Engine re-build tight

[stevenelle]

Have just re-installed all major engine components except head after machine shop work. With crank bolted down and new pisons and rings in place, it sure is hard to turn. Everything pre-lubed. Is it supposed to be this hard to turn over with hand crank without the head installed. Don't know if my starter will turn this thing. Any help or insight appreciated. - steve

[Merle Coggins]

Did you check all of your clearances, piston, ring end gap, bearings, etc? You may have a tight bearing or two, or the pistons may be tight in the bores. As you assembled the engine were you turning the crank as you went? If so when did you notice it getting tight? If you loosen the bearing caps slightly does it turn easier? If it does you may have the wrong size bearings. If that doesn't help it may be the piston fit in the bores (not likely, but possible. Did you oil the cylinders?). It should turn over fairly easy with the head removed. I could turn mine with a 1/2" drive ratchet and socket on the crankshaft pully retaining bolt.

Good luck

Merle

[Guest jtw3749c]

Ditto on the tight bearing. Check and recheck your torque on the rods and mains.

JT

[grey beard]

A fresh engine built to facgory specs will be quite tight. I just went through the same wory cycle myself. Get it all bolted together and filled with oil, then hook up your fesh battery with good proper sized cables. Remove the plugs and kill the ignition system and crank it over. It will turn slowly if your starter is up to snuff - mine was just overhauled. Get it spinning over - pump a few squirts of oil in each cylinder and watch the oil pressure gauge. It should show about 20 psi at cranking speed. Afte a few minutes of this, pull the top off your oil filter canister. It should be full.

Get your radiator hooked up. I sat mine on a piece of 4 x 4 and the hoses kept itg in place. Don't start it without water, cause you want to get it up to a normal tempereature heat cycle before it is shut off the first time. If you've gone this far, now all you need to do is put the plugs in, check for spark, and get fuel to it. I like to turn the idle up at the carb before first startup, so it will not die right away. Run it for twenty minutes or more, varrying the engine speed somewhat, but do not overrev it or try to let it idle. Once this has been done, retorque your head and manifold bolts, let it cool down, and check it over carefully for external leaks. From there, it's all down hill. Don't forget to check initial timing with a light at hot slow idle, once you can get it to do that, and you're ready to ride . . .

Lotsa luck! :)

[Rich Gengo]

Did you put the rods in backwards? There is a slight chamfer on one side and it should go towards the outside of the crank journal and the flat edge towards the other rod end. Just a possibility. It wont turn if its backwards.

[Young Ed]

Dad and I had this problem after assembling one of his flatheads too. Called the shop and after checking everything again he told us to hit the crank back and forth. He called it seating the crank.

[knighthawk]

you should always turn it after you put each piece on, so you know which one causes the problem. Easier to check it as you go, rather than try to find it later. With the engine upside, you should be able to move each rod back and forth, not much , enough to see movement. The one that don't move is your problem. Best not to force it to turn, in case a piece dirt of something got in the bearing.You should be able to turn it with a 1/2'' breaker bar on the front. Kinda stiff, but still should turn, shoud only be feeling drag from rings. What motor is it ? ..

[stevenelle]

Thanks for the info. Here is some more context: When it was just the crankshaft with new bearings, torqued down and turning the cam and valves, it was not difficult to turn by grasping the rod journals and pulling up. As each piston was installed one by one, it became progressively harder to turn. The individual pisons and rings (.040 oversize to match the cylinder re-bore) went in fairly easily and once inside I could push them down by hand. After all 6 were attached, it it now much harder to turn which I guess is natural. I can turn it with difficulty with the hand crank starter (which is essentially a 6 or 8 inch lever). I did not check the tolerance of journals to bearings with plastigage. I took the machine shop's word for it on what size undersize bearings to use.

From some of the replies, it sounds like this tightness is not uncommon.

[Reg Evans]

I've only rebuilt 2 sixes so I'm no expert but I always used plastigage just to make sure all was well.

[Merle Coggins]

I can turn it with difficulty with the hand crank starter (which is essentially a 6 or 8 inch lever).

It probably will be quite stiff with only a 6 - 8" lever. Try it with a socket and long 1/2" drive rachet or breaker bar.

[Don Coatney]

I could spin my engine with a rag (to protect my hands) over the teeth of the flywheel after my rebuild. It was stiff but it was consistent (no binding). I also spun my engine on the bench with the starter for a oil pressure and compression check.

[knighthawk]

I agree, what is your 6'' lever ? Use the 1/2'' breaker bar ( flex handle ) and you shouldn't have any problem. From the way you describe it, it sounds O K . I also agree, you should have checked it with plastic gauge, " just in case " . Just be sure to prime the oil system before starting it.

[Mike Meade]

I had this same problem on my recently rebuilt 230,it turned out that the spacer ring between the two oil rings were overlapped instead of butted end to end.It cocked the pistons just enough to keep it from turning after the rods were torqued,hope this helps.Mike

[grey beard]

Mike,

You are absolutely right. I liked all the parts I got from Terrell Machine excet for those Grant rings. They were quite nice EXCEPT the butt ends on the oil ring expanders. Those devils were extremely difficult to keep in place long enough to get the two side rail scraper rings in place. For this reeason alone, these were the most difficult set of rings I have ever replaced. I'm gonna say it would be almost impossible for a nubie to get them installed correctly without prior experience.

Just having one of those ends overlap could ruin an entire overhaul job. It wouldn't have cost a plug nickle to manufacrture them with the ends bent in so they could not overlap. If our friend on this thread has this problem, the engine WILL be taken apart again - one way or another. No engine can tolerate this sort of internal problem and live and be happy very long. JMHO:(