Kawasaki FR691V cam lobes with ball bearing

[Rocket Surgeon]

Some good points raised.

I had already come across the issue with the valve guide/seal being pushed out of position, and the relationship to running the motor hot with dirty fins and related. I carefully had previously inspected the valve seals with that in mind, and saw no indication of that issue. Also, we keep this husqvarna machine very clean, so I don't believe it has been running hot. I replaced the valve seals in this latest push rod fix.

Following the advice previously given: I disassembled the cam assembly today, and it all looks brand new. The parts breakdown looked exactly like the one posted earlier, but I was guided by my own version in the service manual I am referencing. The ACR spring was in place, and functioned properly by allowing the cam lobe ball bearings to retract upon startup. I have since reassembled it.

As for the smoke color; yes, it was blueish white.

Question: I mentioned the punched out push rod pocket on the block. Should the motor be able to run with the opening to the lower crank area of the case? I would think that it should be able to tolerate a little more oil splash up to the valve train area. Also, I saw a youtube video with a hillbilly hero mower motor mechanic with fake buck teeth that seemed to know his stuff. One of his videos showed the repair of a similar situation on a somewhat similar kawasaki engine where the push rod pinched through the pocket and then ended up in the lower case. He seemed to have just done the rod repair, opened the crank case to remove the rod bent in the shape of a "U", then reassembled it and ran with the pocket punched out.

Thanks.

 

[slomo]

Did you see any valve seats not seated in the head? The valves rest on the seat when the valve is closed. Might resemble a wedding ring like piece of steel.

White smoke means burning oil. Black or bluish means excess fuel.

Kinda hard for me to help as the wordage being used is not exactly what the parts are called.

You said in your first sentence valve guide/seal being pushed out. Did you mean valve seat? I think this is what you meant??

You mentioned you keep the H machine clean. Have you removed the blower/fan housing and cleaned all the dirt, oil, grass and bugs away from the cylinder block cooling fins? Some on the cylinder head also to keep the engine cool.

slomo

 

[Rocket Surgeon]

I stand corrected regarding the valve guide migration due to over heating.

The better description given here of the problem got me thinking: After making the distinction between the valve guide and the valve oil seal, I retrieved the failed head and accurately measured it with a plunge caliper. The twice bent rod valve had indeed migrated as described. It measured .040 higher than the other valve. I had previously only visually inspected it with the valve oil seal in place. Thanks for the insight.

I'll check the other head just to be safe.

Now I only have to figure out this smoking and apparent oil in the cylinders thing...along with the 180 psi compression.

Short of a ring issue, I'm at a loss.

I did read something describing similar symptoms from a clogged crank case breather valve. I'll take a look at that.

Thanks.

 

[Rocket Surgeon]

Slomo:

Sorry for any confusion regarding terminology. I was referring to the valve guides as the component that moved out of position due to excessive heat...which I recently acknowledged did, in fact, happen.

I lapped and dye-chemed the new valves when I installed them, and the valve seats looked good on final assembly.

Regarding the cleanliness of the machine: apparently I didn't clean is as well as I thought

I would describe the smoke as white to blue/white. I believe it was oil, not fuel.

Thanks.

 

[slomo]

What is the compression ratio for that engine? If it's like 8:1 or 8.5:1, 180 psi is way off. I would check cam timing if you have not. That much static compression should have like 11:1 compression. Most mowers are not even close to 11:1.

A valve rides IN a valve guide. Valve guide is pressed into the cylinder block.

Valve seal rides just below the small pencil like tip of the valve, on TOP of the valve guide. Valve keepers and spring retainer ride above the seal.

What is a "twice bent rod valve"? Are you talking about a push rod?

0.040" higher meaning the valve seat is 0.040" deeper INTO the cylinder head?

Take us a ton of pictures so I can help you more. Fire up Windows Paint and edit the files. Point at the parts so I can see what you are talking about.

slomo

 

[slomo]

Slomo:

Sorry for any confusion regarding terminology. I was referring to the valve guides as the component that moved out of position due to excessive heat...which I recently acknowledged did, in fact, happen.

I lapped and dye-chemed the new valves when I installed them, and the valve seats looked good on final assembly.

Regarding the cleanliness of the machine: apparently I didn't clean is as well as I thought

I would describe the smoke as white to blue/white. I believe it was oil, not fuel.

Thanks.

I want pictures of that filthy engine block please LOL.

Valve guides, yes, those moving out of the head, most of the time caused by filthy cooling fins. Engine gets HOT from all that oil and dirt choking the fins. That causes parts to heat up and expand.

slomo

 

[cpurvis]

The Kawasaki shroud is very easy to remove to clean the fins. I use a leaf blower on the engine and mower every time I use it. I leave the engine running and blow down through the screen. And I still remove the shroud about every 25 hours to make sure nothing remains in there.

 

[cpurvis]

0.040" higher meaning the valve seat is 0.040" deeper INTO the cylinder head?



slomo

No, the valve guide moves by itself.

 

[slomo]

No, the valve guide moves by itself.

I'm aware of that. I was trying to make sense, in my head, what the OP was stating. So he meant the guide moved 0.040" out from where it belongs, I get it.

slomo

 

[Rocket Surgeon]

To clarify: the valve guide on the valve that bent the valve push rod sits 0.040 in. above the height of the other valve guide in the same head, measured with the valve oil seals removed. Anytime I said "rod", I meant "valve push rod". Anytime I said "guide" I meant "valve guide". When I said "twice bent rod" I was referring to the valve push rod which, on two separate occasions, was found to be bent. In both instances the valve push rod was replaced.

I believe the bent valve push rod issue is now resolved. Thanks for that.

Dunno what pictures you'd like to see. There is no dirt or clogged fins to show, as the engine was pressure washed when removed from the mower prior to disassembly. The head with the out of place valve guide has been replaced with a new head. Two of the four valves have been replaced, and all four have been lapped prior to installation, with the valve clearance set to 0.004 in.