Onan Tighter Than Dick's Hatband

[HorseFixer 2,012]

Well getting the engine together and just a few hours from buttoning it up. I used Gobs of Assembly Lube, and by the way coated every part. Anyway the Cranks, In, Cams In, Valve Train is In, Oil Pums In, All Gears, In. Used Same crank spacers on each side of crank but new, Rods end play okay.

I noticed with each component I installed..... Starting out After crank seemed a lil tight slipped right in tho

and could barely turn by hand, then cam went in was tighter yet then gears, tighter yet, Valve train tighter yet, so on and so on. Garage is cold went out last night installed oil pump everything meshes good but have to turn over with wrench and used torque wrench and its 23 lbs I Other than all the remaining covers, oilpan, gear cover, heads is prolly all that is left. This thing just seems to tight to me?

Pistons and everything went right in smoothly????? Im just wondering if engine is tight due to being new? What do you guys think?

I was intending on finishing assembly, Install engine pulley, Bolting engine down, fill with oil, and turn

engine overwith electric motor and let run awhile? I was wondering if that thick azz assembly lube and

being the garage was at 40 deg was making it seem tight? Please give me yer thoughts.

Do you think the Electric Moror thing would be good?

~Duke

[massey 111]

Duke, I've never rebuilt one of those but that sure does seem like a lot of drag somewhere. Hopefully someone who knows will chime in. Good luck with it.

Ed

[MaineDad 85]

Are the rods installed backwards on the crank? My first attempt to rebuild an engine I did that and noticed it turned really hard. I reversed the rod on the crank it it turned freely. Just a thought?

[rmaynard 14,894]

Never been inside an Onan, but it doesn't seem to me that lube would be the problem.

It all sounds like it started when the new crank spacers were installed.

If it were me, I would loosen the bolts on the bearing flange shown below and see if it turns easier. Just a thought.

[dennist 139]

Yeah, too much time and money to try, till you have some pros give you more advise IMO. Great job so far!

[HorseFixer 2,012]

Are the rods installed backwards on the crank? My first attempt to rebuild an engine I did that and noticed it turned really hard. I reversed the rod on the crank it it turned freely. Just a thought?

Thanks for the comeback guys! Micah, Nope I don't think so in the Onan assembly instructions and TJ's <<< Onana Parts .com how to on MTF he says ya hafta install the oil hole hole or notches on the Rod up side tword camshaft which is what I thought I did. I will double ck when I get home though.

Never been inside an Onan, but it doesn't seem to me that lube would be the problem.

It all sounds like it started when the new crank spacers were installed.

If it were me, I would loosen the bolts on the bearing flange shown below and see if it turns easier. Just a thought.

Well, Ya maybe onto something there Bob, hate to Buck up a Gasket cause it has SPERMATEX sealer on it But Heyits worth a try? Maybe I can get a bearing flange gasket locally, Other than that I took my time with assembly and everthing went pretty smooth, it just seems like everytime I added something it got less easy to turn like I was adding friction. I wanted to get past this phase and get onto stripping parts (I'm putting together a new electrolysis tank this weekend) I have held off a

couple years (see everyones results) I figure if no one blew themself up by now it must be safe! Anyways if anyone thinks of something else or ideas lemme know. Thanks for your input..... Oh what do you think about the running it by elect motor 1725 RPM thing? I personally dont see where that would hurt anything?

~Duke

[Rooster 191]

The electric motor break in is a good idea...once everything is assembled correctly.

Alot of the race engine builders break in engines that way.

It sure sounds to me like that engine has a problem...I would not turn it over until I found it.

Before putting everything in, did you ever put the crank in and spin it with nothing attached?

When I build an engine, each part gets out in individually, then whatever holds it gets torqued to spec...bearing cover, pan, what ever..then I turn the component to make sure it spins freely.

If the crank was the first component to cause a problem, then most likely it has a fit problem some where. Everything you add after that can be increasing the problem.

[HorseFixer 2,012]

UPDATE: I called my engine doode (who did the machineing) and Bob he suggested the same thing as you did. I loosened the bearing plate and it made a little difference instead of 23lbs it is now 17lbs on the torque wrench. So I will take out 2 thin spacers in there = 10 thousandths. One thing I did notice today it was 45 deg in the garage and it took 35 lbs of tourqe at first to get it turning. I think a good portion of this is how cold it is in the Garage and the effect it has on the Assembly lube goop? That stuff is thicker than SNOT and it gets thicker with cold. Thats the only thing I can figure. Im going over to PU a gasket in a bit in Elkhart, and I left the garage heat turned to 70deg and put a heat lamp shining on the engine. MJ and I are going shopping later tonight I will try again and see what it takes to turn it over. And Rooster now that I think of it the crank without anything attatched did seem to turn over ok, just somewhere along the way things got tighter and it seems Like possibly the first couple nights I forgot and left the heat turned up in the garage. Last night I ran it down to 45 deg which is the lowest setting on the stat so's thats why I am suspecting temp and thick lube. Anyways Will let ya know how that works, If ya can think of anything Lemme know.

~Duke

[varosd 1,185]

Duke,

Great looking project! a lot of time and moola! You are right to stop and take a break to make sure it is all ready. It will be interesting once you have the garage temp back up, will that help. I would also test fire with the electric motor before cranking it over. That is a great idea!

V

[546cowboy 301]

You know if you would have bought that 1991 520 I had at the Charolett show you wouldn't have these problems. You know if you would have offered $900 you could have taken it home and found a new hood for $50. Just how much have you got tied up in this now? I have enjoyed reading about all the repairs you've done though.

[sorekiwi 761]

Sounds like something is not right to me.

What are your bearing clearances like, and what end float did you end up with on the crank?

Unrelated to your present problem, but I am not sure that assembly lube in the cylinder bores and on the rings is a good idea. My feeling is that its too thick to allow the rings to seat in properly. I always use normal (dinosaur!) engine oil to lube the rings, bores and pistons. I would like to use assembly lube on the wrist pins, but I usually end up using engine oil cause I dont want that thick crap getting on the piston walls.

[smoreau 658]

Hay Duke

Assembly lube is thick so it stays there during assembly. It is normal for the amount of lube that you used to turn hard when everything is first installed. I have built several small block chevy engines in my time and some small engines. they all turn hard at first and get better after the spin over a for a min. with the starter and fresh oil in them. I would also change the oil after 15-30 min. of run time to remove the fine shavings that are made from a fresh engine rebuild. But if you have any dought in what was done so far, Buy all means!!! check it out first!!! A gasket or two is allot cheeper then more machine work buy far! I can't tell you if its rite or not, But your no idiot and you noticed a problem, Just make sure it rite before you go any farther. Good luck and I am waiting for the next vid. of this engine running :)

[AMC RULES 36,945]

...or grenading, which ever comes first.

Just kidding Duke, may the force be with you brother.

[Giles 2]

UPDATE: I called my engine doode (who did the machineing) and Bob he suggested the same thing as you did. I loosened the bearing plate and it made a little difference instead of 23lbs it is now 17lbs on the torque wrench. So I will take out 2 thin spacers in there = 10 thousandths. One thing I did notice today it was 45 deg in the garage and it took 35 lbs of tourqe at first to get it turning. I think a good portion of this is how cold it is in the Garage and the effect it has on the Assembly lube goop? That stuff is thicker than SNOT and it gets thicker with cold. Thats the only thing I can figure. Im going over to PU a gasket in a bit in Elkhart, and I left the garage heat turned to 70deg and put a heat lamp shining on the engine. MJ and I are going shopping later tonight I will try again and see what it takes to turn it over. And Rooster now that I think of it the crank without anything attatched did seem to turn over ok, just somewhere along the way things got tighter and it seems Like possibly the first couple nights I forgot and left the heat turned up in the garage. Last night I ran it down to 45 deg which is the lowest setting on the stat so's thats why I am suspecting temp and thick lube. Anyways Will let ya know how that works, If ya can think of anything Lemme know.

~Duke

So I will take out 2 thin spacers in there = 10 thousandths

I have rebuilt many small engines but not exactly like yours but shouldn't you be ADDING SHIMS for more clearance??

[sorekiwi 761]

So I will take out 2 thin spacers in there = 10 thousandths

I have rebuilt many small engines but not exactly like yours but shouldn't you be ADDING SHIMS for more clearance??

An Onan is different than a Kohler when I comes to setting crank end play Giles. The Onan has a thrust washer on each end of the crankshaft, with shims behing them to adjust the clearance. The bearing plate that closes off the crankcase is bolted up tight with just one gasket, unlike the Kohler where you shim this bearing plate to give you your clearance.

[chazm 412]

You only need a thin coat of assy lube on brgings,lifters,ect, I've seen using too much assy lube block oil passages and don't use on piston rings, I've seen it cause problems there also. The rings won't seal. Good luck with it Duke

Chas

[Giles 2]

So I will take out 2 thin spacers in there = 10 thousandths

I have rebuilt many small engines but not exactly like yours but shouldn't you be ADDING SHIMS for more clearance??

An Onan is different than a Kohler when I comes to setting crank end play Giles. The Onan has a thrust washer on each end of the crankshaft, with shims behing them to adjust the clearance. The bearing plate that closes off the crankcase is bolted up tight with just one gasket, unlike the Kohler where you shim this bearing plate to give you your clearance.

Thank you for the explaination.

[HorseFixer 2,012]

Well was gone for about 7 hrs with heat lamp on the engine garage was 70 degrees turned the engine over and the Heat didn't do Dic#. So I got to thinking at waht point the whole thing really got worse. I took off the Oil Pump and waaaaaa laaaaa there is a fiber spacer under the grank gear that has a keyway in it so it turns with the crank shaft. Well the side of this fiber spacer is hitting the side of the Oil Pump! WTF how can that happen? All I did was reinstall this stuff theres only 1 way it can go? I will investigate this in a bit well it now takes 8 lbs of torque to turn over and now the crank is just about able to be turned by hand. We went from 25 initially to turn the crank to 23 once started, now at 8 lbs. I have decided to fix the fiber spacer rubbing. remove the two spacers on crank install the new bearing gasket and install the rest of the gaskets, install the drive pulley fill with oil and

turn it over and let it run awhile with the oil in it and see if she lossens up a bit. Will post my results later about time to make a video of this!

Cheers ~ Duke

Duke,

Great looking project! a lot of time and moola! You are right to stop and take a break to make sure it is all ready. It will be interesting once you have the garage temp back up, will that help. I would also test fire with the electric motor before cranking it over. That is a great idea!

V

Yeah Don I think the electric Motor wont hurt anything and will help break the engine in lightly.

You know if you would have bought that 1991 520 I had at the Charolett show you wouldn't have these problems. You know if you would have offered $900 you could have taken it home and found a new hood for $50. Just how much have you got tied up in this now? I have enjoyed reading about all the repairs you've done though.

CowBoy hindsight is 20/20 Ole Duke gets Bucked more than Hue Heffner!

Sounds like something is not right to me.

What are your bearing clearances like, and what end float did you end up with on the crank?

Unrelated to your present problem, but I am not sure that assembly lube in the cylinder bores and on the rings is a good idea. My feeling is that its too thick to allow the rings to seat in properly. I always use normal (dinosaur!) engine oil to lube the rings, bores and pistons. I would like to use assembly lube on the wrist pins, but I usually end up using engine oil cause I dont want that thick crap getting on the piston walls.

Mike I agree think that Assembly Lube Is No Good and will only use it on main bearings up to Wrist Pins Cyl and everything else will Get Earl! Oh and there wasnt any end clearence thats why Im removing the two thin spacers.

Hay Duke

Assembly lube is thick so it stays there during assembly. It is normal for the amount of lube that you used to turn hard when everything is first installed. I have built several small block chevy engines in my time and some small engines. they all turn hard at first and get better after the spin over a for a min. with the starter and fresh oil in them. I would also change the oil after 15-30 min. of run time to remove the fine shavings that are made from a fresh engine rebuild. But if you have any dought in what was done so far, Buy all means!!! check it out first!!! A gasket or two is allot cheeper then more machine work buy far! I can't tell you if its rite or not, But your no idiot and you noticed a problem, Just make sure it rite before you go any farther. Good luck and I am waiting for the next vid. of this engine running.

Scotty I will start out running with Earl then switch and change after running on elec motor. Yep and I will do a vid.

...or grenading, which ever comes first.

Just kidding Duke, may the force be with you brother.

UPDATE: I called my engine doode (who did the machineing) and Bob he suggested the same thing as you did. I loosened the bearing plate and it made a little difference instead of 23lbs it is now 17lbs on the torque wrench. So I will take out 2 thin spacers in there = 10 thousandths. One thing I did notice today it was 45 deg in the garage and it took 35 lbs of tourqe at first to get it turning. I think a good portion of this is how cold it is in the Garage and the effect it has on the Assembly lube goop? That stuff is thicker than SNOT and it gets thicker with cold. Thats the only thing I can figure. Im going over to PU a gasket in a bit in Elkhart, and I left the garage heat turned to 70deg and put a heat lamp shining on the engine. MJ and I are going shopping later tonight I will try again and see what it takes to turn it over. And Rooster now that I think of it the crank without anything attatched did seem to turn over ok, just somewhere along the way things got tighter and it seems Like possibly the first couple nights I forgot and left the heat turned up in the garage. Last night I ran it down to 45 deg which is the lowest setting on the stat so's thats why I am suspecting temp and thick lube. Anyways Will let ya know how that works, If ya can think of anything Lemme know.

~Duke

So I will take out 2 thin spacers in there = 10 thousandths

I have rebuilt many small engines but not exactly like yours but shouldn't you be ADDING SHIMS for more clearance??

Giles, The spacers are between the two Rod Journals and the outer case the more spacers you add lessens the endplay. Right now it is too tight. :rolleyes:

[sorekiwi 761]

I took off the Oil Pump and waaaaaa laaaaa there is a fiber spacer under the grank gear that has a keyway in it so it turns with the crank shaft. Well the side of this fiber spacer is hitting the side of the Oil Pump! WTF how can that happen? All I did was reinstall this stuff theres only 1 way it can go? I

The phenolic washer goes on the outside of the crank gear, not the inside. Here is a picture from the manual:

This washer is what limits the endfloat of the camshaft, in its present position it will be preventing the cam going all the way in, there is nothing to stop the cam coming out, and it will also screws up where the governor mechanism is sitting.

Oh and there wasnt any end clearence thats why Im removing the two thin spacers.

So instead of just "removing two thin spacers" why dont you set the crank endfloat up properly to the specs quoted in the manual? (.006-.012"). Proper endfloat on the crankshaft is as critical as any other bearing clearance in an engine.

The manual tells you how to do all this stuff, seems that no-one bothers to read them? :scratchead:

[HorseFixer 2,012]

I took off the Oil Pump and waaaaaa laaaaa there is a fiber spacer under the grank gear that has a keyway in it so it turns with the crank shaft. Well the side of this fiber spacer is hitting the side of the Oil Pump! WTF how can that happen? All I did was reinstall this stuff theres only 1 way it can go? I

The phenolic washer goes on the outside of the crank gear, not the inside. Here is a picture from the manual:

This washer is what limits the endfloat of the camshaft, in its present position it will be preventing the cam going all the way in, there is nothing to stop the cam coming out, and it will also screws up where the governor mechanism is sitting.

Oh and there wasnt any end clearence thats why Im removing the two thin spacers.

So instead of just "removing two thin spacers" why dont you set the crank endfloat up properly to the specs quoted in the manual? (.006-.012"). Proper endfloat on the crankshaft is as critical as any other bearing clearance in an engine.

The manual tells you how to do all this stuff, seems that no-one bothers to read them?

Thanks Mike guess I missed that, But intended on looking at the manual again, so prolly would have caught that glad ya solved that for me. I indeed planned on cking the endplay Im just thinking the two spacers removed will do it but I will ck thanks again.

Duke

[HorseFixer 2,012]

Okay I am back on track I dissasembled the whole engine. Cleaned all the parts WD wiped clean with new Microfiber rags. I first assembled the crank and used the good stuff 30 wt oil. The bearing flange I lightly tightened and tryed to spin the crank. Well much of the problem is that I couldnt get a good grip so I cleaned both ends of shaft with brake cleaner and used rubber gloves and once the shaft was moving I could turn fine. I checked the crank endplay and I wound up at 10 thousandths with all spacers in place the crank needed to be pressed in a bit further as the gap was on the side opposite bearing flange so that explains that. I Have installed both the pistons and have the crank gear in MJ's oven to heat up and will install that in a few minutes. Next will be the cam & Valve train. Awe what the hell guess I needed the practice. So far so good.

~Duke

UPDATE: The Crank Gear, Cam and Valve Train are Installed, and I can still turn the engine over by hand I have to admit something here. I had a PM yesterday and this individual gave me a good idea. He was a recipient of The Duke's apple juice and he told me to use some of that to loosen up that Tight engine, He says it worked just fine on him. so thats what I did. Came in outta the garage awhile go, went back out and checked and the damn thing is still spinnin. Anyways thanks for the help, and the Tips!

All is well at the Duke "O" Minium!

~Duke

[546cowboy 301]

I'll tell you Duke with this thread you have probably unknowingly made many here a lot smarter about Onan engines. Everyone should be thanking you for that but of course most hate Onans and would never attempt what you have. For that I think you deserve a lot of credit. Next time we meet I will surely let you know that in person.

[varosd 1,185]

please add video when the big moment occurs....no, not the birth of kids or grandkids...I mean when you do your first fire up!! :)

[HorseFixer 2,012]

Well here is where I am at presently with the engine. Made it over a few hurdles and learned a few things. First rebuild on a twin I have done altho have done a couple truck engines befor years ago. The more I play with it the more I like it. Should have It running over the holidays hopefully the next movie after this one will be it running.

~Duke

[varosd 1,185]

We can't wait for the sequel!!! Great work Duke! you are right on it