Send this back to tech if you don't think it belongs here, but...

2 engines blown and now the question was put to me as to whether it was the combination that I had built that is the problem.

Would you please take a look at my combination and tell me if you believe this is my problem.

1.6 SA RRs with hardened push rods (+.050")
Crane 227 cam 210/224 112 510/552 lift
REV springs good to 550 lift
ported heads with 2" int and 1.56" manley undercut race flow valves.

First engine supposedly spun a bearing at 7000 easy miles.
Second engine apparently swalled a valve with less than 1000 mile on it.

Is it possible that the +.050" push rods pushed the valve into the piston?

Sorry for posting here, but I don't know what else to do, especially when one of the mechanics thinks maybe that the combination is what caused the problems.

 

The lift on the cam, along with the ratio of the rocker arm will determine overall how far the valve opens. The length of the pushrod will change the overall geometry of the system, but not how far the valve opens.

 

Thank you. I have seen a lot of cam profiles on the tech site that have a lot more lift than mine, so I guess maybe the locks gave out, or the spring broke, allowing the valve to go in. I turned the engine off as soon as I heard the clacking, but I guess I probably ruined the engine anyway.

Guess I just wasn't supposed to have the car.

 

Well, you list .552 lift on the exhaust side and yet your springs are only good to .550 lift. Sounds like you're experiencing coil bind.

Are your listed lift rates with the 1.6 ratio rockers?

Mike

 

Are you sure the valve broke off or fell into the cylinder?
Or is it possible you were hitting the piston with the valve constantly?

The above post definitely points out a problem with your springs being a little too small, especially if those lift #s on the cam are with 1.5s like most cam specs are rated with.

 

Pull the motor apart and look at everything on the valvetrain where the broken valve is....

It could be the coil bind issue, weak valves, etc.... these things are blowing up for a reason and in motors it can come down to .001" easy.

Bret

 

The lifts of 510/552 are with the 1.6 RRs. Since the springs were rated to 550 I didn't think there would be a problem, especially since I don't rev the crap out of the engine all the time.

I don't know all what happened yet. I am still reeling from the bad news. I suppose I will have to give the go ahead to dig in a investigate.

I just wish it would all be a night mare and I would wake and everything would be fine.

 

With your setup, the cam lifts the valve to .552 everytime it turns over, regardless of RPM rate. With springs rated to .550, you maxed them out with no provision or clearance accounting for coil bind. Sounds like the spring let go catastrophically.

 

Usually a spring is rated to a certain lift with some allowance for clearance between that and coil bind. That would explain why all of them are not busted. If there was none then this is a huge can of worms.

Bret

 

Well, all I saw so far was that one of the valves dissappeared on the passenger's side. You can see the keepers laying in the head (on had the valve cover up enough to see back in there. The mech. is going to pull the head today and check out the situation.

The springs have been on there since the cam install and noone seemed to think I'd have a problem. Don't know if the springs broke or not yet. The mechanic reinstalled the springs when my heads were ported. he notes in this work order that he installed the springs 120 lbs at 1.800 hght. 275 lbs at .450 lift. with .200 coil bind clearance.

The cam spec sheet calls for closed 120 lbs at 1.875 and open at 312 lbs at 1.375

cam rated at valve float at 6500.

I don't know what the conclusion will be when then get it torn down, but if the springs were too weak, it seems that a reliable mechanic would have at least brought that to my attention knowing the cam specs and the springs which I had them install. But at this point, I don;t know why the valve took a dive.

 

Dang those springs seem light for that cam that is for sure. I never go light on springs. they are just to damn cheap to loose a motor over.

Unless there other un-known issues like piston to valve I would lean towards bad spring combo like the others here.

I know TJ is in your area maybe he can help out?

 

metal expanding from heat can eat up extra clearances in a hurry then bind; and bend snap or break pushrods generaly. let us know what happened

 

Sounds like you were running low on blinker fluid...just let us know the real results before we keep shooting at ghosts in the dark.