iron block pretty soon, so hopefully have some interesting results.

 

I do not think this head is a GTi6 head (thats XU10J4RS right) because of the following, There is no spray bar, no cam sensor and does not have "RS" cast or stamped on it and i don't think the valves are wasted.

Now I have my verniers back I have taken measurements of the valves and got the following:

Intake 34.6mm

Exhaust 29.6mm

Or close enough, Therefore from PunaRacing's post this is 2.0L 16V head (thats XU10J4R right) and a early one from petert's post because of the vernier pulleys.

Buit that makes it 86mm bore so I might be wronge on that as petert points out it hard to tell for sure.

 

Does the 1.8L 16V head (thats XU7J4 right) have the same size valves as the 2.0L 16V version?

 

Is the original Mi16 1.9L the only head with 8 exhaust ports?

Edited July 18, 2006 by Pug_101

[Hilgie 16 2 Cars]

Is the original Mi16 1.9L the only head with 8 exhaust ports?

 

No...the 2.0Mi16 (or S16) has them too.

[16v205 9]

Bit of a thread hijack im afraid, Pug_101 is there any chance you can tell me how the cams get lubricated in that head of yours? I possible need to remove the spray bars on my gti-6 head and would be interested to see how yours works.

 

Btw as youve guessed already its not a gti-6 head, Ive got pictures of mine if you want to see the differences.

 

Cheers

Rich

[Pug_101 0]

No...the 2.0Mi16 (or S16) has them too.

 

Can't be one of those then

 

Bit of a thread hijack im afraid, Pug_101 is there any chance you can tell me how the cams get lubricated in that head of yours? I possible need to remove the spray bars on my gti-6 head and would be interested to see how yours works.

 

Btw as youve guessed already its not a gti-6 head, Ive got pictures of mine if you want to see the differences.

 

Cheers

Rich

 

 

Rich the journals are oiled by the small hole behind the larger hole (photo 1) and I believe the overflow from the journals then drains into a well/bath either side of the journal which the lobe travels though (photo 2, the lobe can just be made out to the right of the photo) and the tappet sits in this bath. The head does have two holes between each set of cam cap bolts of which only one is threaded, it may be possible these could be used for a spray bar, but the untreaded hole is sealed.

If you could post some photos that would be great or send them to me and I'll host them for you. I would like photo of the spray bar connections on the cam cap as well please to see if they are as above.

Thanks

 

photo 1

 

photo 2

 

GTi6 head ie XU10J4RS

2.0L 16V (S16) head XU10J4R

[16v205 9]

Hi mate,

 

Thanks very much for the pics and the reply.

 

Ive taken a pic of the oil spray bar and the cam caps as such. Ive lifted the spray bar out of the cap so you can see where it locates. Feed is the bearing cap closest to the timing belt. There is only one piece of ali material that bolts down over the whole cam. Went to take another pic and the battery went dead Ill take some more in 2 1/2 hours

 

 

Rich

[Sandy 189]

The XU7J4 head has the same valve sizes as the 2 litre 406 one. It's an XU7J4 head, quit guessing!!

[Pug_101 0]

The XU7J4 head has the same valve sizes as the 2 litre 406 one. It's an XU7J4 head, quit guessing!!

 

Yep think your right. How do you rate it against the other heads?

Take it from your other post the exhaust wouldn't need much if any work to it.

I have since starting this thread decided having a 1.9L Mi16 unit and have the matching head, would the XU7J4 be better than the Mi head and/or easier to take up to stage 1 tuning.

I guess the 1.8L cams aren't the best so what cam type fits GTi6?

Sorry for all the questions, just want the best I can get.

Thanks all for replying guess i've learnt something new.

 

Thanks Rich the design is a bit different., although the head overall is quite similar. This one also has a one piece cam cover, Seen your thread about the spray bars I wonder if using this type of cam cap would help you.

Cheers

[Sandy 189]

As a standard head it's nothing special, but the choked inlet ports have plenty material for re-working. Mark shillaber did the one I had and he said it's preferable to the Mi head for a porting job, especially for 1.8 or 1.9 engines, simply because there's more material to work with. The finished article really is nice, but I expect nothing less of him!

 

The 1.8 engine itself is a bit of an unmined gem, virtually a race engine as it comes, regarding the bore/stroke/rod dimensions, short pistons, relatively large valve sizes. Mark built one a couple years ago for sprints, that's pumping 240bhp and sounds like it revs into eternity!

 

I've just been measuring the GTi-6 cams, they have less duration than Mi ones, but more lift. they should (theoretically) yeild a wider torque spread than Mi ones, potentially with a lower peak.

 

The Chamber volume in the 1.8 head could work well on an Mi;)

[Pug_101 0]

I was under the impression that Mi & GTi6 cams could not be swapped over.

 

I like the idea of getting more torque from my engine rather than total power and I am thinking of throttle bodies (probablly bike ones) to help with this. Just doing some porting to the intake sounds like a good (and cheaper) way to achieve some good benfits without incuring big bills.

[Sandy 189]

I was under the impression that Mi & GTi6 cams could not be swapped over.

They can't, I was just comparing the profiles.

 

I'm currently building for my 309:

Mi16 bottom end with 1.8 trapdoor sump and ARP bolts,

GTi-6 head, unmodified,

GTi-6 cams, but the timing will be altered,

GTi-6 tubular exhaust manifold onto standard 309 system,

45mm TB's, custom set up that me and Colin Satchell have been working on, allows more length than Jenvey etc manifolds.

 

You might want to wait and see what the results are like before you decide which way you're going?

Edited July 19, 2006 by sandy309

[Pug_101 0]

Yes I will be very interested in what this achieves.

I expect my bottom end will be now be standard with ARP bolts although have yet to get a crank (maybe diesel?).

[Sandy 189]

After a few un-anticipated hiccups with the parts I had, (valves thought to be straight, but weren't; arp bolt thread letting go before reaching spec torque :mad: and other niggles) this engine won't be built for a while. I'm putting a 1.8 16v on bodies in for now as times is getting away from me.

[mos 1]

hi,

 

can i hijack this and just ask does anyone know what the differences between the 2.0lt s16/mi16 and the gti6 engine are that make it produce more power.

i am just curious really i am putting a s16 lump in my 205 that i have sourced through someone over on the psooc forum and the majority of opinions, particularly the engine builders(pumaracing) on here seem to favour the mi16/s16 over the gti6.

i have done numerous searches etc but cant find the complete answer

puma racing thinks the s16/mi16 is the better head particulary for modification purposes but this is the lower powered of the two engines.

the things that spring to mind to give the gti6 that extra bit are

1) camshafts (someone has stated in this thread that the cams on the gti should produce more low down torque after measuring them)

2) the gti 6 has better gas flow from standard

3) the compression ratio

4)pistons/conrods/crank

5)the inlet or even possibly the exhaust manifold

 

having never seen any of these engines in the flesh i have no idea how they look/comparefrom personal observations and i can only go off the advice of overs and this forum etc

but that is why i am asking.

there must be quite a few people out there like me considering 16v conversions but no idea which route to take and hopefully if someone can answer this question it will help a lot of future converters.

as the gti6's get cheaper and more plentyful it maybe that the s16/mi16 start to command a premium as they get scarcer and actual cost more the gti6 kit if they are the better choice.

 

thanks

 

mark

[Sandy 189]

The Gti6 engine is much better than alot of "experts" give credit I think. There are limitations such as peak lift being limited by the standard spring stack height, and lobe clearance. The inlet valve sizes aren't the compromise some people say they are, they're as good as the same size [as Mi16 etc] and the exhaust valves are slightly larger. Decking the block down will produce an easy CR increase as long as the valve pockets are relieved in the pistons for clearance and the bottom end is generally the highest OE spec available. The standard exhaust manifold doesn't seem to be a limiting factor and offers a decent fit in the 205/309, it can easily be converted to 4-2-1 as well. With a decent TB set up I think you'd see a better spread of power than a similarly installed Mi or S16. Try it!