You know, its an engine 'flutter' or something?

Hi guru's, having an engine issue that it proving troublesome to track down.
Difficult to describe, but it is like a flutter at 2250 rpm and above. Not really a miss though!
I have changed the plugs, new distributor, reset the timing and points and adjusted the tappets/valves.
Also replaced the fuel filter a couple of time, just in case it is a fuel flow issue.

But it is still there. Doesn't really impact on performance (or lack of) but still cruises on the highway and pulls up hills OK.

I'm now beginning to think things such as piston slap, crook gudgeon pin or bearing or something of that nature.
It is more noticeable under load, accelerating etc.

What are my next steps to try and track this down?

Cheers

Steve

 

Gona be hard to trace after all that has been checked without stripping the engine down if you think it maybe a piston!
Compression and leak down test check might help.
Not a loose bit of tinware or such maybe?

 

Is the flutter audible? or just through feeling the car?

 

Steve piston slap, gudgeons etc will usually rattle/knock at idle speed and can be isolated by pulling the plug wire off each cyl ( with due care 30,o0o+ volts are involved). I suggest 1 possibility is that one of the accelerator pump discharge nozzles may have been ingested by the engine and the venturi effect of the air flow sucks the fuel out of the passage, this has strange results.

 

Timing light , does it show a steady point if timing or flicker about?
Check dissy shaft for sideways play.?

 

Compression test is next on the list, thanks.

 

I can hear it, maybe I am noticing it more because I know what to listen for, but you can also feel it through the car, it is very slight, but again, maybe because I know it is there I think I can feel it.

 

Thanks, will try new leads, maybe it is breaking down somewhere.

 

Cheers, I have put a new distributor in, because I thought it may have been the culprit, so there shouldn't be any sideways play.
Will check with a timing light over the weekend.

 

low voltage to the coil?

 

Ok thanks, for the suggestion, now to google to find out how to do this!!!

Cheers
Steve

 

should be as close to 12v as possible (voltmeter between +coil and earth) with points closed engine stationary, ignition on.
That voltage is going all the way from the battery to the ignition switch and back to the coil. (aprox 9 meters) so lots can go wrong.
Definitely no lower than 11.5v if the reading across your battery (pos to neg on the bat with your voltmeter) is above 12v (which it should be)
The voltage drop is usually caused by the ignition switch (dirty contacts).

Not saying this is your problem.

 

I am very reticent to dismantle something if I don't have a fair idea what the problem is, you end up with a million parts on the bench that all look good and then trying to pick an item which is possibly worn/faulty. Even worse if you cant find the problem and put it back together and the problem is still there.

 

And they're cheap to buy & check/eliminate one source of your problem.
Cheers

 

New dissys are often faulty.
Poor build giving play from new or wearing bushes fast .
Points are currently wearing rubbing block faster than normal and require retiming at 2500 km.
Points can have a coating on them that needs removing.
I wipe thru mine with thinners and rag before fitting.
Springs often poor choice and sometimes weights sticky .
This along with crap vac cans can give very rough advance curves.

Check for rapid smooth advance off idle.
Plus steady point of advance shown on scale.
Set mechanical advance all in showing 32 BTDC if running 95 ( assuming standard compression )
Total with vac not exceed 44 BTDC

 

I had a problem with my points on the way back from Bus Stop and the first sign was slightly “fluttering” power delivery. However it didn’t take long for the engine to stop completely. Maybe 5 km. I think that was a combination of the new points having misaligned contacts plus I’m ashamed to admit I didn’t clean them when I installed them.

 

So as a collective we're up to 12v thru power supply/ignition to coil & at coil, bad dissy &/or shitty points.

Never going to change my points again after all the problems I see on here. Just keep filing the square edges until there is nothing left.

Look forward to what it is Deeksy & be nice to meet you at Old Bar.
Cheers

 

I've been using pertronix ignition and coils in cars ever since it's been difficult to find a good set of points (I carry the old gear with me but all has been good for ages)

 

I think i'm going that way too gets rid of another wearable adjustable thing that needs to be maintained. Pertronix Electronic replacement.