KB 3.5 bearing problem

[Michael Villeneuve]

Having an issue with my engine rebuild,
I replaced all the bearings and now as soon as I tighten the bolts down to seal the engine on the crankcase and pto side, the engine doesn't turn over easily. There seems to be alot of resistance.
Any ideas?

Thanks

 

[dave roach]

I would say that you don't have the bearings seated all the way in the case or PTO.You could have the wrong bearing and one is to thick.If it turn over fine before you put bearings in and that is what i would look for.

Dave

 

[Michael Villeneuve]

Should I heat the hole assembly and try to push it in more?

 

[dave roach]

don't get it to hot.

 

[Michael Villeneuve]

Or I can go with a brass lunch and a small hammer to try and seat it properly

 

[Carl Van Houten]

Never use a hammer when installing new bearings. Heat the housing and cool the bearing and it should seat completely into place when pushed.

 

[Walt Barney]

Never use a hammer when installing new bearings. Heat the housing and cool the bearing and it should seat completely into place when pushed.

I put the bearing in the freezer for about 15 min while I heat up the case then the bearing will just drop in I also put the crank in asap to help keep the alignment and to make sure both bearing are seated.
Walt Barney

 

[Dennis Somers]

Carl and Walt;
I know it is advise that's been handed down for decades about "cooling"/"putting the bearings in a freezer", before dropping them into heated cases. Heating the aluminum cases in a 300 to 350 degree oven is good practice to expand the bores evenly and not have them cool too quickly. BUT, putting our bearings into a freezer causes them to form condensation all through the bearing ( not just the outside ) the second they come out into room temps. As you drop them into the heated case bores, you are trapping that moisture deep inside the bearings. The worst part of this is, you can measure your new bearing's OD before you put them in the freezer, and again after several days of being left in there ( I did this by mistake LOL ), and the OD will NOT have changed. So all you are doing is putting moisture packed new bearings into the fresh case. Once installed, sure you can penetrant spray the bearings, but will it remove all the condensation right inside?

Drop the room temp. bearings into the heated bores. They will slip right in the same as the cold, wet ones.

Do the bearing measurement using a good micrometer ( before and after the freezer ) on an old bearing. ANYTHING that you remove from a freezer into room temps will get wet right away.

 

[Carl Van Houten]

I have no issues with this method.

 

[Mike Hughes]

Sounds like the bearing is not fully seated and slightly out of alignment. Here is what I do when replacing. I heat the case and drop the bearing in. I use a propane torch. I rotate the case around to get an even heat. I know exactly when the case is the right temp from the smoke that is given off from residual oil. Once it starts smoking, it is almost there. I then tap on bench and they drop out. I install the new bearings that I have previously clean with white gas. I install the crank, collet, and flywheel to just finger tight. I then spin the crank over. I then take a small brass hammer and tap on the flywheel as it is spinning. I also tap on the end of the collet and flywheel. If the bearings are not fully seated this will get them there without any damage. Then let cool. After cooling, I check them again to see how it spins. If binding, I lighty heat the case again and do the taping routine. Most times the second step is not needed. I have had to a few times remove bearings and wipe down the inside of housing to get them to seat proporly. There was a small piece of crap in there. Getting the bearing clean is important. When the crank is perfect, you can finger spin it and it will go for at least 30 secs or so. Hope this helps.
Mike

 

[Carl Van Houten]

There you go another way to do it. Let us know if you get it worked out.

 

[Dennis Somers]

Not trying to beat a dead horse;
Why are we cooling the brg? Presumably to shrink the OD! Do the pre/post freezer measurement. The brg. doesn't change size at all.
I'll shut up now!

 

[Walt Barney]

Not trying to beat a dead horse;
Why are we cooling the brg? Presumably to shrink the OD! Do the pre/post freezer measurement. The brg. doesn't change size at all.
I'll shut up now!

Dennis ,
You are correct on the moisture on the brg, I also forgot to mention I spray the brg's with Corr-X( Red can) then in stall Brg with crank
Walt Barney

 

[Daniel's Racing]

Last thing you want to do is freeze the bearing. If you ever don't get the bearing all the way in with one swift move the ice cold bearing will draw the heat out of the case immediately. Now your screwed with a new bearing locked up part way in. You are defeating the purpose and gaining nothing and loosing your precious working time only to fill the new bearing with water besides.
Been building and swapping a lot of bearings out in engines. Every single engine I build gets new bearings. I can tell you with all certainty that cooling the bearing is definitely not a good idea.

 

[Carl Van Houten]

I've done it that way for 40 years with not one situation where it "locked up" and never had a bearing full of water??? I put my bearing in a sandwich bag and get them cold and once I have my case hot I pull the bearing out of the bag and POP she slams to the bottom of the bore and I am on to the next project. As a matter of fact if there were any moisture that got lucky enough to form on the bearing during that 5 second window it would surly be quickly dried away sitting in a case that is 200+ degrees. For the guy I was trying to help with his problem, let me know if you get your problem solved.

 

[Dennis Somers]

Carl, I'm not going to change your mind/method, because as I said, guys have done this/been taught this forever. But I would like to know, what are you gaining by putting the brgs. in a freezer? How much do you "think" they are shrinking? Just wondering where the logic is?

 

[Daniel's Racing]

Dennis,
As you well know.
There is no logic to it. Complete waste of time that is clearly detrimental to the process. Doesn't matter if he did it for 100 years still screwing up. Zero benefit and there are several reasons not too.
And your right don't bother trying to change his mind but maybe someone else can benefit.

 

[Carl Van Houten]

My method works and always has.
I'll leave you with something to think about. I used to work for an aircraft company when I got out of school. It was my first job actually. Being the last hired I was given the job nobody else wanted and that was pulling engines out of planes and disassembling them and part of my job after the parts were all put into there designated places was to pull the exhaust seats out of the cylinder jugs. We rebuilt many engines and they all had at least 4 or more cylinders so I was kept fairly busy stripping engines and pulling seats etc. I would place each cylinder jug over a rosebud type propane burner and heat the cylinder until it melted a temp crayon that was used to monitor the heat. Once the crayon melted, I used a large set of thongs to lift the cylinder off the flame to flip it over where I then inserted a special made tool that would mechanically expand into the seat and grip the seat inside the hole. Once the tool gripped the seat cold water was turned on and the tool was designed to allow the water to travel down inside the tool and come into contact with the inside of the seat.
The instant the water hit the seat the seat would pop out of the bore. Now this would tell me that the cold water was shrinking the seat just enough to release it would you agree? The reason this was done this particular way was for one we had to follow FAA regulations. But the point for this method was that they did not want the jugs to be over heated just to remove the seats. Were the seats shrinking when the cold water hit them? Well they never once failed to pop out when the cold water valve was turned on. Could we have gotten the seats out without chilling the seats? OH YES... I could have turned the heat up on my burner and I am sure that at some point they would have just fallen out in the floor on their own.
I don't use temp crayons on these model cases because like Mike mentioned earlier I too watch for the oil smoke to indicate the cases approximate temperature and pop..all done. Do I have to cool it? Maybe not but I am sure that I will continue doing it the way I do because it's hard to screw with a methodology that produces a 100% success rate for you.

You guys can disagree with it all you want I really don't care. I might change out some bearing today and guess what...LOL

 

[Brad Christy]

Carl, I'm not going to change your mind/method, because as I said, guys have done this/been taught this forever. But I would like to know, what are you gaining by putting the brgs. in a freezer? How much do you "think" they are shrinking? Just wondering where the logic is?

Denis,

The logic is sound, there is a real benefit, and it has absolutely nothing to do with thermal expansion. The next time you install bearings, after they are inserted, stick your finger on the small bearing inner race and wait. You'll figure it out soon enough. Have some lidocaine at the ready. In the meantime, your polyamide retainers are screaming in pain.

As for the moisture.... When I install bearings, the bearings go directly from the freezer to the crankcase. MAYBE ten seconds. What little bit of moisture that might gather on the surfaces of the balls and races evaporates almost immediately upon installation. Additionally, the first thing I do after installing new bearings is to oil them up thoroughly, first with WD-40, then after-run oil, pretty much eliminating any residual moisture.

The reality is that we get far more moisture in our engines, and it's present for far longer, when we stuff a boat on the back stretch than we might while installing frozen bearings into a heated case.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

 

[Dennis Somers]

Carl. Your aircraft story is interesting for sure. I can certainly see why the FAA would not want high temps applied to aircraft assemblies. When thousands of different aircraft mechanics are assigned to work on engines, all with varying degrees of precision, there must be standardized tooling so that results are consistent. I would suggest that the cold water (totally unable to shrink a metal assembly that's only partially heated) and the tool pulling straight out on the seat, "shocked" the seat out. The same could be done with a swift snap of a hammer once the case/cyld. was heated. But that would depend on the skill level of the mechanic, and the ability to get a hold on the seat. But releasing used up seats or brgs. isn't the same as sweating IN new brgs. (the case and brgs. have to remain perfect).

Enjoy your engines. And if you are not afraid of the result, do the measure check before and after the freezer, on a brg. that you are working with today. LOL

Bradd. I have had high quality brgs. with composite retainers in the oven at up to 400 degrees on VERY TIGHT cases for over 15 mins. with no problems. But the question has not been answered! Why are you freezing the brgs. in the first place?
You are right about the amount of moisture inside an engine when they are dunked. But, they have been running at that point with a good amount of oil in the mix, and are thoroughly impregnated with lube. The minute we get them to shore, we drain the excess water, and re-fire them to dry them completely.
WHY are you freezing the brgs? They don't shrink in a freezer.