33 replies to this topic

[panelbeaterpeter]

Hey all, does anyone know what the valve clearances should be for 1:5 ratio rockers? they are forged type, running on an MG 1275.

Cheers in advance!

Pete

[Guess-Works.com]

increase the clearance by the ratio, std rockers are approx 1.25, with a 12 thou clearance, therefore 1.5's should have a 15 thou

[panelbeaterpeter]

Ah simple really! cheers guessworks!

[panelbeaterpeter]

Okay. fitted my 1.5 rockers with the correct 15 thou clearance, it pretty well, but there is alot of tappet noise! sounds like an old escort that needs a service! is this normal? sounds a little alarming!

[scottyegg]

try decreasing the clearence ? maybe 14thou or 13 thou ?

[Ollie180]

i just fitted some last weel i was told 15 but i found it to tappety so i did them to 12! and i must say they the dogs BO****

[panelbeaterpeter]

Hmmm interesting... *scratches chin*

Would changing the clearance to 12 thou not change the characteristics of the rockers?

And yeah, they are seriously worth the money! got mine for £50

[scottyegg]

like i said decrease the clearence till the sound goes 14 13 thou

[Guess-Works.com]

reducing the clearance on the valve, also reduces the clearance of the Follower on the cam.... without the clearance you are going to wear the cam at an accelerated rate...

Also, tappets should be set cold which allows for things to expand as they heat up...

[panelbeaterpeter]

Okay, does it do the engine any harm if there's tappet noise? I'm not bothered so long as it's not harming the engine! It just sounds a bit alarming thats all.

[Guess-Works.com]

Both highlift cams and increased ratio rockers need the valve clearance increased, eg Kent quote .4mm (over 15 thou) Valve clearance for all their cams
and that's on std rockers.

Yes the increased clearance will increase tappet noise, but when your putting mods on like this, you're not building a tesco shopper..

Will it do the engine any harm, no not really, and certainly not as much as having it too small

[panelbeaterpeter]

Excellent mate thanks for that I'll just leave it be. Funny you say it's not a tesco shopper, I noticed the tappet noise when I was driving round tescos car park..

[Bungle]

just make sure its not the coils on your springs binding up

[panelbeaterpeter]

What is that exactly? sounds like tappets to me, springs are standard un-touched. I know they should be fitted to match the rockers but they'll do for now.

[Bungle]

take rocker box off spark plugs out and push the car in 4th

watch the valves go up and down and check the coils on the springs dont touch when fully down

i had to change the springs from standard to double valve springs with less coils on them when i fitted my 1.5 rockers