Valve seals/guides or rings?

[Toolman]

Have not done a compression test yet, but will soon. Plug is all gunked up and power is down. There used to be a LOT of smoke on startup, but not so much now. I do not see how valve seals could cause the plug to become coated with this hard coal-like substance, but who knows. I did a search, and still did not come out with a sure idea of what it might be. ranger told how to tell the difference with a compression test, but any other ideas would be appreciated.

Also, can the rings be change without removing the heads? I can not remember how much clearance I have from underneath, but I am doubting I can pull (or should for that matter) the pistons out from below.

And last, how difficult to replace valve seals and guides? I have other heads I would just as soon put on if the job is too big and expensive.

TIA guys (BTW, this is for a customers car, not the turbo )

 

[jelloslug]

The pistons will not come out from below. I don't think you could get the crank out without removing most of the drivetrain anyway even if they would come out from the bottom. You can pressurize the cylinders and change the stem seals like that but 1) the OTC stem seal installer tool won't go over the valve stems and 2) if you changing the rings you will have to remove the heads anyway. My wife changed all the stem seals in a matter of minuets with the heads out of the car. I have never changed the guides but from what I have read the go in about the same way as the stem seals. You will have to have the valves out to do that though.

 

[Dr. Tweak]

And last, how difficult to replace valve seals and guides? I have other heads I would just as soon put on if the job is too big and expensive.

I'm going to have a how-to on this in... a couple hours... days... *cough* *cough*yamahaSHO?*cough* *cough*

 

[DHMag]

theres several ways, other than a compression test to verify if the rings are bad. they are visual/smell observations but usually are about 90% accurate. first, remove the PCV hose from the front valve cover. you should smell oil in it, and there should be a trace of oil residing in the hose. . if thats clean, remove the crossover tube and see if there is oil puddled in the intake. if so on either test, oil blowby has occurred and rings are suspectible. valve stem seals will allow oil to seep into the cylinder. if the seals are bad, then at every startup (every morning) there will be smoke from the exhaust. as for the carbon buildup, it could be caused by several facotrs. though, the buildup should only be on the exhaust valve, since it runs hotter than the intake. the factors are : bad gas, oil blow-by, wrong plugs(heat range or type).

i say wrong plugs because not every Yamaha engine will perform the same with the Motorcraft 32PPs. i burnt thru my 32PPs in less than 4K miles. i have now been running Bosch Supers for close to 3K miles and they still look fine (just inspected them yesterday).

 

[Mr Anonymous]

I'm going to have a how-to on this in... a couple hours... days... *cough* *cough*yamahaSHO?*cough* *cough*

Why not just read it right out of the Helms manual??? It's right there, all written up and everything.

 

[Bizzy]

valve seals in the car are very easy with the proper tools. The tool from Ford Sucks. Buy the one from Lisle tools. Makes each valve seal a 1 minute job.

Also you can buy the thing that screws into the plug well for pressurizing the cylinder for valve seal replacement. Expect to spend $35 for the valve spring keeper too for the valve seals, and $ 5 to 8 for the thing to pressurize the cylinders.

I'd let you borrow mine but I need them next week.

 

[yamahaSHO]

Why not just read it right out of the Helms manual??? It's right there, all written up and everything.

So is the 60k, but some people find it easier when explained by another party with pictures. Helm's is not always the easiest to follow either. I did most of mine with common knowledge because I hate reading that book.

 

[SHOZ123]

I would run two bottles of Auto-RX through it using regular oil and then switch to Castrol GTX Hi Mileage oil. Worked for me. Went from 700 miles per quart to 2500.

 

[sho thing]

Can the valve seals be done with the heads on? Are they rubber things or are they the same as the valve guides?
-Justin

 

[yamahaSHO]

Can the valve seals be done with the heads on? Are they rubber things or are they the same as the valve guides?
-Justin

Yes, they can be done with the heads on the car.. I have a step by step picture process that I am working now... Will be out soon.