1749/1900 BX TD heads

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silverfox
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1749/1900 BX TD heads

Post by silverfox » Tue Feb 21, 2006 3:06 pm

Does anyone know if its possible to fit a 1900 head to a 1749 block?
Ta Geoff.
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Stewart (oily!)
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Post by Stewart (oily!) » Tue Feb 21, 2006 5:20 pm

Yes, the heads are flat and interchangeable.
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DavidRutherford
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Post by DavidRutherford » Tue Feb 21, 2006 6:17 pm

But be aware that the TD models have heads made from a higher grade of aluminium, and the exhaust valves are hardened.

Thus you cannot fit the head from a 1905cc D BX onto a 1769cc TD engine.
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Vanny
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Post by Vanny » Tue Feb 21, 2006 8:25 pm

theres loads od differences between the 1.7TD and 1.9 TD heads, but fortunately (having sat with them side by side for a couple of hours) they all seem to be cosmetic! I couldn't find any actual differences when looking at them, and as mentioned by Stewart there flat heads so there shouldn't be any change in compression.


Are the not differences in the cam? i thought the exhaust was possibly slightly retarded? neve had them sat next to each other!

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DavidRutherford
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Post by DavidRutherford » Tue Feb 21, 2006 8:35 pm

The only real difference and "problem" that I've ever come across is whether the oil gallery has a plug in it at the non-timing-belt-end. Models with the close-coupled vacuum pump don't, and just about everything else does.

The problem is that they are an absolute pain to fit as you need a concave-head punch (and a ball-bearing of the correct diameter!) and even more of a pain to remove (read "impossible")

Other than that, as Vanny says, all other differences are machining differences dependent on what brackets need to be fitted to it for a particular car.

I also have yet to see any conclusive evidence regarding timing differences between ANY XUD engines. Unlike a petrol engine, it's entirely possible that the NA and TD engines do share the same cam timing. If they're not identical, they're very similar.
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Stewart (oily!)
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Post by Stewart (oily!) » Wed Feb 22, 2006 5:47 pm

Dave, on my pug 1994 TD motor the oil gallery hole was tapped and used as a return from the vane type vac pump, I merely cut a piece off a M10 bolt and sawed a screwdriver slot in it, liberally smeared hylomar on it and screwed it home, another variable is the diamond shaped plate on either end of the head one end blanked the other carrying an approx 10mm bore rubber water hose, on the TZD head it was at the thermostat end allowing the system to self bleed back to the expansion tank, on the pug it was at the fuel pump end, I fitted both and now I have a rubber stub with a valve cap type bleed point on the other end of the head.
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Post by jeremy » Wed Feb 22, 2006 8:55 pm

Glass's technical spec for 1989 states that the valve timing for the 1.7 and 1.9 N/A engines is 8 BT-40AB-56BB-12AT

The 1.7TD (which they describe as having vacuum servo brakes!) is 4.30BT-20.30AB-39.15BB-3.45AT

Curiously the Peugeot 405 (XUD9A) non-turbo is said to have timing
44.31BT-83.30AB-89.30BB-46.30AT
and the 1.7TD 51.30Bt-76.30AB-89.30BB-46.30AT

Whats going on here I don't know but the difference is quite extraordinary - and makes me wonder if these figures are so unreliable that I've just wasted my time typing them out!

jeremy

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Re: 1749/1900 BX TD heads

Post by silverfox » Thu Feb 23, 2006 2:54 pm

[quote="silverfox"]Does anyone know if its possible to fit a 1900 head to a 1749 block?

Thanks for all the imput fellas (Am I to assume there are no gals "in the club"! So to speak! :oops:
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DavidRutherford
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Post by DavidRutherford » Thu Feb 23, 2006 3:06 pm

One, I think, but she doesn't post very often.
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