Mopar Muscle Association UK

Blue wrote: Tue Mar 24, 26 5:56 pm Love a bit of cadboard…

You would not if you were left Handed, those Scissors can really bite!!!

I used to sell left handed scissors.

No, really, I actually did.

I've got a pair of those, I don't find them any easier. Electric scissors are the answer.

Finally got the new pan section folded, I made one last week only to realise I had folded it all the wrong way round, hey ho onwards…

I’ll make the infill panels but won’t cut any of the original pan off until I’ve modified the pick up.

Crank scraper, these are hand made to order by Ishihara & Johnson. The mounting holes are deliberately small and each requires hand filing so the scraper halves sit tightly in one position before you start clearancing. Next you clearance the metal frame to the rotating assembly before fitting the teflon strips and then doing the same with those to achieve 40 thou clearance. You need patience, its not a 5 minute job…

Not much in the way of oiling mods needed below 6500 rpm, but I want some spare capacity so….
Melling high volume pump, stripped and checked. Outlet opened up to 1/2” and gasket matched to the cap. One of the main studs always interferes with the pump seating flat on the cap and has to be checked. Previous owner has machined a bit off the stud and nut so just a casting rib to grind down on the pump and all is well.

Rear cap ported to match the oil pump, took some time smoothing out the sharp edges left downstream from the factory drilling. Linished the mounting surface flat as it’s recommended you don’t use a gasket to seal.

Started shaping the teflon for the crank scraper. You can run it a little tighter than the recommended 40 thou as it will wear in during running, any minute amounts of teflon debris will do no harm and come out with the oil change.

seemingly you can also port the inside of the pump
as the inlet window between impeller and ring closes
the outlet window to the block should open
some pumps have a situation where both are closed together for a period of time and the impeller and ring are trying to compress incompressible oil

if oil was compressible this would be a benefit as the oil would "Burst" into the outlet as it expanded
but it doesn't compress unless its all foamy, and hence there ain't no expansion

so all that is achieved is repeated shock loading of the pump drive and impeller shaft, vibration and harmonics in the pump drive, distributor drive and cam.

close inlet window, use a scribe to mark pump body, back plane, on the outlet side and see how far it has to turn before outlet opens. in theory the rotating parts are symmetrical so what impacts 1 position is the same in all.
how much does the ring lobe intrude into the oil space before it opens?
would the pump benefit from a small shave to the leading edge of the outlet to reduce the both closed time period?

Is it worth checking? i have no idea. the race focused hemi 6 guys do.
Hemi 6 oil pumps crack their mounting lugs off and fall into the sump if over stressed...
crazy australians? or onto something? Hard to tell.
the argument for doing so, seems to make sense, but is it a thing?
same pump internals/design, different body/mounts and longer shaft

any oil flow benefits or minor reduction in parasitic losses probable negated by a smidge more windage to deal with, reduced stress and vibration seems to be the driver

Dave

This isn’t something I’d thought or heard of Dave but I’ll certainly have a look at it.

guessing it comes down to how well the body casting was machined
or perhaps a mismatch between old casting a new internals which would be the case for a hemi 6
you would hope that melling et al would get it right
i don't think you'd want both open at the same time although the pump would probably still work
but in theory both closed for a couple of degrees is just forcing some oil down the shaft space and across the cover. its trying to lift the lid off the pump...or driving the gears into the body or lid as it looks for an escape route
maybe thats why you find the odd pump with an truely worn cover that needs to be ground flat again...

some pumps have a tiny groove in the back face to facilitate oiling of the impeller shaft some don't
maybe that is what drives differences.

hard to establish if its something worth doing. is it deliberately built like that to force some down the shaft? potentially not necessary, oil is going everywhere anyway... the pump interior is pressurized regardless, you see it at the gauge, has to be to pump

as you were doing pump work just came back to mind...

dave

I now have the correct depth pick up so I’m back on with pan construction. I’ve clearly been hanging around with Hot rodders too long because I’ve suddenly moved the goalposts and sold the 408 rotating assembly and decided to stroke it out to 426…
With that in mind I’ve been stripping the block and measuring in preparation for getting it machined and found someone’s idea of a ready to go bore, scratched and no crosshatch at all. The block is already at 0.030 over and Today I’ve found out I can get 0.040 pistons so unfortunately its going to end up at 428 ci…

it's a good job you decided more is better or you wouldn't have found out about that bore until it was in the car and smoking.
neil.

I would have found it anyway. I never fit a bought engine without stripping it first and you always find something that needs addressing. It’s not just one bore they are all like it, who puts an engine together like that?