Setting vave clearances

Post by **Thain** » Wed Dec 29, 2004 2:52 pm

Hail
Anyone living near SW12 area mind helping me do the valves?
I've read the theory, but 'aint done the practical before...
Had a tentative look under the rocker box yesterday and if I'm doing it right ( rule of 9 etc. ) then all but one are a lot less than the stated 0.012"
cold. More like 0.007" .
Havent had the car long and not done much mileage, but the fuel consump. is crap! ( 18mpg ) and a little down on power. Could the above be related?
PS mixture and timing are ok

Post by **ColinP** » Wed Dec 29, 2004 3:22 pm

Thain,

if you're following the book(!), you're probably doing it right, but there a few little extras that the book doesn't always tell you...

I'm assuming that you'e doing this with the plugs out & winding the handle.

1)When you measure the clearance, release the lock nut, and press down with the screwdriver in the screw. This will take up any play in the pushrod side of the system.

2) If the engine is quite worn, the top of the valve stem will have worn a slight hollow into the rocker - using a narrow feeler guage (width!) will allow the correct gap to be measured.

3) Check everything once you've done up the locknuts (just in case)

And it's quite possible that the fuel consumption is related (power = quantity of fuel in & exhaust out), so to get the same power, you'll be using a lot more revs.

Colin

Post by **rayofleamington** » Wed Dec 29, 2004 6:45 pm

the valve clearance would have to be way out to affect power, or maybe you have a burnt valve / valve seat.
approx 20mpg is not too far away from the norm in the middle of winter if you do a lot of short journeys (engine is less efficiant when cold and additional choke puts up the fuel consumption). If you do a 100 mile run on the motorway and still get ~20mpg then something is seriously wrong.

Post by **Cam** » Thu Dec 30, 2004 1:25 am

the valve clearance would have to be way out to affect power, or maybe you have a burnt valve / valve seat.

Agreed. It's possible that the valves have recessed too and the gaps are closing up (some worse than others) what fuel are you using?

Also, you say the timing and mixture is ok. What is your timing set at and how have you calibrated your mixture?

And....... what needle is in the carb? if it's anything other than the standard one then the mixture might be fine at idle (where you normally set it) but go WAY out throughout the rev range........

Post by **Thain** » Fri Dec 31, 2004 4:00 pm

Thanks for sound advice, will check on all the above.

Timing is 6deg.btdc ( stroboscophic ) and mixture was set as per Leyland manual ( two turns down and just able to raise the revs slightly by lifting the piston a nadge ) All done on hot engine.

I will have to check all again though as I have installed a catalyst in the tank as it is still a leaded head.
So just started not to use the additive anymore as I have completed the run in period ( 2 tanks with add. ) and will recheck tuning as a matter of course. Petrol is Total premium u/l.

The plugs do show however, evidence of being too-rich ( plenty sooty ) so I will definately check on the needle...errr...what is the standard one?

Oh yeah, the jet was replaced sometime ago from SU carb kit so maybe not compatible to old or maybe worn needle?

Bet you the valves are about to disappear up the head in a cloud of ash though!
Happy new year all...

Post by **grainger** » Fri Dec 31, 2004 4:42 pm

ah .. dont use that catalyst ... they dont work, there is someone on here who opened his head and found this out this year cant remember who it was, it doesnt do anything. the general consensus seems to be use a good petrol like optimax if you can AND add the castrol valvemaster lead replacement additive.

i honestly get better mileage out of my minor than my daughters 1.4 orion, i reckon i can do 50 mpg on a run !!

i did my valves this year, if one is burnt you will be burning oil and power will be well down.

happy new year
grainger

Post by **Alec** » Fri Dec 31, 2004 4:44 pm

Hello Thain,
the standard needle for a 1098 is an AN, with either a BX 1 or an M for the 948.

Other points:- clean air filter, needle correctly located with the shoulder flush with the piston underside, also that the fuel level is correct and not flooding at all, and choke fully returning.

Alec

PS, the needle type is stamped on the shank, so you need to remove the needle from the piston to check it.

Post by **Kevin** » Fri Dec 31, 2004 10:11 pm

have installed a catalyst in the tank as it is still a leaded head.

Sorry but as the others say you have wasted your money as they dont do anything thats why none of them were submitted for the testing done a few years ago, and they dont make a blind bit of difference to the engine running, until the head plays up Gareth can vouch for that.

Post by **ColinP** » Sat Jan 01, 2005 7:10 pm

Thain,

I've just noted that you've checked the timing "stroboscopic" - if you have the standard distributor you'll need to set it statically (i.e. engine not running), because the automatic advance starts about 500-600 rpm and the normal idle is 800 rpm.

At least, that's what I;ve read elsewhere on this board .... and I'm sure I'll be corrected (nicely) if I'm wrong.

How are all your New Year Resolutions? - still intact?

happy New Year ,

Colin

Post by **rayofleamington** » Sun Jan 02, 2005 12:01 pm

Bet you the valves are about to disappear up the head in a cloud of ash though!

very likely if you rely on the 'magical mystery' catalysts or inline magnet junk. Additive works out far cheaper than an unleaded head until you do up to 40,000+ miles but make sure you use an approved additive, as some of the 'readily available' ones failed the engine testing.
The most commonly used one from the approved list is Castrol: valvemaster / valvemaster plus.

Post by **Thain** » Sun Jan 02, 2005 3:53 pm

Good Heavens, I'm off to the Castrol Valvemaster shop already !
How do you guys get the fuel level at the jet right ? My float chamber is not floodig or starving so is it best to leave it ? ( '68 saloon, HS2 carb by the way ) Not sure if the 1/8" bar test applies as float lever is " --¬__ " shaped.
Cheers

Post by **Cam** » Mon Jan 03, 2005 12:01 am

If it's working then leave it.

Post by **brixtonmorris** » Mon Jan 03, 2005 12:52 pm

Hi Thain.
i am in SW9
c ya