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Message started by deadman333 on 04/02/16 at 16:32:21

Title: new head, new rings & combustion blow-by
Post by deadman333 on 04/02/16 at 16:32:21

I own a 2005 LS650. I've started riding in July of 2016. The bike had approx 6,000 miles on it. Since i began riding it I have racked the mileage up to 33k and some change.
Recently I began to notice a loss of power after being on the bike for 20-40 miles. Eventually I began to notice the loss of power within 20 miles of riding.
As it turns out the head was cracked right thru the threads where the spark plug threads in. After removing the head I could see the crack was quite extensive: moving upward from the spark plug and kind of wrapping the exhaust valve closest to the plug.
Since then i have completely tore down and rebuilt the upper engine:
1.Replaced the cracked head and head cover.
2. Removed old rings & replaced with new.
3. Replaced cylinder Jug gasket that sits between the upper and lower parts of the engine.
4. Replaced the head head gasket with a new one.
5. Replaced Studs and Head bolts with new.
6. Adjusted valves to .004in

Upon rebuilding after replacing rings and cracked head all seemed to be in order. The bike started right up & sounded great. I tested compression pressure: It measured between 185-190psi.
On the first ride everything seemed ok for the first 10-15 miles. I was thinking that maybe i didn't have the power i expected, but thought that might be the case until the rings were broken in.
I stopped for gas approximately 10 miles into the ride. No oil leaks, no smoke, and the bike seemed relatively cool.
I filled the bike up and continued on my test ride. Some where around mile 15-20 I noticed my left boot was shining under the interstate sodium vapor lights.
I knew immediately it was oil and it was likely i had blown a gasket. I was near a buddy's house and pulled off the interstate and into his driveway to inspect the engine for the source of the leaking oil. the upper engine was clean. There was no oil from the cylinder up to the top of the upper engine. Of course i had just added oil upon completion of the repairs, and it appeared the leak was in fact coming from the oil cap.
I turned to tighten the cap and it was loose. Maybe a half to three quarters turn. So I added some oil to account for what had been lost and continued my ride to my girlfriends house where i intended to stay the night. Approx fourteen miles.
Upon arriving at her house she opened the garage door and I rode the bike in to check it out under the lights. It appeared that no more oil had been leaking since tightening the oil cap.

The next morning I cleaned the leaky oil from the lower engine casing, made sure the oil cap was in fact tight, and headed for home- almost a forty mile trip.
Before i made it home, but on the last leg of the journey, I noticed my boot was shiny and covered in oil again.
I made it home and immediately inspected the bike. I could see while the bike was running oil was oozing out in the front of the engine at the cylinder gasket. No doubt it was the source.

I immediately ordered all new gaskets and studs and commenced to tearing the bike down and removing the engine.
I was ready for the gaskets when they arrived six days later and quickly but carefully put the bike back together. Feeling confident that i was back in business a few days later I took the bike for a short test drive upon completion of putting it back together.
It was raining and i was late for a weekly gig i play across town so i loaded up my gear in the car and headed out. Knowing i'd be late getting home and would have to rise early to leave for work the next day.
Early next morning I woke up a little late for work and was in a hurry to get on the road. Of course the battery was just a hair too far drained to start the bike. It turned over but wouldn't start. Of course my short test run before my gig the night before was not enough to charge the battery so I jumped it off and headed for work approximately 18-20 mile trip-late.
Within five miles of work I had to stop on the interstate due to traffic. When my left foot hit the ground it slid like it had oil on the bottom of my boot. I looked down and of course it was covered in oil. I carefully completed the ride to work and immediately inspect the engine for the source of the leak. I saw that i still had enough oil in the bike to see it thru the oil inspection window, but it was obvious where the source of the leak was coming from.
It was the same darned cylinder gasket between the lower and upper engine, but this time the entire front side of the gasket was blown out and standing perpendicular to it's the front of the engine. It was standing straight out in the front of the engine and facing the front tire.
I think it is obvious that the engine is experiencing blow by upon compression and is pressurizing the lower end of the engine. Thusly causing my cylinder gasket to blow out.

My question is: What are the possible ways that pressure from combustion can make it from the upper to the lower compartment of the engine? and: What is the most likely cause from those possibilities?

Thank you.

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/02/16 at 16:33:29

Correction: I started riding in July 2014.

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/02/16 at 16:38:56

Did I overlook the
I checked the rings end gap
I made sure that the piston to cylinder wall clearance was good
I cross hatched the cylinder
parts?

Footpeg bolts Must be tight, to close the case halves.
A cylinder can develop a ridge at the top, from the compression ring. Slapping a new one in and not cleaning that up can break the new ring.
Cylinders can develop a bit of a taper.

More to doing a top end than slapping parts in.
I'm hoping you did everything and just need to tighten the peg bolts up.

Title: Re: new head, new rings & combustion blow-by
Post by Kris01 on 04/02/16 at 19:56:16

Clymers lists compression at 145-203 psi with bare minimum being 116 psi. Sounds like the rings might be okay.

Title: Re: new head, new rings & combustion blow-by
Post by gizzo on 04/03/16 at 03:50:15

You didn't happen to block the breather hose on the top of the rocker box by any chance? A fat rubber hose leading from rocker box to the airbox? If that's blocked, crankcase pressure will look for another way out and its conceivable that it chose to blow out the cylinder base gasket. Hope that's all it is. Check the new rocker box you bought has the steel wadding inside, and that it's not blocked solid with old gunk.
That's all I got.

Good effort racking up 25000 miles in 2 years 8-). How's your timing chain?

Oh yeah: to answer your question about compression getting into the crank case:whenthe piston rises, it compresses in the cylinder. But when it falls, it also pressurises the crankcase. The pressure gets out through that hose. Good work btw.

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/03/16 at 19:09:41

okay. thank you for your response. I am disassembling the bike currently to remove the upper engine. I did not know the lower end pressurized and escaped thru the vent. Blockage there would make sense.
I hoisted the bike today to bring it to a comfortable level for working on it, and began disassembly to remove upper engine. This afternoon i first cleaned the bike removing the oil from leakage that covered the lower end and frame of the bike, removed the battery, battery case, Carburetor, and muffler/exhaust. Tomorrow(monday) I will remove the engine from the bike and inspect the steel wadding and vent for blockage.
I agree that the rings are likely not the problem since combustion pressure test was so close to the high end as specs suggest.
Thanks again for the help. I will return with what i find as soon as possible. Hopefully tomorrow evening after work. This leaves me with high hopes for a relatively easy solution that i had not considered.

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/03/16 at 19:17:10

I did not check the ring gaps or measure cylinder or piston clearance. i have purchased a digital micrometer and intend to do all of this. I will post the results as I remove the upper engine and disassemble.
I should have done all of these things already but did not. I have already considered after the fact that one of these factors is causing the problem.
Thank you for your help from a novice wrench turning fool. I will update you with measurements in a couple of days if not before.

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/04/16 at 05:26:30

Someone said your compression is good.
If you have not checked the peg bolts, do.

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/04/16 at 05:33:19

An inside diameter dial caliper will find if it's round or tapered.
I take my pistons and jugs to an engine builder. Yeah, costs a bit, but, I know it's right.

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/04/16 at 06:33:08

Thank you. I understand that compression is good. That is why I included the info in the original post. I have not checked the foot peg bolts because I took them off to remove the muffler in the process of removing the engine to replace the cylinder jug gasket that blew out.
I don't understand how foot peg bolts have anything to do with the cylinder gasket.
If I was having a problem with a gasket on the lower end I would understand how that could be a problem.
Gaskets arrive Wednesday. I will have the upper engine removed today and take measurements of ring gaps, piston , and cylinder.

Title: Re: new head, new rings & combustion blow-by
Post by gizzo on 04/04/16 at 16:42:48

18252E242F33072525382F7D7F4A0 wrote:

Thank you for your help from a novice wrench turning fool.

You're no fool. You're asking intelligent questions, providing the relevant information and acting on the advice you've received. You're doing the work yourself and learning from the experience. Keep up the good work, mate.

Title: Re: new head, new rings & combustion blow-by
Post by gizzo on 04/04/16 at 16:58:47

BTW and just for interest's sake, your old cylinder head with the crack might be salvageable if you know a good welder/machinist engine builder. They can grind out the crack, weld it up and machine it back to shape. They'll have to fit new valve seats too. Worn cam tunnel can be fixed like this, too. Not cheap and probs not worth it in the 'states. You guys seem to have unlimited access to secondhand parts. But in australia, not so much. I've had maybe a dozen Honda RFVC head successfully reclaimed this way. Used to know a really good engine guy but then he died.

Title: Re: new head, new rings & combustion blow-by
Post by Dave on 04/04/16 at 18:41:18

I would be interested in knowing why the head cracked.

This is the first one I have ever heard of.

Was the bike overheated?

Title: Re: new head, new rings & combustion blow-by
Post by gizzo on 04/04/16 at 19:15:15

Same. I only saw in on older Honda XR heads. they crack between the spark plug and valve seat. later models came with smaller valves and more meat between the plug and valves, as well as increased oil capacity and an oil cooler.

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/05/16 at 05:42:19

I must have gotten it wrong. I thought you had a low engine leak.
I didn't notice how you put the head cover on the head.
What sealer you used.
Checking out that vent hose can't be a bad idea.
Just how much of a leak is it again?
I've seen major projects go sadly it awry, a Mack truck engine is dead today, and other smaller disasters. Add up all the wins and losses, I was brilliant. I quit that company with Zero notice and they called Me a few months later to work on a project, alone, after hours,,,, because they didn't know anyone else they could trust to work unsupervised. You walked in, you did stuff, and it's Running. Okay, maybe there were some unknown unknowns, and, maybe something didn't go just right,,but you're no dummy.
I do wish people could find this place before they get real adventurous.

And how Did that head get cracked? That's a really good question.

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/05/16 at 06:19:36

Mmmmkay, I went back and read. You lost the jug / case gasket in a big way. You started seeing real issue After you tightened up the oil fill.

Either something isn't kosher where that gasket sits or the internal pressure is too high or, a bit of both.

Some oil leak hunters have closed off the vent, sprayed soapy water on the engine and put a few PSI in the crankcase.

You might wanna Not block the vent and see if the engine is breathing right.
I'd sure inspect the surfaces that the jug gasket are on.
And how much goo goes on the head cover matters, and what kind, IMO. Not RTV,,

I'm not a real stickler for the torque wrenches, I go by feel on about everything,, but jug and head , I would use one.
Head cover, no.. just keep making passes getting tiny bits of a turn, pinching the sealer flatter and flatter until the bolts tell you
Th Th Th That's All, Folks.
You can feel it. Depends on how you hold the wrench, a closed hand is dangerous.

Sounds like you're going at it hard and fast. You might be ahead to slow down.

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/05/16 at 20:34:26

How did the head get cracked? I am not positive, but I believe it was cracked before it came into my possession, but only the tiniest of cracks.
The first time I changed the oil on the bike I also changed spark plug. The tool provided with the Suzuki tool kit to remove the spark plug did not fit the plug I was removing.
If I remember correctly I had to use a standard 9/16" or 5/8" deep socket to remove it. At the auto store the guy looked up the plug for make and model of the bike, and came back with a comepletely different spark plug. The plug I pulled was definitely longer in the threads an not at all what Suzuki suggests.
I didn't think too much of it nor did I inspect for damage. Although I racked up a lot of miles they were all freeway in non-traffic hours counting 45-50 miles one way to work.
No traffic, riding in the sweet spot as far as rpm's the bike never got hot.
Now a year ago almost to the day I set out for Amirilllo, Tx from Fort Worth, Texas. A 380-400 mile & six hour ride (without stops).
About 60 miles into the trip heading due northwest the wind began to blow sustained at 35-45mph and heavy duty gusts.
The trip took almost nine hours and if the bike ever got hot it was I thin the first 200 miles of the trip. At some point I lost a good amount of power, but the warning light for High Temp never lit.
After making it home a week later when the camping ,fishing, and golfing were all done in Amirilllo I inspected the bike. Changed oil, spark plug , Intake filter.
This was when I first noticed a crack that was just past the spark plug threads. It could have always been there, but I never was looking for it.

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/05/16 at 20:40:02

I have the upper removed from frame and disassembled. I will be posting my measurements and limits for piston, cylinder, and ring gaps, etc. Possiby tonight but tomorrow for sure.
Also I did not include the fact that I did not muse a torque wrench when installing the double threaded studs the run thru the cylinder.
Of course I know it is likely my problem and the answer to my own question.

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/05/16 at 20:47:14

Blowing out the gasket for the second time did slow me down, and the reason I finally registered for this site and stopped using it as a guest so I could post my problem and glean the knowledge of those that know something about this. Bought a digital caliper and a torque wrench graduated in small enough incraments to be accurate below 10ft-lbs.
I will have info on cylinder and piston measurements soon. Replacement will gaskets and new studs and such will be here by the end of the business day tomorrow.

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/05/16 at 20:52:34

Drag a fingernail up the cylinder wall and feel for a ridge at the top.
You can rent a tool to put the crosshatch on it.

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/06/16 at 11:30:47

There was a ring of hardened carbon built up around the top of the cylinder. I carefully scrubbed it clean. Best I can tell there is no ridge.
The top of the cylinder measures right at 94mm.
I actually got 94.04mm 94.03, 94.01 & 94.00. Measured across, perpindicular and two diagonals.
The piston I measured 20mm from the bottom of the piston's skirt as suggested in the manual. It measures 93.78mm & 93.84 on a secondary measurement.
I will measure the ring groves on the piston and the ring gaps while in cylinder today after carefully cleaning the piston grooves.

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/07/16 at 20:32:12

So,if a Deadman survives the challenge, does he become a zombie, by default?

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/09/16 at 10:55:56

here are the measurements and specifications for piston, cylinder, rings, etc:

cylinder bore:
Upper cylinder: 94.03, 94.05,94.00mm
Lower cylinder: 93.8, 93.78, 93.77mm
(i have to assume that the measurements for the lower part of the cylinder are most likely 94mm. I mean how does a cylinder become smaller over time?)

ring gap(in cylinder): .22mm and .36mm
Should the ring with the largest gap be in the top groove on the Piston?

piston O.D: 93.84
Camshaft journal:
right: 24.96mm
center:24.96
left: 19.96m

I also honed the cylinder wall. sometimes known as crosshatching the cylinder. I intend to begin the process of putting it all back together today.
Thanks

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/09/16 at 10:57:59

i believe a zombie to be considered the living dead. My reward will come from another 33,000 miles.

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/09/16 at 12:06:33

Setting the compression ring in the cylinder and measuring the end gap, looking for even the slightest bit of light between ring and cylinder wall, clues as to just how straight and cylindrical the cylinder IS. I don't have ID micrometers, so I pay a machinist to check the bore before I go forward. Maybe just the end gap and cross hatch and go is good enough. Others have more
Deep inside the engine
experience.

Gotta use the piston and slide the ring down to several places and measure the gap. Gap changes? Cylinder diameter must be different.

Title: Re: new head, new rings & combustion blow-by
Post by Kris01 on 04/09/16 at 14:25:53

From Clymers

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/09/16 at 20:34:55

Thank you for including the image of specs and wear limits. I am currently using a downloaded repair manual of unknown origin, but it is thorough.
I noticed in the image provided above the Ring Gap within the cylinder is the same for both the first and second rings. In the manual i am referencing it lists for rings within the Cylinder to be as follows:

First ring within cylinder: 0.012-0.045mm
Second ring within Cylinder: 0.010-0.016

Either way it appears that I included the wrong data on my previous post, i measured or recorded my measurement incorrectly, or my measurements of the ring gap within the piston is evidence that something is not within the recommended wear limits.
I will measure the ring gap within the cylinder again as soon as possible and post the results .
Thanks again.

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/09/16 at 20:43:49

i did use the ring within the cylinder to inspect the cylinder for wear in its center. I did not detect any difference in the gap measurement, but i did not inspect for irregularities in how closely the ring met the cylinder wall as a previous post suggests.
I will do this when I re-measure the ring gap within the cylinder at several places up and down the cylinder wall.
I thought i was within wear limits and was ready to proceed with reassembly, but if it is as it appears I will need to visit a machine shop with my cylinder and piston for professional assistance. Which at least at this point seems like a no brainer. Right?

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/09/16 at 21:47:49

I've done some inside the engine work. Depending on the engine, I decide. Give me a thumper that I can haul the head, piston, rings and cylinder all in the car? Ohh, it's Going to the machine shop. ESPECIALLY if I already
Fixed it
once.
You don't have to go hunting for a bike shop. The same place where the local hot rodders take their engines to get that tricky valve job or get something bored out is where the Yamaha shop takes their stuff.

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/10/16 at 11:38:41

Remeasured Ring Results: The rings are new. However, they do have approximately 75miles of use as per the story /info I shared

Free end gap. 1rst ring=11.77mm. 2nd ring13.86mm
Both of the measurements above fall right where you'd want them to be.

End gap within piston: 1rst ring=0.41mm. 2nd ring=0.38
Again I believe both measurements to be within wear limits.

I used the piston to push both rings thru the cylinder one at a time. I measured the ring gap and closely inspected for any light penetrating between the ring and cylinder wall and measured the gap at every stop. I found no difference in the gap, and no irregularities between the rings and cylinder wall.
This info along with the info provided in my original post(compression test revealed 185-190psi) leads me to believe that the piston & cylinder are not to be held suspect for the twice blown cylinder/case gasket. There is a possibility it still could be, but I believe enough evidence has been established to at least look beyond them as the cause.

Now, moving along. When last I put the engine back Together I noticed after I installed the cylinder over the piston and atop the gasket & case-When I installed the lower cylinder nuts to the studs (located on the clutch side of the engine) the opposite side of the cylinder would lift enough I could see light between the gasket(still sitting atop the case) and thr base of the cylinder.
This happened again yesterday as I was meticulously putting it back together. I have tried it three ways-
1. Without installing the double threaded post thru the cylinder.
2. With the post installed and lightly hand tightened
3. With the post installed without the head in place, but the posts
torqued to specs

Each way returned the same result: as I torqued the lower cylinder nuts ,as the manual suggested, the opposite side of the cylinder base would lift.

I believe this to be the reason my cylinder/case gasket has blown twice, but I can't come up with why the cylinder tends to lift when the lower cylinder nuts are torqued.
I intend to pull the post and inspect for debris at the bottom of the post's threads. Keeping one or both post from seating properly.

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/10/16 at 12:53:25

You don't torque anything until they are All snug. Go around, by hand, just a wrench or socket and get the jug down Flat. Then keep going .
First, hand tight. Cross corners. Front left, right rear.
Front right, left rear.
If you can't just Set the cylinder down and it sit flat, something is wrong.
Lay the torque wrench down, get a 1/4" ratchet and Gently bring the cylinder down.
You don't throw a tire on a car and put one lug nut on and torque it, do you? You snug them, in a criss cross pattern, and continue to tighten them sequentially, until you get it tight.
If you have torqued to spec one bolt and Not had the others snugged down enough to keep the cylinder flat on the cases, you may have messed up the gasket. Remove and inspect.

Get it together using basic hand tools, then the torque wrench for the last bit.
You may be onto something.. if you've got something tight, but the cylinder isn't clamped down, then debris in the hole is a possibility.
Did you scrape a gasket there?

This is why I'm so meticulous in the disassembling of anything.
Of course, that wasn't always the case. I learned that, after building and stepping into several bear traps.
When you pull the bolts, is there crud on the end?

Title: Re: new head, new rings & combustion blow-by
Post by Art Webb on 04/11/16 at 08:31:35

^^^this
when you'r putting a part on that needs even torque, you run the bolts down first by hand, then torque it in at LEAST 3 even stages, criss crossing all the way, and if it's a long piece (that'd be on a multi, not a single) working from the middle out
not by torquing the first bolt to spec, then going round to the next one

Title: Re: new head, new rings & combustion blow-by
Post by Ed L. on 04/12/16 at 12:24:44

Been following this thread but haven't opened up an engine that far so was keeping quite but had a thought. When you torque the jug down are the bolts that hold the engine case together tight? Maybe try loosen them up a little bit.
Here's the logic behind this, if the top bolts that hold the cases together are tight but the bottom long bolts are out since the engine is out of the frame it could be that the top case bolts are pulling the cases halves together at the top to the point where the jug just barely doesn't fit into it's hole. It can't hurt to loosen them for the next assembly and it might just be what is needed to get the jug to seat properly. Luck with it

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/12/16 at 12:29:59

I see where you're going and why, but I would rather see the bottom clamped shut. If he allows the top end to open and torques the jug down,then what happens when he tries to clamp the top shut? I don't even know what bolts are involved in that.

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/13/16 at 07:10:32

Ok, I will find out this morning if what I found was the problem. My bike is now 90% reassembled. Justt a few odds & ends to completion.
When I disassembled this time I was certain I would find debris of some sort at the bittom of the threads recieving the cylinder Dows that hold both both the cylinder and the head to the lower end.
There was debris in the form of fluid. Oil to be precise. It has since come to my attention that if fluid can not escape and pressure is applied it can not be compressed.
Upon reassembling I did not have the problem of the cylinder lifting on the opposite side when I tightened the nuts on the bottom right hand side of the cylinder. Fingers crossed this was my problem!

For further experiment I intend to run a compression test this morning then take the Bike on a test run- maybe 10-15 miles.
Now warmed up I will return to compression test again. Measuring the difference (if any) between the two tests.
I am thinking even a third compression test after a good long ride when it's really warmed up.
If I find a meaningful difference in the results then I'll know I am getting blow by past the rings and into the lower end. Telling me my cylinder and piston (one or both) are outside of wear limits.
If there is little to no difference in compression then my measurements of cylinder & piston were accurate and I'm back on the road!

Thanks to everyone who has posted and shared their thoughts. I will share the results of my compression tests this afternoon or tomorrow.

Title: Re: new head, new rings & combustion blow-by
Post by justin_o_guy2 on 04/13/16 at 09:23:43

Please tell me you honed the cylinder and put a crosshatch pattern on it.

Title: Re: new head, new rings & combustion blow-by
Post by gizzo on 04/13/16 at 15:45:44

Good luck, man. Good work. Can't imagine, with the cylinder pressure you measured before the teardown, that you're going to have excessive blow by. Hopefully was just the rookie error torquing the cylinder down the first time fingers crossed for you!

Title: Re: new head, new rings & combustion blow-by
Post by deadman333 on 04/05/21 at 15:00:24

I just ran across this thread while trouble looking for something else, and realized I never completed the thread.
In the end, the reason the lower gasket keeped failing was because oil had found its way into the recieving threads for the right side front cylinder/head stud. Being that a liquid, such as oil, when enclosed within a finite space can not be compressed. So even tho the head bolts had been torqued to spec the head bolt could not pull the cylinder down and snug against the lower crankcase to cylinder gasket. Thusly, the gasket was being blown out by normal operating crankcase pressure.
I ended up riding that bike for another twenty thousand miles before buying a 2003 Savage.