Can't rotate crank on engine stand

[preston_brown]

Fact is, the alternator might be corroded into the housing. Probably is from the looks of it. The magnesium housing will have "expanded" a little bit and will make removal a serious pain.

Even pounding on the studs (they are really long bolts) as gently as possible, you may have to hit them hard enough that they will bend. That sucks, because replacement is next to impossible. I know, I tried. Once I got my alternator out, most of them were bent pretty badly.

I used this "opportunity" to install a rebuilt alternator...yup more costs.

[Number1_dog]

I'm still not sure what it is.

I rotated the engine on all 4 axis on stand and then it stuck again just before #1 TDC, with 4,5,6 facing down. If I'm not mistaken # 1 and #4 reach top at same time. I put a magnet into the cylinder #4 but noting attached. I've tried to get a borescope but can't seem to find someone who has one. I rotated again with 4,5,6 up and if rotated. If it is an aluminum washer then it may have layed flat. I'm going to get a borescope from e-bay before I am convinced it is the chains.

[tom1394racing]

The best way to separate the alternator from the fan ring is the "John Walker" method.

How do you seperate alternator from fan housing?

[relayswitcher]

Never had had problem with removing the alternator from the fan housing ever.... done it 5 or 6 times. I'm from sunny dry California near Palm Springs and I notice that most of your replies are from Denver due east. Most people in that part of the country deal with severe whether and moisture, etc.. So if you are worried about the studs ..... wire brush them and then just WD40 the heck out of them. Come back in an hour or so and use the RUBBER mallet on the studs. DO NOT use a metal hammer, that's how they break. ALso.... chains don't catch as much if at all with the engine level..... worse when turned on it's side. It's simple logic..... if I"m reading what you are doing correctly.

[relayswitcher]

Again without seeing a photo, it seems to me if it turns off the stand and won't on the stand, something is blocking the rotation having to do with the yoke area. Send some photos of the engine yoke on stand area. Or did you say you removed the flywhl?

[Number1_dog]

I never took it off of the engine stand, With it on the engine stand, I rotated the engine every 90 % and tried to rotate the engine. When I had cylinders #4,5,6 in the up position I was able to rotate the engine. I kept rotating the engine and on the horizontal it still turned, when 4,5,6 were facing down it got stuck again, but this time just before #1 TDC. I now know that it is not a problem with the engine stand. I put a magnet into each cylinder through the spark plug hole and nothing was there. My fear is it may be an aluminum washer. That is why I am asking around here for a borescope to look into the cylinders. Ebay has them for under $100, I may go that route if I can't get one anywhere else.

[lucittm]

Dog,
I have a bore-scope you can borrow but I don't think you will see the cause of your problem. I had the same issue when my engine was on the stand and I panicked when it locked up. My problem was that the cam chain was bunched up inside the crankcase. When I turned the engine in reverse slightly and pulled on the chain, I felt the slack come off the inside of the crankcase and it rotated fine. I was relieved...

From your pictures, the right side (looking at the cam chains) tensioner is at the limit of its travel. Your chain is stretched or the sprockets have worn out. For example, look at the picture below and compare how much of the tensioner piston is showing to your tensioner.



I think the left side looks OK. If you remove the right side cam, rockers, rocker shafts, and cam tower; then you are only out the cost of an o-ring and a gasket. Then you will be able to determine the reason for the fully extended cam chain tensioner. And, you may find that your engine is locked because of the valve train on the right side and not something inside the engine. Have you changed your cam timing accidentally or on purpose?

Having said all that, you may want the bore-scope on Ebay. I find uses for mine all the time, you may want your own.

PM me if you want to borrow my scope.

Good luck,
Mark

[jomama]

i had a problem almost the same thing what i found was the inner cam chain was worn and slipped off the sprocket just enough to jam against the case.this happen when i took the pressure off the tensioner. i could see the problem but could not repair until i split the case or get it loose.the chain was twisted and stretched.i hope this may help you.

[WERK I]

Originally Posted by Number1_dog

Surprise, it turned. I put it on its side with 4,5,6 facing up and it turned completely as a fine oiled machine. I put it back on the horizontal and it turned. I'm thinking that it was the cam chain that was jamming. These are my cam chain tightners and they seem to be extended pretty far out. Should I be replacing my chain?

Looking at the photos, I am a little alarmed by the amount of corrosion present in the engine. This engine has been sitting in storage a LONG time. I would really recommend this engine be disassembled. I agree with everyone the tensioner on one bank is over extended and the sprocket teeth may be worn.

[Number1_dog]

You are right. The whole car had been sitting for a few years when the mechanic I purchased it from first got it. The mechanic has a good reputation if he is building an engine for a customer, but here he was freshining it for a quick sale. He said he split the case, and there are signs of that and it didn't leak oil when it was running. He had installed the Carrera Chain tensioners just before I picked it up.

[Number1_dog]

I got a borescope off of Amazon and it was an aluminum washer in #4 cylinder. Just a little too big to come out through the spark plug hole.

I'm trying to loosen the big nut on the cam. I have the special tools for a 1979, and through trial and error I found that on the claws-foot (or crowsfoot what ever it is called) you have to mount you wrench on a 90% angle or else it slips off the nut real easy. BUT, I can't seem to break it loose, are there any tricks to this ?

There is a deep cold chisel mark on the nut, that is used to set it tight when installed, No? Should I be doing anything else to counter it?

[mca]

That chisel mark should not be there. Looks like someone tightened it in the past without the proper tools!

You should be able to break it free. It does take quite a bit of effort. It helps if you can find someone to hold the cam while you try to loosen the nut - can be difficult to do both at same time.

[burgundyben]

I'd be wanting to replace the nut.

In which case you could do what I did with a damaged nut, drill through it and the cold chisel it open. Once its broken through it will be lose.

Be very careful doing this.

[Number1_dog]

I was thinking of drilling some holes then connecting them with a cold chisel.

I had someone holding the cam, and then when I apply a lot of tension the claws-foot will slip off.

[safe]

Craw-foot sucks. Make a proper tool from a 46mm socket. Weld on a handle and cut the end of the socket so you can slip a holder through. Or you can make some bends in an 46mm wrench so it will clear the chain housing.

[ischmitz]

With an impact wrench and compressed air it takes less than a minute to loosen these

[kodioneill]

Originally Posted by Number1_dog

I got a borescope off of Amazon and it was an aluminum washer in #4 cylinder. Just a little too big to come out through the spark plug hole.

I'm trying to loosen the big nut on the cam. I have the special tools for a 1979, and through trial and error I found that on the claws-foot (or crowsfoot what ever it is called) you have to mount you wrench on a 90% angle or else it slips off the nut real easy. BUT, I can't seem to break it loose, are there any tricks to this ?

There is a deep cold chisel mark on the nut, that is used to set it tight when installed, No? Should I be doing anything else to counter it?

take off the intake or exhaust then extract the washer through the port.

[OldTee]

Harbor Fright has 3/4 socket sets on sale for 50 in both am std and metric size. I belive the nut is 46MM. I bought one from Aubuchon Hardware
@ HardwareStore.com for $20 + shipping.

[Number1_dog]

Thanks, I've been looking, I got the cam nuts off, but they were a little mangled from the crow-foot sliping so they are getting replaced.

Now when you re-install the nut, how are you going to torque it down and hold the cam shaft steady? Of are you only using the 46mm socket to lossen it?

I was thinking of cutting off the top and welding it back on to the side with the socket head offset just like the crow-foot.

[safe]

When I timed my cams I planed on holding the cam with the special cam holder and an torque wrench, but that proved difficult due to extremely poor quality of the cam holder socket (from Pelican).....

I then instead held the cam with a 17mm open wrench jammed on one of the chain housing studs, then tightened the 46 mm until my face turned blue.
I'm not sure if I should recommend that method... but it has held 4 now so I guess I'm on the safe side.