[cmitchell17]

Originally Posted by laynlo15

Sorry, couldn't resist, I've had several failures during my Camaro years, broken ring lands on the original Lt1. Bent valve on my Manley forged motor and then after I fixed that the same motor broke the snout on the crank. Man
the shit that does break hurts the wallet and down time.

Yeah pay to play I guess haha, this will actually be my first failure on this motor, besides the GM induced one because of the oil cooler hose busting.

It gets more interesting, #5 looks like it is starting to burn as well, you can also see the burn/combustion marks on the intake port on #5:

[KingLT1]

Are your heads TSP ported stock castings or their aftermarket casting?

[cmitchell17]

Originally Posted by KingLT1

Are your heads TSP ported stock castings or their aftermarket casting?

TSP ported stock castings. At this point I wonder if it would be cheaper just to buy aftermarket castings.

[KingLT1]

Originally Posted by cmitchell17

TSP ported stock castings. At this point I wonder if it would be cheaper just to buy aftermarket castings.

And there lies your problem which is why I don't recommend porting stock casting without fully reworking the heads...new valve seats, guides, valves are a must imo.
I would just buy their aftermarket casting at that point.

Screen shot below taken off TSP website.

[parish8]

I had a #7 exhaust valve break and my retainers were impossible to get off. I think it is valve float/bounce just beating stuff to death.

I think my biggest issue was the springs were not shimmed properly. They were shimmed(dropped locks) but only .050 where they needed more like .075. These lt valves are longer than the ls and need more shims to bring the springs within specs.

I am not confident of anything, why #7? Aren’t you na? I can adjust timing and fuel per cylinder, should I trim #7 a little different? Hard to tell without more info. Mine was warm the day it broke. Something like 210deg at the start of the run. I am going to watch that a lot closer and make sure it is down to 180 or so before making a run. More questions than answers.

[oldman]

put extension on socket, put cardboard under head bring hammer and hit the thing till it pops off. If it don't hit it harder or get a bigger hammer.

IMO, it ain't the seat, all these fast lift .600+ cams are really race stuff and for Joe Normal, a sub .600 lift gentle ramp would prevent 99.99% of the valve / spring / pushrod / lifter problems. PERIOD.
I went through the LS1 valvetrain wars. I promised that I would not do that again on the LT1, do a search if you don't believe that 2016 era. Well I did it again and I had a valvetrain failure. I will NEVER, ever, don't care who sells it, don't care who runs it, put a .600+ in a street car. It just does NOT belong in one. Valve bounce is bad and it will hammer out anything, destroy anything. My .64X TSP setup failed sub 8,000 miles, my current setup still working: Cam Motion gentle lift .596... been quite a while in fact. Will a TSP .64x lift cam make more HP? Yep probably 20 to 30 all else the same. Do I care? Nope.

[jimadvig]

Originally Posted by KingLT1

And there lies your problem which is why I don't recommend porting stock casting without fully reworking the heads...new valve seats, guides, valves are a must imo.
I would just buy their aftermarket casting at that point.

Screen shot below taken off TSP website.

Is there any reason why more people aren't going with the Edelbrock Performar RPM LT1 heads? They seam to be much cheaper than going with ported or reworked factory castings.

[parish8]

Originally Posted by oldman

put extension on socket, put cardboard under head bring hammer and hit the thing till it pops off. If it don't hit it harder or get a bigger hammer.

If your talking to me Yeah, tried that. My head was ****ed anyways so I had no mercy(BFH) and it wouldn’t come apart.

[KingLT1]

Originally Posted by jimadvig

Is there any reason why more people aren't going with the Edelbrock Performar RPM LT1 heads? They seam to be much cheaper than going with ported or reworked factory castings.

They don't look any cheaper then TSP's PRC casting. TSP is priced per pair, Edelbrock is priced each (1) head.

[oldman]

Originally Posted by parish8

If your talking to me Yeah, tried that. My head was ****ed anyways so I had no mercy(BFH) and it wouldn’t come apart.

No the OP, but yeah that is what a die grinder is made for...

But it does show what valvetrain bounce can do. It is literally hammering all the parts. IMO TSP is just blaming the seat or anything else because they want to sell cams that make HP. Cams that make HP lift and lower the valve faster, which is fine on a RACE car. It is a terrible idea on a street car. I already made the wrong choice (cam was free), the right choice for the street is a sub .600 lift gentle ramp cam. Especially if it is FI, as the HP loss is not even one pulley size, which is way cheaper and way way more dependable. There is no free lunch, the higher the RPM, the higher the lift, the faster the ramp the shorter the valvetrain life, but yes the more HP produced for any given duration.

As an aside that is why I went to all new valves, since I knew my valvetrain failed, I had NO faith in the stock factory hollow valves (figured the were hashed). ProFlow valves are mandatory IMO. No alvalvetrain failure since, will it? Don't know, I give the engine a 75% chance to go 100K miles. Suspect the crank will bust first.

[jimadvig]

Originally Posted by KingLT1

They don't look any cheaper then TSP's PRC casting. TSP is priced per pair, Edelbrock is priced each (1) head.

I could be wrong but I thought I saw the Edelbrocks for $2499.00 for the pair somewhere. That is still more than stock ported heads for sure but for the trouble they have it sounds worth it going with either aftermarket set. Although I am not real familiar with what the Performer heads come with spring and valve wise. I just checked the PRC heads and they are $1799 with springs. So definitely cheaper than the Edelbrock heads by about $700. What are the differences between the two other than cost?

[cmitchell17]

Originally Posted by KingLT1

They don't look any cheaper then TSP's PRC casting. TSP is priced per pair, Edelbrock is priced each (1) head.

So TSP is saying "falling out", I guess that means literally falling out of the seat. I don't think mine have fallen out of the seat? I think #7 failed and the others are starting to fail from being burned. Now I guess the burning could be from bad machining, valve float/bounce and having constant combustion hot gases escape, or something else.

[jimadvig]

Originally Posted by KingLT1

They don't look any cheaper then TSP's PRC casting. TSP is priced per pair, Edelbrock is priced each (1) head.

It looks like the aftermarket PRC heads start at $2549.00 before springs. So it looks like the Edelbrock heads are a little cheaper. But are they worth it compared to the PRC heads?

[oldman]

IMO most failure is caused by bounce. Even a twin spring has harmonics that lead to very low spring pressure. Hence the evolution to a conical spring, as it tends to absorb the harmonic within the spring itself. I know it is hard to imagine that a 300 lbs spring will have very little pressure at certain points in the lift cycle.
https://www.streetmusclemag.com/tech...-horsepower-2/

Once the lifter is no longer in contact with the cam, the entire valvetrain is in free fall. There is a whole lot of energy coming down on that valve seat, hence the bounce.

If I were to do all this again, I would definitely go conical. I figure I'll change my TSP dual spring at sub 40K miles to conical.