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Old 07-02-2009, 08:57 AM
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GregWeld GregWeld is offline
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@ NotNew

This is what I said earlier in this thread... that there must be something else going on here... to have that much 'blow by' to lift the dipstick!

I'd be doing a leak down test on that motor before I did another thing to it...

I've run some pretty potent motors in my day - big and small blocks - and NEVER had that kind of crankcase pressure...

My 427 cubic inch small block will load up the filling in the breather and eventually drip a drop or two of oil on the valve cover... but we're talking about a motor with NO vacuum (8 stack EFI) and NO PCV. I have now (just yesterday as a matter of fact) run a catch can plumbed to a fitting in the fuel pump block off plate... so hopefully that will take the bottom end pulses and keep the breather from loading up with oil fumes. The problem with having no piston / skirt - and a real tight ring pack... I think the compression height of the pistons are 1.100 so there's just not much there to control 'oil'. BUT even at 7000 rpm's -- I've never blown oil out a gasket or lifted the dipstick!!
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Old 07-03-2009, 12:56 AM
BritishGreen68 BritishGreen68 is offline
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Originally Posted by GregWeld View Post
@ NotNew

This is what I said earlier in this thread... that there must be something else going on here... to have that much 'blow by' to lift the dipstick!

I'd be doing a leak down test on that motor before I did another thing to it...

I've run some pretty potent motors in my day - big and small blocks - and NEVER had that kind of crankcase pressure...

My 427 cubic inch small block will load up the filling in the breather and eventually drip a drop or two of oil on the valve cover... but we're talking about a motor with NO vacuum (8 stack EFI) and NO PCV. I have now (just yesterday as a matter of fact) run a catch can plumbed to a fitting in the fuel pump block off plate... so hopefully that will take the bottom end pulses and keep the breather from loading up with oil fumes. The problem with having no piston / skirt - and a real tight ring pack... I think the compression height of the pistons are 1.100 so there's just not much there to control 'oil'. BUT even at 7000 rpm's -- I've never blown oil out a gasket or lifted the dipstick!!
Damn you must run like 8 egr valves on that thing?!?!? lol J/K.. i'm building my 408 small block right now and it has very short piston skirts and i have been planning some sort of breather setup for it because i know it will need a good one.. I like the fuel pump block off to a catch can idea, never thought of that. I run an electric fuel pump too..
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Old 07-03-2009, 08:52 AM
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GregWeld GregWeld is offline
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Originally Posted by NotNew View Post
Damn you must run like 8 egr valves on that thing?!?!? lol J/K.. i'm building my 408 small block right now and it has very short piston skirts and i have been planning some sort of breather setup for it because i know it will need a good one.. I like the fuel pump block off to a catch can idea, never thought of that. I run an electric fuel pump too..


@NotNew

YES!! I do run multiple EGR valves -- but they're not what you think they're for!! I run them just to use up the excess vacuum... since they're "just a valve" and they really don't do what they say they do... and frankly, I like really hot exhaust temps and making lots and lots of pollution.

Okay - seriously - I will de-stroke the 427 the next rebuild... and will use a hypereutectic piston rather than the forged. I know that on this website that would be "insane", but this is just in a street rod... and the oil control could use some improvement... and the sloppy pistons at cold start bug the hell out of me.

PS -- In the close up of the catch can - the 90* fitting on the line isn't done correctly - but used it just for mockup. The fitting stripped before I could get the POS to mate up... so had to take it off and polish up another one for final assembly. I just didn't want anyone thinking that I did that kind of work!! LOL I also oiled the breather after final assembly too! So let's not start a whole new thread about that... please.
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Last edited by GregWeld; 07-03-2009 at 09:08 AM. Reason: explanation
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Old 07-03-2009, 08:59 AM
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@ NotNew

Forgot:

I tapped the block off plate with a 3/8" NPT tap - and got a 3/8" to -10 AN straight fitting... then used a -10 swivel 90 off that... I had to convert the Moroso can from a straight O ringed -12 to a straight O ringed 12 to -10 AN

I already had the -10 hose and 90's... and the hole for the pushrod in the block is only about 3/8's so I used that size to go by for the blow by (clever huh?). The -12 stuff is so big... and I couldn't see using that when the largest hole in the system for air (crankcase yuk) would be restricted by the dia of the pushrod hole. So far this seems to work really well.
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