1Revvin7

Any pictures of this setup?



And when should one consider this setup?



And on a side note, usually don't the front stationary gears/front rotor bearings/teeth mess up before their rear counter parts?

scathcart

Pfft! You call that a crack? Just this week I had someone bring me their engine... endplate was cracked completely in half, with the crack running parrallel to the spark plugs, and about halfway between the coolant seal groove and the stationary gear; basically the entire combustion chamber split wide open, and several tension bolts snapped. I was able to take the iron off in two pieces. The entire rear half of the engine is toast. I don't even want to think about the combustion pressures that will split an endplate....



But, with every downfall comes a new beginning. We will be trying a new port, and using some stonger irons.

GMON

How much boost are you running? What A:F are you running? How much HP are you running? What timing are you running? Every time I ask a good tuner about S4 plates and cracks they tell me to tune it properly and there will be no need till you get well over 500hp. Were you running the Microtech when this cracked?



GregW

BDC

I heard this same thing from some Puerto Rican amigos. They sited something about the heighth of the oil and it also being in the housings pulling in some heat vs. using a line outside (oil temperature). I was thinking about removing that plug from the front oil gallery going to the stationary gear and running a pair of oil lines from the RB oil pressure/temp adaptor to there and to the turbocharger.



The cracking of the rear is caused either by extreme combustion pressures leading to housing deflection (doubtful) or from pressure generated by severe knock (more likely). Main reasons Mr Hanover has already explained (although I blame it on pump gas and lack of trigger accuracy if the leading or trailing timing is set too aggressively).



B

Lynn E. Hanover

I will be happy to take pics of the whole mess. It will take a day or so to get it together.



This is a must for extended periods of operation above 9,000 RPM. The thinking is that the upper gallery is through the dowel tubes and they are threaded thus making for a poor oiling path for the front main.



The rear main is about 7 inches from high pressure oil, while the front is maybe three times as far away. I did run above 9,000 for years without this mod, but I was not making much power, and was not stressing the bearings to any great extent. Actually never lost one, and that with a stock oil pump.



This change came to me on a pro built engine, and it is an obvious good idea. It is easy to do if the engine is apart and if it just saves your butt just one time, it is worth the effort. We have an external three section Peterson pump, and with racing bearings and 90 PSI hot, we are processing a bunch of oil.



The picture is the Peterson pump, mounted low on the drivers side of the engine. The two lines are scavenge from the front cover fittings.



About the gear meshing first??? I have no idea what it is you are after there. If you can rephrase that I will try.



Lynn E. Hanover

scathcart

It wasn't my car, but the engine was a 4 port bridgeport running a carb and distributor, on dual stage nitrous. Retard was controlled by MSD units.

Jeff20B

So you're saying it would be a good idea on a 20B due to its greater length?

BigTurbo74

after i read this thread an looking at an oil flow diagram i saw that recognized that plug and eariler had wondered what it was for. did mazda ever use that plug for an extra oil outlet at anytime, why do they even have it there if they didn't?



on the other topic, so the real problem with the oil flow to the front bearing isn't necessarily the heat but the pressure correct? so in theory would an upgraded oil pump and non-threaded dowel pins remedy this or just put more pressure where it's not necessarily needed? why do they thread those dowel pins anyway? easier removal? last point, let's add some hard numbers to these setups so we know what kind of modifications should be considered at what power levels and rpms.

j9fd3s

that plug is there because they have to drill that passage and theres reall no other way to do it.



as to the rest of it, there is a difference between lynn's 9000rpm roadrace motor vs say a drag motor. lynns motor will see full load and full rpm for hours at a time, where a drag or street motor sees full load and rpm for seconds, theres a large difference there

...

damm i don't have the housing here to take pic

but What I was told is the side of front housing by the spark plugs has a indentation

where it would be drilled and tapped for a oil line....



never seen it done in person

but was told it works good