Thank you! They are on my list but there is another shop with a very good reputation, I will visit them tomorrow to see whats what.
2001 monster s4 worn valve guides
- Thread starter gggrrrr
- Start date
So machine shop gave me a very reasonable estimate for replacing guides / cutting valve seats. Heads are gonna come off.
Couple of question though
- what ar my chances for worn valve stems? Are ducati stems prone to wear?
- cast iron vs bronze guides? Machine shop said bronze is usually better but they are not specialized in ducati.
Couple of question though
- what ar my chances for worn valve stems? Are ducati stems prone to wear?
- cast iron vs bronze guides? Machine shop said bronze is usually better but they are not specialized in ducati.
Of the 2, bronze are better.
I had the guides on my 916 replaced with Colisbro guides; https://columbiametals.com/product/colsibro/ supposed to be better but I think you'll be fine with bronze.
Perhaps see if you can by some genuine Ducati parts?
If I was doing them again, I'd go with the K-line inserts; https://www.klineind.com/k-line-service-tools/valve-guide-liner-system.html as I had in my Guzzi (done because the old Le Mans heads are fragile and banging out the guides could break them which, being made of unobtanium would have left me with a big problem) but they probably require somewhere with the experience/equipment.
I had the guides on my 916 replaced with Colisbro guides; https://columbiametals.com/product/colsibro/ supposed to be better but I think you'll be fine with bronze.
Perhaps see if you can by some genuine Ducati parts?
If I was doing them again, I'd go with the K-line inserts; https://www.klineind.com/k-line-service-tools/valve-guide-liner-system.html as I had in my Guzzi (done because the old Le Mans heads are fragile and banging out the guides could break them which, being made of unobtanium would have left me with a big problem) but they probably require somewhere with the experience/equipment.
Update:
The cylinders / pistons look ok to me, still plenty of crosshatch. The horizontal(this is the one with the lower dry compression reading) has a bit more longitudinal wear but nothing my fingernails could catch on.
Measuting wiggle "properly" on the edge of the valve heads at cca 5mm open position the exhaust guides show 0.6-0.9mm play, the intakes 0.1-0.2. For reference when checking it during valve adjustment: I kinda couldn't feel any play by hand at 0.1mm. I could feel 0.15, weird.
Is there a nominal diamater of the valve stem and id of guides? Somebody wrote the wear was hourglass shaped and indeed it is. I took a lot of measurement and I guess the stem should be 6.98mm. The most worn ones measured 6.95mm right where the end of the guide meets the stem. Manual says when new the clearance should be 0.03-0.045mm. If the stem id is 7mm I'm good. But is it? Couldn't find anything on the web.
Now, the seats and mating surfaces. I think it is pretty obvious none of my exhaust valves seal properly. Vertical intakes look nice but the other 6 seats and valves look super rough and pitted. I've read something about shitty finishes right out of the factory. Is it true or is it abnormal wear?
Fingers crossed there is anough meat on the seats / valves for the machine shop to recut them.
The cylinders / pistons look ok to me, still plenty of crosshatch. The horizontal(this is the one with the lower dry compression reading) has a bit more longitudinal wear but nothing my fingernails could catch on.
Measuting wiggle "properly" on the edge of the valve heads at cca 5mm open position the exhaust guides show 0.6-0.9mm play, the intakes 0.1-0.2. For reference when checking it during valve adjustment: I kinda couldn't feel any play by hand at 0.1mm. I could feel 0.15, weird.
Is there a nominal diamater of the valve stem and id of guides? Somebody wrote the wear was hourglass shaped and indeed it is. I took a lot of measurement and I guess the stem should be 6.98mm. The most worn ones measured 6.95mm right where the end of the guide meets the stem. Manual says when new the clearance should be 0.03-0.045mm. If the stem id is 7mm I'm good. But is it? Couldn't find anything on the web.
Now, the seats and mating surfaces. I think it is pretty obvious none of my exhaust valves seal properly. Vertical intakes look nice but the other 6 seats and valves look super rough and pitted. I've read something about shitty finishes right out of the factory. Is it true or is it abnormal wear?
Fingers crossed there is anough meat on the seats / valves for the machine shop to recut them.
and
Desmoquattro Valves are 7mm stem, I used a 7mm reamer through my 916 guides to clean them up, Desmodue 2-valve engines are 8mm stem.
slob
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EARLY desmodue engines have 8mm valve stems, 1000DS onwards are 7mm like desmoquattro
slob
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(new) guide id should be 7.03-7.045mm
sorry if this is stating the obvious.
what are you measuring the id with?
sorry if this is stating the obvious.
what are you measuring the id with?
Thanks! I couldn't find this info on the web.
I could only measure the valve stems, they are 6.95-6.98mm. Do you happen to know the new valve stem exact diamater too? Is it 7.00mm?
slob
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the stems should be 7.00mm
your .02-.05mm difference could well be measuring error or light wear
your .02-.05mm difference could well be measuring error or light wear
I 've spent a lot of time measuring all 8 valve stems with micrometer and good caliper too. Couldn't find any spot over 6.98 and below 6.95. I'm pretty sure my error is <0.01mm. There is wear on the stems where the guides bottom end rubs them while wiggling. Other than that all of them are 6.97-6.98mm.
Hopefully the shop can make the new guides so your info on the diameters is very helpful.
slob
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maybe production tolerances then? or even the temperature of your workshop in January?
sent you a DM
sent you a DM