Rattle on startup - 1500

[tosoutherncars]

Hi all,

I've got a 1500 engine (Midget) and on start-up I get a rattle for about a second before it settles into an idle. It appeared (or at least, became more evident) after a recent oil & filter, and switch to 20W50.

Hard to convincingly describe sounds, but it's quite 'hollow', almost like someone shaking a ball bearing in a tin can.

It's been a couple thousand miles since the valves have been set, don't know if something may have closed up on me? And if it were a valve, would it then go away?!?

But otherwise... possibilites, starting with the best first? :wink:

 

[guzzul]

Starter motor disengaging?

 

[tosoutherncars]

Hmm... possible that the NAPA filter doesn't have a check valve, allowing all the oil to drain back into the sump?

 

[aeronca65t]

I forget exactly how it works on street 1500s (my race car has a unique oil filter setup), but I think you have to be careful that you've got the oil filter with the anti-drainback valve or the filter will drain down when the engine is shut off.
And then, during a re-start, it will run without oil pressure until the filter re-fills (this is a real bad situation, I'd think).

Since you just changed the filter, that makes me wonder.....

(I seem to re-call this is a similar deal with oil filters on MGBs....someone else want to chime in here?)

 

[AltaKnight]

Does the filter sit vertically or is it at an angle or worse still horizontal?
If it's vertical then it shouldn't matter (I think) about anti drain back construction.
You may have excessive clearance on the bearing journals (mains and/or rod bearings) How's your oil pressure (does the car have an oil press gauge?), what does the pressure do at startup.
The oil pump clearances may be too wide meaning it's struggling to prime itself on startup.
I doubt it's a valve clearance issue; that usualy manifests itself as a tapping sound rather than a rattle.
Probe with a screwdriver with the handle against your ear to locate where the sound is emanating (be real careful about the fan/belt and loose clothing though.

 

[tosoutherncars]

The filter is horizontal, which is what makes me wonder about the ADV. Thankfully I bought two, so I can check the spare.