Locked U20 5 speed and carbs

[mschel]

Thanks for the information.

The time chain wedge is only necessary for an engine that has a tensioner that cannot be accessed without the removal of the timing cover. All L series engines have this issue and has never been a problem with the U20 as it a twin chain engine. The tensioner for the upper chain is accessible through the cover on the cylinder head and therefore no need to wedge the chain. I used the put a piece of wire on the chain so it would not drop into the timing cover, but that’s not necessary as the timing gears on the jackshaft prevents it from dropping to the bottom of the cover. You can retrieve it with an extension magnet.
Dave

[Gregs672000]

Agreed, wedge is not required, but I've just personally wanted to make sure the chain didn't move. So long as you mark the location of the chain to the cam gear with the crank pully timing marks at Top Dead Center (TDC/0) no problem. I did have one time where the chain somehow moved a link on the jackshaft gear, and if i did not understand or have a lot of experience with the chains I might have installed it a tooth off!

The wedge I use is made out of a typical wood paint stick about 3 inches long that is cut to a point of about half its thickness that is tapped in until it secures the chain against the sides of the guide but fits under the cam gear. Honestly, the L is nice to have and since we now have the fix of keeping the chain tight with shims on the tensioner I would keep it if undamaged... but mine is already gone!

[mschel]

Got a bit further today. Balancer came off nicely with the 3 jaw puller. I took all the bolts/nuts off the timing cover and the studs that go to head and oil pan and its not breaking free. Wonder if its seized on the stud like the water pump was. Soaking with some PB for now. Tried tapping with a hard mallet in a bunch of spots. I don't see a large pry area that looks safe to me like on a V8 cover.

Oh, and the distributor hold down screw head is mostly stripped out before I got to it. Ugg. Hopefully I dont have to resort to extraction.

Any tricks there on either? Thanks

[Gregs672000]

The front cover is pinned in the center on both sides, and the head gasket extends over top so that may be holding it up. The waterpump studs do corrode so you may be right there. The oil pan is off, right?
Needle nose pair of vice grips for the stripped dizzy bolt? It shouldn't be very resistant.

[mschel]

I pulled the two little 10mm studs from top of head to cover. Is there another pin somewhere?

I would pull head but need to get L out first to pull cam gear. It's fighting me big time. Haha

I wish there was a good pry point

[redroadster]

Heat with a propane torch moving it around ( the boil tank not an option? )
We had a wrench weld a fine thread bolt head to it then extend the nut to put pressure forcing it to spread
Sorry to hear it broke , possibly
Aluma weld it , I've used a impact gun w/hammer bit, using low air pressure & gently , with good results on such

[mschel]

Wow. A few hours with a torch and penetrant. Finally got timing cover off. Unfortunately it cracked eventually. Was being pretty careful with it.. What do those run?

Evil l doesn't appear to have any bolts to remove it or maybe I am just tired.

Head seems stuck on partially too.

Calling it a night. East coast.. So frustrating.

[theunz]

There are 3 bolts on the “evil L” AKA the upper chain guide. You should have already removed the upper bolt as it is attached to the head. If you haven’t yet removed it that could be part of your sticking head problem, but often the head needs a little coaxing from a rubber mallet. The two bolts in the middle of the upper chain guide may have had their heads ground down by a worn out chain rubbing against them. Here’s a blowup from the online part’s catalog. https://www.carpartsmanual.com/datsun/s ... 6467086372

[mschel]

Thanks, will check for the bolts in diagram. Will look at it after the holiday weekend.

[Gregs672000]

Bummer on the front cover, but that should now allow access to the guide's bolts and allow you to be able to gain some room to remove the cam gear bolt...

[mschel]

Looks like there are some on eBay in 100$ range so not terrible. It was that stud locked in that caused it to stick.

At least I can now get to everything!

Thanks.

[Gregs672000]

These engine are pretty straight forward. However, getting the timing chains aligned correctly is critical... not hard, but just a bit confusing with two chains and several timing marks. There are pics, and we can certainly guide you when the time comes and confirm it's done correctly.

[mschel]

Thanks. The chains definitely different from what I am used to. Taking a few days break from this project. More next week.

[Gregs672000]

Ok, back from Maui (unfortunately, though I am looking forward to driving the Datsun next week! Road trip!).

As promised, here's a picture of the valve spring compressor and how I have it configured to work and give leverage. The claws that grab the cam can be separated such that you use only one claw if needed to get around the cam towers. The part that presses down on the spring retainers has a tendency to splay apart, so you'll likely need to adjust that little screw to keep it tight. Takes some practice and patience to get it right and adjustment of the tool for grabbing the cam, but this is the only one I've found that works on an assembled engine. The handle situated as it is gives clearance and leverage to compress the spring. R engines don't need this tool.

[mschel]

Thanks for the picture.

Have they finished rebuilding from the fires?

Back on this project later in week.