Dizzy blank/bung
Discussion
Is this what you mean ? http://www.megasquirt-v8.co.uk/images/3-5_efi/dink...
Pupp said:
I like the idea of using the dizzy port as an additional breather point - anyone know how much oil gets thrown up there (Spend?)
I dont think its a case of the oil splash, I put plenty of baffles in the design to prevent the splash. It's more the problem of if you allow the crankcase to pump it blasts out oily air continuously (wherever the breather is). On the other hand larger motors with wilder cams are creating massive vacuum compared to the original PCV (orifice / pipe size) which inherently creates far too much flow. Re-calibrating the PCV orifice sizes is very very tricky....Best I have come up with so far for racy high comp 5 litre is plenum to 5mm, trumpet base to 1mm, and inlet (piped from air filter) with 1mm solid orifice (thats as small as I could drill) then epoxied and an oily thin needle to form a @0.2mm restriction.... It seems essential that all 3 have to be balanced together, the ratio between the pre/butterfly & trumpet base being the fine control so that its venting not vaccing and the inlet orifice limiting the flow under low/closed throttle conditions.
It does appear to take quite a bit of testing to get the sizes right, and as soon as you get one wrong the inlet gets filled with oil... I keep thinking there should be a way of making a 3 way adjustable block that all can be piped through (I do like replacing the damned mushroom with a pipe stub connected to the air filter BTW).
OP I probably have a spare serp timing cover / brackets if you want to convert to crank driven oil pump (advised).
brett84 said:
Dave - what's involved in this? Will it make much difference?
Oil pump is crank driven, much stronger & better pressure...Need different brackets / pulleys / belt and a serp alternator.
Good news is parts like water pump, alts... are much more available than the saloon style pre-serp versions.
The million dollar question is what you did you do when balancing the 4.6???? just put the old pre-serp damper on?????
ETA: & of course you can just blank the dizzy hole
EETA: you lose a heater connection with the different water pump, but straightforward to tap and insert a hose tail in the serp water pump and run a hose the extra 6". I do that anyway in preference to having pipes crossing the exhaust to the swan neck on serps anyway.
Edited by spend on Thursday 10th April 10:45
Thank you
I've not long put a new alternator and belt on.
Haven't started working on the engine yet, all in place from the previous owner, it's all new and exciting, learning as I go along.
I think i'll leave it as is for now, after machining down the dizzy to fill the hole. Get it back on the road ASAP, enjoy some summer then get the body off later in the year and look at everything else I haven't done yet
I've not long put a new alternator and belt on.
Haven't started working on the engine yet, all in place from the previous owner, it's all new and exciting, learning as I go along.
I think i'll leave it as is for now, after machining down the dizzy to fill the hole. Get it back on the road ASAP, enjoy some summer then get the body off later in the year and look at everything else I haven't done yet
Gassing Station | Chimaera | Top of Page | What's New | My Stuff