TZD Turbo 1.8TD XUD7TE camshaft options

assembled · Post by **assembled** » Mon Jul 28, 2014 2:48 pm

Hello, I am overhauling my TZD Turbo and have come up to choosing a better camshaft.
Options with high pressure pump drive on the other end I have:

XUD7TE original
Intake opens: 4°30' BTDC
Intake closes: 20°30' ABDC
lift height: 8.25 mm
Exhaust opens: 39°15' BBDC
Exhaust closes: 3°45' BTCD
lift height: 8.5mm

one from XUD9A (1.9 N/A diesel):
Intake opens: 4° BTDC
Intake closes: 45° ABDC
lift height: 9.2 mm
Exhaust opens: 43° BBDC
Exhaust closes: 0° BTCD
lift height: 9.4 mm

There are some rumors about later being an upgrade performance-vise. It should retain low-end torque and increase high-end one.
There are differences in valve overlap, N/A cam has much longer opening times and greater lift height. This should allow more air in to the cylinder, right?
I have found that there are no differences in geometry of XUD7TE and XUD9 regarding pistons and valves: in both engines valve recess and piston protrusion is the same (please do not hessitate to correct me if I am wrong) so different timings and lift height should not result in piston cathing a valve.

I indend increasing turbo boost to some safe value (to be defined) and putting some more fuel.

Thank you for your input in advance!

Post by **Tim Leech** » Mon Jul 28, 2014 3:14 pm

Ive heard that fitting a 1.9D cam give better pick up.

Kitch · Post by **Kitch** » Mon Jul 28, 2014 3:42 pm

N/A cam will give more grunt, purely because the valves open more, and for longer. There must be a downside to the N/A cam (otherwise PSA would have fitted it to all the XUDTs), but I've yet to work it out

Only downside on a petrol with longer duration and lift is you start getting a lumpy idle and a reduction in vacuum pressure for things like the servo, or mechanical fuel injection if you have it. Diesels have vacuum pumps for that kind of thing, and they combust differently anyway. Hopefully we'll have a definitive answer by the end of this one!

Post by **mat_fenwick** » Mon Jul 28, 2014 4:00 pm

I'm running a 1.9D NA cam in my 1.9TD engine, but I can't give a back to back verdict as I changed the cam at the same time I swapped the engine. It certainly ran well enough on standard boost, and even better at 1.1 bar

The earlier square port head had a cam with greater lift/duration from memory, and that head was fitted to Peugeot 205s and 309s right through production. So finding one of those with PAS would give you the provision to drive the hydarulic pump.

I can only think PSA used a softer cam on the TDs for reasons of efficiency - they already had a class-leading diesel in terms of performance so no need to increase that. Or perhaps they were being conservative in terms of engine longevity - I've wondered if that's why they initially used the smaller bore (ie. thicker/stronger cylinder walls) engine when they first developed the TD. Moving onto the 1.9 when real-world experience showed the smaller engine was durable enough.

assembled · Post by **assembled** » Mon Jul 28, 2014 4:05 pm

I have [edit: read] a conspiracy theory that TD was made more petrol-like for better buyer acceptance by using such camshaft design though it seems counterintuitive...

BTW, would you happen to have measurements of your 1.1bar + 1.9NA cam?

Post by **mat_fenwick** » Mon Jul 28, 2014 4:23 pm

I've heard the same theory too, but wouldn't have said the TD was particularly petrol like. I suppose compared to what other diesels were around in 1988, like the 2.3 litre Peugeot unit in the Sierra, it was! Although to be fair, that was replaced a year or so later with Ford's TD unit.

It's actually running slightly less than 1.1 bar now, but Kitch put it on his dyno last year and we got 114 bhp as a best of 4 runs, or just over 100 bhp at the wheels. Torque was 167 lb/ft at 2400 rpm (or for comparison purposes, 174 lb/ft using the DIN method as Citroen did when it was new) - interesting how the peak has moved higher up the rev range.

citsncycles · Post by **citsncycles** » Mon Jul 28, 2014 6:42 pm

If you remember from that same session we put Timex on the rolling road and came to the tentative conclusion that it's got a TD cam fitted. This was because between 2 & 3k rpm the torque and power actually dropped off, which would coincide to the turbo kicking in on a 17TD engine. I've not yet fitted the replacement cam I have so we can't have another go to prove this, but it is one way to reduce the feeling of turbo lag.

Incidentally, the replacement cam isn't a standard one for the 19NA - The 19NA cam that I bought from Jaba will be going the 19TD engine for Fred, and I'll be pulling the 17NA cam out of Fred's old engine for Timex. This is because the 17NA cam has more duration than the 19, and I figured Timex needed all the help it could get power wise. It'll be interesting to see what it does.

assembled · Post by **assembled** » Mon Jul 28, 2014 9:50 pm

Edit: following data is sourced from Haynes manual and does not agree to Citroen data provided later in this topic thus most likely incorrect!

Spoiler: show

themildbunch · Post by **themildbunch** » Mon Jul 28, 2014 10:43 pm

I too have a N/A cam but haven't fitted it yet in my TD...
Until recently my Lucas pumped TD estate was pretty standard and performance off boost was very, lacklustre.

Increasing the fuelling made a huge difference off boost, making the car much more drivable especially in our hilly area.

I've heard rumours these pumps were deliberately setup quite lean from new to differentiate the performance between the models more....

JayW · Post by **JayW** » Mon Jul 28, 2014 11:38 pm

I fitted a 19 n/a cam to the TGDt and i couldn't tell ANY notable difference in any terms!

citsncycles · Post by **citsncycles** » Tue Jul 29, 2014 12:04 pm

I do not have lift specs though. Huge overlap, very late exhaust opening and closing...
If my pictures are correct, 1.8 N/A also has pump pulley on the other end, right?

Yep, all BX diesel camshafts have the pulley at the other end to run the pump.

I fitted a 19 n/a cam to the TGDt and i couldn't tell ANY notable difference in any terms!

It'll be interesting to see what happens with Timex when I put a different cam in. At present, if I keep the revs low and change up as early as poss. it's phenomenally economic, and has loads of torque - up to 2k rpm the rolling road showed more power and torque than The Estate that's now in Tim's hands, and don't forget the square port head on Timex is supposed to mean a power loss of about 7bhp against the later oval port head. On the other hand you notice the power drop off between 2 & 3k, particularly in top, and have to run it quite hard up through the gears if you want to miss it. I'm hoping I can lose the power drop without losing too much low end grunt.

assembled · Post by **assembled** » Tue Jul 29, 2014 3:17 pm

I am eager to see results of that. 1.7 NA cam should reduce low end torque due to overlap, late IVC, but increase high end performance. It might as well boost fuel economy when driven lightly. [Edit: just my uneducated opinion] Anyone would happen to have fuel economy specs of 1.7D, 1.7TD and 1.9D?

citsncycles · Post by **citsncycles** » Wed Jul 30, 2014 1:17 pm

It may take a day or so to look them up but I'm sure I've go them somewhere.

IIRC the 1.9D square port engine (up to about 1987 or '88 in the BX) is supposed to do about 45mpg combined, while the later round port engine does a few mpg better then that. Mine's a hybrid of later block and internals, pump and injectors with early head and manifolds and I generally get about 48mpg with me driving it fairly hard up to the speed limit of whatever road I'm on, and slowing down as little as possible for roundabouts etc (after all, it takes so long to get the speed back!). One thing I have learned about official fuel specs when it comes to Citroens is that they rarely match real life.

assembled · Post by **assembled** » Wed Jul 30, 2014 1:26 pm

Measurement standard is very outdated and is based on 1960s driving conditions (slow acceleration, deceleration, etc.)... What is important at this point, all models should have measurements done under same conditions and consequently have comparable results.

By the way, if someone could find power/torque curves of mentioned motors it would be tremendously informative in scope of this topic!

assembled · Post by **assembled** » Sun Aug 03, 2014 11:06 am

Some more research.
It seems that there are two interchangeable long camshafts: 0801 C9 from 1.8TD turbo and 0801 C2 from many other versions.
There also was a short camshaft 0801 E8 used in old 1.8D 161A/A9A motor with completely different timings and 0801 F7 used in 1.9SD motors. Not usable in 1.8TD, but mentioned here as I have their timings (see below).

Lift height Data from Citroen document:

unlit 09/86 161A/162
Intake 8,8 mm, exhaust 9,4 mm

from 09/86 161A/162 and A9A/D8A/D8B/D8C/D9A/D9B/D9D/DHX/DHY/DJY/DJZ/DHV/DHW
Intake 9,2 mm, exhaust 9,4 mm

AJZ/A8A/A8B (the 1.8TD engines)
Intake 8,4 mm, exhaust 8,8 mm

Timing information (French):

BX:
DIESEL FUEL AND 1,769L AND 1,905L EXCEPT PRESS PUMP 6+2 + NON-SINKING
0801 C2 ENGINE CAMSHAFT

DIESEL FUEL AND 1,769L AND TURBO
0801 C9 ENGINE CAMSHAFT LONG

DIESEL FUEL AND 1,905L AND PRESS PUMP 6+2 + NON-SINKING
0801 E8 ENGINE CAMSHAFT SHORT

C15:

XUD7 DIESEL UNTIL RPO 06264

0801 C2 ENGINE CAMSHAFT - UNTIL RPO 04773 LONG
0801 E8 - SINCE RPO 04774 UNTIL RPO 05169 SHORT
0801 C2 - SINCE RPO 05170 UNTIL RPO 05650 LONG
0801 C2 - POWER STEERING SINCE RPO 06171 LONG
0801 E8 - SINCE RPO 05651 SHORT

XUD7 DIESEL SINCE RPO 06265

0801 E8 ENGINE CAMSHAFT - EXCEPT POWER STEERING SHORT
0801 C2 - POWER STEERING LONG

Xantia I:
DIESEL XUD9 UNTIL RPO 06264 OR TURBO DIESEL XUD9TE UNTIL RPO 06264
0801 E8 ENGINE CAMSHAFT

Xantia II:

DIESEL TURBO XUD9SD SINCE RPO 06265 OR DIESEL XUD9 SINCE RPO 06265 OR TURBO DIESEL XUD9TE SINCE RPO 06265
0801 E8 ENGINE CAMSHAFT - DIESEL XUD9
0801 E8 ENGINE CAMSHAFT - TURBO DIESEL XUD9TE
0801 F7 - DIESEL TURBO XUD9SD

From above data we have different cams:
Short (not interesting...): 0801 E8. It is used in huuge list of cars:

Spoiler: show

Another short one 0801 F7, used in Xsara, Xantia 1.9SD, engines DHV, DHW:

Spoiler: show

Long:
0801 C2 Used in:

Spoiler: show

Long
0801 C9:

Spoiler: show

Final compatibility conclusion:
1.7TD motor can be equipped with originally mounted 0801 C9 with narrower lobes and smaller lift or a wider/higher camshaft 0801 C2.

If there are any mistakes in my information, please do not hesitate and say so.

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TZD Turbo 1.8TD XUD7TE camshaft options

TZD Turbo 1.8TD XUD7TE camshaft options

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Re: TZD Turbo 1.8TD XUD7TE camshaft options