Just got my motor back from my "reputiable engine builder" I havent put 300 miles on it since delivery, and already the number 5 cylinder intake spring has broken twice!!!

Also the number 6 cylinder rocker arm stud (exhaust) snapped! Luckily no damage,

what in the heck would cause something like this???

 

The "reputiable engine builder" perhaps if he installed and adjusted the valvetrain. If someone else did the valvetrain install or adjustment, it might be wrong pushrods or really fouled up installation. Sort out who did what on the engine before you point any fingers. There have been cases where the problem was caused by the owner, not the builder. Often the owner wants someone else to blame. It doesn't always happen that way...but often enough.

How did you break the #5 intake TWICE? What did the builder say after you told him you broke it the first time?

 

Thats just it ... he wants me to trailer my car 2 hrs to his shop to fix it ... he built the motor from the ground up, I just gave him the block, he gave me a new rotating assembly, all I provided was the intake, carb, oil pan!

I have no idea how it was the same valve spring twice ... bad luck?

 

Could also be the quality and wrong application of the parts used.
If studs are breaking ya got to much spring,to much rocker ratio or the springs are in coil bind.
Could be just that one binding enough to break,but ya can bet if that's the problem the others are real close.

 

I'm thinking coil bind for the broken spring. Maybe the valve guide isn't cut down enough and the bottom of the spring retainer is hitting the top of the guide at max lift?

Perhaps too much lift for the rockers and the slot isn't long enough allowing it to hit and break the stud.

Not enough information to give an accurate guess as to the fault. Either way, it sounds like a valve train interference issue somewhere causing problems.

 

I agree w/ Stephen and others,coil bind is prob. whats causing the spring to break. Springs breaking one time,maybe bad luck...but the same one breaking more than once....not just bad luck.

What kinda heads,camshaft type and specs,spring pressures,and rockers are in there??

 

So who put the second valve spring in?

 

I was trying to play nice and not ask that.

Thanks for asking, however.

Bad luck had very little to do with the problem.

trickytye,

If the builder wants the engine back to analyze the problem and fix it, oblige him. If you don't he really has no way to help you and his responsibility probably ends when you refuse to take it back.

Whoever the builder is, he deserves the chance to help. If he mucked it up and fixes it at no cost to you, you are a winner, and his reputation isn't hurt too badly. If someone else mucked it up and the builder finds the problem and helps you fix it, you are a winner, and his reputation gets better.

Other than a 2 hour trip each way, you are not out much if the problem gets fixed. It won't fix itself.

My $.02

 

haha thanks for all the good info ... the engine builder put the new second spring back in,

as far as the specs are concerned ... the builder is a little hesistant to tell me ... i know for a fact that they are new vortec heads ... so the do have self aligning rockers ... the camshaft is a custom ground to his specs

i'm trying to give him the benefit of doubt but ...

this guy builds all kinds of racing application motors, just wondering what made him mess mine up ...

again thanks for all the help

 

Oops! I'm reading things that send up a red flag. I can understand not telling you exact cam specs, for instance, but valve spring installed heights, etc. aren't big secrets. Replacing a spring without determining why it broke isn't my idea of a corrective action.

FWIW, was this engine a "bargain" pricewise?

 

yea he chucked it up as a "defective spring"

he said he was going to send it back to the manufacturer . . .

 

With aluminum heads, assembly of the rocker stud directly to the head boss can cause material deformation and loosen the stud to head mechanical joint (a potential for stud fatigue failure). I had a problem with SA rockers and ARP studs. You need a quality head bolt washer under the stud to distribute the load (Also note the chamfer on washer and stud fit!). I also use blue lock-tite. Lucky I caught this potential failure. I've since gone to pro-mags and guide plates. B.

 

sounds like coil bind

he needs to go back and recheck it.


was it russ racing? I had one of his last week.....280# on the seat installed@1.71 on a big block with a hyd roller


oh well **** happens