Wildguzzi.com
General Category => General Discussion => Topic started by: Pescatore on February 08, 2023, 03:22:43 PM
-
I am preparing to remove the left side head on a 1991 V65 with 21,000 miles. It leaks oil and it's spreading all the way to the swing arm.
Compression is still 150psi on both sides when cold.
From the posts I have read, it seems a straight forward job. I am armed with workshop manual and Guzziology.
I am expecting the head will not come off easily. My question is about the cylinder base gasket. It does not leak and I worry that prying the head off will compromise that joint.
What is the best way to remove the head without consequences? Or is it a crapshoot?
The right side head is clean, so I don't plan on opening it. However, I plan on taking the left head to a machine shop and have it taken apart, cleaned and checked out.
Does it make sense to remove the other head as well? I guess I can do it at a later time, if I see differences in performance of the two sides.
-
Why you are at it… I would treat both sides to refurbished heads, head gaskets and base gaskets. You will be much happier in the end. The bike will be easier to tune and run much better in the end if you do both sides at once.
But if you only want to do one side you can probably not worry about the base gasket. But you’re only 15 minutes from pulling the jug, replacing the gasket and sliding the jug back on. Just need to collapse the rings when sliding it back on. If you don’t do it now it’s an afternoon worth of work to get back to the base gasket.
-
Mind you, I’m only speaking from limited experience with a much newer V7 II, but I would have an extra base gasket on hand as a backup, and have a second set of hands hold down the cylinder while you take a combination of dowel, mallet, and prying device to work at the head.
-
When I first got my V65 Mongrel LaMonza (Monza frame, Lemans tank, V65motor), the PO pointed out a leak from the right side jug, he thought it was the head gasket. Turns out it was only the rocker cover gasket folded over.
But I assume you've checked that.
FarmallA
Steve
-
When I first got my V65 Mongrel LaMonza (Monza frame, Lemans tank, V65motor), the PO pointed out a leak from the right side jug, he thought it was the head gasket. Turns out it was only the rocker cover gasket folded over.
But I assume you've checked that.
FarmallA
Steve
Good comment….
-
Compared to that gearbox this is cake Maurilio. I wouldn’t freshen one head and not the other. Don’t forget that breather hoses come out of the back of the heads on the small blocks and into the air cleaner Check to make sure that a hose isn’t cracked and blowing out oil by just removing the rocker cover. Also, gently tap the head with a hide or rubber mallet to loosen it. Don’t pry.
-
Also, gently tap the head with a hide or rubber mallet to loosen it. Don’t pry.
Only commenting to say that also, breaking fins is unfortunately easy ... :angry:
-
Never tried it but what would happen if after removing the push rods and of course the nuts and bolts you put the sparkplug in and crank the motor over? 150 psi should blow the head clean off as Dirty Harry would say.
-
probably separate the assembly at the base gasket unfortunately since it's the smaller of the two, neat idea though!
-
Never tried it but what would happen if after removing the push rods and of course the nuts and bolts you put the sparkplug in and crank the motor over? 150 psi should blow the head clean off as Dirty Harry would say.
Hold my beer... :grin:
-
Hold my beer!
Was when you just loosen all the head nuts about 1 millimeter and crank it over live. Each cylinder fires once and the heads are free!
-
Ear muffs Pescatore.
-
Hold my beer!
Was when you just loosen all the head nuts about 1 millimeter and crank it over live. Each cylinder fires once and the heads are free!
Well you could go a threaded compression tester and some compressed air, I'd leave the head bolts in a few threads. Not sure about the V65 but on the old square fin big blocks there is a blanking plug that allows access to a head bolt (I think) sealed with an o-rung. When that leaks it looks remarkably like a head gasket.
-
Nothing like that on the smallblocs
-
This is getting very entertaining. I'm holding the beer, nsmith. Did it work?
Compressed air from the spark plug is interesting too.
Thanks for the tips, folks. I was thinking about prying the head, so I won't push on the fins. Holding the cylinder makes sense. Compressed air should keep the cylinder down as well.
I have a whole gasket kit from Scout63 and the valve cover gasket is dry.
I'm overthinking it because I'm in the camp of not fixing what's not broken. And I've been tearing and rebuilding this bike for the past 4 winters. Exactly one year ago, Scout63 helped me fix the gear box.
And there's more to do. Front shocks seals and a leaky carburetor plug. No idea what to do on the latter.
Anyway, I have tools, manuals, parts, space, support, money and no flipping time to do it.
So it might take a while, but I'll git'er done.
-
Finger nail polish should stop the plug leak.
-
I recall Richardson talked about smallblock head gasket leaks. Here is my summary, from another website;
Head Gasket Leaks - The distance between the studs is long and the gasket web is thin, so leaks happen, especially on the outward side near the oil passage. I've solved leaks with Permatex Super 300, as recommended in Guzziology by Dave Richardson.
Take off the head, apply Super 300 to both sides of the head gasket with a little extra in the problematic bottom part, near the oil passage. Wait a short time for it get tacky, and bolt everything back up. I've had luck re-using the old gasket if it looks decent. Torque again.
Base Gasket Leak - Richardson reports that a during manufacturing a drilled stud hole can break into an oil passage, causing base gasket leaks. The fix is to clean the hole, seal stud with Loctite, and reassemble. I refer you to Guzziology for photos and details.
-
I was thinking I don't need ignition, just the piston compression. Your idea sounds more fun, Huzo.
That's one way of decorating the bike with oil and shooting the head across the garage.
Thanks for the Guzziology reference.
I remember reading about the Permatex for valve covers as well.
Does Permatex harden and make it difficult to remove the gasket later?
-
Reportedly Permatex does not harden, but nothing is eternal, right? I used it years ago, and I would say it slooowly hardens, over years.
-
We used to use it on iron exhaust manifolds when they had a divot on the sealing flange or were warped and wouldn’t seal with a new gasket. In that application it got hard and generally worked well.
-
I finally had time to work on this project. The head came right off with a slight tug. The cylinder stayed in place (but maybe not).
Here is what I found:
(https://i.ibb.co/6HsKZ1P/20230708-175659.jpg) (https://ibb.co/6HsKZ1P)
Looks like this side is running lean. The spark plug has the same light tan color.
But why don't both valves have the same color? A problem for later.
To clean the soot I tried a number of chemicals. The only thing that worked was engine degreaser.
Acetone worked well on some of the gasket remnants, but in the end I had to pick at it with a piece of wood... and still not done.
(https://i.ibb.co/xs3rxmW/20230708-202353.jpg) (https://ibb.co/xs3rxmW)
I can see why the head was leaking. There is all kinds of pitting/corrosion that formed under the gasket.
A lot of pitting at the spark plug too.
(https://i.ibb.co/YLbqWQC/20230708-195941.jpg) (https://ibb.co/YLbqWQC)
The cylinder is not much better.
(https://i.ibb.co/sw0NbZx/20230708-201015.jpg) (https://ibb.co/sw0NbZx)
What can I do about the pitting? I am hoping some of you have seen this before and can provide guidance.
Would Permatex fill the gaps? Should I get a copper gasket made, or is it time to have it resurfaced?
It is not easy to see from the photos, but I found a gouge toward the top of the head, across those oval holes.
My finger nail sticks into it. It is away from the compression chamber, so maybe it's fine.
After a few hours of smelling nasty chemicals, I packed things up and noticed oil on the floor. :shocked:
While cleaning the piston, some of the cleaner got into the stud hole in the lower right. It must have dissolved the oil
and maybe loosened the base gasket :cry:
(https://i.ibb.co/d42wmqD/20230708-203544.jpg) (https://ibb.co/d42wmqD)
I think I might as well pull the cylinder.
-
It's possible your Cam chain is too tight and it's causing a leak.........
-
Never tried it but what would happen if after removing the push rods and of course the nuts and bolts you put the sparkplug in and crank the motor over? 150 psi should blow the head clean off as Dirty Harry would say.
Amen. Time tested method.
"Works a treat!" as some would say!
-
Amen. Time tested method.
"Works a treat!" as some would say!
Here, hold my beer for a second
Loosen all head bolts about two turns and start her up.
BANG BANG and the heads are free, but captive.
That's the time tested method. :grin:
-
Here, hold my beer for a second
Loosen all head bolts about two turns and start her up.
BANG BANG and the heads are free, but captive.
That's the time tested method. :grin:
I'd say the method chosen is highly dependent upon how much beer is consumed previously.
Complete removal of capturing bolts makes a better Youtube video......
But, if you are buying the beer, I'm opened minded enough to thoroughly discuss!!! :wink:
-
It's possible your Cam chain is too tight and it's causing a leak.........
?? Pushrod engine, so how would a too tight cam chain cause a leak?
-
?? Pushrod engine, so how would a too tight cam chain cause a leak?
But Huzo said....... :wink:
-
Luckily I didn't have to do anything special. The head came right off, probably because the joint was already compromised.
The air compressor method also sounds good
When I saw the pitting I immediately freaked out. After lubricating with beer and sleep, I went to YouTube University and found some useful information.
The cause is still not clear to me, but I have read about improper grounding of the engine. I can see how this is important for the head since it
holds the spark plug. But the plug electrode is much closer and the spark should jump there. Unless the spark propagates through the
compressed mixture as well and prefers a path to ground in between the valves. This doesn't explain the pitting under the gasket.
I guess I will add a wire to the rear most nut, but... damn... really?
Anyway, I need to figure out the repair path, assuming I have to fix it. Again YTU shows some methods.
One interesting idea is to use JB Weld and sanding down the whole thing flat.
I guess it's time to get a spring compressor, but I am probably going to chicken out and go to a machine shop.
-
The improperly grounded engine is a popular "cause" for leaky head gaskets on Subarus. The theory is that it grounds through the coolant and this causes electrolysis and the degeneration of the gaskets. Kind of rules out that particular theory with an air-cooled engine, and I am not sure how much I buy into this theory, but I regularly check the condition of my grounds on the 'roo just in case!
-
Seems to ne the tie rods into the main case are reasonable connectors to the head's earth connection.
-
Head gaskets use a metal ring to help seal and the metal reacts(water, salt, combustion byproducts?) and eats away at the least noble metal. The aluminum in this case is less noble than the head gasket and it is reacting. It isn't leaking so why would we mess with it .The heads central area looks to be getting too hot as in a bit lean. I would start with a spark plug one range cooler. This motor seems to be perfectly serviceable and appears to only need a new gasket. Why not just do that and run it until it needs a real rebuild.
-
Quote from: Mike Tashjian on Today at 10:49:44 AM (https://wildguzzi.com/forum/index.php?topic=117942.msg1861350#msg1861350)
Head gaskets use a metal ring to help seal and the metal reacts(water, salt, combustion byproducts?) and eats away at the least noble metal. The aluminum in this case is less noble than the head gasket and it is reacting. It isn't leaking so why would we mess with it .The heads central area looks to be getting too hot as in a bit lean. I would start with a spark plug one range cooler. This motor seems to be perfectly serviceable and appears to only need a new gasket. Why not just do that and run it until it needs a real rebuild.
Thanks, Mike. The gasket was leaking and I was getting oil all over the frame.
I am getting "ants-in-my-pants" about fixing the bike, so I went to a machine shop today. They said the same about the gasket reacting with the aluminum (sp? Huzo keep calm).
They will take a few mils off the head and the cylinder. The head also has a slight bow between the studs.
The shop also mentioned the lean mixture issue or possibly timing, based on pitting at the spark plug area. I will try a cooler plug. I think I am using NGK BPR6ES.
The exhaust valve was not sealing well. So... valve job too! I am waiting for new valve seals and should be back together soon.
One bit of good news is that the valves measured to nominal spec, so I will keep the same dual springs. I am referring to this thread: https://wildguzzi.com/forum/index.php?topic=119007.0 (https://wildguzzi.com/forum/index.php?topic=119007.0)
-
I removed the cylinder and found a nasty surprise. The piston is gouged and the cylinder is a bit scratched. :shocked:
This is above the rings, at the top of the piston and cylinder. :cry:
(https://i.ibb.co/KLt5grK/20230711-223756.jpg) (https://ibb.co/KLt5grK)
(https://i.ibb.co/4stVbPy/20230711-223622.jpg) (https://ibb.co/4stVbPy)
Something must have gotten in the chamber, scratched the piston and then got blown out the exhaust. I didn't find anything when I popped the head.
I am guessing the cylinder can be repaired, but the piston is probably trash... or is it?
Does this matter, based on where the damage is?
-
Serviceable is when you can tidy up a part and run it. The cylinder is not scratched where a ring will go so, no issues there. A light hone on the Cylinders to break any glaze is also something that should be done while apart. Since you are doing head work and gaskets, new rings should be considered. The piston, I might run depending on how much it has worn. The piston can be filed to remove any raised gouges that would create hot spots. Of more concern will be if the top ring is stuck or piston head or land cracked . You will need to free it up(top ring if stuck) and be sure it has clearance to move with no damage. Time to get the micrometers out and at least measure everything up.
-
You guessed right, Mike. I was wondering where the third ring was. This picture shows it stuck in the track.
(https://i.ibb.co/7jkchYR/20230711-223700.jpg) (https://ibb.co/7jkchYR)
I need to get a pin puller and a micrometer. Maybe the machine shop will measure it for me.
Is this style puller: https://www.amazon.com/BikeMaster-08-033K-Piston-Pin-Puller/dp/B00BANZAZQ (https://www.amazon.com/BikeMaster-08-033K-Piston-Pin-Puller/dp/B00BANZAZQ) better than
this style? https://www.aircraftspruce.com/catalog/topages/atspistonpin12-04810.php (https://www.aircraftspruce.com/catalog/topages/atspistonpin12-04810.php)
This is a major bummer, but on the upside, I am learning something new.
Thank you for the advice, Mike.
-
Every Guzzi pin I've pulled came out with finger pressure if you lightly heated the piston. I've done it with with both a heat gun or a Bernz-O-Matic torch. Pin floated out below 200°F. Be sure there is no burr once you remove the retaining clip to stop the pin from moving outward.
-
Thanks, Ron. I'll try that.
-
Heating the piston for removal may loosen that top ring. Gentle prying on the ring gap should get it moving. See what you have from there. Ring removal tools are cheap. I have a couple of them. I don't always use one for one or two pistons. Just be aware the ring edges are sharp and can cut you use if your finger slips.
-
+1 on the heat gun. Get it good and hot, the pin will slide right out. Wear heavy gloves, learned that the hard way.
kk
-
Thanks, guys. It was that easy. I pushed with my fingers and felt the pin move.
I pushed it out with my thumb using a socket extension. The gun was ready, but no heat was needed.
I was able to free the top ring with a wooden dowel. The ring was stuck from gunk/soot/something. Now it rotates
fine inside the track. I don't see deformation of the track, nor burrs.
The machine shop has already honed the cylinder and the bits at the top of it were the piston material.
They have it in a washer now to soften the gasket.
This bike originally came with the Motoplat ignition and it smoked (coils included) many years ago. Then it was converted to points with some missile looking coils.
The scar may have been there since then, with no apparent performance issues.
The piston has some wear on the skirt. I could just file the bumps and put it back in. I don't think I will find a new one.
The shop recommended to send it to Swain Technology for a thermal barrier coating. Has anyone tried this before? Is it overkill?
The pin has some wear. I will look for a new one and clips. Hopefully still available.
(https://i.ibb.co/F3QKPVM/20230714-092355.jpg) (https://ibb.co/F3QKPVM)
The bushing looks worn, but there is no way I will get that out without unbolting the rod. That's not happening.
(https://i.ibb.co/mBFBP4b/20230714-081108.jpg) (https://ibb.co/mBFBP4b)
The cam has some wear. Not touching it!
(https://i.ibb.co/JFSxN4k/20230714-080924.jpg) (https://ibb.co/JFSxN4k)
I think I will open the other head.
-
The pin has some wear. I will look for a new one and clips. Hopefully still available.
I think I will open the other head.
Make sure your replacement piston wrist pin weighs the same as the old one.
Always a good idea to address both heads and cylinders at the same time. :thumb:
-
Thanks, Guido. Both pins weigh 79 grams. How close do the new pins have to be?
The workshop manual says the two pistons should be 1.5g from each other, but no indication of weight for anything.
I opened up the right side. This head has less pitting than the left side. It looks like it will eventually leak too.
This wrist pin did not slide easily. I pushed it out with a C clamp while heating the piston. Thanks again for that tip.
The right piston skirt has similar wear and similar scarring, but on the upper side. I wonder why the north or south edge gets scraped like that.
(https://i.ibb.co/4Fy3BKg/20230716-111956-Right-Piston.jpg) (https://ibb.co/4Fy3BKg)
I noticed that both exhaust push rods have this kind of spiral wear. They must be dragging on something.
All four push rods are perfectly straight. Should I replace them, along with the oil caps?
(https://i.ibb.co/vhmpqHm/20230716-095952-Right-Rods.jpg) (https://ibb.co/vhmpqHm)
Any tips for removing gasket residue on the crank case, without getting bits into the engine?
Thanks for reading!
-
Piston can only rock one way on the wrist pin. The scores you show are 90 degrees from the wrist pin.
I just stuff a clean cotton t-shirt into the case all around the rod to catch the debris from gasket removal. It keeps the rods from banging up the edges of the case. Remove with care before reassembly.
-
Head and cylinders resurfaced, valve job, new guide seals and a good cleaning.
4mils removed on each. I hope compression will not change much.
(https://i.ibb.co/5xCtgwG/20230729-145648.jpg) (https://ibb.co/5xCtgwG)
The pistons have been coated and... now they don't slide in the cylinder :angry:
(https://i.ibb.co/WH8TD7R/20230812-134625.jpg) (https://ibb.co/WH8TD7R)
This is turning into a disaster.
-
Why would you expect that the piston (with a coating added) would now fit into a bore that was properly sized for the piston before you added a coating?
If the bores are iron they can be honed to fit the oversize piston. If they are nigusil they can not be honed oversize.
-
Time to measure the pistons and maybe visit the machine shop again. Honing would bring the bores to size if they are plain bores. If they are Nikasil, I would probably remove the coating on the piston skirts. It really will depend on how thick the coating is and the condition of your bores. Remember to fluid test your valves as I see they are in the head. Personally I like to do the final assembly and check the contact area with a bit of valve grinding compound. I tend to to trust no one and correcting a problem at this stage is much easier than on an assembled engine.
-
I’m lucky to have a machinist right nearby…
He suggested bringing the rods, bearings, wrist pin, rings, wrist pin circlips, piston and cylinder to the shop
He set the rods straight and true, made the interference fit on the big block wrist pin, measured fitted and assembled rings onto piston, then assembled piston into cylinders.
Now you don’t have to fight the piston and rings into the cylinder while attached to the motor. Just Slide over the studs and torque the rodbolts
Just realized this may not be possible on the small block
🤷♂️
-
Thanks Ron, Mike
I had discussed this possibility with the shop. They measured the parts and the coating was supposed to be only a few microns. I'm going back to see what can be done.
The cylinders have Nigusil and are in perfect shape, so I'm hoping the coating can be thinned down or removed. I guess they can put it on a lathe.
The shop suggested honing, but that sounds like a bad idea.
Mike, the valve seats have been ground because they leaked, but I'm not sure how the shop tested them.
Do you pour gas into the ports to see if it leaks out?
Chuck, I read somewhere that the rod bolts can be accessed from the cylinder cavity.
I would need the hands of a child to work in there.
And that's way beyond my skill set.
I bought a ring compressor that should make it easier.
Maybe if I botch this piston job, I will take the whole engine to someone who knows what they are doing.
Thanks again for the advice. As you can imagine, I am not a trained mechanic, but fixing my own bike has turned into an irresistible passion.
I think the lesson here for me is not to make a 30 year old bike perfect again. I should not have messed with the piston.
-
For the valves I usually just squirt some thin liquid into the port and then watch the head side. Depending on what is on the shelf and time of year. I like starting fluid(evaporates with no residue) if I can open a door or WD 40 is OK if I can't.
-
In the aircraft shop I supported the cylinder with the combustion chamber facing up. Then fill it with mineral spirits and watch to see if any seeps into one or both of the ports. With Wright cylinders we had a fixture with which I could pressurize the cylinder to check the joint where the head was screwed on to the cylinder. This was the only make we overhauled that had the head attached to the cylinder, the rest were all one piece. If the joint failed the test the cylinder had to be scrapped as it was non-serviceable. It was an eye opener in that a cylinder would pass the liquid test but would leak air at a valve. But we pressurized to a 120 lbs so not a big surprise.
kk
-
In the aircraft shop I supported the cylinder with the combustion chamber facing up. Then fill it with mineral spirits and watch to see if any seeps into one or both of the ports. With Wright cylinders we had a fixture with which I could pressurize the cylinder to check the joint where the head was screwed on to the cylinder. This was the only make we overhauled that had the head attached to the cylinder, the rest were all one piece. If the joint failed the test the cylinder had to be scrapped as it was non-serviceable. It was an eye opener in that a cylinder would pass the liquid test but would leak air at a valve. But we pressurized to a 120 lbs so not a big surprise.
kk
The upside down cylinder is interesting. I could bolt the head to the cylinder, but after having spent a good part of a week scraping
off gasket material... yeah, nah. In another life, this would be a good application for a 3D printer. But I diverge...
For the valves I usually just squirt some thin liquid into the port and then watch the head side. Depending on what is on the shelf and time of year. I like starting fluid(evaporates with no residue) if I can open a door or WD 40 is OK if I can't.
I have all those fluids and it's warm out!
Thanks
P