The engine mechanical sound while it's running, not the exhaust. My stock 1974 1.8 L-jet makes a kind of soft klacklacklacklack sound when it runs. Is this normal?

Mine goes...Vroom vroom..ahhh...Vroom vroom..ahhh

I think thats normal. It's just the sound of the valves, since it doesn't have hydraulic lifters.

if you are SURE your valves are adjusted to spec for your engine, it's probably normal. you may be ablt to hear the injectors click too.

clack/tick noises are often your engine telling you it wants its valves checked.
if they ARE adjusted to spec and that noise goes away (hard to tell, 'cause it's usually gradual...) you probably have a valve tightening up (bad) and you should check into it soon.

This is what mine sounded like last year.

Here's another one.

Very nice, Sean!
What muffler were you running?
Steve

If I was to describe the sound of a stock, fuel injected 914 engine........If everything is working correctly and everything is adjusted perfectly, it sounds like a well oiled machine. It has a mechanical sound with a slight sing/ring to it.

Steve,
that is a Triad muffler.

Do a search here and you'll find lots of pictures and testimonials from guys using them.

They are loud with lots of mechanical sounds when cold. When they are at operating temp the engines are fairly quiet especially with the stock muffler.
Geoff

Sean:
Thanks. I just linked to the Triad site.
The dual pipes are very nice, indeed.
At about $325, though, that's almost 75% more than a Bursch. Are they that much better?
Steve

Just had to add...

I drove my electric 914 to a local mechanic who knows 914s. I silently cruised up to him. He says, "Man I've never heard valves on type 4 dialed in like that!!!"

Thanks for the sound bite seanery. That is almost exactly what mine sounds like. Except when I rev mine, it pops from the exhaust a bit 'cause I got's a couple holes in mine.

What would a valve which is tightening indicate?

A tightening valve usually means the seat is receding into the head.

it -can- mean the valve is receding, possibly due to erosion, or it can mean the valve is stretching (somewhat more likely, i think...) due to having been overheated or just fatigued from long life.

but tight valves are on their seats less time than loose valves, meaning they cool less well, and at some point, they just don't close, and they can burn easily. however, very small clearances also act like more cam (increased duration) which is yet another reason aircooled engines tend to run best right before they explode... producing more power == more heat but less time on seat means less cooling, which means more heat, which means the valve is more likely to stretch, which further tightens the clearances... that path can lead to destruction pretty quickly...

loose alves are kind of self-limiting. the engine makes noise and runs bad, and eventually almost anyone will notice and do something about it. when valves tighen up the engine runs better and quieter - right up until the time a valve breaks or the increased heat loosens a seat ...

Chitty-chitty bang-bang

Get an empty coffee can, and put about a dozen ball bearings in it. Shake vigorously.