Disaster on the dyno

[MOPOWER871]

My buddy john had his big inch high compression Hemi on the dyno at Jack Merckel race engines long island n.y. and on the 12th pull on the 7th day approaching the 800 hp mark the intake valve seat came loose hung the intake valve open, the exhaust valve hit the intake valve, the piston hit the, well you get the picture, needs a new sleeve, piston, head ... these heads where brand new Edlebrocks out of the box that where just outfitted with better valves and springs and ported... what an epic disaster. think edelbrock will make good on at least the head. just thought I'd share .

 

[kiwigtx]

Ouch. Sorry to hear that.

 

[HEMI-ITIS]

Scott will help make it right!

 

[Car Nut]

Damn what crappy luck, that made me cry!

What is the sorry button!

 

[FU64RY]

Modified from what the sent you.
Probably no warranty.

 

[Qbrozen]

Yeah, I'm a bit confused why Edelbrock owes anything.

 

[mmissile]

Big inch, high-compression, and 800 h.p.? I'm guessing there are more issues. Who did the heads?

 

[1967coronet440]

Sucks that happened but The heads were modified, you will get nothing from edelbrock, nor do they owe anything. I would be asking the person that assembled the heads, he’s got more to do with the failure than edelbrock.

 

[Ranger16]

Dyno's scare the hell out of me.

 

[MarPar]

 

[fbs63]

View attachment 529610

Did they put oversized intake valves in? If so if you make the seat too thin they lose their press fit.

 

[68 HEMI GTS]

Yikes, I'm also curious what they messed with. I have a set I'm putting on my hemi.

 

[MOPOWER871]

Yeah, I'm a bit confused why Edelbrock owes anything.

A brand new head out of the box and a harden valve seat drops out . never seen one do that. who knows where there making these heads probable farmed out to meh e co.

 

[68 HEMI GTS]

A brand new head out of the box and a harden valve seat drops out . never seen one do that. who knows where there making these heads probable farmed out to meh e co.

Happens from time to time. Usually caused by bad castings or improper press fit. Also like stated if they were cut for bigger valves. The early alum mopar heads that edelbrock cast had some issues with this. I would have hoped that they got the vicjr's right. This is the first issue I've heard of on these heads. Hopefully a fluke. May have a hard time proving that the valve seat fell out first though.

 

[MOPOWER871]

WILL TRY TO GET THE SKINNY ON WHAT WAS DONE TO THE HEADS

 

[moper]

I never run anything out of the box. But the risk is there is no warranty once anything is done. If a seat fell out, especially an intake seat - there were issues with that engine. Period. 12 pulls in seven days? How was it performing? What do the bearings of the non-destroyed cylinders look like?

 

[67BELVSLEEPER]

Dyno's scare the hell out of me.

It’s all about the Dyno Operator. Dynos are safer than a 1/8-1/4 mile pull if the Operator knows what he is doing. Not sure why this guy did 12 pulls? I was just at a Mustang Club for a dyno day last week and there were 5-6 cars in the mid 700 hp range. One Terminator made 860 rwhp with a bunch of boost. The dyno owner ran probably 30 cars, zero issues. This is chassis dyno as well so some of these were approaching 1000 hp at the crank. The majority in stock bottom ends.

 

[67BELVSLEEPER]

At what rpm did it let go on the dyno? What seat pressure did the valve springs have?

 

[MOPOWER871]

I never run anything out of the box. But the risk is there is no warranty once anything is done. If a seat fell out, especially an intake seat - there were issues with that engine. Period. 12 pulls in seven days? How was it performing? What do the bearings of the non-destroyed cylinders look like?

This was an all out race motor.They where trying to get it right 7 days because they where pulling bearing to check them and trying different cams.It happened around 800 HP mark.These where out of the box meaning brand new never run, but he had better valves, springs...installed to match the cam profile.
The intake valve seat is suspect because it was cracked in two and not hammered like it being slammed up and down.
bearings looked like the crank was twisting. (scat crank)

 

[Qbrozen]

You wrote they were also ported, so the seat could certainly have been affected during that process.

Also, if we're talking stiffer springs, then they would be putting greater pressure on the seats than the manufacturer intended.