Broken valve!

 

Damn.....whats the story ??

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Valve head broke off... That's it! Not an exciting story.

 

LOL....ok

whats was the build ??

Those do not look like Gen III pistons......but they appear to be stock.

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Ouch
Sorry about the luck. Is the block ok?

 

Nothing stock about it.

They are wiseco pistons. It was a forged lq9, Ysi powered 364ci. Was happily making 900+whp before the valve head broke off. Just bad luck.

 

I haven't taken it apart yet but at first glance it looks ok, cylinder wall took a beating from that stainless valve head banging around but I think .060" will clean it up. We shall see.

 

10-4...sorry about the luck also......

Going to rebuild it back the same ?? Or plans to make some changes ??

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Do you have a picture of the valve? (both pieces) Brand? What heads/cam/springs/rockers? Curious as to what caused the break.

 

Dam buddy hate to see the bad luck on the motor. Where you into it hard when it went. Plus what valves did the heads have in it.
More info on the block as you are able to work on her. I know you will have it back befor long even better...Robert

 

More pictures will follow. The engine belongs to a good friend of mine, pulled it out of his car yesterday. The valve let go towards the end of a day of road racing at road America. The heads were worked over factory 317 castings and the valves were Manley stainless covered by patriot springs and pushed by crane gold adjustable rockers. None of the other valves show any signs of loss of valve control or float. Looks like nothing more than valve failure to me at this point, perhaps do to the extreme heat generated with a engine that powerful in a road racing application.

I will be tearing the engine down soon, hoping the block, crank, and rods are ok. If its just machine work, pistons, bearings and heads it won't be to horrible. Still sucks though..

Thinking of trying a set of factory cast lsa heads on it this time around do to how cheap they are and the fact that they are a stronger casting. Can't seem to find and good info on them though as far as valve compatibility or even a definitive answer on what size the combustion chambers are. So we will see. Aftermarket heads simply are not in his budget.

 

I am seriously looking into the LSA heads on my new motor. Arun recommended them. They are pretty cheap, contact Arun if you have questions about them as he has some knowledge on them. If I remember correctly he said they are 68cc.

 

I tried to contact him actually, I get he is busy though. See I get conflicting info on the chambers. I hear 68 but I also hear 70. I also hear that people don't recommend shaving them but I personally cannot see why that is a issue. I have some homework to do on them still, but I wouldn't mind giving them a shot. I need to be able to get the compression up around 10.0-10.2 though, it was a 9.5 engine, not doing that again.

If I can find out what the chamber size is and what valves they use I can proceed. I am unsure If aftermarket ls3/l92 valves will work in them and Manley and rev do not list a part number specifically for that head. If the spring set from the 243/317 heads will work that will make them even cheaper as I have a lot of prc and patriot stuff laying around already.

 

Great info here Tony, please share your findings about these heads. I also am looking for 10.0 ratio. I am not planning on doing any CNC work, just slapping on a set of these heads with proper springs and going to let Arun do his magic and pick out proper cam setup. He believes these heads will flow 900+ out of the box with no work done to them, I will be more than happy with that.

 

The heat is what I was thinking but didn't want to jump to conclusion. Now that you mention the rest not showing any signs of float then it seems more plausible. How many miles/track trips were on the springs and did you test them all? Might be worth testing them in order that they were running just to rule out a weak spring.

Likelihood of it being the heat, consider going to inconel exhaust valves on that motor. They aren't cheap but they are worth it.

The lsa heads require a ls3 type manifold don't they? I'm not real sure. I'd add up the cost of the swap and consider all head options that don't require any changes other than the head.

Stock 317s *stock* will take a beating and make good power so I'd keep them on the table when looking at lsa heads too. (put inconel exhaust valves in them) Basically, I'd use whichever ones fit the amount of $ I want to spend because you can make them perform equally.

 

From what I have seen, the heads are 68-70cc, the chamber is nice and smooth-almost like the anti-detonation work done on my TFS 245's.

I personally would not mill them, the more material the better.

I would use the factory issue hollow stem intake valves-there's no worries about them breaking. The exhaust valve has all pressure on them-which is exactly what broke on your setup.
The lighter intake valves is a huge plus on big power boosted setups.

The spring sets from the LS1 heads swap right over to the LS3 stuff.

I would worry about the 9.5 CR, especially if your boost level is double digits. You can compensate that easily with a cam change.

That's the other nice thing about the LS3/LSA heads-you don't need much of a cam to make some good power with them.

I am considering getting Charlie@RPM run his CNC port program on a set of heads for me.

 

The car made about 18lbs at 6500rpm and close to 20 at 7000. The engine was a 9.5 comp and the cam was speced out by ecs. The combo seemed to work great but I personally feel the 9.5 comp made it a bit lazy out of boost so this time around I was going to try to get it up around 10. I am open to discussion as to why I shouldn't though. I feel the higher comp will help with responsiveness and even fuel mileage. Isn't your engine in the 10s?

Really appreciate the info Arun.

 

I agree with you. Ls3 intakes are cheap though, have a ported ls2 he can sell. Inconel exhaust valves are a must this time around for the exhaust side. Arun seems to feel the factory hollow stem lsa intake valves are the way to go though.

As I want to increase compression this time 317s are no longer a option and I'm interested in this lsa head, it looks like an amazing factory part.

 

I am higher than 10-but I have done combo's as low as 9.1, driving them around you would never know the difference between 9.1 and 10.1

These are all 4" stroke motors though.

From 9.5 to 10.1-there's no discernible difference.

 

Does anyone know if the lsa head has a factory inconel exhaust valve like the ly6 head? If that is the case I believe Arun could be dead on with just changing the springs and letting them eat.