Use top or bottom breather- or both - on TP 107 motor?

[LA_Dog]

Hello all and Happy New Year. Quick question hoping someone can give me a solid answer with reasoning behind it-

My motor is a 2001 TP 107, with TP case, TP jugs, Edelbrock heads and SS rocker boxes / SS rocker covers. Has a Jims breather gear. Rockers have umbrella valves. The entire motor in regards to case bolt pattern and camchest offset is patterned exactly after S&S V series motors. Same engine gasket set etc etc.

Up until I tore the motor apart for a rebuild, it has been breathing both from the crankcase and from the heads.

> crankcase vents to below motor using braided line- no checkvalves or anything.
> front head vents to rear head banjo bolt via crossover line, rear head banjo bolt vents to below motor with braided line. no checkvalves or anything.

Should I be using both the crank and head breathers? Should I block the head breathers and only use the crank breather? Or vice versa?

I'm not able to find a solid answer in ref to this type of Evo motor- so if anyone knows I'd love to get the scoop. I'd also like to understand the logic / reason for the answer.

 

[Oscar Maldonado]

If you are breathing from the case, you do not need a head breather. You can run it to the ground, but I also installed a small filter on it.

anyone else???

 

[LA_Dog]

Thanks Oscar- I'm also looking for tech facts on this. I don't have filters on mine, if their main purpose is to vent crank pressure outward seems to me the filter would just soak up with oil.

 

[LA_Dog]

This is a response that I got from TP Engineering on the subject- wanted to share. Anyone else have insight on top only vs bottom only vs both?

@TP Engineering: If you are looking to clean up the appearance of the motor and want to eliminate breather lines, then keep the breathers at the heads and block off the crankcase breather. Although, if I recall your motor has S&S rocker boxes which use a "reed" for the breather, by using only the head breathers they can become taxed and will start to lose their ability to form a tight seal when closed. You should not have any check valves, the breathers are there so the motor can regulate pressure. Sounds like it should be a strong runner, let us know-thanks

And I asked the specific question in ref to my motor, what would happen if I blocked the head breathers and only used the crank case breather, here is TP's response:

@TP Engineering: you will have the least issues(leaking gaskets, excessive oil out of breather lines) if you keep your current configuration and maintain using both breathers, eliminating one will increase workload of other. By utilizing both you will have the least issues. If you want to eliminate one the only one you should consider blocking off would be the crankcase breather. Blocking off the head breather will cause excessive pressure in the heads which will lead to leaky rocker gaskets or a possible blown head gasket.

 

[RRRUFF]

I believe the more you can let it breathe the less problem you will have with leaks. I am currently venting both the crank case and from the head/valve rocker box.

 

[Blaster]

For what it is worth, everything I have read would make me want to use both. The more air that goes through your motor the faster you go. The more it breaths the better.

 

[Th3InfamousI]

Reed valve was not standard on our dogs. It was the standard Breather Gear, the Reed valve is an upgrade and sometimes done if someone drops in a new cam.

Not sure why you would want to block one? Let the engine breath as it was intended.

 

[RCAdd1ct]

I would rather have extra capacity and use both breathers than block one and have uncontrolled oil vapor.

 

[FrankBDPS]

Those of you that are using the head breathers are you running them to the air cleaner,to a puke can or something else?

 

[john sachs]

I always recommend using both. I've found several horsepower on the dyno using both.
I do use a pcv valve, or a S&S black and white one way valve in the crankcase breather.
John

 

[LA_Dog]

so I thought I'd revive this thread- i have a lot of oil puking out head breather when riding. no sumping or oil on startup. i have both case and head breather and no oil out of case breather. i even put a pcv valve on the case breather / no help. after a 12 mile ride i get about a 1/2 cup of oil. after a 50 mile ride it was about 2 cups. i am using a redbull can as a catch can.

i have 230 miles on motor, new SS HVHP oil pump, oil pressure when hot at idle is 20lbs and revving it pins up to 60lbs. i do see oil return in the tank, but not sure if it is enough.

 

[FrankBDPS]

I was sorry to read about your continued issues. I was wondering what kind if oil you are using. I thought I read someplace where Mobile was supposed to mist less than some if the others. That's a lot of oil to be pushing out. If it where going thru the carb could you imagine the smoke screen. I hope you get this straightened out. The bike looks killer.

Mine is still on the lift table. Waiting for tripple tree parts to be finished. Weather is shitty here any how. Going to be a short riding season and the fact that I am going back to work Monday and working six day a week sucks too.

 

[LA_Dog]

Frank- I was initially running cheapo 20-50 from AutoZone. I expected some foaming but this is way more than that. I just switched to Valvoline 20-50 4-stroke motorcycle oil (Dino), which has a lot of anti-foaming agents. I'll see if it makes any diff. But I suspect that there is simply more oil going into the rockers than can drain out fast enough. I have read where sometimes engine harmonics at certain RPM can actually impede the gravity flow of oil through return lines. Also the oil pressures on gauge seem suspect being so high. Also the breather gear could be set sub-optimally since it is only puking when running and even more when I get on it.

I'm going to swap in an S&S breather reed valve to see if it makes any diff on the oil carryover - I need to take a peek in the cam chest anyway to see if everything is good.

Hope you get your bike wrapped up and on the road soon- I totally know how it is to want to ride but not be able to cuz bike is down... ;p

 

[Th3InfamousI]

so I thought I'd revive this thread- i have a lot of oil puking out head breather when riding. no sumping or oil on startup. i have both case and head breather and no oil out of case breather. i even put a pcv valve on the case breather / no help. after a 12 mile ride i get about a 1/2 cup of oil. after a 50 mile ride it was about 2 cups. i am using a redbull can as a catch can.

i have 230 miles on motor, new SS HVHP oil pump, oil pressure when hot at idle is 20lbs and revving it pins up to 60lbs. i do see oil return in the tank, but not sure if it is enough.

12miles -1/2 cup of oil. WOW

At normal operating temp you should be around 10-15lbs at idle. 20 is a tad high....but 60lbs is WAY too much at normal operating temp, hell my oil gauge would be pinned at 60. You should be around max 30. Hold bike at 3k RPM what does it read? Note you really have to be warm - so at minimium 10 min at idle. I would wait until your oil reaches operating temp around 180-200 before reading the pressure.

Is your gauge in the tappet screen hole?

You can try the reed valve but I'm wondering if something is wrong with your new oil pump...

 

[LA_Dog]

thx- I'll be out running an errand so I'll get 'er good and hot and get an exact reading @3k. Gauge is in the normal location, not in tappet screen hole 'cause I just checked the tappet screen at this last oil change.

 

[francoblay1]

12miles -1/2 cup of oil. WOW

At normal operating temp you should be around 10-15lbs at idle. 20 is a tad high....but 60lbs is WAY too much at normal operating temp, hell my oil gauge would be pinned at 60. You should be around max 30. Hold bike at 3k RPM what does it read? Note you really have to be warm - so at minimium 10 min at idle. I would wait until your oil reaches operating temp around 180-200 before reading the pressure.

Is your gauge in the tappet screen hole?

You can try the reed valve but I'm wondering if something is wrong with your new oil pump...

Good point there about the location of the gauge.... I did change mine from the tappet screen hole to the oil switch sensor hole and I am getting HIGHER readings!!! 5-10 psi higher!


Either way...... it is puking too much oil.... so the gauge´s location in this case I think it´s irrelevant! I would have a "serious chat" with the Builder!!!

 

[LA_Dog]

Yeh I just ordered a new gauge that comes with the correct adapter for the tappet hole. Now I need to find a block off plug for the oil sender hole- anyone know what size that is?

I just spoke with two senior builders at S&S. They said that I will have much higher pressure with that pump but it does sound a bit high. I also talked with TP Engineering and they said the pressure sounds a tad high but not much different than their new smart pumps, which put out about 19lbs at idle hot.

S&S wanted me to check the oil pump pressure valve under outboard top screw of pump to make sure it has free travel and is closing properly- so I'm gonna do that now. And, they also told me it is perfectly fine to block off the head breathers since my motor does have an effective case breather. It will not build excess pressure in the rocker boxes and they advise it at times on even the new SSW+ motors, which are still designed as both top and bottom breathers. They went on further to say the only reason for the change to head breather / block case breather was for EPA and venting gasses back into the carb, not for any mechanical or performance reason. Early case breather evos could only vent out the case, but later evos can vent either way (or both). I pressed them a bit on this and they took the time to explain how the case, cam chest and top end are all pretty open to each other as far as internal air flow, and if there are any pressures no matter where they are in the motor it will expel through the case breather. There would be no effect on motor HP. They feel that the return holes in the rockers are probably not large enough to drain fast enough, and their newer SSW+ motors have enlarge drain holes. So I could enlarge them if needed.

Anyway not gonna try blocking the breathers yet, but so far that is one legit source that says it's ok to block the head breathers if a functional case breather is present.

 

[Th3InfamousI]

I just spoke with two senior builders at S&S. They said that I will have much higher pressure with that pump but it does sound a bit high. I also talked with TP Engineering and they said the pressure sounds a tad high but not much different than their new smart pumps, which put out about 19lbs at idle hot.

.

Cool - Glad someone's talking to you other than me and Franco, we are useless...haha

60lbs is seriously too much, TP seems to downplay it which is strange.

Blocking off the breathers seems like a stupid idea- you still got 60lbs if it's not going out the heads its going to go somewhere and it will just puke out the bottom...

I'm still leaning towards something wroing with the oil pump at this point...anyone with an 05+ is running the HVHP S&S pump and not approaching the same PSI readings so obviously we got a problem here. I would start with S&S recommendation -

I would also look at the check ball! I wonder if it is seated properly?

Here is a diagram this is from a Shovel but the design hasn't changed at all...

 

[LA_Dog]

Cool - Glad someone's talking to you other than me and Franco, we are useless...haha

60lbs is seriously too much, TP seems to downplay it which is strange.

Blocking off the breathers seems like a stupid idea- you still got 60lbs if it's not going out the heads its going to go somewhere and it will just puke out the bottom...

I'm still leaning towards faulty oil pump at this point...anyone with an 05+ is running the HVHP S&S pump and not approaching the same PSI readings so obviously we got a problem here. I would start with S&S recommendation - it's not a valve by the way it's just a ball it looks like a ball bearing.

LOL well you guy are awesome forum brothers so that counts for a lot :2thumbs:

S&S wants me to rule out a faulty gauge first before troubleshooting further and that sounds like a good idea. blocking the head breathers was not a suggested remedy for the high oil pressure, only for stopping any carryover out the breathers if the oil is not able to drain fast enough through the rockers, and there would be no negative consequences of doing so as long as the case breather remains open.

I just checked the relief valve- it is the outside top screw cover- it is a cylinder slider with a spring on top. the pressure pushes the slider up against the spring tension until it exposes a side port escape hole, and excess pressure is bled off. ERT Products makes a "pro-just" kit with an adjustable top cap so you can dial your pressure up or down. The checkball is the inboard hole but that is not for pressure relief AFAIK.

Anyway the slider looks fine no binding- but that is one damn stiff spring on top of it.

See #36 in the diagram below- that is the pressure relief valve slider

http://www.justanswer.com/uploads/HarleyTech/2008-11-30_214359_oil_pump.jpg

 

[LA_Dog]

ok quick update- just did a test idle to see how pressures are. I've got it reading more normal now. I took the spring out for the pressure relief (item #17 in photo) and worked the spring back and forth a few times to "break it in". I also squashed it about 1/8" shorter. Now the pressure reads 30 cold idle, hot it reads 17lbs idle and 42lbs revved up to 4k. Guess this allowed the relieve valve (#36) to open a bit more easily. Gonna go take it for a spin.