Best way to judge a used engine?

on-to-berlin · Unread post by **on-to-berlin** » February 4th, 2017, 1:00 pm

Since the weather is still not good enough to work outside I was working on the engine and started to take it apart. The engine did not ran the last 20 years and I cannot tell about compression etc. So I have to judge it from the looks. The cylinders show some small rust pimples and burn residue. The head and the valves only show burn residue. So what shall I do?
Simply install new gaskets put it back together again and see what happens?

Horst · Unread post by **Horst** » February 4th, 2017, 1:36 pm

of course a little hard to tell from the pictures but I would say this is a worn engine. I don't say any cross hatching any more on the cylinder walls. What you could do is measure the cylinders against the specifications in the TMs if you have the right tools to do so. I would throw it together with a new gasket set and see how it does.

How does the crank, the crank and rod bearings look like? Measure the crank if you can and compare again against the TM. If it is in specification and depending on the looks of the bearings, I would probably throw in a new set of bearings.

Horst · Unread post by **Horst** » February 4th, 2017, 2:23 pm

BTW,

I have a good camshaft if yours is worn. You can get it cheap. I also have a crank which is measured within specification, it might be however corroded by now, I need to check, you could have that one for free as I am sure it would need polishing of the journals by a machine shop. I also have a usable block left but that one was measured outside of spec and needs to be bored one size over stock. Just in case yours is beyond repair. I sold the heavy duty head to a member some time ago.

Mr. Recovery · Unread post by **Mr. Recovery** » February 4th, 2017, 2:34 pm

Hi, if it was me I would take it apart and clean it or have it cleaned, then I would check all the cylinders and bearing sizes to see how much it is worn, if it is still within standards then I would do a refresh with new rings and bearings. I would clean and rework the head also, Here is a link to my motor rebuild that may help.

viewtopic.php?f=3&t=3348&hilit=+My+Motor+Rebuild

Hambone · Unread post by **Hambone** » February 4th, 2017, 2:44 pm

If you have the money to spend, I would do as Dan said, if you're trying to save money, do as Horst said, how much of a ring groove do you have at the top of your cylinders? might get by with a good clean up and honing, you can do a ring gap check, haven't checked manual but should be about .012-.022, just depends on your budget.

on-to-berlin · Unread post by **on-to-berlin** » February 4th, 2017, 6:39 pm

I think I will take it apart further tomorrow and then see how the crank shaft is doing. At the moment I tend towards putting it back together with new gaskets. But will give an update here.
What about the reenforced head? Are they any better? How can I distinguish them from regular ones?

Horst · Unread post by **Horst** » February 4th, 2017, 6:43 pm

Bigger mounting bosses for the exhaust mounting clamps. I think you have one.

Unread post by **rickf** » February 5th, 2017, 1:41 pm

#2 exhaust valve looks like it was hit with water or steam. I cannot see the head gasket seal between numbers two and three but possible head gasket leak there. That is not a big deal, clean it up and replace the head gasket and torque according to manual. I think 90% of the blown head gaskets on these were due to bad torque. Some of that was head holes that were not tapped correctly so buy a bottoming tap and run it down every head bolt hole to be sure they are all parred all the way to the bottom.

on-to-berlin · Unread post by **on-to-berlin** » February 5th, 2017, 3:48 pm

Today I removed the oil pan and checked the crank shaft and cam shaft.

The crankshaft bearings look ok. The cam shaft however shows signs of heavy wear.
At the moment I am leaning towards putting new gaskets in and see how it goes. In case it breaks I will go for the total overahaul.
Or getting a NOS engine if I find one.

Unread post by **rickf** » February 5th, 2017, 5:11 pm

Those bearings look like new and I do not see the heavy wear you are talking about on the cam. The lobes would be rounded over all the way across the cam and that one appears to have just a little wear on one side which is normal wear. I would strongly say go with gaskets and run it. Be sure to use a 15W-40 Diesel rated motor oil so you get the higher sulfur and zinc amounts for the flat tappet cam.

on-to-berlin · Unread post by **on-to-berlin** » February 5th, 2017, 6:02 pm

O.K. but on the cams there are scratches that you can feel if you scratch with your fingernails. If that is normal wear I am more than happy.

What would be the best way to remove the smudge on the pistons and on the valves/head?

Or just leave it and put it back together again?

Unread post by **rickf** » February 5th, 2017, 6:49 pm

Scratches are not normal and considering the only contact point is the lifter you need to find out what caused the scratch. As far as cleaning the carbon off, everyone has their own favorite solution. If you are taking the pistons out then you can soak the tops of the pistons in a pot of carburetor cleaner. If you are leaving them in then a rag soaked with Acetone rubbed on the piston heads or even mineral spirits for a slower but more thorough cleaning. If leaving the pistons in you have to be careful of getting stuff caught between the piston and cylinder. Always make a final wipe of the cylinder after the piston rides down. The head can be propped upside down with the plugs in and the chambers filled with acetone or plain gasoline (do this outside). The side effect to this is if you see the gas coming out of a intake or exhaust port shortly after putting it in the head then you know the valves are leaking.

You are not really looking to get rid of every bit of carbon on the parts, just the flaky loose stuff.

on-to-berlin · Unread post by **on-to-berlin** » February 6th, 2017, 2:59 am

Thanks for the advice! I found a dry ice cleaning place not far awar. Maybe I will try this with the head.

Unread post by **rickf** » February 6th, 2017, 12:45 pm

Dry ice blasting? I have heard of it but never saw it in action. If you want to send it out then glass beading would be perfect. I thought you were going to just do a quick cleaning and reassemble. If you get into a major cleaning involving the block then be sure to clean and flush the oil galleys after removing the crankshaft and camshaft. You can still use the original bearings but be absolutely sure you mark them for the original position they came from. If you are going that far I would advise new bearings just because of the chance of a mismatch or any contamination that could get behind a bearing shell and change the wear pattern.
There is a quick clean and reassemble and then there is a full on inspection and reassemble. There is a fine line between when you start replacing parts and once you start replacing parts you have to decide what parts you are going to replace.

on-to-berlin · Unread post by **on-to-berlin** » February 7th, 2017, 5:17 pm

Here is a video of how an engine head is cleaned:

https://www.youtube.com/watch?v=tBQTso2vd1k

A friend of mine told me about how it works a couplde of weeks ago. The ice crystals are shot on the surface and explode when they hit the surface. Taking off all the dirt and also gaskets etc. ANd there is no residue like it is with sand or glass blasting. Metal parts or also rubber parts as on propeller shafts etc are left undamaged. I think it sounds quite intersting.
Bad news is only the guy is busy the next weeks. So I might end up cleaning the block and head with oven cleaner and a brush.... Do it the old school way.