Lots of blowby

[ijames]

Don, I think you need to complicate it even further . Keep the breathers on the valve covers but add a check valve so air can only flow into the motor, not out. Put the vacuum pump suction down low. Off boost you get airflow into the valve covers and down into the motor which will sweep all the volatile vapors along with it and out the vacuum pump. On boost the blowby starts to pressurize the block and the check valve closes so there is no more flow path for the blowby upward to fight against the oil trying to drain downwards. Yes, for the duration of the boost you aren't efficiently keeping water out of the oil, but all the rest of the time you are which should keep it clean.

 

[Alky V6]

I went with Dykes style rings on mine , this was recommended by JE for my application and I have nothing but good things to say about them. Mike

Thanks. I've heard that ring model name thrown around before. I'll give them a try on the next PMing.

Will the Dykes fit in a typical piston ring groove, or is the groove special for a Dykes?

 

[Alky V6]

I was TOLD these were not real good for a high heat app.
Something about heat getting caught between them causing them
to actually bend up and or down.
Using a total seal on the second ring was ok in his opinion.
Being that your on meth, i am not sure your cylinder temps and
weather this could be an issue or not

I can see that happening with the thinness of gapless ring package. Especially since I'm running a metric size.

 

[Alky V6]

Don, I think you need to complicate it even further . Keep the breathers on the valve covers but add a check valve so air can only flow into the motor, not out. Put the vacuum pump suction down low. Off boost you get airflow into the valve covers and down into the motor which will sweep all the volatile vapors along with it and out the vacuum pump. On boost the blowby starts to pressurize the block and the check valve closes so there is no more flow path for the blowby upward to fight against the oil trying to drain downwards. Yes, for the duration of the boost you aren't efficiently keeping water out of the oil, but all the rest of the time you are which should keep it clean.

I like the idea, and I agree with you about the amount of contamination not being a big deal 'during' the run, but I don't like the idea of blocking off any escape of excessive pressure that is building up. Obviously, the vacuum pump and the drysump pump alone are not enough to keep up with the amount of blowby I'm presently seeing. The cam plug blew out at one time, and presently the lifter valley plate is bowing off the end sealing surfaces at the block. If I were to block off the breathers with one-way valves, I would just end up chewing up the crank seals with all the pressure they would be seeing with no relief at all possible until a gasket blew out.

 

[BlownV6]

Thanks. I've heard that ring model name thrown around before. I'll give them a try on the next PMing.

Will the Dykes fit in a typical piston ring groove, or is the groove special for a Dykes?

My pistons have a special grove in them specifically for a dykes ring. Not sure what might be available for your setup. I would most defenetly steer away from any type of low tension ring set up because with no vacuum you will see ring flutter and loss of seal. Mike

 

[Alky V6]

My pistons have a special grove in them specifically for a dykes ring. Not sure what might be available for your setup. I would most defenetly steer away from any type of low tension ring set up because with no vacuum you will see ring flutter and loss of seal. Mike

That is exactly what I picture is happening.

 

[Alky V6]

I did some looking back at some pictures of the engine and found that the TA block has one relatively small hole leading from the timing chain area to the lifter valley. Blowby pressure that is building below has to travel to the timing chain area, and then through that small hole to the lifter valley, and then up through the drain back and pushrod holes in the heads to get to the breathers and vacuum pump. So, even with monster breathers on the valve covers, it may not do real well with the restriction to flow leading to the lifter valley. The additional breather at the timing cover is looking very attractive.

 

[BlownV6]

I like the idea, and I agree with you about the amount of contamination not being a big deal 'during' the run, but I don't like the idea of blocking off any escape of excessive pressure that is building up. Obviously, the vacuum pump and the drysump pump alone are not enough to keep up with the amount of blowby I'm presently seeing. The cam plug blew out at one time, and presently the lifter valley plate is bowing off the end sealing surfaces at the block. If I were to block off the breathers with one-way valves, I would just end up chewing up the crank seals with all the pressure they would be seeing with no relief at all possible until a gasket blew out.

My guess is that the rear cam plug came out from expansion of block and oil pressure pushing on it from rear bearing. I really cant see crankcase pressure ever getting high enough to push that out without something else giving first.

On your drysump scavange at the rear of the lifter valley , do you have a screen at the opening?? I learned years ago that is a bad idea because it really restricts the oil and air will form a tornado back there and oil will stop being sucked into the fitting. It will just suck air. Mike

 

[Alky V6]

My guess is that the rear cam plug came out from expansion of block and oil pressure pushing on it from rear bearing. I really cant see crankcase pressure ever getting high enough to push that out without something else giving first.

On your drysump scavange at the rear of the lifter valley , do you have a screen at the opening?? I learned years ago that is a bad idea because it really restricts the oil and air will form a tornado back there and oil will stop being sucked into the fitting. It will just suck air. Mike

No screen at the lifter scavenge opening, and the entry sits lower than the lifter valley floor.

There were other signs of excessive crankcase pressure before the cam plug blew out.
I used to run the type of front crank seal with the large self-centering lip. On one of the early runs after the last PMing the lip blew out to where it was facing forward. Pressure is the only explanation for that. That's when I modified the timing cover to include a removeable front seal retainer that I designed to keep the seal from being able to move rearward or forward. It incorporates a short lip seal.

 

[BlownV6]

No screen at the lifter scavenge opening, and the entry sits lower than the lifter valley floor.

There were other signs of excessive crankcase pressure before the cam plug blew out.
I used to run the type of front crank seal with the large self-centering lip. On one of the early runs after the last PMing the lip blew out to where it was facing forward. Pressure is the only explanation for that. That's when I modified the timing cover to include a removeable front seal retainer that I designed to keep the seal from being able to move rearward or forward. It incorporates a short lip seal.

Wow thats hard to imagine!! I have vacuum on my racepac and for a couple of years it would read say -2 or so. After having constant small oil leaks here and there I could not understand how it could leak and have vacuum. After sending part of the analog equipment back to update the fuel pressure to a higher rating I asked them to check the vacuum sensor. Turned out it was fine!! -2 meant it had positive pressure , so that told me that a 4-stage drysump pump wasnt going to keep up with the boost I was running at the time so I installed the #16 breather hoses and a large catch can. That turned out to be one of my better moves!! Mike

 

[ijames]

Ok, move your breathers from the valve covers to the intake valley pan, then do the checkvalve/timing cover thingy .

 

[Alky V6]

Ok, move your breathers from the valve covers to the intake valley pan, then do the checkvalve/timing cover thingy .

There won't be a checkvalve in the timing cover thingy. Just open to a vent tank.
That's another good idea. But, instead of moving the breathers from the valve covers, leave those where they are and just add more breathers to the intake valley cover.

Breathers all over the friggin place. :biggrin: What the heck. Can't hurt.

WHOA!!! The TA block has a passage at the back of the lifter valley that can be used as a drysump scavenge pickup. I'm not using that passage, and I have it pipe plugged. It now has a new use? It pickups higher off the valley floor than the passage that I setup for scavenging.

 

[turbobitt]

There won't be a checkvalve in the timing cover thingy. Just open to a vent tank.
That's another good idea. But, instead of moving the breathers from the valve covers, leave those where they are and just add more breathers to the intake valley cover.

Breathers all over the friggin place. :biggrin: What the heck. Can't hurt.

WHOA!!! The TA block has a passage at the back of the lifter valley that can be used as a drysump scavenge pickup. I'm not using that passage, and I have it pipe plugged. It now has a new use? It pickups higher off the valley floor than the passage that I setup for scavenging.

Don,

I'm no expert on vacuum pumps but I need to ask this question,
If the blowby is overtaking the pump, then why run one ? Is it worth the expense ? It would seem that from a performance standpoint, the crankcase pressure it eliminating any performance benifit from the pump.
Are you running the pump for oil contamination reasons ?

Allan G.

 

[Alky V6]

Don,

I'm no expert on vacuum pumps but I need to ask this question,
If the blowby is overtaking the pump, then why run one ? Is it worth the expense ? It would seem that from a performance standpoint, the crankcase pressure it eliminating any performance benifit from the pump.
Are you running the pump for oil contamination reasons ?

Allan G.

During simple running of the engine, the vacuum pump forces crankcase ventilation. That's the only reason I'm running it. Before putting the pump on the engine, oil contamination was happening very quickly and I'd need to change the oil after 4 to 5 passes. After installing the vacuum pump and some other engine operation techniques I've employed, I can go for mulitiple meets before changing the oil. In fact, when I change the oil, it still looks good enough to keep using. I just change it because.

 

[Alky V6]

Hmmm. Turbo Bitt made me think here. If I only need a pump to provide crankcase ventilation, I could use a simple electric one, and free up the accessory space to install a mechanical fuel pump. I'm maxing out the electric fuel pump I'm using now.
Dang! Thanks, Turbo Bitt. You've just helped me solve a long standing problem I've been facing.

 

[BlownV6]

Hmmm. Turbo Bitt made me think here. If I only need a pump to provide crankcase ventilation, I could use a simple electric one, and free up the accessory space to install a mechanical fuel pump. I'm maxing out the electric fuel pump I'm using now.
Dang! Thanks, Turbo Bitt. You've just helped me solve a long standing problem I've been facing.

Don , I have an Lti vacuum pump that I did some work on so that it moves a lot of air and will still pull 3" of vacuum. Id be happy to send it to you to try out if intrested. Mike

 

[Alky V6]

Heck, I'm game. Let me know how much. You can send it to the shop.

 

[BlownV6]

Heck, I'm game. Let me know how much. You can send it to the shop.

PM me the address and I will send it to you. Mike

 

[Hot Air]

Donnie,
I watched some of your video's the other night. Did I see smoke rolling out the engine on one run? Maybe you hurt something!
Conrad

ps...not sure when the video's were made....may be old!

 

[Alky V6]

Donnie,
I watched some of your video's the other night. Did I see smoke rolling out the engine on one run? Maybe you hurt something!
Conrad

ps...not sure when the video's were made....may be old!

That's the latest video you saw with the puff of oil out the exhaust at the end of the run.
That's the subject of this thread. Oil is pushing past the rings due to over-pressurization of the crankcase. This recently became a big problem with the latest step up in power.
You'll notice at the end of the video the oil smoke quickly goes away before I turn off the track. The smoke only shows up at the end of the run.