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Lapping the head to repair a head gasket comments thread

38K views 145 replies 32 participants last post by  jkv357 
#1 ·
exactly how effective is this technique for lapping the head and barrells?

can it go wrong?

Dale
 
#52 ·
A filler ,but too much (2 coats) is a disaster and will prevent the proper Action of the seal.

I am getting the same sort of help from the Merceedes Benz foum. So far they have saved me over $3000. In dealer service fees.

FOG
 
#53 ·
I asked a local engine/machine shop if they'd perform this for me and they basically just said no. The guy i talked to told me to get a large piece of glass and use a really fine grit sand paper and wet it. He said that the lapping compound would be hard to come by and that sand paper would do the trick. What are your thoughts on this? I don't even know what a lapping compound is lol.
 
#54 · (Edited)
The glass is OK do not use sand paper under any circumstances Use only free abrasive (as in Lapping compound) sand paper will not get the surface flat and will confuse you as it will wrinkle up to clean all but not be flat

Agin no sand paper.

And why are you going to ask a no nothing who can't/won't preform the work, yet take was he says as gospil.? Since you chose this thread to post too you must have read it, Did I miss something


FOG
 
#55 ·
1. I'm obviously a "no nothing" as well. I literally have no mechanical experience versus a man that works in an engine repair shop and seemed to have more knowledge than myself.
2. Gospel? I didn't go out and do what he said. I came straight to you and asked your opinion.
Am I missing something?

Anyways, I do appreciate the info. I went ahead and ordered a piece of glass so now I'll just have to track down some lapping compound.
 
#56 ·
Also, I used to live in in Rea Valley just south of Cotter and my family lived in Mountain Home for a while after i left. Spent plenty of time in Mountain Home. I love Texas but i sure do miss the great outdoors up there. I never had a bike when i lived up there but imagine it'd be a blast to ride them twisty roads. Especially with that scenery.
 
#58 ·
I think your the first one from this list that really understands what beautiful country the Ozarks is. I was very close to purchasing 40 Acres in the Rea Valley back some 5 years. Just couldn't come to terms with the seller.
On beautiful roads for MC riding. I agree, but As a former racer I couldn't keep from going fast and dragging an occasional knee. That is until I realized that the loneliness of my favorite road AR 341 (Push Mountain Road) was going to kill me if I made a mistake,as no one would ever see you go off and you could starve to death.

So I had to sell my VFR for safety sake.

FOG
 
#60 ·
As to painting the old head gasket, back in the day of small-block Chevys and steel shim gaskets (like the EX), we used silver or aluminum spray paint, as it has a fairly good content of powdered aluminum. Or used to, anyway. That powder helps to fill the little gaps that might lead to the next lapping job.

Hey, anyone ever contacted ARP in Cali to see if they have (or would make up) some NASA grade studs for the EX cylinders? Sure, the whole crankcase would then be pulled into a pretzel, but every little bit helps.
 
#61 ·
Gasket painting

Caution use only ordinary spray can enamel 1 coat only 1
More than that will prevent the spring seal around the cylinder from working properly


FOG
 
#62 ·
Hey Fog, I have my heads puled off the block but am having a heck of a time removing the cylinder shafts (or whatever it's called) from the transmission portion of the motor. Is there some trick or maybe a sneaky bolt that I'm missing? It's is really tough! I definitely don't want to break anything.

Also, the head gasket was covered with some sort of liquid gasket and there are slight file marks on the heads. *facepalm!
 
#66 ·
We got it! For the love of all things holy, that thing was so difficult! Anyways, we got it off and the base gasket was trash as well as the cam tensioner gasket. The head gasket was fairly pitted so I went ahead and ordered one of each. They're all supposed to be in Wednesday.
I went ahead and lapped the heads and cylender mating surface. That was amazing! It looked better than if it had been machined. I can't wait to get the parts in and get her back together.
 
#67 ·
Both gaskets are solid steel and can e re used if you clean them with Laquer thinner and steel wool, then re paint them with a spray can 1 coat each side.

FOG
 
#69 ·
No lock tight anywhere yes the head torque increases to 40 lbs ft in three increments from the center outward. don't rush this is where you can destroy you nice flat head. gently to 20 then 35 then 40 and go around 3 times @ 40
 
#70 ·
This may be a silly question but do we dress the gasket with any sealer or is the enamel all I need to do.

I just finished lapping, put the bike back together and after a moment got white smoke, needless to say engine is apart again do I need to relapp I was planning on it. Just trying to see what wrong.
 
#73 ·
Yes ,but it will go quickly if it was lapped correctly once, A new head gets stress relieved when run taking on the shape of whatever stresses were in it then relaxed;. Upon a second removal most (all) the original stresses are gone ,so a second re lapp is more of a check.;.

Do it anyway

FOG
 
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#74 ·
Alright here I am tail between my legs once again... new head is on the way, I'm painting the gaskets and notice that the enamel I'm using is a ceramic formula for high temp engine applications... is this going to cause me any problems? Should I bake at 200° for an hour to cure like the label says? Or should I just go buy different enamel?
I would like this to be the last assembly for a cool minute if I could.
 
#77 ·
Reviving this thread, mostly because it's been revived several times, and I need to clarify a few things .

Quick background. I have a '02 Vulcan 500 that's been sitting for a few years, had to pull the cylinder head. While I am at it, going to just go ahead and replace the head gasket. Someone in another place linked me here, and suggested I look into this. Figured I might as well try it, I'd rather not have problems down the road. Never done this before, will hopefully never do it again.

Here's what I think I understand:
I need a cut granite plate from a counter top, not a granite tile, or a decent pane of glass, right? I need lapping compound, which can be found online/auto parts store.
I realize by reading the article, I don't have to replace the head gasket, but I'm erring on the safe side, and will be saving the old head gasket.
Can the base gasket be reused?
I don't have to replace the cylinder base gasket, but I do have to pull the cylinder base out in order to lap/resurface the top side to match the cylinder head. I don't have to resurface the bottom. I put the lapping compound on the granite or glass, rub the cylinder head/base in a figure 8. I can paint/dye the surfaces where they will meet to ensure that it's flat enough.
I don't have to paint the new head gasket going in, but it will help to just give it ONLY one coat on each side.
I don't have to remove the pistons, or the rings, but upon reassembling, I'll have to finagle them inside the cylinder. I don't understand how you're using the hose clamp or the paint stick to reassemble. Do you have any pictures or can you give a better explanation of assembly for someone that's never done this?

I appreciate any help you give. Trying to restore this bike, and want to do things right. I don't want to run into issues because I overlooked something, or was lazy. Thanks in advance.
 
#78 ·
Hose clamps and paint stick:


All of your other questions, I think you basically got it down. I am not an expert and everything I know I learned here on this forum. The only advice I have to offer from when I lapped my head and cylinders: if you buy 2 part valve compound (coarse and fine) start with the coarse. I was concerned about taking too much material off and started with the fine lapping compound. After literally five+ hours of lapping it was still not flat. For my second piece I started with the coarse, it went nice and quick, and finished with the fine.

Seems like you've done more research than most so you should be fine.
 
#79 ·
Hose clamps and paint stick: (IMG)

All of your other questions, I think you basically got it down. I am not an expert and everything I know I learned here on this forum. The only advice I have to offer from when I lapped my head and cylinders: if you buy 2 part valve compound (coarse and fine) start with the coarse. I was concerned about taking too much material off and started with the fine lapping compound. After literally five+ hours of lapping it was still not flat. For my second piece I started with the coarse, it went nice and quick, and finished with the fine.

Seems like you've done more research than most so you should be fine.
Thank you for the quick reply. Since ducatiman pointed me here, my head has been filled with his, trying to wrap my mind around it. My wife woke me up the other night, and I was sleep talking about what I needed to do before I bolted it back up, :grin2:.

How do you get the hose clamps off after you fit the cylinder head back on? I don't understand what the point of the paint stick is for? I'll be sure to get the 2 part and start with the coarse. Good advice. I don't have 5 hours to push a cylinder head around on my workbench. Did you reuse the cylinder base gasket? Or get new one? I have to figure out where to find a suitable piece of glass/granite I suppose.
 
#80 ·
The hose clamps come apart after the rings are in the bores . The paint sticks keep the pistons square and even preventing the crankshaft from turning as you push the cylinders down.

don't add paint to a new painted gasket. use it as is. Too much paint will destroy your work.

FOG
 
#84 · (Edited)
After successfully completing this procedure, I thought I would toss in a few comments on what I learned.

The bike was a 2009 500 with less than 4000 mi that we have owned for about a year. It started pushing coolant from the radiator into the overflow bottle and out the hose. When it cooled the radiator was low and the bottle was full. We tried a new cap, thinking it may not be holding pressure, but there was no change. After doing some research here we determined it was a failed head gasket/warped head.

After starting basic take-down I felt we needed a Service Manual of some kind for correct procedures, specs, etc. We purchased the Kindle manual for the 500 off of Amazon ($26 - Cyclepedia Press LLC)) and found it to be very helpful. I have years of professional automotive body experience, where I did moderate mechanical work (no engine disassembly). Even with a huge toolbox full of tools I don't feel it's a quick or particularly easy process.

After removing the head and cylinder we didn't see an obvious breach in the gasket. We lapped the head and cylinder (removed the intake valves) on a piece of Quartz cut-out from a neighboring shop that does solid surface counters. According to the owner, Quartz is flatter than Granite. We purchased lapping compound from NAPA. After initial lapping there were no obvious flaws that showed-up on the head or cylinder.

Looking closely at the head gasket it appeared that there was corrosion on the gasket around the openings for the water jacket, so we replaced the gasket ($32 + shipping online). It may be possible to remove the cylinder without removing the waterpump, but the manual says to pull the pump. If you do, you will need an outer gasket for it also.

While it was apart we adjusted the valves (a few were tight), removed the cap on the idle mixture screws and set them to 2 turns out, synced the carbs, and reset the idle speed. Interestingly, the idle mixture screws were not the same - one was set at 1.5 turns out the other was 1.0 turn out.

Flushed the cooling system first, then refilled with fresh. Changed the oil and filter.

It's running well now, with no signs of the previous issues - so it was a successful project.

I did find this post very helpful, especially when trying to diagnose the problem. A local cycle mechanic I spoke with about the problem wasn't convinced that the head gasket/warped head was the cause, but after reading the info here I felt confident it was.

Thanks to FOG for posting.
 
#91 ·
WORD OF CAUTION Those Banjo bolts are thick hollow washers uses as terminus for oil lines. Problem is they are fragile and can be bent or indented by too much tightening pressure. when this happens a subsequent re assembling can miss align the copper washer with the previous indention.
when ever the oil line is removed be sure to check the flatness of the banjo washer. if you find they are bent in you can re flatten them by stoning .
the problem is K used a copper washer smaller than the internal diameter of the banjo . failure to do this can and will cause a oil leak .
Mainly of the large end

FOG
 
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