Bent valve? Or something simple?

Soooo I finally got around to checking my valve clearances. Work has been crazy, so I've been out of the loop a month or two. Anyway, first off I should say to any other rookies out there, take the time to do it. It's not nearly as bad as I thought it would be, and by the time I got to cylinders 3 and 4 I was feeling pretty confident and comfortable (though cylinder 3 exhaust was a PITA to get the shim out) That being said, I need some help/advice from some of the experts out there, because I've run into a bit of a problem. After checking my clearances, the cylinder 1 intake seemed incredibly tight so I went to double check it. Now for whatever reason, there is a HUGE gap between the cam and the shim. To the point that I can see light between the two. I tried to measure it with my feeler gauges, and the closest size I could find was .50mm WTH?! How in the world did it go from being SUPER SUPER tight, to that loose? Only thing I can come up with at the moment is that there must be a bent valve, and/or a broken spring and it's not returning to it's normal position. I've sealed it back up for the night, but I'll check in the morning when I've had some rest and see. Hopefully it's just something stupid and I'm blowing things out of proportion, which I tend to do.

On to the clearances, info was as follows. I also pulled every shim so that I would know what exactly was in there (which ended up being a bit of a challenge since some of them were upside down and the markings were almost gone or in one case completely gone) I swapped shims around until I figured out that cylinder 3 intake and cylinder 4 intake are the same size.


Intake .04 .15 .14 .08

Shim 290 290 275 275

Exhaust .25 .20 .23 .20

Shim: 295 305 310 320

 

I always check them with the vernier gauge or micrometer regardless of what is printed on there.

 

How it went from super tight to very loose is indeed because it's sticking, or being held open.

You have probably burnt/cooked that valve and it is no longer straight so it's binding in the guide occasionally. That or there's a WHOLE LOT of carbon and deposits in the chamber and a boulder of it got under the head of the valve.

Probably not the springs but it wouldn't hurt to check.

Turn the motor over a few times. If that valve continues to stay open (wide gap) or gives you widely varied readings, it's definitely sticking. If that's the case, time to pop the head off and fix it.

 

DO a Compression Check.

The results will point you in the right direction.
You may have made a simple Mental Error.
Determine if anything is amiss before you wind-up tearing-down the Head for what might have only been a matter of you being distracted.

 

Since you found shims put in "numbers up", you KNOW that the PO had no clue about repairs, and when you have time you should make sure your brakes and other critical things were done right.

 

Thanks Fitz, I had some errands to run this morning and haven't had time to look, but I'm free this afternoon so I'll turn the motor over a few times and see what I find. I'm hoping I was just overly tired and overlooked something simple, but if not I'll be pulling the head.

Rick, you always have amazing advice and I'd be inclined to agree with you, but in this case as far open as the valve is my compression is going to be abnormally low. I don't have a compression gauge, or I would do it just to see, but I can't justify the expense until I get paid again, and I don't see how it would help given that the valve won't close all the way. Also as tight as my initial reading was (.04mm) I'm a little nervous that the valve may be burnt anyway. Thanks for the input though, and thanks for all your help on this site.

Time, I knew when I bought the bike that PO was not mechanically inclined. I'll get around to the brakes, tires, brake lines, etc. before I do any riding. The only time it's been driven since I bought it two months ago was from his house to mine (about 25 miles). Hopefully work will ease up and I'll have some free time and money to get this thing back on the road before it gets too cold. If not I'll be sorely disappointed.

 

Well I went ahead and pulled the head. The valves actually don't look all that bad, but the intake on number 1 is definitely open a little bit. I'm not sure why, don't have time to tear the head down tonight, but I'll take a peek in a few days and see what we've got.

Next question is, while I've got it this far, should I go ahead and change the piston rings as well? I'm kind of thinking I might as well. I don't know if it needs it, never did do a compression check, but it can't be THAT much more work, can it?

 

New rings are a lot of $$$$$$$$, then you would at least have to hone the bores. Sounds like you have one or more warped valves, this happens when there is a carbon build up, the valve doesn't shut fully & can't dissipate the heat back to the head. Replace the damaged valves & lap the whole lot in, then whack the head back on, set the clearances, then check the compression, if the 'wet' test improves the readings then you will have to look to the rings / bores, but you might be lucky & the work you have done to the head is not wasted.

 

I agree. Roll the motor over slowly and inspect the cylinders, if everything looks good LEAVE IT ALONE. Check the cylinder deck for flatness, and get on with your valve job.

How many miles on the motor?

 

How much is a lot? haha. I'd hate to skip it now and then realize later I should've done it. That being said, I've only got $1000 in the bike right now so depending how much it is, I might be better off to cut my losses. I have big plans for this bike, but I'm kind of on a limited budget so we'll see.

I'm not sure exactly fitz. Odometer doesn't work, but it reads 14,400. There wasn't anything that stood out last night, but I'll take a closer look when I get home this evening and see what it looks like in daylight. What exactly am I looking for?

 

Anyone know where I can get a head gasket now that I've pulled the head? Chacal doesn't have them listed. I found what supposedly is the right head gasket on ebay for $90 but that seems pretty high, especially when there's no guarantee it's the right one.

 

XJ1100 engines:

HCP5474 Aftermarket TOP-END GASKET KIT, for all XJ1100 engines.
$ 89.00


HCP54 Aftermarket COMPLETE ENGINE REBUILD GASKET KIT, for all XJ1100 engines.
$ 99.00

If you want JUST the head gasket, email Len, he may have a special part number for JUST that gasket.

 

To my knowledge, intake valves don't warp - but - here's 2 ways of checking.
You have a valve spring compressor already?
Remove the suspect valve, roll it on a piece of glass and see if it wiggles.
Or, chuck it in a drill and spin it. Compare with another valve, don't mix them up.

I found a whole XJ gasket kit on E-Bay for $20, but that's just luck there.

If you're under 40,000 miles, don't even think about rings. These motors are 90% bulletproof. (the weak bits being the plastic chain guides, the starter clutch, and 2nd gear if abused).

 

Thanks KrS14 I'm not sure how I overlooked that.

My dad was a professional mechanic for 30+ years, and he has a valve spring compressor. I would imagine it would work just fine. I'm not sure what's causing it to be stuck, but I'm sure I can figure it out once I get the head broken down. I don't know exactly how many miles are on it. The Odometer says 14,400 but it doesn't work. I would guess it's probably under 40k miles so we'll just leave the rings.

Thanks for the advice

 

As far as the valve spring compresser goes, maybe. You need the "cylindrical" type, with a head that looks kind of like a spark plug socket with the sides cut out. One that works on Ford V-8s won't work; one that works on Toyotas and Hondas, maybe.

I agree on the rings; even if it's double what the odo says you're not in much danger of anything having been worn out.

You're on the right track; keep us posted.

 

Don't struggle with a Compression Tool that isn't made to Compress the slightly-biased Valve arrangement and doesn't have the Open-ended end that Compresses the Collar into the Bucket Bore with cut-out to gather the keepers.

Automotive Spring Compressors, even with the "Adapter" are awkward to use.

This set costs $35.00
Made for the job.

http://store02.prostores.com/servlet/ei ... etail?no=8

 

Haha Fitz it's funny you mention ford V-8's because that's the only thing I've ever used it on before. He may have another one somewhere, I'll ask before I buy one, but thanks to Rick it looks like even if I do it won't be too bad.

Thanks Rick! I'll probably be placing an order soon.

 

What service manual are you using? Does it show the necessary orientation of the valve springs? Pay attention/take pictures when you disassemble the head; what appears bone simple sometimes is far from it.

 

I'm not sure where it came from, PO had it as a PDF on a cd and I printed it off. It's 190 somethin pages, but doesn't say who made it. I don't have it with me at the moment, but I don't recall seeing a picture. It does however have a warning that the tighter wound end of the spring goes towards the head. I'll take pictures/screenshots when I get home if you want. Might help.

 

The coils have to be oriented in a particular direction, roatation-wise.

PM me with an email address and I'll send you a scan from a 550 or 650 book; that detail is the same.

 

PM sent. Thanks Fitz.

 

Well guys, it's been almost a year but I finally got the time last weekend to break the head down, and sure enough the intake valve on cylinder 1 was bent.

The rest were ok, and I have a replacement on the way (should be here Friday). Money is kind of tight, but I'm hoping next week I can order the gasket kit from Chacal in which case I'll have her running again by June!

Thanks for your help, and I'll keep you posted.