Engine component weight reduction

[dougie]

Re the DW head - I've met two people who've had breakage problems with the DW aluminum valve spring keepers - would stick to the steel.

I had them for one race season.....too soft. My new race engine doesn't have any DW parts.....

 

[Bob_Spidell]

I had them for one race season.....too soft. My new race engine doesn't have any DW parts.....

Begs the question: Who do you get race-worthy parts from?

 

[bob hughes]

I don’t think 10 lbs will be a problem given the mass of the clutch assembly, the rotating inertia of the crank, and the engine’s inherent low end torque. There’s still a lot of inertia in there.

Rob

We are talking of almost 18lbs here



Bob

 

[dougie]

Begs the question: Who do you get race-worthy parts from?

Using mostly bespoke American made internal parts, Comp SBC throughout the head, and AH Spares/Sideways Engineering for misc.

 

[Bob_Spidell]

Thanks, Dougie. Healey porn.

 

[steveg]

Thanks, Dougie. Healey porn.

I agree

 

[bob hughes]

Drool



Bob

 

[twas_brillig]

Sometime down the road, when it's time to get hardened inserts in our head for unleaded gas, I'll be looking at the aluminum head as a potential alternative. Doug

 

[Michael Oritt]

Recently while I was checking valve timing after changing the chain on the 100 I found one broken AL DW keeper. I chose to replace the set with another from DW as mine is not a race engine and the break occurred after about 14 years/60K miles. That said if this were a racing engine I would be using steel keepers and that is what I have on the race engines of both Elvas and the Ginetta.

 

[Michael Oritt]

Here are some pictures of a valve (just the head, luckily) that broke off at the base of the stem on the MGA engine in my Elva Courier. The valve is epoxied into the piston for display purposes. It destroyed the piston and scratched up the bore but I was able to hone it out and go slightly oversized. A new piston and I was, literally, off to the races.

If the valve were to fall into the combustion chamber stem and all due to a broken keeper/collet, etc. the results would not be so minor and a seized engine, broken crank, etc would be a very likely result.

 

[Bob_Spidell]

... If the valve were to fall into the combustion chamber stem and all due to a broken keeper/collet, etc. the results would not be so minor and a seized engine, broken crank, etc would be a very likely result.

Not only that, bits and pieces can be blown into the other cylinders. Happened to me in an airplane.

 

[Michael Oritt]

Bob--

One of the problems with aircraft is that you cannot pull over to the side of the road to assess/fix a problem.
I'm glad the incident did not end catastrophically and since you lived to tell the story please share it with us.

 

[Bob_Spidell]

Bob--

One of the problems with aircraft is that you cannot pull over to the side of the road to assess/fix a problem.
I'm glad the incident did not end catastrophically and since you lived to tell the story please share it with us.

Glad you asked Michael . I don't remember the year, but it was 25-30 years ago. I was returning to Palo Alto from Burbank after visiting my then girlfriend in LA in a decrepit Cherokee 180 on Easter Sunday. I was over the Grapevine Pass (I5) level at about 6,000' altitude. The pass is about 2,500' feet or so, but there are some pretty high mountains on the west. With no warning, the Lycoming O360 engine started shaking violently and ceased producing almost all power. In hindsight, I should have shut it down as it's not unheard-of for engines to shake themselves off their mounts--in which case I wouldn't be writing this now--especially if the prop throws a blade, but I left it running (in a fashion).

I looked down and the obvious first choice for an off-airport landing was the freeway, but it was pretty busy and there wasn't a long, straight section. My second option was the frontage road, but it had no straight sections and I knew from training there are usually signs, wires and other obstructions near two-lane roads. I spotted a fairly straight dirt road, and felt comfortable with that having practiced emergency procedures in similar terrain (including some large power lines nearby). I did a normal left-hand pattern to the dirt road but overshot the base-to-final turn--which was fortuitous as I found out later there was a large 'sand trap' in the road--and aimed for a clearing just ahead (I remember looking around and, since it was spring the clearing and hills were covered in green grass and poppies in bloom, and thinking "well, if I don't make it they can just dig a hole here and throw me in it"). After I touched down I saw a large berm--buried gas line--but had just enough groundspeed to pull back on the yolk and lift the nose gear over the berm (lucky break# 2). Anyway, I made a decent approach and landing but relaxed just a little at the end and groundlooped about 45deg to the left.

I radioed ATC and let them know I made it down and they dispatched a CHP officer and a local deputy (the highway patrolman later told me I was talking pretty fast for a while). I was not too far from the little town of Gorman, which had a Greyhound stop but missed the last bus. The CHP got permission from his captain to give me a lift to a town about 20 miles away--forgot the name--which had a later bus. Somewhere in there, I made a call to my parents, who were having a little pool party with some family; when I told my mom what happened she fell in the pool!

As luck would have it (lucky break# 3) I'd landed in a county (I think) park called Paradise Valley or similar, and one of the rangers was an airframe & powerplant mechanic; after a week or so he made arrangement for a deputy friend to close the road temporarily and we loaded the plane on a flatbed, in one piece, and trucked it to a nearby airport called Quail Lake, with police escort! We pulled the engine and found that one of the sodium-filled exhaust valves had separated at the stem and blown pieces into the other three cylinders. We also found the engine had an incorrect camshaft for the engine; whether that caused or contributed to the valve failure is speculation. To this day, I wonder if I could have made Quail Lake if I'd known it was there, but I doubt it and would probably have ended up in the lake on the west side of the runway.

We hung the new engine and I flew around the airport for an hour or so to do the preliminary break-in on the engine, during which I got buzzed by an A6 Intruder! Turns out that area is an MOA--Military Operations Area--and is used for low-level military training. We even got buzzed by a couple Phantoms when we were loading the plane on the flatbed.

Looking back, it was a great adventure, but one that I really don't want to do again (I haven't flown in a few years, but often entertain thoughts of getting back in the cockpit before nature determines I can't).

Side story: When departing Burbank once--don't remember if it was before or after the 'incident'--there was a couple spit-polish green A10 Thunderbolts--known better as 'Warthogs'--sitting on the ramp near the FBO (they were probably doing an airshow demo nearby). Both had their canopies open and their air stairs extended--pre-September 11, of course--and I remember thinking "I wonder if they left the keys in those things."

 

[Michael Oritt]

Bob--

That will be a great story to share with your grandchildren or anyone you might want to thrill. Myself, I wouldn't like seeing the word "decrepit" describing any airplane, much less the one I was in, but we were all young, foolish and bulletproof.

I spent many years living upon a 48' single-diesel trawler (pictured) and while there were many situations where a loss of power would have made for a bad situation the boat would float without power and I always had easily-deployable ground tackle (anchors) at the ready plus sails to get somewhere and maintain steerageway if offshore. I've often been tempted to take up flying but the thought of being in a vehicle without an effective "neutral" always kept me from actualizing the thought.

 

[Bob_Spidell]

Actually, engine failure is one of the more manageable problems in an aircraft (being over water or rough terrain excepted). Fire, and 'flutter,' where the aircraft can shake itself apart in a matter of seconds are scarier. Most light aircraft have a power-off, clean--no flaps and gear up--glideslope of 10:1, which means if you're at about 5,300 feet above terrain you can glide for almost 10 miles.

 

[DerekJ]

Great story! Thats why I never fancied flying, but somehow my son is an airline pilot!

 

[Bob_Spidell]

The thing to know about aviation is that, unlike driving, boating, motorcycling, racing and almost any activity involving motion in a machine the risks are almost entirely manageable. Take motorcycling: you can do everything right and still get taken out by an old lady turning left in front of you with no warning (nothing against old ladies, it's just a good example). Almost every aviation accident involves an 'accident chain;' i.e. the crash started hours earlier when the pilot took off inebriated or ill, had skimped on maintenance, wasn't up on his/her training and currency, didn't sump his/her tanks and, way too often, didn't check and account for the weather, etc. If any one of the links in the chain were broken the accident would not have happened. The accident that claimed John Kennedy Jr., his wife and sister-in-law is a classic example: He was injured--I believe he had a cast on one foot--got behind schedule and launched too late in the day, had not had enough instrument training to save himself, and on and on (note I've done dumb things, but been lucky; some weren't).

Being entirely responsible for your life and your passengers in a foreign and complex environment is extremely sobering, but also immeasurably rewarding. Of course, it's not any different when you get behind the wheel of a car--and bad stuff usually happens even quicker--but, for some reason a large section of the public doesn't seem to realize it. I urge anybody with, well, an urge to fly to at least give it a try. There are a couple of accomplished pilots--Sean Tucker, Jr., for instance--who were either afraid of flying or afraid of aerobatics who became champions when they gave it a try (I was fortunate to have flown with Tucker's instructor, Amelia Reid, a few times). There is no greater challenge that us 'average Joes' can undertake.

 

[bdcvg]

Lol after 26 years as an ATC, flying is definitely an "only to cross the ocean " activity for Me.

 

[steveg]

Suggest reading "Fate is the Hunter" by Ernest K. Gann. A collection of articles about commercial and transport aviation from the days of the DC-2 until he retired out of the DC-6. It's a fascinating, yet horrifying book.

Those of us in cars have a hard time comprehending the life-and-death quality of aviation.

I distrust "expert systems" and general aviation is certainly one.

 

[Bob_Spidell]

...

Those of us in cars have a hard time comprehending the life-and-death quality of aviation.

...

Yeah. Nobody ever dies in a car.