hello people! just got my 305tbi stroked to an 336cuin tbi.ran fine for 3 weeks, then went out to start it and it almost died out.i felt ticking under the dr-side valve cover.... my mech said an intake valve broke! he mentioned he never heard of a in-valve just breaking like this!? he asked me if i dropped anything in -to cause this,i said nope!he retained the original valves and hyd.lifters during the rebuild too.... COULD HE BE MISTAKEN ABOUT KEEPING THE ORIGINALS?OR HIS MISTAKE?FYI:STILL UNDER WARRANTY! roller comp cam, z28 valve springs,k-black pistons,eagle crank,arp fasteners/bolts,edelbrock perf tbi,hot chip,flowmaster 80 dual tips,k&n......
thank-you- -----brad

 

Probably not the valve, they very very rarely break unless something else breaks first.

Could be the valve spring broke (very likely, with those crap stock springs, if your cam & rocker combo produces more than .500" of valve lift), could be just that the rocker nut has backed off.

 

well,just got off the ph with my mech: it looks like the valve spring did break--IN 3 PLACES!!!i guess it just shattered with the load the big roller put on it!he said he'll replace the (z28) v-spring-(while the others checked out ok)with a replacement.if i have problems again he'll put in an further upgrade to compensate for the type of roller cam combo-for free....
so.......WHEW-HUH!
thank you for your input SIR!-brad

 

Well I hope he likes swapping them out, and doesn't mind doing them one at a time every week or 2, and won't mind R&Ring your motor when a valve drops at 6000 RPM....

If I was you, I'd get him to put some sort of real springs on there, save himself a bunch of headache and money on down the road, and yourself a bunch of time and grief. Consider this one a sign of things to come.

 

sucking a valve into your cylinder bores is no joke. I can't beleive it didn't do any damage to your walls or piston. Did it hang in the guide or something and not fall all the way in?

Well then again, I remeber in the army if we had a glow plug break off into the head of a HMMWVE we just fired it up and revved it till the rattle went away.

But seriously, if he won't put better springs on it, I would look into doing it myself with the air compressor or rope method so you don't have to disasemble. Crane makes some heavy duty springs for rollers that will fit close to the stock size pocket if that's a problem.