7 replies to this topic

[topcat]

Hi, Is there any way to tell if I have standard rockers or not? Just got the Mg engine in which is going well but theres a slight tappety noise, so I'd like to know what valve clearances they should be. Thanks.

[Big_Adam]

i do belive the valve clearnce are....

*runs to haynes book*

0.30mm from what haynes is telling me. BUT! if you have the orginal cast manifold its written on that.

[miniboo]

12 thou for standard rockers

[topcat]

Cool, OK i'll try that next. What actually causes the tapping/ticking noise?

[Big_Adam]

wel....they tap. thats why their tappits. as the cam moves up and down the push rods hit the bottom of the tappits. this makes the tappy noise. should be too bad. my El Gordo is rather tappity. need to get them sorted as tappits confuse me.

either that or your chain is about to go bye bye. well i say bye bye nut its a good idea to change them arond 60,000 miles.

[topcat]

Chain is brand new so that should be OK. I checked the clearances after puttin the head back on and they were about 0.35mm, adjusted one because it was a bit more. I'll try 0.3 and make sure they are all the same. Always find it a bit vague and hard to get it dead accurate. Hard to keep then the same when tightening them!

[Big_Adam]

not too tight....thats bad.

althought i can't rember why. i think it has to do with bending the push rods....or somthing.

i mean its an engine. if it makes a little noise it not too bad. its when it go silent at high speed you should be worried

[The Matt]

Tappets are not called tappets because they tap, they are called tappets because that is an engineering term for a part that is used to transmit motion (like from the camshaft to the rockers).

The reason there is a specified clearance (plus a tolerance) is to allow that motion, plus any hydraulic effect, to work correctly. If valve clearance is too tight, then there is a chance the valve will not close properly, causing misfire, there is also a chance of component damage, yes bent pushrods etc.

If the valve clearance is too loose, you will get excessive noise as the components are tapping into each other. Set the clearance as per the manual (unless your rockers are a different ratio). I am not certain how to identify the rockers as standard, but would think there would be a casting number on them somewhere???