ZX camshaft into a BX?

Post by **mat_fenwick** » Fri Feb 01, 2008 10:11 am

Hi there, been a while since I was last on here but I'm hoping for some advice...

I'm putting a 1.9TD Xantia engine into my BX but want to keep the BX hydraulics as they are, so I need to drive the pump off the end of the camshaft. As the Xantia cam does not seem to have any provision to fit a pulley I was going to have a look round a scrapyard tomorrow to hopefully get a replacement cam.
The yard has quite a few diesel ZXs, and I know they had a vacuum pump for the brake servo - so does anyone know whether it's as simple as fitting a ZX cam and bolting the BX pulley on the end?

(I live in the middle of a national park so the nearest decent scrapyard is about 60 miles away!!! That's why I don't really fancy just popping round for a quick look!)

kermit the frog · Post by **kermit the frog** » Fri Feb 01, 2008 12:14 pm

I think the person you need to sort out this is the DOC.

Regards Kermit

Post by **docchevron** » Fri Feb 01, 2008 7:28 pm

You'd be better off looking for a XUD from a Puggy.

Most ZX diesels had the vacuum pump mounted on the side of the head and had a T drive straight off the cam, so it will be no good for mounting a pulley for the BX HP pump.
There were some ZX's that had the pulley / belt driven vacuum pump, but I've only seen two.

Whereas most of the Pug 405's I've come across used the pulley / belt method to drive the vacuum pump but had a double pulley, but the BX pulley is a straight swop.

Alternativly, you could use the cam thats in your engine in the car now..

Post by **mat_fenwick** » Fri Feb 01, 2008 9:32 pm

Thanks Chris,

I was considering using a cam from the N/A diesel as I have heard that it's similar to a 'performance' cam that's available for the TD. Don't know how much difference this would make - I plan to up the boost and fueling slightly at the same time. So think I'll look out for a Pug diesel instead.

But if I could use my existing cam (1769cc TD) then that would save a trip... Is it pretty similar to the Xantia TD cam in profile?

Post by **docchevron** » Fri Feb 01, 2008 9:42 pm

Fitting an N/A cam will give better torque at lower revs, and allows the engine to breathe better at higher revs, without fuelling / boosting changes it gives about 5 BHP, but tweak the fuelling / boost and it makes things alot more interesting.

The 17TD and 19TD cams are different in profile, but not massively.

Post by **mat_fenwick** » Fri Feb 01, 2008 10:57 pm

Think I'll look for an NA cam tomorrow. Thanks for the advice!

What's the trade off for the better low end torque then? Less mpg? Not too worried about that, with my current wheels I'm pleased if I can get above 15mpg (but at least it's on LPG!!!)

Post by **docchevron** » Sat Feb 02, 2008 12:35 am

If you get the fuelling and boosting right, and dont drive it flat out all the time, there really is NO trade off at all.

My little 1.7TD is tuned to hell (at this time running 135BHP) and I can still achieve 62MPG on a steady run, even driving it hard I'm still getting low 40's.

If I'm brutal with it (ona track for example) I've got it down to 35MPG, but in normal circumstance that just isn't an issue.

Fitting a N/A cam is really getting free power, likewise if you're sensible about how you power tune an XUD you can get fairly good power and torque increases without losing too much in economy.

My advice on power tuning would be that even 135BHP is right on the edge of long term reliability. 125BHP seems to be easily and VERY cheaply doable with excellent reliability.

As is always the case with diesels it's the gains in torque that really matter, and with more torque lower down the revs then economy can be improved if that suits your driving style.

Post by **mat_fenwick** » Sat Feb 02, 2008 4:29 pm

Like the sound of free power!!! I went to the scrapyard today, a couple of 405s but they were both late TDs and had the vac pump on the head anyway. But I did see a 205 with 94k on the clock, signs of recent servicing so I got the cam from that. The only downside is that it is the 1769cc NA diesel. I guess you're going to tell me that it's of no use to me:(

(Although looking in the Haynes BOL there is no mention of different valve timing for the 2 capacities - can this be right?

Maybe any difference is purely in the amount of lift???)

Post by **docchevron** » Sat Feb 02, 2008 10:03 pm

From memory, and along time ago at that I believe the 17NA cam is a little more retarded than the 19NA cam, but I've never owned a 17NA and it's something I remember reading somewhere.
Either way a 17na cam should still give increased torque, it's still a higher lift than a turbo cam, therefore it'll still breathe better.

Post by **mat_fenwick** » Sat Feb 02, 2008 11:57 pm

OK, thanks for the info. Best thing to do is suck (blow?) it and see I reckon.

Will turn it over by hand first very gently I think, make sure there's no contact between valve and pistons

Hopefully it will all be on the road by this summer, my friend has bought me a shiny new hoist for Christmas so no excuses! Mind you maybe it's because I have another project car in her garage (stored for the last 2 years!), reckon it's some kind of hint?