droning engine

[jaxom28]

navara D21 4x4 auto 1996.
Cooked engine in january. Repowered with same engine out of a mistral (diesel 2.7t) Replacement engine drones through most of the rev range. Old engine did not. Does any one know why this is? This engine has done about 190k.
Also has poor fuel economy. did glow plugs, and went from 11.6l/100 to 11.2l/100. Old engine did 10.7l/100km @ 370k.

[fh2014]

you didnt replace a black top for a silver top ? different head design i think black top has a little more power

[churchill]

Check for intake and exhaust leaks.

[jaxom28]

Excuse the late reply.
Churchchill, I checked the inlet and exhaust manifolds and all intact. Also no exhaust leaks.
fh2014, yes I swopped black to silver top as there were no black top engines. Looking online all that I could find said 73Kw for both engine. BUT there is definataly less power , you notice it's absence when overtaking.

[fh2014]

Yea they might have changed the head design. There's a sticker on my blacktop saying 115ps and I'm sure the old Silvertop I had wasn't as torquey. And all the ps ratings are 100 for them.

Anyway I digress, but perhaps they got different muffler designs? or the injector pumps are different too? Maybe one of your engine mounts is damaged causing the motor to resonate and drone? Food for thought

[Crash bandicoot]

yep, my 98 black top mistral also has bigger injector nozzles too. mine creams anything in the same capacity range and more, 128 hp and thats standard, and puts out more power then its bigger brother td42 and only 22 less then a td42-t.....not as torquey though or compared to the later QD32's .

[jaxom28]

I looked at the engine mounts and they appear to be intact. How do I tell if they are damaged?

[Crash bandicoot]

look for cracks in the rubber like a perished tyre would have or fresh looking lines of rubber where the two pieces have rubbed together. block of wood and a jack take some of the load off the mounts.