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Learning how to build Lotus Seven replicas...together!
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PostPosted: January 30, 2019, 5:45 pm 
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Location: meadview arizona
back to the front cover and the crankshaft pulley seal.

well all the measuring and research that i did was for nothing. the dam thing leaks like a sieve !!!!!

so back to the drawing board, this is what i discovered, first when did ready sleeves start getting smaller and smaller, the ready sleeve i fitted was only 3/8" wide but the pulley has a boss on it that measures .812" so you had better get the ready sleeve in the right spot and as the ready sleeve has a flange on the outside edge that should not touch the front of the seal and the seal lip is .3" from the front of the seal that leaves you .075 to play with but when you fit the pulley through the seal the lip moves back further about .010" so now the target is.065 wide where the lip fits round the ready sleeve, now bearing in mind that you don't want the lip to be near the edge of the ready sleeve then you had better be right in the middle, a 1/32" to deep with the sleeve and you will set the lip on the step between the sleeve dia. and the pulley dia. or too shallow with the sleeve and you risk the flange wearing the front of the seal,

now the original mahle seal has a special lip which lays flat on the pulley, i guess its an attempt to not wear a groove in the pulley, the problem with that seal is it is not a tight fit in the timing cover which is why i choose to go with the duralast seal which is made of metal,

the problem with that seal as i found to my dismay is that i doesn't seal, this may have been due to the measurements i took to locate the sleeve was with the mahle seal and the lip is off the sleeve when using these measurement for the duralast seal.

solution, fit the duralast seal and then fit the mahle seal in front of it so the duralst seal stops the mahle seal falling inside when you put the pulley in the hole, now i have the mahle seal lip on the sleeve and the duralast lip on the pulley boss.

bummer i had to take the whole thing apart because of this, i'm glad i keyed the crank and pulley though because none of my timing has changed, now all i have to do is clean all the oil from the front of the engine bay and put it back together.

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PostPosted: February 4, 2019, 7:50 pm 
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Location: meadview arizona
i am now convinced that my sealing problem is due to blow by
.
so i have decided to fit a pump, ac delco 215425 and a heater control valve to switch from PCV circuit to a powered suction circuit controlled with a vacuum solenoid and a vacuum switch.

the idea is that when cruising or at idle when there is vacuum signal in the manifold the system will be passive and work through the original PCV sealed system, where air is drawn into the valve cover, pass through the engine and be sucked out through the PCV valve into the manifold before the supercharger, via the heater valve energized by the powered up solenoid from the vacuum switch

when the vacuum drops to a predetermined level under load, the pressure switch will deactivate the solenoid closed and vented which will allow the heater control valve to swap ports and at the same time power up the air pump, drawing crank case pressure out.

when the throttle is then closed it will revert to PCV operation

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PostPosted: February 4, 2019, 10:25 pm 
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Joined: April 17, 2009, 1:28 am
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Location: San Tan Valley, Arizona
John,
Why not just put the PCV suction side back where it was when it was the replacement for the road draft tube?
Waltj


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PostPosted: February 5, 2019, 1:43 pm 
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Hi Walt,

as it is now is how the PCV system was as from the factory, but from the factory it didn't have to cope with boost.

this engine is modern by which i mean it is a "low tension" engine meaning the rings have low tension, due to this it requires crank case vacuum to prevent excessive blow by.

in the N/A state it almost never sees 0 vacuum even at wide open throttle, if it did the engine would stop, so the ring seal is maintained, however in a boosted situation i am likely to have the blow by overcome any vacuum present at which point crank case pressure due to blow by becomes a real problem with oil blowing out of any and every point and the front seal is the first to go.

if i do not remove this pressure the ring seal is compromised causing more blow by.

i could run a vacuum pump all the time and disable the PCV system but from information gained over the past week it appears that these suction pumps do not like to run continuously so you must find a way to give it a break so to speak so with this system it can revert to the passive PCV factory system when there is vacuum present.

when you have no vacuum on the manifold side of a PCV valve and pressure on the crank case side the valve will be forced open and gasses from the crank case will pass through, a large part of these gases is combustion and is unmetered by the MAF so your delicate A/F ratio is now too rich, yes rich not lean as there is very little 02 in the blow by gases and the MAF is still delivering a fuel load to the PCM equivalent to air the supercharger is demanding when boost is present.

this brings us to what the supercharger is actually delivering which may be air with a percentage of crank case gases so you are now trying to set an A/F ratio when you don't know what the air mass is as it is not just air but by what percentage is open to speculation.

this can give false 02 readings for the fuel map and the spark map from your wide band sensor.

all in all you must have a negative crank case pressure at all times to limit oil leaks, blow by and intake air dilution.

it should be said that too much crank case vacuum will limit the oiling of wrist pins which is of no concequence in a short run time race engine but critical in a street engine.

at least i think that is what is happening now with just the PCV system, if you have more to add i would appreciate your comments as i am only guessing.

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PostPosted: February 9, 2019, 1:05 pm 
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i have a question that i can't answer.

i need to install a drain line for the catch can to return its contents to the pan or at least the lower crank case on the exhaust side of the engine.

so what i want to know is where to drill a hole in the block that doesn't hit water and is thick enough to tap to 1/4 npt?

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PostPosted: February 9, 2019, 3:18 pm 
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John,

Can you feed the drain into the dipstick hole? Make the drain removable, same as the dipstick, so that you can swap between dipstick and drain depending on need.

Bill

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PostPosted: February 9, 2019, 4:11 pm 
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Hard to picture with none, but I'd likely put a AN6 or 8 male flare bulkhead fitting it in the side of the pan with a 45-90 full flow fitting for pushloc hose. The shoulder would go on the inside, sealing washer on the outside. Trim off the excess flare and thread on the inside for clearance.

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PostPosted: February 9, 2019, 6:22 pm 
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on examination, there is an unused engine mounting boss on the exhaust side of the block just above the dip stick, i tapped it to 1/8 npt then screwed in a straight fitting and drilled down the inside into the crank case, removed the fitting and replaced it with a 1/8 npt x 1/4 barb 90* elbow.

i will now fit a 3/8 x 1/4 barb fitting into the catch can.

the same vacuum pull is on this fitting as is on the one from the valve cover so when there is vacuum in the catch can a vac signal will be pulled on this line but it is smaller than the 3/4 line from the valve cover and is below the oil separator.

when no vacuum is present, then it should drain the contents of the catch can into the pan.

should i have a problem with the hose leaking, i now have the ability to change over to an 1/8 npt x -6 or -8i have mounted the vacuum pump in the nose of the car.

i have ordered a different valve cover with the 3/4" vent pipe at the rear of the passenger side as opposed to on the top at the front, it is also bigger than the "make up" air pipe which was 5/16".

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PostPosted: February 24, 2019, 7:18 pm 
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as well as fixing the front crank oil seal i also have oil leaking from the bell housing.

i have pulled the engine again and found that the rear main seal is not leaking from the seal itself but along the bottom where it connects to the pan.

when i built the motor on an engine stand there was not enough room to install the rear seal between the block and the engine stand using the seal installer so i went ahead and installed the pan, that was a mistake as i now have a leak.

i installed the seal after the engine was off the stand and hanging on the crane, i did run a bead of silicon along the pan prior to installing the seal and thought it would be o.k.

when i removed the timing cover to do the front seal i noted that the permatex silicon was not dry and now i have removed the rear seal i noted that the silicon was not adhered to the seal plate at all, i did clean the whole area with cleaner prior to installing the seal and the seal itself.

after studying the seal and the pan i saw that the area at the seam was extremely narrow and the bonded on rubber seal was not making contact with the pan rail,.

there is nothing clamping the seal to the pan !!! and although the seal was in the right place and the dowels on the seal were located on the block this provided no clamping to the pan and relied on the silicon bead to seal the joint, however as described with the timing cover the silicon was suspect with regards to curing.

a strip of gasket paper was cut and placed across the exposed section of the pan coated in silicon i then coated the lower edge of the seal plate with silicon and installed with the tool supplied with the seal.

i noted that the dowels were out of line so i clamped the seal plate to the pan rail which pulled them into line, installing the bolts.

i believe the gasket paper will fill any gap that the silicon did not, i will leave to dry for as long as it takes.

a note about bad design practices here, the rear of the block is machined to install the seal and the back face of the pan is machined to align with the back of the block, if the poor engineering had been better then the end of the pan rail would have been machined at the same time as the end of the pan to match the bell housing, this would have provided a flat face for the seal plate to attach in one plane instead of two and the seal plate sealing lip could have continued completely round the periphery of the seal plate and not relied on luck and a blob of silicon to keep the oil in, trying to seal a joint in two planes is almost impossible especially when there is no clamping force applied in one plane.

i could have removed the pan prior to installing the seal but then what do i do at the front, take off the timing cover?

if i had done something similar when i was a design draughtsman , i would have been repremanded for it and told to re think it.

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PostPosted: March 26, 2019, 2:11 am 
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so its all back together with no oil leaks and positive crank case vacuum at all engine speeds and loads.

the A/F is 14.8 for idle and cruising, when in boost its 11.8.

now i am working on the spark map slowly adding in advance a bit at a time especially at mid range.

and its going faster and faster to the point that its hard to make the 1-2 shift quick enough without hitting the rev limiter if i go full throttle.

when cruising, i have about 10 Hg of vacuum in the inlet.

the motor still feels a little fat but that's a good thing when adding in advance.

the cruise is where most of the work is needed as i need some economy because i live in the middle of nowhere.

slowly slowly catchy monkey as it were.

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PostPosted: March 26, 2019, 12:02 pm 
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I ran into a similar problem with the rear seal. The Chinese seal that came with the rebuild kit from the machine shop leaked as you describe. I replaced it with a German seal, Mahle, I believe and have had no further problems. It was slightly more generous with the rubber along the sump side.


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