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Das Beast: My E30 track / street build

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  • dvallis
    replied


    Not too late. Just gotta do it all again. : - )

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  • ForcedFirebird
    replied
    Too late now, but could have run the clay over the squish band to measure piston to head clearance while at it :/

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  • dvallis
    replied
    Timing Is Everything

    Finally got down to business building the bottom end, now that all the prep work is done. Today we're checking valve clearance.

    All the parts ready to go. Black timing belt has one extra tooth. We had issues with belt tension so I bought it to try.



    All parts get generously coated with assembly lube..



    This ring compression tool is SO much better than "juice can with giant clamp". Highly recommended.



    Add rod cap and light torque. Repeat six times.



    Add 1/16" clay worms to valve pockets, set bottom end timing so piston 1 is at top, install old head studs and spare gasket



    Torque down head. 25 ft-lbs on all bolts per ARP pattern, then 50. This is only for clearance so no need to go to 75 ft-lbs



    Install all the running gear on the front of the block. Careful not to jack the seals or lose the tiny springs inside them.



    Before timing belt install.



    Timing belt installed easily. Tension is perfect.. I'm sure the previous issue was our 0.120" head gasket had the head separated from the block by just a bit too much. Caused huge tension issues. This build uses custom JE pistons machined for a stock 0.070" head gasket but with 10:1 CR and much deeper valve pockets. We're running a 284/272 cam and apparently the pockets can handle an even bigger one.



    Moment of truth. Turn the crank clockwise 4 times, back to TDC. Remove flywheel, covers, timing belt and head.

    All of our 1/16" worms were undisturbed. So we've got at least .0625" clearance in all valve pockets. Success!!

    Do I want to add more clay and see exactly HOW much clearance? No, it's enough and I didn't want to stress the valves with a bunch of clay.



    Called it a day and planned for the next session. I need a couple of random gaskets.

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  • McGyver
    replied
    Nice printed tool!

    I made a similar thing using scrap plastic on a lathe at work. I'm stoked to try it out some day

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  • dvallis
    replied
    Heliwhat?

    Did some prep on the bottom end. Block threads for the oil pan bolts got a good cleaning out (gunk removal) and checked with an m6x1 tap. Two of the damn holes in those aluminum bearing carriers front and back were wonky. Par for the course on M20s I suspose.

    Bolts in photo are just to keep dirt out. M6x25 are too long and will bottom out. We've got a new set of M6x20 on the way. Will give max thread with our crank scraper plus oil pan stack.



    Decided to helicoil them both



    Drill out the hole. Screw in helicoil. Knock out the tang & extract from hole. Both hold torque now.


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  • Elysian
    replied
    Love the 3d printed ring tool.

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  • dvallis
    replied
    Lord Of the Rings

    Feeler gauges organized. I hate dicking around with all of them on a key ring.



    Insert ring



    Seat with handy ring tool



    Check the gap



    Grind, just a bit. Drill turns toward INSIDE of ring



    Measure again. Repeat until within spec. We used 0.022" for the 2nd ring per Total Seal.



    Ring set installed on piston. Tops are "gapless" which is really two rings with big gaps, but they overlap and interlock. 2nd ring seated correctly with notch inside and down. Bottom is a 3 ring sandwich.



    Ubiquitous blue tape holds clocked rings in place.



    Repeat 6 times. Done.




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  • Digitalwave
    replied
    Keep 'em coming!

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  • dvallis
    replied
    Original piston assembly weight 256.4g



    New piston assembly weight 200.7g. Looks like we're saving about 0.75 lb on the rotating mass.



    Rod bearing shells are the right size. Unlike the 1st build :-)



    We dorked around forever installing the first set of rod pin clips. You know the drill: sore thumbs, clips flying across the room, crawling around the floor looking for lost clips. So, we made a tool that does it in 10 seconds.

    Get a thin wall tube about 0.85" in diameter
    Cut it off about 4" long
    Get a solid plunger that fits inside the tube
    Insert ring in tube a shown



    Insert wrist pin temporarily. It gives the clip a surface to push against.



    Put tube perpendicular to piston with gap up



    Insert plunger. Press down with smooth firm motion. Ring will click when it seats



    Voila



    Slightly remove pin. Insert rod. Repeat on opposite side.



    More next time
    Last edited by dvallis; 04-25-2021, 03:33 PM.

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  • dvallis
    replied
    Started on the rebuild today.

    Did a light de-glaze on the bores


    Started installing the rings. Oil ring was good out of the box with 0.0015" clearance.



    2nd ring needs 0.0022" per total seal specs.


    After checking online we realized ring gapping tools come in three varieties: cheap junk, over priced and unavailable. We built our own. Made the platform large enough to support the entire ring, decent thickness aluminum for rigidity with a clamp point underneath for the vice. Variable speed AC drill finishes it off. Looking forward to trying it next time.


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  • dvallis
    replied
    Glad to have helped. Rob and I frankly knew nothing about M20 engines when this whole adventure started, so it's been fun sharing the learning along the way. We have a "Wall Of Shame" for all the funny screw-ups: Bent valves, upside down rings, "plastic shard of doom" that lunched the first turbo. Will have some more good details with this next bottom end re-assembly.

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  • halesyeah
    replied
    Hey amazing build thread. Been following it the last few years in awe. I want to thank you for documenting the process so thoroughly, especially all the mistakes. I'm putting together a 2.9L stroker and got the bottom end together a few weeks ago. Put the oil pan on and then remembered your whole oil ring fiasco. I of course couldn't remember if I checked my 2nd rings to see if they were directional. Nothing in the documentation about it. So reluctantly I pulled the oil pan and scraper and 2 gaskets and checked the pistons one by one. Sure enough #5 and #6 rings were upside down. And they are clearly marked TOP on the rings. So thanks for saving me from trying to diagnose a smoking engine by putting all the good and bad in this thread.

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  • ForcedFirebird
    replied
    It's not the lawn mowing I am concerned about with the oil pan, debris is also a culprit. Besides "two off" is a legal pass, even in TT. :p

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  • moatilliatta
    replied
    I would take. Flat edge to the gasket surface to confirm flat before bolting it up. I do this even if a baffle is welded and most get hit on a big belt sander.

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  • dvallis
    replied
    We kept about the same depth, just scaled out. Wanted to keep the same flow dynamics around the oil pump pickup. I'm sure Hans has some engineering into it.

    We refer to Hans a lot in the garage. Usually "F@#$ HANS! You HAD to put that bolt THERE?"

    If it gets to needing a skid plate, Crew Chief's reply is "Stay on the track, idiot."

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