Author Topic: Engine Breathers (Read 3089 times)

Greg H · « **on:** July 12, 2014, 12:30:14 pm »

Hi all . I've just spent a little time welding a larger diam breather tube onto my "K" oil tank to match the larger diam gearbox breather on my "F1 crankcases. My question is , am I doing the right thing utilising the stock engine breathing system, bearing in mind that I'm building a large displacement race motor . Cheers .

bear · « **Reply #1 on:** July 12, 2014, 08:37:16 pm »

Without a doubt.
A large displacement SOHC race motor needs all the crankcase ventilation it can get.

Cheers,
Brian

scottly · « **Reply #2 on:** July 12, 2014, 08:53:00 pm »

Guys, the spigot on the back of the gearbox is more of a drain for the oil/air separator in the oil tank than a breather. The main crankcase breather is the one on the cam-cover. The early K oil tanks had their own vent, separate from the drain, which the F and late K tanks lacked.

Greg H · « **Reply #3 on:** July 13, 2014, 12:38:51 am »

Thanks guys

. I'm sure that I've read on here somewhere that the rear crankcase breather/drain is more about supplying lube to the chain than anything else , am I right ? .If that's the case I may plug the new larger tube on the tank and just have the crankcase breathing to atmosphere along with the breather off the cam box and have both going to a common catch tank . .

bear · « **Reply #4 on:** July 13, 2014, 02:47:07 am »

Quote from: scottly on July 12, 2014, 08:53:00 pm

Guys, the spigot on the back of the gearbox is more of a drain for the oil/air separator in the oil tank than a breather.

Not on mine Scott.
The spigot is no longer connected to the oil tank. It has been enlarged and feeds into a catch tank, along with another two we have welded in.
Our oil tank breather also feeds into the catch tank.

Cheers,
Brian

dragracer · « **Reply #5 on:** July 13, 2014, 08:16:14 am »

If you aren't using an onboard starter, you can also vent the crankcase by puting a plugs with a hose barb in the starter hole and run it to a catch can. In my cases, I disassembled an old starter and used the head piece since it already the right size. I went to the local hardware store for a hose barb that was threaded about the same diameter as the opening where the starter shaft fit, then simply threaded it in. I siliconed the plug in place, connected the proper size hose with a clamp with the other end to a catch can and you're done. Made on big difference for me to lower crankcase pressure that was causing oil leaks on my 1030cc drag race motor.

Greg H · « **Reply #6 on:** July 13, 2014, 10:58:41 am »

Quote from: dragracer on July 13, 2014, 08:16:14 am

If you aren't using an onboard starter, you can also vent the crankcase by puting a plugs with a hose barb in the starter hole and run it to a catch can. In my cases, I disassembled an old starter and used the head piece since it already the right size. I went to the local hardware store for a hose barb that was threaded about the same diameter as the opening where the starter shaft fit, then simply threaded it in. I siliconed the plug in place, connected the proper size hose with a clamp with the other end to a catch can and you're done. Made on big difference for me to lower crankcase pressure that was causing oil leaks on my 1030cc drag race motor.

Thanks for that mate .I intend using a remote starter so your mod sounds good to me

.

bear · « **Reply #7 on:** July 13, 2014, 06:50:32 pm »

Like Frank we have one welded into the starter hole, also have one welded into the top of the clutch cover.
These as well as the valve cover, crank case and oil tank breathers hook into a manifold that feeds into a catch tank.
.
I have attached the only pic I could scrounge, it shows the breather on the clutch cover.

Cheers,
Brian

Sorry the pics not real flash but it's the only one I could find.

Greg H · « **Reply #8 on:** July 14, 2014, 12:03:21 am »

Thanks for the pic Brian . Your set up sounds good to me mate

.And also thank you to you to Frank for your input, I know you two have a stack of" real world " experience between you . Cheers Greg "H"

seanbarney41 · « **Reply #9 on:** July 14, 2014, 03:17:43 am »

I have often wondered how much breathing (or lack thereof) contributes to oil leaks on even stock sohc's. What can be done to ensure good crank case breathing?

POPS 911 · « **Reply #10 on:** July 14, 2014, 05:05:50 pm »

SIMPLE FIX : Vacuum pump to valve cover vent like PRO-STOCK motors, that first sound you hear on those motors when they flip the ON switch are the one or two vacuum pumps running, then turn the motor over a few seconds, then flip the ignition switch ON = AIM-HANG ON . You can got to a auto junk yard and get a 12Volt EPA required vacuum pump off a GM car like the 90's-2000 Camero [ HAVE ONE IN MY HAND NOW ] or buy one from V+H or STAR RACING $200 or more. Shaft seals have to be reversed and silicone in place = some do and some don't.

Greg H · « **Reply #11 on:** July 15, 2014, 12:36:10 am »

That would work . If I wasn't building a accurate copy of an early seventies bike ,and was building an up to date as possible all out sohc drag motor ( which for me would only make financial sense if I had a business to promote) a vacuum pump would be fitted

. So it's going to have to be an old skool fix for my build .

Jim F · « **Reply #12 on:** July 15, 2014, 08:56:28 am »

I added a couple of more threw my tappet caps
but don't have any routing back to the oil tank
my 2 cents worth

Jim

Greg H · « **Reply #13 on:** July 16, 2014, 03:21:16 am »

Quote from: Jim F on July 15, 2014, 08:56:28 am

I added a couple of more threw my tappet caps
but don't have any routing back to the oil tank
my 2 cents worth

Jim

Another good idea

. I suppose that it doesn't matter where they terminate , as long as it isn't on your footpegs or worse still your back tyre

.

MRieck · « **Reply #14 on:** July 16, 2014, 05:47:43 am »

I'll post a pic of my extra breather.

Jim F · « **Reply #15 on:** July 16, 2014, 08:41:33 am »

I thought I had some close ups but I dont
I drill and reamed a hole then welded the tube in place for the tappet
caps for #2 and 3
routed everything back behind the tail section

bear · « **Reply #16 on:** July 16, 2014, 06:28:34 pm »

Nice settup Jim.
Wish my attention to detail was up to your standards.

Looks like you use a clutch cover breather as well.

Cheers,
Brian

MRieck · « **Reply #17 on:** July 16, 2014, 06:49:30 pm »

Quote from: bear on July 16, 2014, 06:28:34 pm

Nice settup Jim.
Wish my attention to detail was up to your standards.
Looks like you use a clutch cover breather as well.

Cheers,
Brian

I think that is his oil return from the turbo Brian. I...however...have an extra breather that looks like that return line. I been busy....I'll get a pic on here tomorrow.

Jim F · « **Reply #18 on:** July 17, 2014, 08:04:02 am »

I should have noted that you can just see the clear tube that is routed out of the #3
cap
yes that is the return line from the turbo

Jim

kmb69 · « **Reply #19 on:** July 18, 2014, 08:47:42 pm »

Quote from: MRieck on July 16, 2014, 06:49:30 pm

I think that is his oil return from the turbo Brian. I...however...have an extra breather that looks like that return line. I been busy....I'll get a pic on here tomorrow.

Hey Bro, would that "tomorrow" be the second Tuesday of next week?

Pics or it didn't happen!

$:-\$

MRieck · « **Reply #20 on:** July 19, 2014, 09:53:13 am »

Wise a$$

MRieck · « **Reply #21 on:** July 19, 2014, 09:54:10 am »

I included some pics of my latest project. What a boat anchor!

Jerry Rxman Griffin aka MuthaF'er · « **Reply #22 on:** July 19, 2014, 11:03:45 am »

Sonofa#$%*, thats one mean ass primary chain! I'd hate to pay the price to have a 6 cylinder head done to your standards! Now you gotta tell us about the CB(X).

Why at the clutch?

POPS 911 · « **Reply #23 on:** July 19, 2014, 01:28:03 pm »

GREG H : Like the hundred of dragsters I see weekly with the hose from the valve covers going into each header pipe on their exhaust with one way out valve [ like the PVC VALVE ] in older cars the exhaust pulls out the pressure in the motor thru the valve covers. I made a set up like that for my 400cc HONDAMATIC drag bike and put the hose line in to the pipe on a 2 into one header with a PVC valve in line as a cheap vacuum system.

MRieck · « **Reply #24 on:** July 20, 2014, 11:11:42 am »

Quote from: Jerry Rxman Griffin aka MuthaF'er on July 19, 2014, 11:03:45 am

Sonofa#$%*, thats one mean ass primary chain! I'd hate to pay the price to have a 6 cylinder head done to your standards! Now you gotta tell us about the CB(X).

Why at the clutch?

Convenience plus I could run a -6 line Jerry.

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Author Topic: Engine Breathers (Read 3089 times)