grim outlook for the GT

[mnde]

To the OP: Any chance of putting a little vid on Youtube so we can hear the rattle. I'm curious, as my XU5 engine isn't the quietest compared to others I've driven either.

Thanks,

Mark.

[frog]

How did that work then?

Because in UK the 1905cc multipoint fuel injected engine (that you would typically find on a BX TRi/Tzi estate) has an inlet manifold porting arrangement on the cylinder head which is not compatible with the inlet manifold from a 1.6 or 1.9 Carburated engine.

Hi Kevin, my brother originally did the engine conversion but as far as I can remember we had no issues with regards to mating the Carbureted inlet manifold to the late 1.9 (DKZ/XU9JAZ) head from the TRi 122/TZi. I will check with him and get back to this if he remembers otherwise.

When we bought the GT it had a DFZ/XU9J1 Block in it, presumably from an Australian delivered TRi. I think that a previous owner had put the standard 19GT head, inlet and exhaust manifolds on it. We later changed this for the late model DKZ/XU9JAZ head from an Australian delivered TRi 122.

Also I am interested to know what you had to do to raise the compression ratio from the standard 9.2:1, to 10.5:1 (which is in excess of the 16v D6c engine which has a CR of 10.4:1).

From what I understand the Head of the early 1.9 motor found in the Tri (DFZ/XU9J1), has a larger combustion chamber of 49cc than the later 1.9 motor found in the Tri 122/Tzi (DKZ/XU9JAZ) which is 34cc.
The dish in the pistons of the early motor (DFZ/XU9J1) is also smaller than that of the late motor (DKZ/XU9JAZ). The blocks are the same.

So combining the later DKZ/XU9JAZ head that has the smaller combustion chamber and the early DFZ/XU9J1 pistons that have less dish offers a much improved compression ratio.

In my car I had this DKZ/DFZ set up. The head had also had about .2 of a mm shaved off of it, and at one stage my brother was using a .5mm copper head gasket which is about 1mm smaller than standard. This gave it a CR of closer to 11:1, though with the normal gasket as it is now it's around 10.5:1. This CR was taken advantage of with a cam that had a much higher lift than standard, and an adjustable cam sprocket.

Engine particulars for the BX TRi estate:

Cylinders: 4
Valves per cylinder: 2
Capacity: 1905 cm3
Bore x stroke: 83,0 x 88,0 mm
Compression: 9,2:1
Max power: 90 kW (122 hp)
Max power RPM: 6000 rpm
Max torque: 150 Nm
Max torque RPM: 3000 rpm
Fuel system: multipoint injection
Engine type: sohc

This would seem to be the TRi 122 with the later model 1.9, hence the 122 hp.

I hope I've made sense.

Cheers,
Chris.

[B-Hive]

To the OP: Any chance of putting a little vid on Youtube so we can hear the rattle. I'm curious, as my XU5 engine isn't the quietest compared to others I've driven either.

Thanks,

Mark.

I dont think the sound quality on you tube would really do the din any justice.. Like most things though I let the problem rest for a day or so and re-approached with fresh ears.

I realised that if it was a big end issue there would be also low oil pressure, especially on cold start which is NOT the case. So I listened again. On idle its a bit tappety (which I always realised) but give it more revs and the rattle goes very thrashy. (a much "faster" noise than if it was one or even 2 worn big ends). I'd almost expect to see rocker arms under the cam cover, so thoughts have come full circle back to the head/valve gear.

I am aware that the pug lump is not the quietest of power plants, however the TRi I just bought is so much more refined, and it has basically the same heart. So this is the bench mark. Admittedly, being a GT the valves in the head may be bigger and its general breathing may be more raw. Are you aware of internal differences with the GT/GTi 8 valve motors compared to say the TRi or TRS? I posed this before but thus far no one has pitched a reply.

Also does the valve gear fail catastrophically or does it just get noisier? because I could live with that. How can I determine the level of wear of the camshaft bearings? The bearing surfaces are machined in and generally look okay on the caps but what I'm thinking is "a little worn" may be actually "well worn".

[mnde]

Well look, here's mine as I'd uploaded it anyway.





It's done about 34K miles like this under my ownership...

It's relatively quiet at idle, but yes, give it more revs and the rattle becomes more thrashy (say around 1800 rpm), seeming to peak at certain revolutions, or pulses in and out (louder and softer) - with the pulses of inconsistent duration. It seems to have "quieter days" and "louder days"

I'd love to know exactly where it's coming from. I've done some listening with a screwdriver placed against different points, but this has been inconclusive.

All I know is:

In previous ownership (late 90s or early 00s 0 - can't remember) it had cambelt failure and all the valves and engine seals (inc stem seals) were replaced by the servicing Citroen dealership. I assume this was the last time the valve clearances were done.

I had the cambelt replaced (again) in 2006, and the garage did not replace the tensioner. I was told there was no need as it was "ok".

I've been meaning to have a tweak with the timing and check the operation of the vacuum advance, wondering if this had any influence on engine smoothness.

EDIT: Similarly, my friend Chris gave me a lift in his 16TXi at the weekend and this was far more refined in comparison. I've also been meaning to check whether the clutch cable grommet in the bulkhead is missing and I'm hearing more engine noise than I should be! I realise mine doesn't have quite the same engine as in your GT, but thought my videos might give an interesting comparison... Mark.

[MULLEY]

From memory that sounds louder than my 8v Gti, but thats a slightly different engine even if the displacement is the same. Does it appear to give decent performance? Would worn engine mounts cause it to have an oscillation sound at certain revs?

[mnde]

Yeah, engine mounts is something I hadn't considered before... funnily enough I read this as a potential cause of rattly noises last night.

The engine gives decent performance except that there has always been a pronounced flat spot on hard acceleration. It's fine if I drive it economically ... also it has little power low down in 2nd gear. Squirting into a quick gap onto a roundabout is impossible unless I change down to 1st first. It struggles up steep 2nd gear hills as well. If I lose momentum and press the accelerator further, there is a flat spot and the threat of stalling. I don't know if this is accelerator pump, mixture, timing, vacuum advance, wear/coking or what...

What's yours like performance-wise 2BXORNOT2BX?

Mark.

[Tim Leech]

Strange, I find my 16 to go well, its a bit gutless at very low revs but happily sits on the Motorway at 70-80 and if you use all the rev range its impressive. The 19GT reallly does fly cosidering its 105bhp and is very torquey in all gears.

[B-Hive]

What's yours like performance-wise 2BXORNOT2BX?

Mark.

Well topical question..I have only driven the GT about 10km and that was on its trip home from its previous owner. So I wasn't really testing it out as I was more concerned keeping a watchful eye and ear on things..That said I was still impressed at how well it pulled, and I've been looking forward to getting it registered (MOT equivalent), and giving it a bit more.

I will be keen to see how the GT stacks up against the TRi which I took delivery of today. That was a 300km drive home, and wow I am so impressed at how well it goes and infinitely more drivable than the TRS auto 1.6 it is.. The injection really make such a difference and it is so responsive and torquey. Even with significant ascents, I never had to drop it back out of 5th, just a little extra squirt and it climbed effortlessly...As its has a rebuilt head with the non-taper sparks plugs, it may well have a hi-performance/bigger valve head!!!

So yes.. As much as its going to be much less refined (especially with all this engine din) I'm keen to see how the GT compares..As it is meant to have quite a bit more torque than the TRi.

[MULLEY]

I think the injected motors are quite a bit nicer performance wise than the carb models, i think its approx 20bhp in the 1.9's which in a light bx is quite a lot more

[B-Hive]

I have seen the light..

As much as the "new" Tri spoils me with how good a BX can be, its the aesthetic and character of both my mk1's that has steered me towards keeping both as well..so yes thats 3 BX's...ALL entirely different in their own ways.

So the GT will have to wait for donor bits from a true write off..as I cant break such a mechanically well sorted car as the TRi...sure the body is tatty but straight and rust free...i just have to pretend that the cars parts are not interchangeable. just have to wait for a head??, HP pump and clutch kit. (all of which are perfect in the TRi that was intended as parts donor)...its a disease I think!!!...

Another thought about the general engine clatter...has any one experienced noise from the oil pump chain..Thinking it may be transmitting clatter up to the top of the engine...or are these chains robust?

[djm666]

i have never heard of chains going before, they are fairly robust, and i have had petrol bx's with 300000miles on the clock and have no oil in the engine and they dont make noise.
sounds like it may have spun a shell??

to find out pull the engine out. i did mine the other day now on the rebuild, waiting for a clutch kit the only thing holding me back.