RV8 mysterious tapping noise?

[chesterak]

With the rocker covers fitted there is a "tapping" noise from (predominantly) the nearside bank. Remove the cover and it dissaperes.
The only bit I can't ckeck is if a lifter has not pumped up.
Can the rocker cover act as an amplifier? Any ideas?

[wilf]

Do you have the standard Rover rocker covers or rockers? I ask in case you have some aftermarket versions, and a rocker is hitting on, maybe, the oil baffle or somesuch.

Rocker covers do amplify noises, but there should be a noise to begin with! If it disappears completely when you take the cover off it indicates a problem with rocker cover/rocker clearances somewhere.

[chesterak]

Hi Wilf,
I've fitted a set of Ford "cobra" covers - same gasket as 351W so I assume same or similar cover dimensions as the Ford engine.
I checked for any witness marks etc and cannot see anything obvious. This noise, when I think back, was there with the RV8 covers but nowhere near as loud. I have a rolling road session booked for this Saturday and its just a bit off-putting as the engine is going to be (hopefully) finally tuned for best power etc.
You're quite right, there has to be a noise to start with - just finding the source.
Bit of a bu**er realy

[stu e]

Hi

I had a similar noise to the one you're describing, after fitting new lifters and checking the pre load the noise was still there. Someone on the forum suggested I look at the top of the pushrods, as the ends wear.
Replaced the faulty rods and no more noise, just wish I'd tried that first.

Regards Stu

[chesterak]

Stu,
Nice one! I have checked that the inserts in the end of the rocker arms were not loose, but not pushrods.
One question, if the preload is set how do you get the noise as the end of the pushrod will be in "firm" contact?

[Sidecarbod]

Originally Posted by chesterak

Stu,
Nice one! I have checked that the inserts in the end of the rocker arms were not loose, but not pushrods.
One question, if the preload is set how do you get the noise as the end of the pushrod will be in "firm" contact?

What you say is true, also for the same reason why would the pad at the end of the rocker be able to make any noise?

Also if the noise goes when the rocker cover is removed its got to be a rocker hitting the cover or the baffles in it (like Wilf said). Some of the nice shiny covers do need a bit of fetling. I'd look VERY closely for marks indicating contact

Regards,

Pete

[JamesP]

In the past I've had a bit of success using a length of wooden dowl, putting one end on the area making the noise and the other end in your ear (carefull now - you can actually put it on the bone next to your ear and get the same result).
This can help to locate a specific area making the noise and will pick up a rocker hitting a baffle.

James

[stu e]

Pete

I understand what you're saying.
I have standard rocker covers and had changed everything else( lifters rockers and rocker shaft), but still had a tapping sound. Looking at the top ends of the rods you could clearly see wear and on replacing them the noise stopped, i was sceptical of the advice I was given but it worked for me.

Stu

[Sidecarbod]

Originally Posted by stu e

Pete

I understand what you're saying.
I have standard rocker covers and had changed everything else( lifters rockers and rocker shaft), but still had a tapping sound. Looking at the top ends of the rods you could clearly see wear and on replacing them the noise stopped, i was sceptical of the advice I was given but it worked for me.

Stu

Hi Stu,

I guess its getting near the point where Chesterak should not take anything for granted. Maybe the rocker shaft needs to come off and everything washed in solvent then checked very carefully.

At least the bits are easy to get to! (Apart from the lifters).

Regards,

Pete

[chesterak]

Right chaps, further info.
Looked very closely for any sign of rubbing on splash plates fitted to rocker covers. There may just be a small witness mark, Im unsure, but I have now reshaped both sides to eliminate any possibility.
Rockers and shafts look OK, no wear. I've measured each pushrod length on the nearside bank (odd numbers?) and the results are below - counted front to back

8.0205
8.0110
8.0190
7.9990
8.0270
8.0150
8.0250
8.0210

There is a 28 thou variation from longest to shortest. Any significance to this?