Question on Assembly of 372XP crankshaft into crankcase without the case tool

[HuskyFan1977]

Well I assembled my 372XP Farmertec crank into the crankcase halves without the proper tool. I put the crank in the freezer and left the case halves room temperature. I was able to get the crank into the PTO side bearing far enough by hand so that I could get all the crankcase socket head screws in fairly deep. I then tightened them very evenly with a slight creek on each (usually). I got it all together fine and the crankshaft turns fairly easily by hand. Does anyone foresee any issues, or is there anything I should check before running it? My squish w/o the base gasket turned out to be .7mm on average on 4 sides of the piston. This is my first saw build, so I appreciate any feedback good or bad. Thanks in advance!

[weimedog]

Heat differential method works....if that crank turns free, the bearings are seated properly, the seals where they are supposed to be & not cooked or "prolapsed" should be fine right? It's having the bottom end all together in a proper way more than how you get there.......unless the "how" damages parts along they way... Gouging cases w/ out of alignment bearings or when pulling old seals, over heating the nylon or seals, pounding the bearings to the point something gets compromised, flexing cases too much, etc.

( Can "tap" that crank to free it up & center it if there is still a little binding before the seals are in, have to use some thing to protect the threads....cover that in video over and over  Without seals that crank should be easy and free to turn. seals add a little resistance. )

[Al_Smith]

I don't recall if I've ever split the cases on a Husqvarna but I have done a number of Stihl saws .I for one am not enthusiastic of using a so called case splitter because you are pulling and pushing the bearing subjecting stresses where the inner and outer races making side pressure on the bearing balls .

I prefer the heat,cool method which has been outlined in the Stihl manuals .It's not quick but I think it's a better method .Keep in mind with a ball bearing if the balls or races are damaged it's not if they will fail it's when they will fail because in a matter of time they will .A properly installed ball bearing should last a very long time with proper lubrication.Which could lead off into a long winded conversation of fuel mix ratios -----so I'll just stop there ,for now . 8)

[Al_Smith]

I might add to the above in reference to a dealers manual covering Partner brand chainsaws and cut off saws from around 1983-84 .They recommend the exact heat cool method I said in the previous post .Sometimes the age old methods have a lot of merit to them . 

[HuskyFan1977]

 Thanks for all the replies everyone! It runs great now but I had a minor issue that could have ended very badly had I not caught it in time. I was going to not use the base gasket to increase my compression however I used too little Copper RTV and I had a leak. I looked as though the decomp was spewing but it was the base where i had the RTV too thin. I had great compression at first but after I gently ran it at idle for about a half tank the compression dropped way off. I checked the decomp and it was OK. I had a sinking heart feeling like we all know. I figured I had toasted the top end or worse the bottom end. Nice part is the 372XP (non X-Torq)are so easy and fast to disassemble I had it apart to check my P+C in 30 min. and back together in another hour as I had to clean off the RTV and use the base gasket. For my first ever internal combustion engine build I should have just used the gasket from the get go. However, Walt makes applying the RTV look so easy, but I found out im not too great at it hehe. Just glad I caught it before I damaged my P+C or worse the bottom end...

[Al_Smith]

----which brings up another bone of contention .Some who attempt to boost  compression advocate a base gasket delete for the simple fact  it's the easiest way to do it .They smear some kind sealant on it as if it could take the place of a gasket and call it a day .Some times it just doesn't work out well .---just saying ---

[weimedog]

----which brings up another bone of contention .Some who attempt to boost  compression advocate a base gasket delete for the simple fact  it's the easiest way to do it .They smear some kind sealant on it as if it could take the place of a gasket and call it a day .Some times it just doesn't work out well .---just saying ---

And the "success" on that approach completely depends on a couple of thing. Cleanliness of sealing surfaces. BRAND and specific product used as a sealer. How much distance across surface area makes up the sealing surfaces. A few years back when all the established experts were discussing the merits of the no base gasket or "goo" gasket builds I did some of my own testing with different options and brands. Now almost ten years later I have built a little confidence in an approach that has proven statistically as reliable in MY small world as actual OEM base gaskets. And I stress....in my world with my saws and my customer saws.
If those surfaces where not "carb cleaner" clear of any oil and dirt...the seal would fail. MOST brands of sealer didn't last over time anyway. None of the standard options from Napa or other Auto Parts Stores worked for me. One brand has worked now consistently and I have used that grey 1194 now 1184 stuff from Three Bond ever since and have NEVER had one fail. Not a one.  I have had several test cases now in the hands of folks who run them daily to make a living. In some cases for years. All Husqvarna's. 390's, 372's, 576's both OE and XT. And that brings the last and probably most important issue. Surface area. Saws with cylinders like those Hustl/Farmertec ms660 56mm "big bores"  don't have enough and really need to have their metal gasket. Conversely saws like the Husqvarna 576's have plenty. So depending on the saw cylinder / case design, the brand / properties of sealer used, and work practices, your chances of success will either be good or not. When in doubt? Use an OEM gasket..

( Don't ask me what other brands and model's work as the only one's I have any real knowledge about are the ones pointed out in my post...if it isn't there, I don't know enough about them to matter! )

[Al_Smith]

Although I don't subscribe to gasketless assembly methods it has became a practice done by nearly every manufacturer of automotive engines in the world .They don't leak .The bench mark standard of world  is Loc-Tite 5900 RTV .I've made reference to it before with arguements there from but I've seen the results first hand .
If this stuff is applied  correctly  the manufacturers had to include "jacking bolt " threaded holes to able to remove items such as oil pans,front covers ,cam covers etc .if repairs were need at a later date .This stuff literally sticks like glue .

[Pine Ridge]

----which brings up another bone of contention .Some who attempt to boost  compression advocate a base gasket delete for the simple fact  it's the easiest way to do it .They smear some kind sealant on it as if it could take the place of a gasket and call it a day .Some times it just doesn't work out well .---just saying ---

And the "success" on that approach completely depends on a couple of thing. Cleanliness of sealing surfaces. BRAND and specific product used as a sealer. How much distance across surface area makes up the sealing surfaces. A few years back when all the established experts were discussing the merits of the no base gasket or "goo" gasket builds I did some of my own testing with different options and brands. Now almost ten years later I have built a little confidence in an approach that has proven statistically as reliable in MY small world as actual OEM base gaskets. And I stress....in my world with my saws and my customer saws.
If those surfaces where not "carb cleaner" clear of any oil and dirt...the seal would fail. MOST brands of sealer didn't last over time anyway. None of the standard options from Napa or other Auto Parts Stores worked for me. One brand has worked now consistently and I have used that grey 1194 now 1184 stuff from Three Bond ever since and have NEVER had one fail. Not a one.  I have had several test cases now in the hands of folks who run them daily to make a living. In some cases for years. All Husqvarna's. 390's, 372's, 576's both OE and XT. And that brings the last and probably most important issue. Surface area. Saws with cylinders like those Hustl/Farmertec ms660 56mm "big bores"  don't have enough and really need to have their metal gasket. Conversely saws like the Husqvarna 576's have plenty. So depending on the saw cylinder / case design, the brand / properties of sealer used, and work practices, your chances of success will either be good or not. When in doubt? Use an OEM gasket..

( Don't ask me what other brands and model's work as the only one's I have any real knowledge about are the ones pointed out in my post...if it isn't there, I don't know enough about them to matter! )

Good information to know weimedog, i will now be picking up some threebond to use in the future.

[steele109]

I have built somewhere around a hundred saws with no base gasket and not one failure. I use three bond 1184, I clean the surface with a scotchbrite  pad and lacquer thinner.Then wipe it with a clean paper towel.You have to get all the oil off the surfaces. Apply a thin layer of three bond to both surfaces, let it set til it gets dull looking. Put the parts together and God help you if you have to take them apart. You literally have to beat them apart. Three bond grew up with the motor cycle industry, those engines have more compression than most saws.You can clean it up easily with lacquer thinner and a scotchbrite.Paper gaskets will blow out mainly on larger saws. 

[ZeroJunk]

All of Stihl's clam shells are stuck together with Dirko.  I think if everything is machined properly you could put it together with nothing and it wouldn't leak enough air that you couldn't tune around it easy enough.