Chrome Rocker valve covers

[Cozylover]

Hi Cozy builders and flyers,

 

I'm installing 4 brand new cylinders on my Lycoming O-235-C2A powered COZY (Experimental Canard).

 

Strange enought the rocker valve covers are not included with the cylinders (seems to be normal). So I will use the ones from the original engine.

 

Does anybody know if the rocker valve covers, may be "chrome plated"?

I suppose car experts can do this...

 

I know this is only an aesthetic thing... makes the engine a bit more shiny, but of course not better...

 

Any consequencies or thoughts on the above?

 

Cozyflyer Bjorn

 

[chuckthedog]

I,ve have read, and been told chrome causes the clyinders to run hotter.

[Cozylover]

Hi Chuckthedog,

 

Thanks for your reply... could well be true!

 

Anybody else to confirm the above...?

 

Also, if the rocker valve covers won't be "chromed" they will defenitively need some paint...Which paint should I use? I've seen specific "engine paint"..., but would normal paint do the job as well? Any first hand experience more than welcome!

 

Thanks and regards,

 

Cozyflyer Bjorn:)

[Marc Zeitlin]

Originally posted by Cozylover

Anybody else to confirm the above...?

 

There's "chrome" cylinders, and chrome on the rocker covers. They're two different things - I think Chuck is referring to the first. I'm no engine expert, but it's possible (and I've heard A&P's mention) that cylinders that have had the barrels chromed may run hotter during break in than unchromed cylinders, and this seems to match with what Chuck has heard.

 

On the other hand, it's __extremely__ difficult for me to believe that any appreciable heat is dissapated through the rocker covers, and that any coating, be it paint, chrome, or anything else might have any measurable effect on CHT's.

 

Not to mention that about 1/2 of the show planes that you see at OSH have chromed rocker covers. They look great.

[Spodman]

Probably not critical for the rocker cover, but if you aren't going to chrome them I'd use high-temperature engine paint rather than ordinary finishes. They're available here from car parts suppliers and come in dramatic colours if you are so inclined.

[Joe Patterson]

Powder coating.......I like Purple.

[Juan Rivera]

You can get chrome rocker covers and chrome push rod tubes and intake pipes from lycoming or you can just take yours down to the plateing shop and have them done, I even had my old style internal wrenching cylinder hold down nuts plated.

[Edge 513]

You can get chrome rocker covers and chrome push rod tubes and intake pipes from lycoming or you can just take yours down to the plateing shop and have them done, I even had my old style internal wrenching cylinder hold down nuts plated.

A fellow builder asked me, and I just got a phone quote for chroming the valve covers for 38.00 each and the same per pushrod tube. Can the pushrod tubes be simply buffed out to a chrome-like appearance? Inquiring minds want to know....

[longez360]

I have chrome on my engine (rocker covers and induction tubes). It's still in good shape after 150hrs or so. Would I do it again, probably not.

 

In terms of the rocker covers, I have also read it does have an impact on increasing cylinder head temps.

 

For heat, paint the engine black. Powdercoating the rocker covers should be explored.

 

For finding oil leaks, perhaps lycoming grey is perhaps the best choice.

[TMann]

I just found a source for 'spinner' hubcaps for my mains.

Do I need to be concerned with any 'Gyro' (not the sandwhich) effect while I'm retracting my gear?

[Marc Zeitlin]

In terms of the rocker covers, I have also read it does have an impact on increasing cylinder head temps.

Can you point me to a reference? Given the minuscule amount of heat that's dissipated through the rocker covers, it's extremely hard for me to believe that the color or surface finish of the covers could have any measurable effect whatsoever on any engine temperature(s).

 

For heat, paint the engine black.

Do you have any reference for data on how engine color measurably affects CHT's or oil temps? Again, the radiative heat transfer at the temperatures at which these engines operate is a small part of the overall heat transfer, and at these low temperatures, the color of the paint is less important than the chemical composition of the paint. Again, it's difficult for me to imagine that the engine color is a large component of the determinant for engine temperature(s).

 

For either of these issues, if the difference is a degree or two, I'd be surprised, and that's so far below the measurement accuracy as to be meaningless. But I'd be interested in being proved wrong, if any data exists.

 

Now, if you're talking about something like exhaust pipes, which get VERY hot, I could imagine that the coating and color could make a substantial difference. But rocker covers and case? Not so much.

[Lynn Erickson]

A fellow builder asked me, and I just got a phone quote for chroming the valve covers for 38.00 each and the same per pushrod tube. Can the pushrod tubes be simply buffed out to a chrome-like appearance? Inquiring minds want to know....

I would say that is cheap for the speed gain you will get. most every thing in aviation cost about $1000 for every 1 Knot increase in speed. everyone knows that if it is chrome it will go faster.

[Edge 513]

I would say that is cheap for the speed gain you will get. most every thing in aviation cost about $1000 for every 1 Knot increase in speed. everyone knows that if it is chrome it will go faster.

Very funny Lynn...wery wery funny. I refute!! A 56 chevy with chrome bumpers is not that fast!!

But to ask the question again, can the pushrod tubes be polished out?

[rickh]

... But to ask the question again, can the pushrod tubes be polished out?

Assuming they're aluminum, and of a suitable composition, yes.

 

Speaking as a motorcyclist, who knows "chrome won't get ya home", try these buffing products. All should be available an Manny, Moe, and Jack. Never-Dull (blue can, cotton wadding), Flitz (sometimes in a tube), and/or semichrome polish (not certain of my spelling). Doubt you'll get a chrome like shine with any of them, but they do brighten aluminum up nicely. I like Never-Dull.

 

Rick

[longez360]

Can you point me to a reference? Given the minuscule amount of heat that's dissipated through the rocker covers, it's extremely hard for me to believe that the color or surface finish of the covers could have any measurable effect whatsoever on any engine temperature(s).

 

Do you have any reference for data on how engine color measurably affects CHT's or oil temps? Again, the radiative heat transfer at the temperatures at which these engines operate is a small part of the overall heat transfer, and at these low temperatures, the color of the paint is less important than the chemical composition of the paint. Again, it's difficult for me to imagine that the engine color is a large component of the determinant for engine temperature(s).

 

For either of these issues, if the difference is a degree or two, I'd be surprised, and that's so far below the measurement accuracy as to be meaningless. But I'd be interested in being proved wrong, if any data exists.

 

Now, if you're talking about something like exhaust pipes, which get VERY hot, I could imagine that the coating and color could make a substantial difference. But rocker covers and case? Not so much.

 

 

Hi Mark, I believe chroming rocker covers would have negligable effect on CHTs - I just recall reading the information at some point over the past 20 years. I recall it was in an article also describing atomisation in induction tubes with vaious coatings, and why one should not chrome (or polish smooth)fuel servo elbows (again for atomisation). It was an article on coatings specifically. I am uncertain if it was supported with qualified data from an authority on the subject, although it was reasonably comprehensive. The painting of the engine black was noted at an Oshkosh forum, listed in a CSA article and I have come across it from time to time. The effect again is unknown as I do not believe data was published with the feedback. I will keep it in the back of my mind and if I come across it, will publish the references.

 

In retrospect, I am uncertain why one might change what lycoming prescribes without conclusive data.

[michaelj]

If you decide to have them chromed make sure the shop only chromes the exterior. My AI guru has heard of chrome showing up in an oil analysis which really causes red flags to be waived. My rocker covers and induction tubes are chromed. I too am a fan of powder coating but not on the engine mount.

[longez360]

If you decide to have them chromed make sure the shop only chromes the exterior. My AI guru has heard of chrome showing up in an oil analysis which really causes red flags to be waived. My rocker covers and induction tubes are chromed. I too am a fan of powder coating but not on the engine mount.

That's a good point Michael. I noted my covers are also only plated on the exterior surfaces for the same reason.

 

Engine mounts should be painted IMO. Crack detection is paramount.

[Cozy Girrrl]

I would say that is cheap for the speed gain you will get. most every thing in aviation cost about $1000 for every 1 Knot increase in speed. everyone knows that if it is chrome it will go faster.

The words out of a hot rodding friend "If it don't go, chrome it"

...Chrissi

[Tyson]

Do you have any reference for data on how engine color measurably affects CHT's or oil temps?....

Not exactly hard data, but a simple discussion on this topic:

http://www.newton.dep.anl.gov/askasci/eng99/eng99494.htm

 

Another discussion on the topic. Of note is the issue of heat 'absorption' issues as related to engine compartment objects as they relate to paint color etc. Perhaps this is why white is a common engine mount color:

http://www.sacskyranch.com/paint.htm

[Marc Zeitlin]

Not exactly hard data, but a simple discussion on this topic:

http://www.newton.dep.anl.gov/askasci/eng99/eng99494.htm

Good discussion, explaining why the color of the paint is meaningless.

 

Another discussion on the topic. Of note is the issue of heat 'absorption' issues as related to engine compartment objects as they relate to paint color etc. Perhaps this is why white is a common engine mount color:

http://www.sacskyranch.com/paint.htm

Another good discussion of the issue.

 

Thanks for the pointers. Both of which support my suppositions, not surprisingly :-).

[Lynn Erickson]

Not exactly hard data, but a simple discussion on this topic:

http://www.newton.dep.anl.gov/askasci/eng99/eng99494.htm

 

Perhaps this is why white is a common engine mount color:

http://www.sacskyranch.com/paint.htm

white engine mounts make it easier to spot cracks.

[ronny]

Guys,

Anybody have any idea how warm/hot the rocker covers get?

 

I was actually thinking of getting them done in carbonfiber.

 

thx

Ronny

[NeilK]

One would have to assume worst case senerio... Lyc specs max cyc head temp at 500F. (Normal cruise at <400F) Good luck finding resins for that kind of temp.

[ronny]

Hi Neil,

 

That is very interesting 400F is nice and warm

 

Have a look at this websit http://www.aeroeliservizi.it/index2.html

These guys install carbon covers on O 320 engines on their helicopters.

Or is it that helicopters run a lot cooler?

 

Ronny

:D :D

[NeilK]

Helos would run just as hot (if not hotter) as aircraft. There are some high temp resins available. They’re just not very common and not usually available to the average homebuilder.

 

I’m reminded of a VEZ that used an automotive (or was it marine) fuel flow sensor that was made of plastic. It failed in flight and the pilot lost his life during the off-airport landing.