Topic: Want to paint cylinders/head - need some quick info

[Tim.]

Hi all - my CB550F is in the shop awaiting the arrival of 4 spanky new 0.5mm over pistons.  The head and cylinders are sitting loose, begging to be cleaned and perhaps given a fresh paint.

I only have a few days before the pistons arrive and the cylinders will be sent to the machine shop for boring and reassembly.  So, I figured I'd swing by the shop, nab the bits, and clean/paint.

QUICK!  I need some links/pointers on doing this.  Never done it before.  How to clean / prep the pieces, what paint to use for a good color match and application process.

I don't have a lot of time to do the research, so if anyone knows straight out how to do this well, let me know.

THANKS!!!

[Lumbee]

as far as the paint goes...I'v heard folks just use regular ole cheapo paint...heads and cylinder are air cooled...so don't get to hot...

[CTCStrela]

I'd recommend a high-temperature engine enamel, as there are hotspots on aircooled motors that do get pretty hot...

[kghost]

Use the high temp or it will flake off

[Tim.]

Ok - got the hi-temp bit.  Any hints on prep work and specific brands/colors to use?  I'm only painting the cylinders and head, so they need to match the bottom end as closely as possible.

[Terry in Australia]

When I restored my CB750F2 I didn't want to get the head and cylinder block bead blasted (too much cleaning to remove every last bit of engine destroying grit)) so I bought a 5 gallon bucket of Auto spray paint gun cleaner, and dunked them in that stuff overnight.

It's a lot more potent than any thinner, but doesn't contain caustic so won't hurt the alloy surfaces like paint stripper, or make 'em go black like oven cleaner either. This stuff just washes all the paint, grease, tar and dead bugs off, so all you need is a paint brush to move the paint offa the bare alloy. Good stuff, just make sure you remove any rubber components before dunking, or you'll be sorry! (although it doesn't effect the anti-vibration rubbers between the fins on the head) Cheers, Terry.

[Bill Vaughan]

If you do go the paint route, I've had good luck (both color match and durability-wise) with Duplicolor Hi-Temp Aluminum (DE1615).  Just clean the pieces with a household grease remover, rinse well, let dry and spray away.

A bit of advice:  Do not paint the cylinder jugs unitl AFTER the machining process.  The best shops use an ultrasonic cleaner to remove debris after machining and it will destroy your fine paint job.  I learned this the hard way and ended up repainting the cylinders.  No fun the second time around.

[Tim.]

Excellent advice - I'm going to have a good look at everything to confirm painting is worthwhile.  Frankly, once the machining is completed, both me and the mechanic working on the bike are going to want it out of his shop asap, so there will be no time to paint them unless I insist on it.

[kghost]

I suppose it depends on what your cases look like.

Nice clean shiny cylinder and head will get really annoying on dirty flaked cases.

BEWARE. This is how it starts. Next thing, you turn around and there are parts all over the garage. Your watching E-Bay for that one piece of unobtainium.

Its a slippery slope friend, as many here will tell you............

[Terry in Australia]

I suppose it depends on what your cases look like.
Nice clean shiny cylinder and head will get really annoying on dirty flaked cases.
BEWARE. This is how it starts. Next thing, you turn around and there are parts all over the garage. Your watching E-Bay for that one piece of unobtainium. Its a slippery slope friend, as many here will tell you............

True story Kasper, I agree entirely. My Visa card statement is a constant reminder of how things can get away on you when "A quick clean up" becomes a total ground up "last nut and bolt" resto, boo hoo! (and I still can't get the f!@#$%g rotor off!) Cheers, Terry.

[SteveD CB500F]

The 500 shown in my avatar had red head and black barrels. I used Gunk to clean them (this was 1977 don't forget) and Sperex VHT (1200 degree) paint from an aerosol.  Baked in the oven per the instructions.

It was very durable and still looked good when I traded the bike for a 550 in '79.

[057 adnoh]

  harley davidson makes a great silver paint, its high heat and really easy to use this paint also looks better after a few heat cycles!

[Tim.]

Trust me - I know all about the slippery slope of restoration.  I have so many Honda parts wrappers from the new genuine spares I've ordered for this bike, many with no real reason.

For example, I got a brand-new brown vinyl seat for $50 on eBay (got very lucky).  I saved the rubber cusions from my old seat which I sold (for $75 .  But, I decided, well, I'd better order brand-new rubber cushions for my brand new seat - nothing wrong with the old ones, just that they were old.  So, I'll have nice new rubber cushions sitting under my seat where I can't see them.

I also replaced all the bolts in my light lenses, including those very long skinny ones on the tail light with stainless allen heads.  Not just the engine cases for me man, every bolt I could reach and source a replacement for has been replaced with stainless hex heads.

My Honda dealer loves me needless to say.  Just waiting for my new cam chain, cam guide, cam slipper, oil seal for the tach drive (so that's where all the oil was coming from!) etc. to arrive at the dealer.

[Bobby]

TinTin, I just sprayed my SOHC using Duplicolor Hi-Temp Aluminum DE1615 and Duplicolor Hi-Temp Satin Black (jugs and head) and it turned out sweeeet.  I spent a ton of time and elbow grease prepping the darn thing but it looks finger lickin' good now.  Just gotta remember where the heck I put the dang mounting hardware...

-Bobby

[Tim.]

TinTin, I just sprayed my SOHC using Duplicolor Hi-Temp Aluminum DE1615 and Duplicolor Hi-Temp Satin Black (jugs and head) and it turned out sweeeet.  I spent a ton of time and elbow grease prepping the darn thing but it looks finger lickin' good now.  Just gotta remember where the heck I put the dang mounting hardware...

-Bobby

Yeah - it's the prep work I'm really curious about (now that I have some brand/color referrals).  What did you do to prep it?  Just a de-greasing, or something a little more intense like stripping/bead blasting etc.?

[Lumbee]

...looks good Bobby...where'd u get u'r paint from?

[cb750_chris]

The Dupli color works much better than other high temp paints that I have used. 

I got some 1000* paint with flames on the can.  The crap came off like powder just from toughing it.  I don't remember any instrucitons about baking it.  I think it's just junk. 

[nigel1114]

has anybody just said to heck with the paint and polished the engine? if so, how hard was it?

[Chrisboden]

Could you have the whole thing Chromed? Anyone done this?

[SteveD CB500F]

If you polish your engine it will take a load of work and re-oxidise immediately - you'll have to laquer it anyway.

What would chrome do to the heat dissipation qualities??

[Quail "Owner of the comfortable k8"]

has anyone Had a polished engine clear powder coated?

[cben750f0]

mate i just polished my engine covers, and that was bad enough... wouldnt even onside doing the engine cases... unless i was rich , and found someone else to do them!!!..peace

[kghost]

I powdrecoated my cases black, not clear. I think polishing them would look cool but might just drive one mad. Its a "heart of darkness" thing

[Jonesy]

I read somewhere that matte black cylinders are the best for emitting heat. After my heat transfer lab back in college, it proved to be better than polished aluminum.

[Terry in Australia]

The early Yoshimura Suzuki and Kawasaki race bike engine's cylinder and head fins were first vertically bored, then sandblasted with very coarse grit, (the ensuing pitting increased the surface area by about double aiding cooling) then the engines were painted with a high temp "flat" or "satin" black.

I'm sure that if there was any advantage in polishing cases, the factory teams would have done it, but seeing they haven't, I have to assume that there can be little or no advantage in polishing an engine, apart from it looking nice. Cheers, Terry.

[capnspif]

kghost, did you also powder coat your cyclinders and head, or would that work against heat transfer? Has anyone had the cases or other parts dipped? It's been a long time since I worked auto parts but I seem to remember engine shops would dip engine blocks to completely strip them inside and out.

I've got my '78 completely torn down now and need it cleaned much better than I've been able to do before reassembly & paint. But I was leaning towards powder coating.

[kghost]

Nah, I chickened out and left the head and cylinders in the rough. Just powdercoated the case's

[Terry in Australia]

Well I took my spare f2 engine apart last weekend to start rebuilding as my "Endurance Racer Project" engine, all the grotty engine components are currently soaking in a big tub of diesel fuel I and took the cases and cylinders over to get chemically stripped. The guy there recommended bead blasting as he said that the "Hot tanking" they do isn't all that sucessfull in removing all the paint and corrosion.

They also do powdercoating there, but he recommended against it, he said that as powdercoat is an excellent insulator it'll keep the heat in (not good) so he'd definately recommend against heads and cylinders, and to a lesser degree, crankcases. Hmmnnn. so what do i do now? Paint comes off when it comes into contact with fuel additives, powdercoat isn't recommended as it keeps the heat in, what do I do?

Tony, the guy who runs the business, is a biker too, and suggested that as my bike is really only going to be a weekend "toy" anyway, to just leave the cases bare? He did his beautiful Kawasaki Z1 900 7 years ago and left the cases bare, and they still look good, so that'll do me. I'll polish the outer covers but the top and bottom cover, cylinder block and head will be "au natural". It'll sure make assembly and fitting back into the frame a snap too.

I saw this in a British bike mag, and all the owner did to combat road salt etc was to spray the whole thing with WD40 once in a while, but as this bike won't be seeing any of those sorts of conditions, it should work fine without it. Cheers, Terry.

[MetalHead550]

LOL!  Or John Deere Yellow!

[Quail "Owner of the comfortable k8"]

I find it hard to believe that a coating of polyester, acrylic, polyurethane, (we call it powder coat) melted onto an engine, would retain heat more than a coating of acrylic, enamel, laquer, polyurethane paint sprayed on an engine.  I know bare metal is the best.  But what could be the reasoning other than "wive's tales" that people have come to belive from fourms such as this.  Every thing is coated and baked in production today.  It may not be applied as a powder but  raw plastic powder or powder mixed with a solvent and sprayed on to a static charged metal part and baked to cure the plastic has to be the same thing.  Engines on new bikes encased in plastic shrouds have to run hotter than these exposed engines we use.

 kghost 
Nah, I chickened out and left the head and cylinders. 

I wish you would check the temp of a painter case and your powdered case and see if I am right. 

[Terry in Australia]

Well Terry, there's coatings and coatings, I guess. Paint sprayed on to engine cases is measured in microns and is a lot thinner than powder coating.

If you've ever had to remove surplus powdercoating from a bearing surface etc, you'll know what I mean, it's an onerous task, that stuff is not only very hard, it's very thick.

Ceramic coating, which is becoming popular lately, is used primarily to retain heat, to insulate exhaust systems in race cars to keep the heat down in the engine bay.

As for the "wives tales", well with respect to the rest of the very knowledgeable contributors on this forum, I reckon I'd certainly listen to the words of my powdercoater, particularly seeing he's losing business by recommending against powdercoating engine parts. Cheers, Terry.

[kghost]

I sort of have to figure.........

The coating is baked on the surface.

The surface as neither increased nor decreased in size or area.

The transmission of heat is based on surface area.

The amount of Radiant heat transer should remain relatively the same.

Black pigmentation increases the absorbance and dispersion of heat.

what the Hell the cases were painted to start with.

[Terry in Australia]

That's right Kasper, in the grand scheme of things, whether or not powdercoating retains engine heat or not should not be of much concern to anyone riding a stock bike, the factory will have built a degree of flexibility into our bikes for various riding conditions and operating temperatures, and for standard engines (such as my F2 or K3) powdercoating is certainly an excellent finish for cases, although I wouldn't consider it for cylinders or cylinder heads.

Re: the factory paint, it was a super thin coat with no primer, and paint, as opposed to plastic coating, "breathes" through it's pores, just like our skin breathes. Plastic coating, being an insulator, does not.   

As the engine that I'm building now will generate a lot more power than a stocker, therefore a lot more heat, I've decided to leave the cases bare, I had to have them blasted rather than "Hot Tanked" so they'll be slightly pitted, which will actually increase their surface area and aid cooling, and with the help of one of my (superb) oil cooler adapters, I'm hoping that it'll stay as reliable as my other bikes. Cheers, Terry.

[kghost]

My point is.............

"Plastic" baked onto the cases will be the same tempurature as the cases.

I will agree that the cylinders and head left bare are probably a good idea. Thats why my are bare. I am not however worried about the other parts.

Oil tempurature will be as good an indication of internal temps as any. It carries away heat. As long as the oil temp (which is really the most critical to engine life) remains within limits, why worry?

I run a 836 in mine. But as you may have noticed there is a cooler. The  cooler is there to combat the high ambient Texas summer temp.

The highest temp I have measured in the tank (where it matters as this is the oil going into the engine) was 93 C. This was after a really hard flog.

Based on experience with aircooled aircraft engines ranging in size from 183 cubic inches to 2800 cubic inches the highest I would tolerate would be about 100 C. While I realize this equates to 220 F (which is the operating range of liquid cooled engines) The oil along with fuel ( remembering the atomization in the carb decreases the air charge temp.) is what adds to cooling.

I haven't experienced any problems with powdercoated cases.

As an aside, what do you plan on doing to prevent corrosion of the cases?

[Terry in Australia]

G'Day Kasper, well I'm not going to do all that much. I've been told that a regular light spray of WD40 will keep the alloy from corroding, but I'm not convinced.

We don't get too much rain around here, not even in winter, and there's no such thing as snow for over 100 miles in any direction, so I don't have to worry about road salt exacerbating the problem.

The bike will live in my garage and will only be used as a weekend toy, so I guess it's not a real problem, but I guess if it looks like the WD40 isn't holding up well, it won't be too hard to pull the engine, degrease it and give it a coat of high temp paint.

Then all I have to worry about is fuel additives lifting the paint like it did on my beautiful F2. Geez, no wonder I drink so much, ha ha! Cheers, Terry.

[kghost]

I too have been toying with the idea of polishing the cases on my next engine. Thought about "engine turning" them too. But, I'll probably clear paint or powder them as
I couldn't bear the thought of repolishing them again