Leaky base gasket

[lumbee]

Hey guys, did a fresh engine build from a box of parts. Its was torn all the way down to the tranny and I built it back up. Was stocked about that cuz I've only done from the top end up in the past.

Any hooter...doing some shake-down runs everything seems fine...shifts nice, but have a bad oil leak on the left side of the base gasket. Did the drill of re-torquing three times up to 30 lbs to no effect. Leaks pretty quickly also, when I say shake down run, I mean just up the road and back a 1/2 mile or so. I even set the kick stand on a block so the bike sets even, started it and let it run a few minutes and you could see the oil coming from the left side of the bottom cylinders. Tore it down yesterday and nothing seemed out of place. The only thing I did see what the orange rubber o-rings that go around the barrels were sort of shoved up in the small gap between the cylinders and the casting. I honestly can't remember if I did that purposely or it happened when I torqued it down. But either way, just to be clear, the o-rings should go on first, and slide them down flush at the base of the cylinder, then the gasket goes on top of the o-rings?

Also, should I pack the o-rings into that gap, or just let it sort of sit on top? I sort of feel like this probably did not cause the leak, but I thought I'd ask.

Also, what about using some grey gasket sealer around the base gasket? Can't hurt right?

I just don't want to put it all back together and get the same result...definition of insanity and all

Thanks in advance.

 

[jetmechmarty]

Did you use a green gasket?

 

[jpdevol]

The Athena, green gaskets are problematic. I understand you've checked the leak source - and now torn it back down - but you know oil leaks will travel (especially in base gasket area) a dusting of talcum powder over the area will leave a trail and help identify the real source (future reference). The oil pipe joint and cam chain guide bolts are popular leak sources that can appear at the base gasket.

Anyway, how about some pics of both gasket surfaces and the dowel pins?

 

[Jan_P]

We have had that discussion here at times

Also, what about using some grey gasket sealer around the base gasket? Can't hurt right?

Back in the day the magic word was Permatex. People smeared that on things and lots of it.
Some here dont use chemicals And it works for them .. But I have tried cut back on the chemicals and ends up doing it over again feeling like a fool

If it is a New ish bike tightened with torque wrench it is one thing. But if it is an old bike with warped or Scratched surfaces its another case.

If it is the right chemical ( No snake Oil ) Reputable company and used properly. I Use it i would most definitely as in your case do it a second time.
Taking the engine out a third time I would hate myself for that.

Something is wrong if it leaks after a few minutes Would it do that even with no gasket .. The O rings and check that it goes all the way down

Dumb here but there is a tightening pattern that helps . I take a little at a time and follow the pattern
A rubber mallet perhaps to start with.

 

[jpdevol]

Permatex (or any RTV): (sorry Jan, lol)

Yamabond, Threebond or Hylomar only if needed and applied thinly with a brush so no squeeze-out

 

[Jan_P]

Permatex (or any RTV): (sorry Jan, lol)

Yamabond, Threebond or Hylomar only if needed and applied thinly with a brush so no squeeze-out

Yes Sir
As I said there are many views cant remember anyone had a torque wrench back then. Exotic expensive things. And the bikes leaked a lot.Even after smearing on those chemicals. Permatex. Pretty much everyone got fooled on their first bike .. Buying cheap sometimes as a project.
And within 6 months bought a better one that did run also . And not necessarily that far.

I trust you on this one -- Also -- There is a learning curve that can get expensive that is why this forum is good.
Base gasket it can be hot there so ask the experts.

I am no Guru Electrics I know a little about because on crap bikes it is always a Problem. I can read a Schematic and use a Voltmeter.
But I am still on that learning curve . Take advice and corrections .
Especially in this crowd. I don't say that often .. Some here are actually Gurus .I respect that ..Good spirit also

 

[jpdevol]

Good spirit also

Yes Sir, I may have overreacted a bit , but I've seen it overdone with bad results......

 

[lumbee]

-Yes, Athena green gasket
-Three bond is the gasket sealer I was referencing
-Regarding travelling oil leads...JP, I hear you, but I really took time to observe where the source of the leak was coming from. The base of the oil pipe did have a little something coming from it, but I'm 98% sure it was coming directly from the base joint on the left side.

Assuming the leak is coming from the base gasket, it's just oil splashing around from the rods right? There are not any oil passages coming up through the cylinder case are there?

 

[jpdevol]

Assuming the leak is coming from the base gasket, it's just oil splashing around from the rods right? There are not any oil passages coming up through the cylinder case are there?

Correct. I try to use Vesrah or Cometic brand gaskets when available - 650Central.com, Mike's XS, sometimes HVC Cycle. New dowel pins if in doubt

 

[lumbee]

Upon close inspection, I did find this ding on the left side (right were the lead was appearing) so I'm hoping this was the issue. I'm guessing someone was trying to pry the cylinders off the case. I did a little work with a flat file so I'm hoping that does the trick.

 

[Oldnwiser]

Something that can also happen is crud can accumulate in the holes where the dowels go and keep the jugs from squeezing down. Clean is mean. Especially if you have a stack up of dowel length. I may sound silly but I draw a diagram and number the dowels on where they go and put them back where they belong. And the top and bottom of where they go in the assembly use a Quadrajet secondary metering rod as a cleaning tool the send that connects to the secondary arm that lifts and lowers them and just lightly dig around in the spots where the dowels seat with some cleaner and you’ll be surprised what is in there it’s like cleaning your ears. That combined with Print to seal type gaskets and if it makes you feel better a smear of Yamabond around very light is the key. And use the torque pattern eliminating any friction that might cause a false number on your torque wrench and be sure you sneak up on the final torque avoid tightening and backing off. If you use the yamabond it will squeeze out evenly or I go around with a flashlight and look for any gaps. I hope this helps.

 

[Oldnwiser]

I don’t know if anyone else does this but even now I can disassemble an engine . I have a large workbench, as I disassemble it I put each piece in order, including bolts washers dowels etc as I go and make rows as I go until it is stripped. Cleaning parts in my parts washer I clean it and dry it and put it back. When the parts come back from the machine shop, I clean and dry the block heads, rifle brushes through the oil passeges (why I build Ford FEs because I have been building them for 50 years) I have a set off measuring tools that I use Bluetooth and it tells me what it is. I love the details of building an engine and only fatigue keeps me down, my joints are stiff but you have to be organized and it is so fun to get it in a car with open headers and that first fire up is so awesome, I sill love big raunchy flat tappet solids that require 20 minutes of break in and then putting the springs on that go with the cam, and breaking in the rings by having my son take me for a ride and rip it from 30mph to 60 a few times, which applies to breaking in a new set of rings on a bike , then a balls out rip to 7000 with open headers is the prize for that hard work. Hmmm! A 277 bike sounds like that I bet. I really need to try it.