Author Topic: K8 Engine Damage - cam shaft sprocket in pieces (Read 9308 times)

Remcod · « **Reply #100 on:** August 24, 2020, 11:37:01 PM »

Quote from: PeWe on August 24, 2020, 10:29:21 PM

MLS head gasket does not need o-rings.
I used 2 for oil feed just for sure, but not thicker.

Too thick o-rings can collapse blocking the hole. This has been up on decked cylinders.

You use the ones standard in a gasket set?
But in fact can do without with a MLS? Did you ever try this and it failed or why did you decide to put these in?

Just asking, since im going to use a mls first time soon also like the op

PeWe · « **Reply #101 on:** August 25, 2020, 12:21:12 AM »

CycleX who sells the MLS head gaskets recommends no o-rings.
But they have a newer model with wider oil return holes (

where the later oil seals and pins can be used according to their website. Also on this no seals OK.

Check so the rivets keeping the plates together are not trapped between the mating surfaces. My K6 head and cylinder mating surfaces cover these rivets. I hammered them flat and drilled small dents were the hit. On both sides, head and cylinder.

Some remove the rivets. If not taken care of, no seal, huge leak seeing light between head and cylinder.

Head and cylinder surfaces must be truly flat, smooth surface. I grinded mine on a table with a thick flat board clamped, 2 x A4 sized paper glued and taped. Moved head sideways with water. Cylinder too.
Needed a few rounds of grit 240 to remove scratches, making flat. Then a few rounds of 400 paper.
When you are working with this check if valve cover and side covers need to get a good surface too. Easy and quickly done.

Remcod · « **Reply #102 on:** August 25, 2020, 02:29:07 AM »

Quote from: PeWe on August 25, 2020, 12:21:12 AM

CycleX who sells the MLS head gaskets recommends no o-rings.
But they have a newer model with wider oil return holes ( where the later oil seals and pins can be used according to their website. Also on this no seals OK.

Check so the rivets keeping the plates together are not trapped between the mating surfaces. My K6 head and cylinder mating surfaces cover these rivets. I hammered them flat and drilled small dents were the hit. On both sides, head and cylinder.

Some remove the rivets. If not taken care of, no seal, huge leak seeing light between head and cylinder.

Head and cylinder surfaces must be truly flat, smooth surface. I grinded mine on a table with a thick flat board clamped, 2 x A4 sized paper glued and taped. Moved head sideways with water. Cylinder too.
Needed a few rounds of grit 240 to remove scratches, making flat. Then a few rounds of 400 paper.
When you are working with this check if valve cover and side covers need to get a good surface too. Easy and quickly done.

thanks for the explanation, appreciated

anotherCB · « **Reply #103 on:** August 25, 2020, 06:56:51 AM »

Great input thanks. Mine have the large holes so I assume I should use o-rings.
Also the rivets are outside the mating surface, so I think I am ok.

PeWe · « **Reply #104 on:** August 25, 2020, 10:57:32 AM »

Not those holes. I meant the oil return holes which are the smaller version on yours.

I have used same gasket with stock O-rings on oil feed, the 2 bigger holes on IN side.

But that gasket is made to run without o-rings and dry assembly, no sealer anywhere. Smooth and flat surfaces a must.

anotherCB · « **Reply #105 on:** August 25, 2020, 01:23:19 PM »

Ok I see what you mean. Yeah, obviously the sleeves with the fat rings won't fit in the return bores with this gasket.

So you say you have used this gasket with o-rings on oil feed, but it is made to run without o-rings on oil feed, meaning either is fine?

anotherCB · « **Reply #106 on:** August 26, 2020, 02:31:59 PM »

Moving along fine. Valve stem seal will be in the mail tomorrow.
Been looking at the cam towers. I am 99% sure this engine has never been apart and I am also 99% sure I did not mix up the cam bearing shells. Nevertheless for the last 1% I tried to find markings on cam towers and shells. I see the following, but both are the same for each tower bearing. There is no individual marking. Any ideas?

bryanj · « **Reply #107 on:** August 26, 2020, 03:10:36 PM »

Early ones had no stampings not sure how they would end up on a K8.
Put the cap on and see if it makes a circular bearing hole or if it is "stepped" to one side, if no lip at the join it will be fine, cam never touches the caps anyway

anotherCB · « **Reply #108 on:** August 28, 2020, 11:38:08 AM »

Ok sounds good, thanks.

Something else came up. I put on the head today, torqued it all down and did a leak down test. Got almost 20% on 3 cylinders and 15% on the last one. What the heck? I may not have the perfect adapter, it seems to me that a tiny bit of air may have escaped through the adapter connection as well. But what are acceptable leakage numbers for a refreshed engine (new piston rings and valves lapped)? I am hearing 5%-10%.

I need to get a better adapter and see if I can tell, if air escapes anywhere else (inlet or outlet valves). Hopefully it's not piston ring related, I triple measured them and all looked fine and went together well.

754 · « **Reply #109 on:** August 28, 2020, 02:23:48 PM »

Use soap and water on the adaptor..

anotherCB · « **Reply #110 on:** August 28, 2020, 03:45:38 PM »

I measured again (multiple times) with a better adapter. Now I am getting around 7-10% on cylinders 1-3 and 17% on Cylinder #4. I can tell that air escapes through intake and outlet valves (this was the corroded valve seat).

Here is my question, obviously it sucks that 3 of 4 turned out better, however how bad is 17%. Is it worth taking the head off? Head is torqued down to spec with MLS gasket and I know I can reuse the MLS gasket If the engine hasn’t run, but is it worth it? Head leak because of reusing the gasket would suck as well. What are y’all’s thoughts? Thanks!

anotherCB · « **Reply #111 on:** August 28, 2020, 06:20:31 PM »

Ha, I am a genius, or an idiot, you tell me

I grabbed the valve with the Vise Grips and turned it back and forth in its seat with the head still installed. Leakage is now down to 12% on that cylinder. I think I can live with that or did I do something really stupid??

anotherCB · « **Reply #112 on:** September 03, 2020, 07:35:35 AM »

Made some progress, engine is in! Just need to bolt on a few things and hoping to start her up this coming weekend!

754 · « **Reply #113 on:** September 03, 2020, 09:38:59 AM »

Did you get seats cut ? Or just lapped the valves?

anotherCB · « **Reply #114 on:** September 03, 2020, 11:30:08 AM »

Just lapped the valves. All seats except one looked really good. The engine only had 15k on it, but the bad one was where the valve was open with the bike in storage for 25 years. Lapping took a bit longer but I was able to get 12% on the leak down test on that one, versus 8% on the other ones.

PeWe · « **Reply #115 on:** September 03, 2020, 12:09:52 PM »

My K6 had some bad seats after long storage. Lapping them could not fix the pitted seats. (Small rust holes) I used other old valves to not lap the good valves too much destroying them.
Lap too much and seat look strange.
All seats cut by professional for a good result.

anotherCB · « **Reply #116 on:** September 03, 2020, 01:00:17 PM »

Mine looked pretty good at the end, wasn't too bad I guess, but definitely has some pitting.

beemerbum · « **Reply #117 on:** September 03, 2020, 10:51:03 PM »

Does anyone really care anymore about this guy's problem?

bryanj · « **Reply #118 on:** September 04, 2020, 01:44:39 AM »

Yup, want to know when it runs.

robvangulik · « **Reply #119 on:** September 04, 2020, 01:47:13 AM »

Why not, people are still reacting, and like Bryan says, we want to see the result

PeWe · « **Reply #120 on:** September 04, 2020, 03:33:06 AM »

People in need of help post here.

anotherCB · « **Reply #121 on:** September 04, 2020, 04:50:35 AM »

Quote from: beemerbum on September 03, 2020, 10:51:03 PM

Does anyone really care anymore about this guy's problem?

Why do you reply if you don't care? I think I "owe" it to everyone who helped me with my problem to tell the story to the end.

Alan F. · « **Reply #122 on:** September 04, 2020, 07:41:36 AM »

It's been a good story to follow along with. I don't have much of anything to add but I'm picking up things here and there that I didn't already know.

bryanj · « **Reply #123 on:** September 04, 2020, 07:48:43 AM »

It was an unusual failure and needs documenting till the end

754 · « **Reply #124 on:** September 04, 2020, 08:28:24 AM »

At least he listens, to what works........... and is not waiting for a second and third way to do it
I am thinking, lapping is less sound than cutting seats. When you turned it and it changed , evidence right there,
But hell just put it together and run it before you run out of season here. ,

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Author Topic: K8 Engine Damage - cam shaft sprocket in pieces (Read 9308 times)