GT6 noisy tappers when set to 0.25mm

[dellyend1]

Hi All,

 

have adjusted all valve clearances to the recommended 0.25mm and now the tappers are noisy at idle, could not really hear before. Had several valves that had a slightly too large gap ( 0.35mm on a couple) and one that was less than the 0.25mm and could not insert the feeler gauge. So it did need it and it ticks away like a sewing machine but just wondering if this is ok ? I’ve always been told slacker valve clearance is better than too tight . It’s a rebuilt engine so no idea what happened on the irregular clearance thicknesses ? 
 

if an aftermarket set of rockers , are there any other gap / clearance figures I should be using which is why I have the tapping 

 

many thanks 

 

jeremy

[68vitesse]

Gap for standard rockers is 10thou cold, if non standard I suggest speak to the supplier.

Regards

Paul

[Pete Lewis]

we assume this is a std triumph cam not something special

0.010" is 0.25mm   thats the normal clearance  for a cold engine

did you use the rule of 13  ie 1 down set 12  and so on ???

worn rockers will have a stepped wear on the pad so a feeler will bridge this and you get a false feel to the feeler fit

click adjust can help with this but they can e a bit fiddly as it takes up any wear on the pad

with it idling   does using an old feeler  inserted quieten it ???

Pete

[68vitesse]

Oops sorry didn't realize you are using a foreign measuring system.

Regards

Paul

 

[Pete Lewis]

it is oxford    ha !  

you cant beat old money  

Pete

[dellyend1]

Ok, thanks All. I have no idea if standard cam or not as I can’t contact the previous owner who had the engine re-built. No idea how I would tell either other than looking at the car itself. I used the Haynes manual sequencing for the valves which states when 2 are fully open (down) adjust the following two. 
 

would you recommend a further crack at it using the rule of 13 and doing each valve individually ? 
 

many thanks 

 

jeremy

[Pete Lewis]

your 2 down do the other two  is fine providing the other two are 180 deg from the firing order so with   1 and 2 dropped   you check 

from 153624  the opposing cylinder on its compression TDC stroke or you end up witha hopeless nighmare  

sounds like thats where you are right now 

so if you are uncertain about all  this ( it does save more engine turning) but is often misguided so a 13 rule on the 6 cyl  cant go wrong 

pete

[dellyend1]

21 minutes ago, Pete Lewis said:

your 2 down do the other two  is fine providing the other two are 180 deg from the firing order so with   1 and 2 dropped   you check 

from 153624  the opposing cylinder on its compression TDC stroke or you end up witha hopeless nighmare  

sounds like thats where you are right now 

so if you are uncertain about all  this ( it does save more engine turning) but is often misguided so a 13 rule on the 6 cyl  cant go wrong 

pete

Cheers Pete, I’ll give it a go. All good practice 😊

[Badwolf]

When I reset mine, (for the first one ever) I found out that they were 'set' to about 20 thou imperial. No wonder she sounded like an overgrown sewing machine. Reset to 10ish (well, my first attempt!!), now much quieter. Makes me wonder if the previous person that set them set them to 25 thou instead of .25mm. Makes you think. If the Yanks can crash a multi million dollar probe on Mars/Venus (can't remember which) by sending the right numbers in the wrong unit of measurement, there is little hope for us.

[Pete Lewis]

well mars are getting smaller and ive nver met a Venus     live in hope  
its inches for me   your inside leg in mm  sounds horrific .

Pete

[dellyend1]

Thanks All, before I commence the rule of 13 method, excuse the daft question but how tight should the gap be with the feeler gauge inserted ? I’ve always done it so that you tighten and move the feeler gauge until you feel slight resistance or tension. I’m just wondering if people’s experiences on the GT6 is that it should be tightened and the feeler gauge is a lot harder to remove with a lot of resistance but stopping short of clamping it dead ! Many thanks . Jeremy

[Pete Lewis]

a good  "feel" to give some noticable resistance on moving the feeler  nothing is pecualiar to any triumph engine 

to tight  NO its easy to start to compress the valve and the gaps is tight 

biggest problem is worn rocker pads so the feeler bridges the wear and the gap will be greater at the contact point than the feeler you are using

then a small amount of less gap can resolve a rattler  as i said if some are persistent stick an old feeler in the gap when its idling

if that solves the tapping its a worn pad 

something the click adjust type of tool will solve  but they are not the easiest tool to master 

Pete

[PeteH]

With worn (potentially) Rockers. (assuming you have access to such). I find the use of a Magnetic base and Dial Gauge can produce an acceptable result?. More of a fiddle, that I admit, largely due to finding a place to "stick" tha base, but can improve accuracy.

Pete