Valve springs - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Gunman · 11-14-2018, 12:55 PM

So, reading some of the many 86 valve spring recall threads, got me thinking...

...in a inline, slant inline, V, or W engine design, if a valve spring breaks, it can "drop a valve". What about in a boxer engine? does it "toss the valve to the side"?

8RZ · 11-14-2018, 01:34 PM

I asked this same question in one of those threads and I believe someone told me that the FA20 is an interference engine so the pistons could uppercut the valves if the timing is off (or if the valve springs fail).

humfrz · 11-14-2018, 02:41 PM

Quote:

Originally Posted by Gunman

So, reading some of the many 86 valve spring recall threads, got me thinking...

...in a inline, slant inline, V, or W engine design, if a valve spring breaks, it can "drop a valve". What about in a boxer engine? does it "toss the valve to the side"?

Yes, and depending upon which side it gets tossed to, when, - makes all the difference -

We didn't have this "valve dropping" problem back in the flathead days -

humfrz

8RZ · 11-14-2018, 02:48 PM

Also, the RPM can play a factor as well.

Sapphireho · 11-14-2018, 02:54 PM

I have a valve story for you. Once I was helping a friend tear down his blown V8 in his boat (wife and he did speed skiing competitions). We took one head off and one cylinder was missing a valve. It was just gone. The valve got sucked all the way to a cylinder on the other side. Block and everything was mangled.

humfrz · 11-14-2018, 03:19 PM

Quote:

Originally Posted by Sapphireho

I have a valve story for you. Once I was helping a friend tear down his blown V8 in his boat (wife and he did speed skiing competitions). We took one head off and one cylinder was missing a valve. It was just gone. The valve got sucked all the way to a cylinder on the other side. Block and everything was mangled.

Was alcohol involved in that rebuild - ??

humfrz

Sapphireho · 11-14-2018, 03:49 PM

Quote:

Originally Posted by humfrz

Was alcohol involved in that rebuild - ??

humfrz

Well, the blown and injected 500+ cubic inch chevy did run on nitro.

bcj · 11-14-2018, 06:04 PM

The wormhole geometry going from initial conditions to final end point are doing my head in.

Was Windows vers.xx in the block involved?

Gunman · 11-21-2018, 03:49 PM

I think I'll go back to the term we used at a previous employer, when a jet engine had a blade failure, and say that the "valve liberated itself".

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11-14-2018, 02:54 PM	#5
Sapphireho Famous Potatoes Join Date: Mar 2016 Drives: '15 ultramarine Location: Idaho Posts: 14,049 Thanks: 5,816 Thanked 19,655 Times in 9,246 Posts Mentioned: 163 Post(s) Tagged: 0 Thread(s)	I have a valve story for you. Once I was helping a friend tear down his blown V8 in his boat (wife and he did speed skiing competitions). We took one head off and one cylinder was missing a valve. It was just gone. The valve got sucked all the way to a cylinder on the other side. Block and everything was mangled.

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