The V8 Owners Forum -

Hallo..everyone

I wanted to hear if anyone can help me with my questions.

I have an 4.6 L V8 (short engine from John Eales) with Peter Burgess Heads with standard valve, guides and spirngs. The Camshaft also from John Eales.

I did not build the engine, but bought the car car recently with the new engine in it.

Yesterday a spring broke in 2 places and dropped a valve... The whole engine is no more than 1500 miles old..

My question is if it is a common problem for 4.6 L? maybee because of to high revs..or if I was just unluckly..?

Regards Troels

http://www.v8forum.co.uk/forum/viewtopic.php?t=7461

I have got same proplem, but i have got realsteel "performance" spring..

Troels,

What camshaft is fitted? if the lift exceeds the available compressed height of the standard springs then this could have caused the problem.

Also with a higher lift cam you normall have to machine 100thou. off the top of the valve guides otherwise the spring retainer can hit the top of the guide.

Inspect everthing carefully including the cam.

Kevin.

need more info like the spec of the cam. As others have said if the springs and guides dont match the lift of the cam your in trouble.

If you have already done 1500 miles I dont think it will be excess lift. Excess lift will normally clip the oil seals and bend a pushrod in instantly. Or at least once the whole lot has warmed up and expanded in a couple of minutes.

Maybe you have the correct guide height but the springs are just binding by a few thou. I can see this causing spring trouble. But I would still say that the effect of this would cause a rod to bend first.

If the lift is high and the springs are ok but the valve top hits the guide, the result again should be a bent rod??

Strange??

Without full information it's just guesswork but performance cam? and standard springs and high RPM? would point to the valve spring being stressed beyond their normal limit with resultant failure, but as I said I'm just guessing.

Kevin.