Valve cover gasket blew out on Impluse Turbo Nytro

[sled pilot]

Great day on the mountain yesterday until the valve cover gasket blew out during a climb. I run approx 10lbs boost and burn 94 octane. The sled belched out a puff of black smoke (oil hitting the hot turbo) and oil soaked the engine compartment and the valve cover gasket blew out at the half circle portion behind the battery. Turbo looks good. Only change I have made is the four stroke solutions one way valve (yes it is installed correctly). Looking for some advice from the turbo guru's out there...Should I be putting in a bigger breather tube into the valve cover? Should I be doing a compression check?(too much blow by) Anything else I should be considering? Thanks in advance.... Thomas

 

[JTAB]

Check breather tube to make sure it is free flowing I had one freeze up and blew the gasket out on mine. My 2 cents.

 

[MTN_VIPER]

Thomas, do you have a filter at the end of your brearther hose? If so, most guy's remove it. Since it can get wet, then freeze causing a blockage. Similiar to what JTAB said above.

 

[sled pilot]

Breather hose

No I do not have any filter on the end of the hose but I noticed that the valve cover hose did not flow great. It had less resistance on "suck" vs "blow" (yes we are still talking about a turbo nytro) but I wondered if the addition of the turbo and the added pressures associated with this setup made this breather insufficient? Blow by was my other concern.... What should my compression be with the Impulse racing system 2871 Garret? Thanks for the help so far...Much appreciated. Thomas

 

[Menace1]

Too funny, exact same thing just happened to me, same half moon section on motor too, will be interesting to figure this one out, any help or ideas would be appreciated. I might try a bigger hose myself, plus going to run the machine in the garage and check what kind of pressure is coming out of the hose. Go from there.

 

[sled pilot]

Breather hose

I would agree that checking the pressure is a good idea. A buddy of mine that races a turbo diesel truck runs a monster breather hose off his valve cover ... more pressure more venting required.

 

[andre162]

Have you done a Bleed down test? Mine did the same thing and it turned out that I had one piston that got a little hot and was just a little bent on the top lip between that top of the piston and that first ring. seld ran fine just kept blowing out the gasket.

 

[red]

It could be just bad luck. I know some people stake the 1/2 cups in the head with a pin punch to give the gasket something to bite into. Likely should do a compression test, a leak down test is alot better, it will should a leak if you have one, if it leaks out the breather, you know your problem. Years ago, cpr kits would use the turbo to suck the crankcase fumes out. He put a nipple in the end of the airfilter to the vent of the crankcase to help with this issue.

 

[RACINSTATION]

Ill tell you a quick test. Start sled, run for 10 seconds, shut it down, listen to valve cover breather tube......if it is still bleeding off air after you shut it off ( you will hear a faint psssssssssss) you are not gonna be happy. Detonation station, you have blow-by. Most like from detonation. The ones I have seen have some slight scarring on the piston and need new pistons and usually cylinder repair.

 

[franklin]

Ill tell you a quick test. Start sled, run for 10 seconds, shut it down, listen to valve cover breather tube......if it is still bleeding off air after you shut it off ( you will hear a faint psssssssssss) you are not gonna be happy. Detonation station, you have blow-by. Most like from detonation. The ones I have seen have some slight scarring on the piston and need new pistons and usually cylinder repair.

I've never seen one that you couldn't hear bleeding off after you shut it down...

 

[RACINSTATION]

To an extent this is correct, but when you have blowby it will almost sound like a tire leaking. You can also put your finger on the breather tube end and it will have some good pressure on it. You are right, they all bleed off a bit, but you will KNOW when you have pressure build up.

 

[Menace1]

Have you done a Bleed down test? Mine did the same thing and it turned out that I had one piston that got a little hot and was just a little bent on the top lip between that top of the piston and that first ring. seld ran fine just kept blowing out the gasket.

Going to do a leak down test after one more ride, seasons over for me then anyways.

 

[TurboMatt]

Years ago, cpr kits would use the turbo to suck the crankcase fumes out. He put a nipple in the end of the airfilter to the vent off the crankcase to help with this issue.

This brings up a good point. Actually something I have wondered about for awhile. Why don't kit mfg. do this anymore? When we build custom kits for our cars that's how we do it: run the vent tunes to a catch can, then to the turbo inlet. Helps, keep the pressures incheck. That's what I'm thinking of doing with my sled. Seems way better than just venting to atm.

 

[sled pilot]

Leak Down Test

What all is involved in a leak down test...How is it performed? I like Red and Turbo Matt's idea of the catch can and the hose rerouted into the intake side of the turbo setup for negative pressure rather than atmospheric pressure. Some good feedback ...Thanks for all the help Thomas

 

[red]

Each cylinder to brought to tdc, all valves are closed, then shop air is put into the cylinder. If there is a leak, it will leak out the exhaust system, intake system, or the crankcase. If there is no pressure drop engine is in good shape. There is going to be some lost, its impossible to stop all it. If doing yourself just make sure have a bar in the clutch to hold the engine from spinning.

 

[Shermanator]

Blew the gasket on mine as well, breather hose was plugged! Sherm

 

[TurboMatt]

Do all the big name kits for the Apex and Nytro just vent to atmoshpere?

 

[Zipperno]

Do all the big name kits for the Apex and Nytro just vent to atmoshpere?

MCX has a oil breather built into the intercooler.

 

[SPOOLED]

i dont think that there is a breather plumbed into any intercooer. all apex kits have iac plumbed into the intercoolers do most nytro kits. but no way would any kit pressureize the crankcase via "breather" to the intercooler.

 

[MTN_VIPER]

Leak down testers

What all is involved in a leak down test...How is it performed? I like Red and Turbo Matt's idea of the catch can and the hose rerouted into the intake side of the turbo setup for negative pressure rather than atmospheric pressure. Some good feedback ...Thanks for all the help Thomas

Here is link to a write up in car craft that explains it pretty good.
A leak down test IMO is the best way to check an engines condition. Usually I like to see no more than about 8% leakage. http://www.carcraft.com/techarticles/116_0406_cylinder_leakdown_tester/index.html

I prefer to use testers that have a pressure regulator on the inlet as well. Sometimes if you have an engine that has a sticking valve/valve guide, the high shop air pressure will force the valve closed leading to miss-diagnosis. By regulating the shop inlet pressure down, you can avoid the condition where the shop air would be closing a sticking valve.

Testing for leakage past the rings into the crankcase, higher shop pressures wouldn't be as much as a concern. So a un-regulated inlet (shop) air supply should work ok.