N12 Engine Sounds like a Diesel

[SamJJJ]

Hi People. Just wondering, I have a 1986 N12 Pulsar & it sounds quite like a Diesel engine. I have seen others driving around & even the later N13's & they all sound like this & there's nothing wrong with my engine so I was just wondering is this just what they sound like? A very clunky sounding engine? & if so, why?

[baz]

Your issue is just there, It's a N12 Pulsar

[Kimmo]

It's valvetrain noise. Engine was designed without hydraulic lifters : (

[SamJJJ]

Haha Baz. I still think their a brilliant car. They are just so reliable it's ridiculous!

& Kimmo, thanks for that mate. Appreciate it.

[Reswob]

Yeah, I noticed that a healthy N12 or N13 engine sounds a bit like a small truck. If they sound like anything else, something is probably astray. When I first sat behind the wheel of my N12 I was quite shocked about how noisy and rattly the thing was, but I figured that was the nature of the beast. Interesting to listen to...as I only have the stock AM radio as an alternative anyway.

What is this valvetrain noise/lack of hydraulic lifters deal?

[Kimmo]

A hydraulic lifter, also known as a hydraulic tappet or a hydraulic lash adjuster, is a device for maintaining zero valve clearance in an internal combustion engine. The conventional means of adjusting valve actuation always requires a small clearance to be left between the valve and its rocker or cam follower to allow for thermal expansion and wear. The hydraulic lifter was designed to ensure that the valve train always operates with zero clearance, leading to quieter operation and eliminating the need for periodic adjustment of valve clearance.

The hydraulic lifter consists of a hollow expanding piston situated between the camshaft and valve. It is operated either by a rocker mechanism, or in the case of one or more overhead camshafts , directly by the camshaft. The lifter is filled with engine oil intermittently from an oil gallery via a small drilling. When the engine valve is closed, the lifter is free to fill with oil. When the valve is opening and the lifter is being operated by the camshaft, the oil feed is blocked and the lifter acts just as a solid one would, oil being incompressible.

http://en.wikipedia.org/wiki/Hydraulic_tappet

[SamJJJ]

I'm confused as to why Nissan wouldn't build those engines with Hydro Lifters. I mean, Hydro Lifters have been around well before these cars. My Dad owns a 1961 Holden EK & a few years back he put a 1971 red motor straight 6 in it & even THAT had Hydro lifters. Were Nissan cutting costs or something?

[Kimmo]

I think you'll find they're a bit trickier to implement on an OHC engine.

[sgs]

Besides, I dont think you can rev the snot outta the hydro thangs

[tassuperkart]

Well, if your tappets are noisy then youve adjusted them WRONG. Do them AGAIN...and AGAIN....AND AGAIN until you have done them CORRECTLY.
Simple as that.
When adjusted correctly, they make little or NO noise at all.
This goes for the vast majority of engines without hydraulic lifters.
End of story.
L8r
E

[Kimmo]

That's what I would've thought, but I've seen folks saying these engines are always noisy, ie it'll only stay quiet for a week or something.

I did mine once and it made a difference, but a week later the belt tensioner let go when its stud broke... so I wouldn't know.

So it's worth the hassle then? It'll stick for a decent while?

[tassuperkart]

You were unlucky.
They dont magically "unadjust" unless the valves are badly and repeatedly floated.
l8r
E

[chezza]

Perseverance with adjustment, and you get a very quiet engine indeed.slightly awkward with the feeler blades though.

[tassuperkart]

Can be yes. Is why I have a pair of guages I have bent to shape just for the job!!
L8r
E

[Kimmo]

Sweet, I'll put it on the to-do list