33 replies to this topic

[Guess-Works.com]

Good point Bungle... and also, don't got for super strong valve springs if you do ( apart from opening a rather deep wound on TMF ) that MAY damage you entire valve train from cam upwards.

Edited by GuessWorks, 25 July 2007 - 10:08 PM.

[panelbeaterpeter]

Ah right. I don't think it's this as I reckon I'd have noticed when setting up the valve clearances, plus it wouldn't make the same noise as what I'm getting. I'll check anyway to be on the safe side! Cheers.

[panelbeaterpeter]

Good point Bungle... and also, don't got for super strong valve springs if you do ( apart from opening a rather deep wound on TMF ) that MAY damage you entire valve train from cam upwards.

haha yes lets not get into that again!

[panelbeaterpeter]

Okay all sorted, turns out two of the rockers had a couple of a thou too much clearance, I must have messed up adjusting them! It's sounding sweet now at 15 thou. I checked the springs for clearance and it's all fine, about a ml at the highest point of compression.

[Bungle]

dont think anyone said on roller rockers you need to push the feeler gauge in side to side and not front to back

[samwell]

have i actually just read a thread with bungle helping out and giving sound advice?

[Ethel]

You can stick it in from the front - it's easier. But you do need to be able to wiggle it sideways while it's in. phnarr, phnarrr.

[Gizzum]

You can stick it in from the front - it's easier. But you do need to be able to wiggle it sideways while it's in. phnarr, phnarrr.

He He. Phinbar Saunders and his double entendres!

Edited by Gizzum, 27 July 2007 - 04:56 PM.

[panelbeaterpeter]

Haha! they are not roller rockers! forged ones! rollers are over estimated! Running brilliant now

[ginigwunkle]

i was talkin with the guy who setup me engine and he said to set mine to 22thou!

thats kent 296md double valve springs and 1.5 ratio....

[panelbeaterpeter]

Bloody hell! you must have a pretty savage spec for that!

[MRA]

22 thou is really excessive............. also think about it like this..... a cam is like going up hill then downhill..... ok the same hill but start walking at an "imaginary" height of say 22 foot and the same the other side... draw a picture if necessary..... this decreases the time the valves are open for and also changes your valve timing by the length of ramp missing by this extra clearance.....

As GW says valve clearance is to allow the engine to warm up but still keep the valves closed, if you start at 22thou get the engine warmed up and it still rattles like h*ll then let it go "COLD" then reset them 2thou less etc...... long term damage will result if you allow too much tappet clearance as it will cause impact damage to the surface of the cam / followers etc...... too little will cause your valve seats and valves to overheat. 16thou is more than enough for a 296 cam with 1.5 offset rockers.

And yes roller rockers do change you valve opening and closing contours. they also cause less damage to your valve guides..

[The Matt]

have i actually just read a thread with bungle helping out and giving sound advice?

Yup, very sound advice.

When I bought my 1.5:1 roller rockers and Kent MD286 cam I worked out what the maximum lift was and then bought valve springs from Minispares that allowed for that much lift.

My valve clearance for that setup is at 16 thou IIRC.

[Gizzum]

Guys... while we are the subject... Why don't people supply 1.5 rockers with a stage 3 kit for a 998. Is there some specific reason why a 998 can't run them??

Confused!

[Sprocket]

There is no benefit with more lift when the valves are so small on the 998, the cams provide all the lift a 998 will be able to usefully use