Cylinder Head Inspection....and questions

[Wez_]

Using the Clymers Manual, I was able to fabricate a spring compressor tool out of a piece of pvc along with a large C clamp, gorilla tape and a piece of scrap metal.






"Borrowed" some foam from work...



Number 7 Intake Valve and seat...



Combustion Chambers...Number one looks bad....

 

[Wez_]

The rest of the combustion chambers....



Two



Three



Four



Found some scoring or former workmanship damage...



The bores....



Fabricated a shop vac attachment out of a recycled plastic....This attachment worked really good as I was able to squeeze the tip to a narrow opening that curved. I was able to suck nearly all the tiny debris nestled on the top of the top piston ring. The bores look really clean after initial cleaning



Found some damage....

 

[Wez_]

Not sure if this is major.....

 

[Wez_]

Questions:

Can i rotate the engine?

Can i soda blast the chambers if i plan on a professional clean/magnaflux?

Is this head usable?

Will the number one combustion chamber need grinding?

 

[amc49]

So far very possibly useable. Gotta clean all the rust out to see how bad the actual seat area is. Pinholing in it from rust. Often not but sometimes is. The valves same, a wirewheel brush in like bench grinder what I use to clean valves off. The head is aluminum, wire of any type being steel will remove aluminum and no to cleaning the head. I use a combination of light pressure slot screwdriver tip and other tips to scrape most heavy off then glass beading but the oil passages need masking taping off to avoid loading them solid with glass (or your soda, fine), the glass later comes loose and tears engine up. Light amount of dust OK as you will clean the oil passages religiously. Consider who you will blast with, they pay big money for blasting media and prefer a dry part with no oil and most bulk material already removed, it makes their job go faster and they waste less media and often your consideration gets seen there and they do a better job then cleaning part.

Don't know which one has the rust but that cylinder hole needs piston dropped to see how much water damage in the bore itself, the usual scrap maker there. Engine with no head can be turned while holding the camchain up by hand to simply let it rock over the lower teeth on crankshaft, you have to hold it or it slacks out to let chain bunch up under crank and then locks you up. Make it easier, reach in and press toward back of motor on the vertical tensioner with nuts loose and push back against it to spring it back and tighten nuts lightly to hold it in that place. Gives you more room to look down in chain tunnel at the sprocket for viewing while turning. If engine not turning easy then stop, the rust in cylinder is locking it and you got damage forcing it. Should turn with relatively easy effort.

I see a pic of a tensioner with the spring breaking through the what was a rubber cover over it. I'd probably be breaking off the rest of the cover, it will come off in pieces later not doing it and through the motor. Flex the tensioner in bright light and look for cracks, light fine cracking is OK for a while but more major and need another tensioner, these motors eat them.

Cam journals use 600 sandpaper to lightly sand the hole to remove the highs ONLY, do NOT try to pick up the lows. If the high pile tall enough VERY judicious use of like a modeler's round profile file to remove much of it then finish out with the sandpaper again. All dents consist of usually a low dug by excessive tool use or other and the resultant high where the tool piles up material to make a high around the hole from metal displacement. You must remove the high as it kills operating clearance to seize parts up, the low is harmless if it does not flaw like an oil port to leak wrong and there is no damage like that there. Your damaged journal is OK with the highs removed, I saw that all the time. They even come out from Honda like that sometimes, there being a lot of special moving around needed with all the dang parts to install there.

The tappet? The spin circle may be nothing or not. Look at the cam lobe for that tappet, it may be beginning to scar up there. If you can polish up both the shim and cam again with 600 and fine then good to go. Depends. The shim can be flipped to get new surface if no highs in the circle to throw clearance when flipped off. All cam lobes need to be within .010" (ten) of each other as far as lobe height or one is going flat.

 

[amc49]

I'd save potential massive work, go after the rusted chamber first. Clean up those two valves (KEEP YOUR PARTS DEAD IN ORDER), the head valve openings at least enough to remove the major trash around seat and then using valve lapping finishing (fine) compound (NOT the rough) lightly lap the valve to its' seat to see how bad the contact point is on both valves. Need to also see that affected cylinder bore wall and clearly. The danger being often how much water got down beside piston to rust the ring up and eat pinholes into the bore wall.

 

[amc49]

You say 1 but before I thought you said 4. No biggie but 1 is on the left as you sit on bike looking down. Just trying to save me typing and confusion. Looks like 4 from pic#7 post 2.

 

[Wez_]

I really appreciate the advice amc...seriously!

It's both 1 and 4 now. Chamber 1 has the rusty seats and bubbling of the casting head material i was concerned about in the above pictures. Chamber 4 has the severly rusted single valve.

Whats wrong with soda blasting?

I do own one and it cleans up amazingly. The local machine shop will do a peofessional clean and magnaflux to check cracks....i was hoping that process would clean any leftover material....

 

[Wez_]

No water/rust whatsoever down in the bores. They cleaned up shiny with only surface rust/moisture at the top of the bore.
before


after


found an article that talked about glass vs soda blasting and soda blasting was preferred so I went ahead with cleaning the cylinder head. Next will be the valves.

 

[Wez_]

The more I cleaned this area off the more I realized if I could just knock some of that material off, the seat would most likely be clean...So I chipped at it with some tools...




broke a piece off...success...


Used some files and the pick to continue cleaning...

 

[dirtdigger]

I would be worried about running that chamber, its gonna want to collect carbon, probably gonna cause some preigniton or pinging issues especially when it gets hot.

 

[amc49]

Try not to damage the seats themselves, 3 angles there and the middle one is it. I would be trying to see if the damaged cylinder has a good seat at the damage before wasting time on the rest of the head. Looks like something blew up on the head but not the other parts, like OEM head was changed to the damaged one.

You lucked out bigtime with the water not hitting the bores.

Nothing wrong with soda at all if it gets you the cleaning you want, the lower the destructive you can get the better if it still cleans. Your work is very acceptable. Glass pretty much what everybody uses in shops here. More aggressive. Can't use it like on piston ring grooves.

The seats are always rough and exhausts are worse. The problem being, the norm is to lap the valves in trying to get seal back, often you can get most or all intakes to but not the exhausts, the dents being too deep. The seats are no issue but the valves are only surface heat treated and once you lap enough to visibly remove any material at all off the valve you are past the heat treat and on super soft steel that won't hold a valvejob at all. 5K miles and valve is burned. Why you can grind the seats but not the valves, replacement only.

You'll be needing to cruise Youtube for all the valve lapping info you can get. Car or bike, the process is the same.

 

[Wez_]

As far as the tensioner goes...So if it has light cracks, I can remove the remaining metal jacket and use it that way? It looks like replacing it new is almost more than I paid for the bike. Maybe a used replacement from ebay.....Not sure which way to go here.

 

[Wez_]

I would be worried about running that chamber, its gonna want to collect carbon, probably gonna cause some preigniton or pinging issues especially when it gets hot.

Here are my 4 options in my opinion...what would you do if you were in my shoes?

1. stop now and try the head out as is

2.) continue to try and smooth out the casting with a small dremel tool

3.) have a machine shop add material and then grind the chamber smooth

4.) source a new head

 

[Wez_]

Try not to damage the seats themselves, 3 angles there and the middle one is it. I would be trying to see if the damaged cylinder has a good seat at the damage before wasting time on the rest of the head. Looks like something blew up on the head but not the other parts, like OEM head was changed to the damaged one.

You lucked out bigtime with the water not hitting the bores.

Nothing wrong with soda at all if it gets you the cleaning you want, the lower the destructive you can get the better if it still cleans. Your work is very acceptable. Glass pretty much what everybody uses in shops here. More aggressive. Can't use it like on piston ring grooves.

The seats are always rough and exhausts are worse. The problem being, the norm is to lap the valves in trying to get seal back, often you can get most or all intakes to but not the exhausts, the dents being too deep. The seats are no issue but the valves are only surface heat treated and once you lap enough to visibly remove any material at all off the valve you are past the heat treat and on super soft steel that won't hold a valvejob at all. 5K miles and valve is burned. Why you can grind the seats but not the valves, replacement only.

You'll be needing to cruise Youtube for all the valve lapping info you can get. Car or bike, the process is the same.

OK, got it...youtube valve lapping and verify seat to valve surfaces retain seals after I lightly lap with fine compound starting with the worst seat. I'll go from there.

 

[amc49]

Don't get lapping compound into the guide and when done with the work be 110% sure you have all of it cleaned out as it eats engine if not removed completely.

A good test for valve seating in head lying on side with the ports tested facing up and gasoline poured into that port, tight sealed valves will not leak any out.

 

[Wez_]

Don't get lapping compound into the guide and when done with the work be 110% sure you have all of it cleaned out as it eats engine if not removed completely.

A good test for valve seating in head lying on side with the ports tested facing up and gasoline poured into that port, tight sealed valves will not leak any out.

Great point. I caught myself trying to insert dirty stems into the guides, and remembered what the Clymers manual said about disassembly of the valves and not to draw material in them as it will damage. The only worry I have is with the Permatex compound I was limited to buying locally. It is pretty gritty, but I only lapped lightly (about 30 seconds each valve). The machine shop ground the valves and suggested going ahead and lightly lapping with this material. He said with Stainless Steel valves, they are hard enough to withstand the lapping....All valves have a nice concentric dull mark centered in the large angled portion of the valve face

 

[amc49]

The machine shop ground the VALVES????!!!

Although they seem to finish out nicely that is a huge mistake, they can only grind the seats. The valves are 100% absolutely NOT grindable.

'...the valves are only surface heat treated and once you lap enough to visibly remove any material at all off the valve you are past the heat treat and on super soft steel that won't hold a valvejob at all.'

I can absolutely vouch for that. And if they didn't cut the tips to match what came off the valve then none of your shims will be right now either. Problem is, you remove the heat treat from the tips there as well.

The Permatex IS pretty rough. I use Clover but not sure it's sold any more. Those had both fine and rough in the can.

Yes, the dull gray ring is what you are looking for.

 

[Wez_]

The machine shop ground the VALVES????!!!

Although they seem to finish out nicely that is a huge mistake, they can only grind the seats. The valves are 100% absolutely NOT grindable.

'...the valves are only surface heat treated and once you lap enough to visibly remove any material at all off the valve you are past the heat treat and on super soft steel that won't hold a valvejob at all.'

I can absolutely vouch for that. And if they didn't cut the tips to match what came off the valve then none of your shims will be right now either. Problem is, you remove the heat treat from the tips there as well.

The Permatex IS pretty rough. I use Clover but not sure it's sold any more. Those had both fine and rough in the can.

Yes, the dull gray ring is what you are looking for.

Not sure why this machine shop was adament that i would have no problem.....i explained this concern to him and he said he never had a problem with stainless steel valves. So new valves lapped in its what i need?

 

[amc49]

You do NOT have stainless valves there at all. So, any talk of that is moot. The OEM Honda valve there is soft steel with a nitrided surface to bump the surface hardness way up and even a really intense hand lapping can remove that. Why you MUST keep the valves in the OEM running places too. You can lap but do as little as possible and the intakes are usually OK, sometimes some issue with the exhausts as they have more denting in them. If you lap enough to look at the valve dead-on from the side and the seat has sunk in concave to the eye then likely the hardcoat (nitride) will be gone and then the seal goes like lightning if an exhaust. The hardcoat is a variable thickness but usually no more than .005" or so thick.

The machine shops usually have no clue about which valves are like that, commonly small 4 valve stuff like bike is where car commonly uses hard material throughout the valve. The service manual tells you indirectly by insisting the valve must be changed rather than cut. Both to keep tappet clearances in order and because they know about the heat treat thing.

You can likely still get stainless valves for them but wait till you see the price, commonly from $25-$30 each. Many of the sources have dried up too.

I had heard of that valve thing and decided to test the idea out on a smaller engined bike way back in the mid '80s and yep, the valves when ground go like lightning, the valvejob was dead in about 6K miles, the valves were pretty much all scrap.

Another reason for why they have no compression and then run like crap and then owners go after the carbs for often no reason. The bikes were made in a era of low lead fuel, well it turns out even low lead had quite a benefit. Once the lead was 100% removed to be zero then the valves go through utter fits. I had a Ford MII at the time and the last year before they induction hardened the valve seats. The car went forever until the fuel went to low lead, then I started having to do a valvejob every 50K miles or so and then when the lead all came out the duration of a good valvejob was only maybe slightly over 10K miles, and why all those parts had to get much harder with 100% unleaded fuel, the lead made life much easier as far as the valves and seats went.

The nitride coating was just enough to handle the low lead fuel of the times but not 100% unleaded for long durations, lucky it's a bike, if a car you'd never get the miles you expect out of one.