Big Twin Flathead Puking Oil

[JBinNC]

No! Do not block off the pressure relief. But it would be good if you could redirect the excess oil outside the motor to cut the volume in the cam chest.

In the flywheel cavity, you should have 4 to 8 oz. of oil when you drain it after running the motor for a while.

About the little valve: you said you used some sealer in place of the gasket for your breather tube base. In general, any kind of silicone sealer is the kiss of death for an H-D motor, and small bits of this sealer may be getting in the valve and blocking it from sealing. I would start by pulling that breather tube and checking it carefully for rust holes or cracks at the bottom that might leak. And I would get, or make, a proper gasket for it, and clean ALL the sealer out of the cover.

I'm just trying to give you anything that might help the problem. I know some or all of it may be worthless to you.

Jim

[CDeeZ]

I wish that was the case flatman.

The cam cover seal ring, a football shaped piece which rides up and down on a spring and two pressed in pins was the reason I swapped cam covers to begin with. That seal ring is part of the oil separator/scavenging setup, as far as I understand it.

That seal ring, rides on the face of the generator gear which also has a slinger or oil separator on it. On my old cam cover, the seal ring was roached, stuck down and wouldn't freely float like it's supposed to. I bought a new seal ring and wouldn't you know, the pins that it came with were much smaller than the corresponding holes in my old cam cover. I kept the old cam cover, but for sake of expediency, I just bought a new cam cover which already had that seal ring installed.

At some point, someone decades ago had used the wrong generator gear. Rather than the correct gear with the oil separator, it was for a knuckle or pan I believe. Jim helped me get sorted on that one.

I have addressed each item, individually as I came to learn they were not correct or in good working order, each item thinking that surely one of them would be the fix for the thing puking oil from the breather tube.

Here's what I've tried:
Multiple flutter valves
Checked the breather timing more times than I can even remember
Installed the correct generator gear for a flathead with it's incorporated oil slinger
Swapped cam cover only for the purpose of gaining a functioning cam cover seal ring
Verified a steady stream of returning oil to the tank.


The cam cover seal ring circled in red:


Old seal ring removed and new one ready to install (but like I said, the pins were much to small)



I welded bolts to the old pins to remove them. Can also see the new pins and seal ring:


New seal ring and pins:


The WRONG generator gear I took off (pan/knuck?)


WRONG generator gear again:


The correct generator gear and how it interfaces with the seal ring:




For decades, having the wrong generator gear with no oil separator never was an issue, because the stock oil delivery was probably so shit, it wouldn't have mattered that it was missing. Some may wonder why I didn't go back to the bone stock oil pumps setup and have been trying to make something else work. My dad built this bike in ~'97. He never opened up the motor himself however. And since '97, the engine has destroyed 2 or 3 top ends. He always had a local indy shop redo the motor as needed.

The stock oil system on a BTSV was pretty bad. No, really bad. The 45s seem to be able to get away with it, but the big twins not so much. I WAS trying to adapt an ironhead pump before I learned about these Swedish oil pumps. I got the idea from Dick Linn. He pretty well lays out WHY anyone would want to subject themselves to any trouble to redo the oiling system on one of these BTSVs HERE:

https://dicklinn.webs.com/

I have talked to Dick on the phone, and he was super helpful and nice. Long story short, I was having my fair share of trouble with getting the ironhead oil pump to be much better than the stock pumps. Dick made it work, but for whatever reason I wasn't so lucky.

After swapping to the Swedish oil pumps, the pressure and flow seems to be fantastic, especially compared to what it was stock. The feed pump is a modern gerotor design, so no wonder that works so well. Now, with all this excellent pressure and flow, I just need to get it to stay in the motor somehow. All of this in the name of hopefully making the motor more reliable and longer lasting than ever. With good oil pressure and flow to keep everything lubed and most importantly, cool I think in theory this tractor motor of a flathead should pretty much run forever. I do realize that these HDs don't need much in the way of pressure, flow is what is important.

[CDeeZ]

No! Do not block off the pressure relief. But it would be good if you could redirect the excess oil outside the motor to cut the volume in the cam chest.

In the flywheel cavity, you should have 4 to 8 oz. of oil when you drain it after running the motor for a while.

About the little valve: you said you used some sealer in place of the gasket for your breather tube base. In general, any kind of silicone sealer is the kiss of death for an H-D motor, and small bits of this sealer may be getting in the valve and blocking it from sealing. I would start by pulling that breather tube and checking it carefully for rust holes or cracks at the bottom that might leak. And I would get, or make, a proper gasket for it, and clean ALL the sealer out of the cover.

I'm just trying to give you anything that might help the problem. I know some or all of it may be worthless to you.

Jim

Ok I will leave the pressure relief open. Yes, I am aware that any kind of use of sealer, silicone, RTV or the like is to be used with extreme caution on an HD. It can clog oil passages and whatnot, I was careful to only use a very light amount of it there, very light.

The oil is pouring from the hole in the center, not around the gasket mating surface. Last I had the breather tube out, it was in good condition. No rust holes or anything.

Thanks Jim

[CDeeZ]

Everything checks out, except the flutter valve. But like I've said, according to HD's super scientific test of literally sucking and blowing on it, who knows what to make of that. Plus the fact that I must be on my 5th flutter valve by now, as indicated above.

Checked everything yet again and just finished buttoning the engine back up. Still pouring oil from the hole in the breather tube..... It doesn't happen immediately on startup, only after it's been running for a while.

Noone said anything about my idea for a catch can style or recirculating line to connect the bottom of the breather tube back to the oil tank while also providing it a filtered vent of some type. I can't see any reason why that wouldn't work. I also can't see any reason to try anything else to try to get it to work the "correct" way having exhausted all the possibilities at this point.

[flatman]

From the pic it looks like the two springs are differrent size? smaller id. maybe just the pic. I see no reason the catchcan wouldnt work. only concerns would be if it pressurized the oil tank, or it you filled the oil tank way up and then the engine returned more oil than the tank had capacity for? last ditch effort, take the old cam cover and repair/fix/restore the seal/football and see if it works. it worked til the generator gear ate it up.right? just thinking out loud.

[CDeeZ]

Thanks flatman.


Cool, glad to get some feedback on the catchcan/modified breather tube with a line and vent returning it to the tank. I think that is what I'm going to try last. I think just drilling a hole in the oil tank cap, and then fitting a T fitting would do the trick. Of the 3 holes in the T fitting, one connects the line coming from the cam cover breather tube, one connects to a small air filter and the last one goes into the oil tank. Something like this basically, but the red tank would represent the HD oil tank:

http://www.dwjenkins.plus.com/catch-tank3.jpg

The oil that is failing to be scavenged by the HD design works it's way up the custom line, and drops right back into the oil tank to be recycled. The filter allows the crankcase to breathe, and keeps the oil tank from becoming pressurized.

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Nah, the springs for the cam cover seal are the same. Must be the angle of the picture, I see what you mean now looking back at it.


The generator gear didn't do the damage seen in the picture. That was from me welding bolts to the pins in order to remove the pins and therefore the seal ring itself. The pins are steel and the seal ring appears to be some kind of brass maybe? So the heat from the welds did that.

The oil puking from the breather tube has ONLY been present ever since I put these Swedish oil pumps on.

With the stock flathead pumps, and with the ironhead pump I tried for a while, no oil was spewing from the breather tube. Both the stock flathead pumps, and the ironhead pump were NOT leaking from the breather tube DESPITE having the following problems:

1.)The seal ring stuck and not freely moving up and down in the cam cover as designed.
2.)The WRONG generator gear installed, i.e. no oil seperator
3.)Multiple flutter valves that were probably failed as soon as they were made.

Only after switching to the Swedish pumps was oil puking from the breather a problem. And after addressing all of the issues above, it is still a problem. I wrote an email to Carl who made the pumps. Hoping maybe he can shine some light on it. But honestly, he's probably as sick of hearing from me as I am of dicking around with this thing. If he can't offer some reason as to why his pumps are causing oil to puke from the breather tube (and how to fix it), and a catchcan doesn't fix it........ It'll probably be time to consider moving on.

I've received a lot of great help from guys like all of you on this forum, and a few others. Also had the privilege of calling/texting a few private individuals I've come into contact with from the forums and otherwise, but it seems like most people just don't know about these BTSVs compared to the knowledge and experience base of the later iterations: knucks, pans, shovels, sportys etc. Especially so when you've modified the recipe like I have. But I explained above why I feel that was worth pursuing.

------I appreciate the insight everyone has offered so far, and I hope you all continue to brainstorm with me. I'll keep updating as I go here, but I feel at this point there's really only one thing left to try and that is the cathcan/modified breather tube setup I have described herein.

[flatman]

sounds like you need to just throw the stock working pumps back on , just saying........ has the lower end ever seized up on you with the stock pumps? You mentioned several top ends. worn out or mechanical failure? stuck postons or stuck valves? Is the top end the reason you want much better oiling? not trying to be a dick, just wondering?

[JBinNC]

sounds like you need to just throw the stock working pumps back on , just saying........ has the lower end ever seized up on you with the stock pumps? You mentioned several top ends. worn out or mechanical failure? stuck postons or stuck valves? Is the top end the reason you want much better oiling? not trying to be a dick, just wondering?

I like pragmatic solutions. I'm with you. But I would go back to the original feed pump, and leave the new scavenge pump in place as a first step.

Jim

[CDeeZ]

sounds like you need to just throw the stock working pumps back on , just saying........ has the lower end ever seized up on you with the stock pumps? You mentioned several top ends. worn out or mechanical failure? stuck postons or stuck valves? Is the top end the reason you want much better oiling? not trying to be a dick, just wondering?

Not being a dick at all. I don't have a functional stock feed pump anymore. I had to modify it to the point of no return when attempting the ironhead sportster pump conversion before I switched to trying these Swedish pumps. You can see what I mean in that Dick Linn thread I posted towards the bottom of my post #17 regarding how the stock feed pump is modified for the ironhead pump conversion.

The top end failures that happen are the pistons. I'm convinced it's from heat. Which is probably a two fold issue. One, the very low pressure and flow of the stock feed pump just isn't able to circulate enough oil to enter the engine and absorb the heat and then return it to the oil tank to cool off. And two, the stock iron heads with their stock combustion chamber design seems to create a hotspot right over the piston crown itself. Check out post #3 from Frankenstein, and really any of his posts in that thread since it's only 1 page. That is Dick Linn:

https://forum.sscycle.com/viewtopic.php?f=12&t=12568

I installed some Flathead Power aluminum heads with a KR style chamber very recently. That alone may be enough to keep the engine from having a hot spot right over the piston crown. Dick also talks about this in that same post #3 in the link above.

I like pragmatic solutions. I'm with you. But I would go back to the original feed pump, and leave the new scavenge pump in place as a first step.

Jim

Jim and flatman,

I'm starting to think you guys are right. But like I said I don't have a stock feed pump any more. Most of the "original" ones on fleabay are pretty roached and hella expensive.

Stock feed pump is a 2 vane design. I found this one with 4 vanes. I'd like to try to incorporate at least something that is an upgrade over stock. Maybe this 4 vane pump is the ticket? A little more flow than the stock 2 vane pump, but not enough to overwhelm the stock scavenging design with that cheesy flutter valve

https://www.ebay.com/itm/224231579146

[pan620]

The top end failures that happen are the pistons. I'm convinced it's from heat. Which is probably a two fold issue. One, the very low pressure and flow of the stock feed pump just isn't able to circulate enough oil to enter the engine and absorb the heat and then return it to the oil tank to cool off. And two, the stock iron heads with their stock combustion chamber design seems to create a hotspot right over the piston crown itself.
How did they live back in the day? I helped build a 1938 74" 3 years ago, now 18,000 miles late still going strong, all stock as possible, soory you are having problems but this is my recent experience.

[montuckymatt]

I thought this might be of some help for anyone interested in oil mods

[CDeeZ]

How did they live back in the day? I helped build a 1938 74" 3 years ago, now 18,000 miles late still going strong, all stock as possible, soory you are having problems but this is my recent experience.

Well back in the day there weren't nearly as many paved roads, there was a minimal highway system and most cars had a comfortable cruising speed of maybe 50 mph? If the roads even permitted them to travel that fast for very long?

I'm not trying to ride this bike to the moon or anything, just exploring some options to make it a little more capable for modern road conditions. Modern road conditions where everything moves a little bit faster than it did in the 1930s, and you may get stuck idling with minimal airflow over the motor at traffic lights.

I don't know, I could be chasing a frivolous pursuit here by trying to do ANYTHING other than the stock oil pump. But when I found Dick's website a few years back it made sense to me. It made more sense to me after chatting with him on the phone about these BTSVs.

From his website:

"There’s enough oil there to keep roller bearings lubricated, but not enough to supply the extra cooling that these motors need under modern conditions. I came to this conclusion through lots of seat of the pants research and development. Meaning, I’ve been riding Big Twin Flatties since 1974, and been blowing them up almost that long. Now, I’ve done lots of stupid things that I can’t blame Harley for, but the recurring theme is that the top end destroys pistons within 10,000 miles, usually sooner."

Maybe I'm totally off base here, but that guy was riding flatheads before I was even born. So I guess I was kind of looking to him as a sort of source of knowledge and inspiration on how to make it better, just like he did???

I thought this might be of some help for anyone interested in oil mods
[ATTACH=CONFIG]107524[/ATTACH]

[ATTACH=CONFIG]107525[/ATTACH]

Hey Matt! You're probably sick of hearing me whine about this by now aren't ya?!?!

You are still happy with your 4 vane feed pump? Found this thread with ya here:

https://www.jockeyjournal.com/threads/flathead-oil-upgrade.213040/

I'm going to try that next. Anything I need to watch out for with a 4 vane pump? Anything special that needs to be done?


(Matt was nice enough to give me his number a while back and I've texted him periodically for insight on my flathead travails. Tell me where to send the beer money Matt and I will)

-Chase




-------------------


Just got an email back from Carl who made the pumps currently on the bike.

Again for anyone who has joined the thread late and maybe hasn't read the prior posts:

His scavenger pump is just like stock but with larger gears for more scavenge capacity.

His feed pump is a gerotor design as opposed to the vane style stock pump.

He said:

"Is the issue when engine sits over nite or how long time does it take until oil comes out of the breather.
Seems like the check valve is not sealing properly. When sitting for month it's OK , but if it happens in short time it's not acceptable.
You can return the pump and I'll check it up and return it to you with the problem fixed.
Not uncommon on stock pumps also.
Sorry for the inconvenience .

Best Regards Carl "


Thinking I'll get either a stock type 4 vane pump, or a bone stock 2 vane pump and try one of them. Maybe I'll buy both to experiment with both. And I'll send this gerotor pump back to him to check out and see what gives there.

[montuckymatt]

I've been very happy with mine. I purchased a setup from the guy who designed them originally. He is no longer in business. I do know that you really need to make sure you are using the correct thickness of gasket for your feed pump. The repop ones are usually too thick. I also think that I read somewhere that the repop 4 vanes that copy the original design are too tall and need to be modified to work properly. Some searches should clarify this.

These are dependable motors but I do think the extra mods help with today's traffic/speeds. I put 600 miles on mine in one day 85+degrees and average speeds of 65-73mph. A loose gas tank bolt was all that happened...my buddy on his evo chopper was impressed at the dependability.

I am more than happy to help out where I can. Especially when it comes to talking bigtwin flatties! Let's do that beer in person sometime. Cheers!

[CDeeZ]

Let's do that beer in person sometime. Cheers!

Sounds good to me. Thanks Matt.


__________________________



I have a stock feed pump on it's way to me. Like I mentioned, I had to sacrifice the one I had. I bought a new repop stock style 2 vane feed pump, should be here in maybe a week or so.

[CDeeZ]

The new stock feed pump showed up today. I'll see what it does. In the meantime. Anyone know if this is a strong enough return flow of oil??? You can really see how bad it pukes also.

https://www.youtube.com/watch?v=1cQR2qfuePU