460 BB fitment issues...

[CaseyForrest]

Got my BB from Baileys tonite, threw it on, and craked it by hand with the flywheel, and the skirts hit the case!!!! Took it apart, and cranked it with just the piston, and it BARELY fits into the case. Put it all back together, left the bolts loose and jockeyd the jug around while turning the flywheel untill I found the sweet spot where I could get full range with the jug screwed down tight.

Just wondering if this is common. Do I need to do some trimming somewhere?

 

[Patrick62]

I had different issues...

Something muse be different with your crankcase. Mine fit the case well enough. Second kit (first one siezed) is working well.

It could be snaging on the gasket, it is a tight fit there. Good luck!

-Pat

 

[carvinmark]

Something muse be different with your crankcase. Mine fit the case well enough. Second kit (first one siezed) is working well.

It could be snaging on the gasket, it is a tight fit there. Good luck!

-Pat

Casey,Pat may have a good point there.I would try it without the gasket and see if you can get it to snag,if it doesn't then it might just be that dam gasket.Hope you get it sorted out cause I may go the same route on mine.Good luck.

 

[Lakeside53]

I'm interested in that you say you could move it around to get a fit? How much movement do they allow? The stihl gasket (metal) allows zero movement and the holes in the cylinder are pretty tight also.

Something sounds a little flakey... (the design).

 

[Grande Dog]

First you'll have to excuse the drawing. We've found that some of the crankcases from Stihl are offset a little. The amount of offset won't interfere with a stock piston. If seen a few where about a 1/4" of the lower piston skirt will rub on the crankcase. The size of the bolt holes in the cylinder will allow some fudge factor but for very few this isn't enough. For myself, I just grind a little off the crankcase. I've had a few customers that were leery of this ( totally understandable ). We've offered this fix or full refund. So far I think everyone has tried the fix.

 

[CaseyForrest]

Well, I dont think its the gasket, the flat parts of the gasket dont fall in line with the skirts.

I did notice, however, that the opening in the case where the cylinder drops in at the bottom of the stroke isnt even all the way around. The front edges of the case dont match up exactly. SO, I dont think its a problem with the BB kit.

Grande Dog, maybe you should make that info about the issue available in the listing. I know Im probably not going to grind my case down any. If I feel like its not going to work, Ill probably send it back.

Im going to pressure test this weekend, and if theres a leak, Ill snap some pictures so you all can see what Im talking about.

EDIT: Just occured to me that maybe the gasket isnt centered with-in the cylinder opening, probably like Pat was saying.

 

[carvinmark]

Well, I dont think its the gasket, the flat parts of the gasket dont fall in line with the skirts.

I did notice, however, that the opening in the case where the cylinder drops in at the bottom of the stroke isnt even all the way around. The front edges of the case dont match up exactly. SO, I dont think its a problem with the BB kit.

Grande Dog, maybe you should make that info about the issue available in the listing. I know Im probably not going to grind my case down any. If I feel like its not going to work, Ill probably send it back.

Im going to pressure test this weekend, and if theres a leak, Ill snap some pictures so you all can see what Im talking about.

Good luck Casey,I'll be watching to see what your outcome is.

 

[CaseyForrest]

I'm interested in that you say you could move it around to get a fit? How much movement do they allow? The stihl gasket (metal) allows zero movement and the holes in the cylinder are pretty tight also.

Something sounds a little flakey... (the design).

Lake, there is no more movement than with a OE set. Just a little within the bolt holes on the jug. Where talking Fractions of an inch, like maybe 64th or 32nd, nothing major.

Now that I think about it, maybe I could grind the case even. Id be worried about getting all the filings out of the case when Im done, thats what would bug me.

 

[NWCS]

i have put together many bigbore kits and have not seen this problem, unless it is something like the 046BB on an 044. that one is an extreme pain but can be done. 024 case with 026 crank and MS260 cyl takes some case grinding also.

 

[Lakeside53]

Lake, there is no more movement than with a OE set. Just a little within the bolt holes on the jug. Where talking Fractions of an inch, like maybe 64th or 32nd, nothing major.

Now that I think about it, maybe I could grind the case even. Id be worried about getting all the filings out of the case when Im done, thats what would bug me.

Hmm, sounds sway too close to me to be reliable. I see this same offset in many stihl cases, not just the 046/460.

I wouldn't grind the case if it was mine... unless it was completely broken down (crank out) and the bearings taped over. There is no way to keep the junk (paint, magnesium and grinding stone/whatever debris) out of the case bearing and crankshaft rod bearing.

 

[CaseyForrest]

Well, pressure and Vac test passed, so Im not tearing it apart. I think it was the piston hitting the gasket, I did not think about the fact the 54mm piston is trying to get through a 52mm gasket, so Im thinking the gasket has to be just right. It moves freely now, So Im going to run with it.

 

[Reddog]

Sounds way to complicated CF. Just sell it to me for my 046.

 

[Lakeside53]

Well, pressure and Vac test passed, so Im not tearing it apart. I think it was the piston hitting the gasket, I did not think about the fact the 54mm piston is trying to get through a 52mm gasket, so Im thinking the gasket has to be just right. It moves freely now, So Im going to run with it.

Didn't they supply a bigger gasket? sure hope things don't go clunk. ping, bang when things expand with heat.

 

[CaseyForrest]

Sounds way to complicated CF. Just sell it to me for my 046.

If I run it, and it doesnt work, Ill let you have it for $150, does that work?!?!

 

[CaseyForrest]

Didn't they supply a bigger gasket? sure hope things don't go clunk. ping, bang when things expand with heat.

No, they didnt. I wonder if an 066 gasket will fit?

 

[Lakeside53]

No, they didnt. I wonder if an 066 gasket will fit?

Nope.. different...

The probem is that the saw calls for a crush-steel type gasket and they are impossible to modify and can only be used once. You might try a paper gasket, 0.5mm thick. Easier to modify.

 

[CaseyForrest]

Well, what I did was put a little sealent on both sides of the old gasket, and reused it. That what I had to do to the 066, even with a new gasket. Figured its been working fine since, so Ill stick with it.

Dont the paper gaskets come in 1mm thickness, essentially cutting your compression psi?

EDIT: I just re-read your post, Answered my own question.

 

[Justsaws]

If it is a crankcase issue, fill the crankcase with oil and grind the opening. After you are done grinding use Q-tips to pick the shavings off the top of the oil. Drain oil, rinse well with mix. Blow dry with compressed air and in a dark room use a flashlight to look for shavings. Rinse until no shavings are found. Should not be any if the first part was done well. I use a heavy gear lube. It does not get sucked up into grinding bit. Be careful to not fill crankcase to level of grind. You can also use a shop vac with a small nozzle if you can set it up or get someone to hold it. If you do the shop vac make sure to use a heavy oil. I hope this makes sense. Good luck, I am going to try one of those kits soon.

 

[CaseyForrest]

I dont think it was the CC, I think it was the original head gasket. I got it to work, but time will tell, untill I get a chance to fire it up.

 

[carvinmark]

Casey,
Thaught you would have fired that thing up by now lol. I'm just anxious to get the report.