TD Cams

[ohms]

Hi all,

My BX has had severe cold starting problems from cold, more or less since I bought it a few months back. I came to the conclusion that it was probably the Lucas pump that was at fault, I've had a lot of hassle with this crappy pump in the past, so set about sourcing a Bosch repplacment. My old friend Stewart(oily) in Wrexham, once again sorted me out with the said item and into the bargain also supplied a 306 1.9 engine. Admittedly it's taken me a while to get to this stage but I'm about to embark on transplanting the 306 engine. Now obviously I need a BX cam in there to drive the pump, but my question is which one. I intend to give this engine a useful tweak in performance with the addition of more boost and increased fuelling, but this also got me thinking of cam choice. I know from tuning petrol cars that it is always a useful hike in performance when fitting a nat aspirated cam into a forced induction motor and wondered if the 1.9TD engine would benefit from BX nat asp diesel cam?

Can anybody see any potential problems with this choice of cam or better still has anybody ever actually fitted one to a TD?

Thanks chaps
Bryn

[jeremy]

The 1.9TD engine works well but in reality doesn't produce as much power as you'd expect especially when compared to the 1.7TD. I'm sure Citroen would have liked more power from it - and the fact that the 2.1 has a 3 valve head suggests that the problems are rather fundamental - ie it just can't be made to breath as well as they would have liked.

I appreciate that an engine designer has to pay attention to boring things like emissions and reliability when tuning the things but I think Citroen actually bothered rather than sticking any old cam on it as its different from the 1.7 and is not symmetrical (Jaguar and Triumph produced a number of engines with the timing for inlet and exhaust reversed - which sounds to me more like the results of an alcoholic lunch than scientific research. - (Series 11 XJ6 4.2 - 17; 59; 59; 17 ) as their functions are entirely different)

[jeremy]

Incidentally the least powerful N/A BX diesel engine has the wildest cam - 8; 40; 56; 12. This would be the square port engine and produced 47kw and 87 lb ft. ( I think 47 kw is 63 BHP)

[docchevron]

wondered if the 1.9TD engine would benefit from BX nat asp diesel cam?

Can anybody see any potential problems with this choice of cam or better still has anybody ever actually fitted one to a TD?

Thanks chaps
Bryn

Hello mate, you have a fine choice in frineds! Stewart is a real gentleman.

In short, yes a N/A cam will give you a bit more oomph.
Unless you're playing about with the fuelling / boosting you wont notice a dramatic difference "on boost" but you will notice the engine has more torque lower down the rev range.
Up the boosting a touch, and match the on boost fuelling to suit, and you'll really notice the difference.

I have a N/A cam in mine, and whilst I never RR'd it when it had the TD cam I know there was an improvement, and at one stage I was running 150BHP from a 1.7TD. Until the head blew itself through the bonnet...

There were several reasons why the 2.1 had a multivalve head, which wasn't actually very good and doesn't allow the engine to breathe anywhere near aswell as it would with a big valve 8v head. I know, I'm building one!

[ohms]

Excellent, just as i thought!

The engines got the KK turbo which i know is not as good as the Garrett, but I'm not going for otherworldly altering performance, just a nice increase in drivability. So, more boost and fuelling adjusted to suit.

Will let you know how it all pans out. Need to locate a BX NA cam now, so if anybody has one lying around and feel inclined to want to part company with it then please let me know. cash waiting and all that.

Any other problems with mounting the cam in the 1.9 engine or fitting the pump I should be prepared for.

thanks chaps

[docchevron]

Just remember to set the tappet clearences up!

Other than that, it's a straight swop.

[ohms]

Thanks mate