please help me what could cause this. I post in LT-1 tech and I have one reply only from dave1w41. the original post http://web.camaross.com/forums/showt...hreadid=143604
the new link for the pics http://www.geocities.com/amjadalgaro...alveseats.html
please help me I paid more than $6000 on this engine and I don't wanna lose more

Hindsight is 20/20 as they say...but if I had to guess, my money
would be on incorrect spring pressure or lash settings.

What sort of camshaft did you have solid, or hydraulic?

I'm thinking the valve was coming down too hard on the seat.

I don't think it's heat related since it's the intake valve.

FWIW, I know exactly how you feel, I just stuck a connecting
rod through the block and lost $4000.00 in parts.

Build it better, bigger and faster.

I have comp cams 306 HR cam, 1.6 roller tip rockers.
I lost the first engine because of Intake valve too. I installed the springs with shims at the springs seats, so I thought it's because of Hi pressure. the first Engine was with stock internals. the bits broke the piston crown and f***ed the block. on the current engine I have forged 355 with 12.2 cr. I removed the shims cause I thought that wll cure the problem. but it was not the springs. I don't know what to do. now I am porting new heads since I still have the short block. but I don't want to loose the block too. I want to find the problem first.
please any advice.
thanx

I have seen this with incorrectly installed seats and seats that were cut to thin.

Stroker and a few others can give a better insite to this.

Hi again next week I'll be doing some assembling on my engine so I thought of bringing this up may be some one will bring something up.
thanks

Your head may have been over ported in the bowl area, whiched caused the seat to come loose then break. This happened to my last motor. Valve seats kept falling out. Your cyclinder head looked just like my old ones, from the piston beating the crap out of the valve seat. This very thing took out both heads and two pistons. Parts shot over to the other side of the motor through the intake and took that side out too.

Neal

I don't know what to say may be some one got more experience than me take a look at the pics can tell if I over port them.
what about the rockers spinning even that I have guide plates? I
thanks any way for the reply
I start to make bigger view with all the replies I got. the more replies will even help me more.
every time I look at the head something I can't explane goes inside me.
still have the heads if you need better pics I will shot them again.

Whats the deal with picture # 5? Where is the fullsize one?
How often has that happened and do you know why? Is that just on the cylinder with the damage?

-brent

Hi full picture No5 where the piston is, is working. if you look closely from 6 o'clock to to 10 o'clock marks you will see the damage broken seas have done. this is the scond tine on the scond engine.
Why???????????? don't know

Could be a few things.......

Incorrectly installed seats and seats that were cut to thin, are they aftermarket seats or stock ones?

Your head may have been over ported in the bowl area

As the guys have said, those are possiblities.

The valve train didn't do it, unless you used the wrong springs. Bad valve control on closing will cause seat bounce and that's not the best thing to have happen. On a over cut valve seat, that could cause this.

Ouch, if it happened twice, REALLY ouch.


Bret

the seats were stock never removed.May be the shop cut them too thin on the 3 angle job the done??.
the springs are what CompCams recommend for this cam. and istalled firist with the recommended spring height. at the scond time I install them with no shims at all and they have less seat pressure I guss.
can you tell by looking at the pics if I over port the bowl area.
now I am lookin more on eather the seats were cut too thin or over porting the bowls, I don't have the experince to tell if I over port them.