Fleathead Fresh Rebuild very tight

[markdtn]

Background-I have an 8BA flathead that I rebuilt for a 9N tractor. Stock, .030 over. I got it back from the machine shop (Roberts and Sons here in Chattanooga) with the crank in, cam in, valves done. I put the pistons/rods in and finished it up. It has a rope rear seal and one of the Offenhouser 1-piece front seals. When I finished it, I didn't have a crank pulley so I made sure it was at #1 TDC with the cam gear dots aligned. I got a pulley and put it on (with a puller not a hammer). I noticed that it did not even try to turn while I did that(out of tractor). It is now installed in the tractor. You can turn it tooth by tooth with the flywheel and a prybar, but cannot turn it with the front bolt. Plugs are out, carb is off, fuel pump off, distributor is in. It turned fine before I put the oil pan on with just a crank socket so I have no doubts that it got this way after I put the pan and heads on. I do not believe it is a input shaft against pilot bearing, there was no issues with mating them together.

Question-So, can the rear rope seal make it that tight? I intend to put oil in it(I primed the pump before I installed it), put a starter on (just rebuilt) and see what happens. It that an OK plan? Should I try to drop the oil pan and see if it gets easier? I have read that these are tight, but it seems really tight to me. I have built many engines before, but never a flathead. I am so deep $$, I don't want to mess anything up.

Thank you for any advice!

[markdtn]

I can't edit the title. That should be "Flathead"

[Ronnie]

How easy was it to turn when you aligned the timing marks?

R

[edhd58]

my engine builder wanted the crank pulley at reassembly. he said he has to turn the crank as he tightened everything to keep it from not being able to spin once the reassembly was complete.

[Jack E/NJ]

>>>So, can the rear rope seal make it that tight? >>>

Was it installed dry or oil-soaked?

Jack E/NJ

[Bored&Stroked]

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Was it still loose after you put the pistons and rods in? I would have thought you'd have had the seal in before that part of the assembly - as the lower seal has to go in before the crankshaft? When was the last time it turned over easily - what part of the assembly process?

Question, you said it turned over fine when you got it - so the machine shop didn't put the rear seal in? That is a bit strange - normally that is a part of the crank installation procedure. Just wondering out loud . . .

D

[flatjack9]

To answer your question, yes the seal can provide a lot of drag.

[corvette8n]

Post some pictures when you get the tractor done, at one point I thought about putting a flatty in my 8N, but right now it's a working tractor.

[Richard in Florida]

Originally Posted by markdtn

You can turn it tooth by tooth with the flywheel and a prybar, but cannot turn it with the front bolt.

When I rebuilt my first flathead back in the Mesozoic era, I forgot to file the ends of the rings to provide clearance when they are compressed when the pistons are installed. It took herculean force to turn the engine over but I actually got it started.

I drove about four miles before the engine died and would not turn over again. The engine was saved but not my pride.

[JWL]

The rope can add some drag but I don't see that being sufficient to prevent crank rotation from the pulley bolt. I think something else is going on. I would begin by removing the bolts at the bell housing and sliding the engine forward then put a socket and large ratchet on the front crank bolt to see if the crank will turn.

Surely the crank was rotated during the assembly process and gave a "feel" for what the internal drag/friction was??

[markdtn]

To answer the questions asked:
-It was pretty easy to turn when putting pistons in and aligning the timing marks. I was using a crank socket and big crescent wrench with no trouble.
-rope seal was installed dry
-The machine shop put the block side of the seal in, I put the pan side in when I put the pan on.

Sounds like I should have oiled the seal. Do I take it back off or will it oil when it starts?

[markdtn]

Here are a few photos.

[chap52]

I would back track the assembly. Pull the pan, check if it will rotate. Those rope seals should be soaked in oil before installing. A socket, breaker bar and sometimes a "leverage bar" (I use a 3' piece of chain link fence pipe) can budge the crank, DON"T FORCE it. Seems that if it budges with a pry bar it should turn.

Were the pistons changed. I replaced my pistons with aftermarket supposedly "stock" pistons and they were taller hitting the stock heads. Would turn a bit then stop when turned by hand. Now that's a whole different adventure,

[Capt Kirk]

Finally, pictures of a shop environment I can relate to!

[BABAR40]

I agree Capt. Kirk! Hey Mark, did you turn motor over after the flywheel install. Don't ask me how I know how the "wrong flywheel" can happen.

[markdtn]

Originally Posted by BABAR40

I agree Capt. Kirk! Hey Mark, did you turn motor over after the flywheel install. Don't ask me how I know how the "wrong flywheel" can happen.

No, but it is the same flywheel that came with the engine.

I also don't think it is pistons. They are flat-tops. Then don't really come above the deck.



It's not stopping anywhere, it's just really tight. You can take a prybar (orange handle in photo in previous post above) and turn it tooth by tooth. I went about 1/4 turn so far.

[scooder]

Flat top pistons in an 8BA? You sure there flat?
Martin.

[Mart]

It's too tight. If you could turn it with a 2' breaker bar on the crank nut and it was tight to move then went easier I'd say it was ok, but having to lever on the flywheel teeth is a no-no. If its not on the stand now,get it out and back on there and loosen the main caps and see if that makes a difference. Before that, you could take the cam gear off and see if that helps (unlikely). If the head gaskets are new and it hasn't run you should be able to refit them if they come off cleanly. Likewise with the others. Get it stripped down and meticulously inspect the parts, concentrating on the bearings.
See if the big ends can wiggle a bit or are tight on the crank pins.
The front and middle main caps may be switched or on backwards, or from another engine.
You have the motor there, you are in the best place to troubleshoot it. We can only guess and give a few pointers.

I had one that was ok until the final torquing of the main caps. They were from another engine. I found two more that fitted well enough to allow it to turn ok. Not ideal but people have done it over the years.

I'm with my mate Martin: What's up with flat top pistons? Only very early motors had flat tops, from the mid to late 30s they were all domed. Somethings not right.

Mart.

[markdtn]

OK, maybe not flattop. They have a small dome. They are not high compression.

I am going to drop the pan and oil the rope seal and maybe trim it a little. I am 99.99% sure that will fix it. Pretty sure there will be no need to drop main caps or cam gear or flywheel. As I said early on, it rotated just fine until I put the oil pan on. The complete rotating assembly shown in the photo was relatively easy to turn.

Thanks for the advice.

[my4dv8]

What sort of rings do you have? Just a thought that we found with a relieved block on a new build that on assembly the ring compressor failed to hold the oil control expander in place due to the relief step down . Two pistons had the oil control expander slightly displaced and catching on the bore making it tight to turn. No damage as it wasn't run, just a slight mark on the bore that we were able to hone out.

Also is the sump un damaged , another one we had was a slightly dented sump contacting the crank. Though it wasn't noticed till start up when we had a horrendous racket.