2nd Engine Failure!

#1

My father had his second engine failure this last weekend. He was running a junkyard motor that was recently installed by Strickly German at Road Atlanta in August. Before his failure, I adjusted his valve clearances to .006 on the intake and .008 on the exhaust valves while the engine was cold. I was a bit rushed, but had the proper tools and relatively confident that I didn’t have them too tight. We haven’t done a leakdown test, but #2 makes zero compression and completely ate the electrode and spark plug tip. It appears that the #2 exhaust valve failed, the valve bounced around inside and destroyed the plug. The Bentley manual says .010 for valves, but others have recommended the tighter settings. Would it make sense that the tighter clearances caused excessive exhaust gas leakage around the valve and subsequent meldown of the valve head? I think I’m going back to .010 all the way around…

#2

A difference of 0.002" in the exhaust valve lash isn’t going to result in failure of the valve. And even if that allowed some exhaust gas leakage and burned the valve you’d loose compression on that cylinder and have obvious problems way before the burning could cause a valve failure.

My guess, and that is all it is, is that an over rev was in this engines history. Depending on exactly what failed, there are other possibilities.

#3

curious to what is the “safe” or less aggressive setting .009ish?

#4

FishMan wrote:

I don’t believe this was a Spec car, but technically the shop spec of 0.010 must be followed.

Sorry to hear about the engine failure.

#5

Steve, the subjective definition of .010", what does it really mean?
I like a tight .010, but that does not translate to .006…

Regardless, in this situation I’d have to agree with Yoda Levie.

RP

#6

Patton wrote:

Per the CCR, you get 1/2 of the last specified digit, so go for 0.0095". :laugh:

#7

Sounds like a good tight .010 to me.
Thread hijack,next topic: Does it really make a difference?

Better yet, how 'bout measuring my cam lobes…

RP

PS cam lobes will be an issue…but it hasn’t happened yet.I’m not the rules guy, but the HP rule should be…this is for others to discuss.

#8

Jim Levie says that BMW released a TSR recommending .006 intake .008 exhaust after a spat of rocker arm failures. If so, that makes it legal.

I don’t buy that .008 caused the valve to fail.

Strictly German is a fine place, but that doesn’t mean that everything you buy from them ends up being cherry. Engine #3 came from them and turned out to be a dog. In the second weekend it’s oil pressure went so low I didn’t race. When I pulled it apart we found thrashed bearings and the head from a 323, not a 325.

I would have liked to have gotten a refund for that motor, but when I told Strictly German that it had a 323 head on it, I think they decided that I was a loony.

Get a replacement head from some kid at BF.c, and send it to a machine shop for refresh. If the cam and rockers are still good, it’ll probably cost you <$400.

#9

Steve D wrote:

[quote]FishMan wrote:

I don’t believe this was a Spec car, but technically the shop spec of 0.010 must be followed.[/quote]
Chuck was the first one to tell me about this, stating that there was bulletin late in the life of the M20 engine that specified the tighter tolerances. I later talked to a BMW Master Mechanic (now retired) that remembered a tighter spec being used. I can’t prove that BMW issued a TSB for this, all of that is apprently lost in the mists of history. But if that is the case the adjustment is legal per 9.3.1.2.6

#10

Patton wrote:

[quote]
Regardless, in this situation I’d have to agree with Yoda Levie.

RP[/quote]

Jim, I think you just acquired your new nickname. :lol:

#11

Rich,

I have a line on a running motor for you. I might even be able to pick it up for you. Email me at anthony DOT magagnoli at tema DOT toyota DOT com

Question for the guru’s: Is the .010" spec (or .006/.008) supposed to be set COLD or WARM? I thought it was supposed to be warm.

#12

Z3SpdDmn wrote:

The factory manual says maximum 95 deg F spec is 0.010". At operating temp (thermostat open) the spec is 0.012". Seems like the conventional wisdom is to do it cold. I am so slow that even if I started with the motor hot, it would be cold by the time I got to the last one (1 5 3 6 2 4 for those playing at home).

#13

PS - It says the installation temperature for the cylinder head should be 120 deg F. Or “low” if you use your wife’s kitchen-mounted cylinder head warming apparatus. :laugh:

#14

Fred42 wrote:

[quote]Patton wrote:

[quote]
Regardless, in this situation I’d have to agree with Yoda Levie.

RP[/quote]

Jim, I think you just acquired your new nickname. :lol:[/quote]

I love these.

#15

Anything that was intended to be adjusted can be adjusted however you want it. Otherwise you better have your side mirrors in the factory position or I’ll protest your ass! If you still have the vents in your dash they better be in the factory position also because the rules don’t specifically say that you can aim them.

#16

turbo329is wrote:

9.3.1.4.1. All valve sizes, seat dimensions and angles, etc., shall conform to factory specifications.
That little “etc.” is a bitch, ain’t it? I wonder of valve clearance is included in that.

#17

Steve, I don’t agree with your interpretation. The paragraph you referenced appears to be talking about items you would replace or recondition during a head R&R. Restricting valve clearance adjustment from that paragraph is a stretch. Regardless, I plan to adjust to factory specs for Max durability.

#18

Z3SpdDmn wrote:

[quote]Rich,

I have a line on a running motor for you. I might even be able to pick it up for you. Email me at anthony DOT magagnoli at tema DOT toyota DOT com

Question for the guru’s: Is the .010" spec (or .006/.008) supposed to be set COLD or WARM? I thought it was supposed to be warm.[/quote]

Thanks for the offer, but found a motor yesterday with good compression numbers. I’m picking up the car after work and pulling the engine tonight.

#19

Steve D wrote:

[quote]turbo329is wrote:

9.3.1.4.1. All valve sizes, seat dimensions and angles, etc., shall conform to factory specifications.
That little “etc.” is a bitch, ain’t it? I wonder of valve clearance is included in that.[/quote]

All of those would require machining or non OE valves. Although there is a factory recommended setting for valve lash it doesn’t mean you have to follow it. There are factory recommended spark plug gaps, tire pressures and alignment settings also.

#20

turbo329is wrote:

[quote]Steve D wrote:

[quote]turbo329is wrote:

9.3.1.4.1. All valve sizes, seat dimensions and angles, etc., shall conform to factory specifications.
That little “etc.” is a bitch, ain’t it? I wonder of valve clearance is included in that.[/quote]

All of those would require machining or non OE valves. Although there is a factory recommended setting for valve lash it doesn’t mean you have to follow it. There are factory recommended spark plug gaps, tire pressures and alignment settings also.[/quote]
I recall getting into this same philosophical conversation before. The CCR is like the Constitution. If it’s not in there, it’s not allowed. How far you push “not allowed” is up to you, but don’t fool yourself into thinking that your idea is ok just because it’s not specifically banned in the CCR.

My oil pan shield currently has big holes in it. That’s not allowed. Screw with the rules at your own peril, but we can all read english. Particularly “Only modifications specifically authorized are allowed; and competitive adjustments are not allowed. Other than the modifications specifically allowed in these Rules, every part of the
car must remain as it came from the factory.”

With few exceptions, we’re all adults here and will understand that there are logical exceptions, but debating each one is a little tedious. Use common sense, armed with a clear understanding of the series philosphy.

Fish: Re. setting lash to .010 for durability. IIRC Jim said that the later .008/.006 was spec’d in order to make rocker arms last longer.