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    Entries by Dr. Jeff Harper (34)

    Reassembly - At Last!

    After four months waiting for ARP head studs and Cometic head gaskets to arrive in Bangkok, the motor is finally going back together.

    A photo from yesterday taken by my engine guy, Art, at Voodoo Racing in Pattaya. It's coming back together! The cams still need degreeing, and other details . . . but it is getting close.

    One Day Soon!

    Will race again one day soon . . . with the supercharged V-8.

    Timing Is Everything

    Yes, timing is everything . . . good and bad.  My Cometic 1.5mm (.060) head gaskets finally arrived, but in the meantime I also ordered a set of "standard" cylinder head STUDS, that will take two more weeks to get here.  Why standard size?  Well, I listened here, and to other places and people, about the unusability and unreliable torque readings of reusing the standard head BOLTS, the bottom end is already assembled and in the car and I do not want to disassemble it for the machining, and I am not going for 1000hp.  "Just" 450hp with the blower and an occasional addition 100hp with the dry NOS for big event qualifying.  The good multi-layer Cometic gasket plus the head studs should do the job. I am fully aware of the development path for the "ultimate" 1UZ, so I do not need advice for that kind of project.  I do not want to build a 1000hp 1UZ and then run it at 450hp. I race in a particular drag racing class that does not require me to evolve ever greater amounts of power to be competitive, but rather tune for consistency and predictability run after run. But about that timing:  I leave for a two-week winter photographic expedition to the remote parts of the South Island of New Zealand this Sunday.  Bad timing.

    This is how the right and left side Cometic head gasket arrived.

    Looks good through the bubble wrap.  These gaskets along with the standard head studs and 60 ft.lbs. of torque should work fine with my combination.

     

     

    Some Progress: Heads Back From Machine Shop

    My race 1.3mm Cometic head gaskets have not arrived yet.  It has been three weeks coming from The States . . . . .  However, the cylinder heads are back from the machine shop after having the "humps" removed from the cylinder head chambers.  This is the right way to lower compression on these 1UZ motors . . .  as well as eliminate a source of detonation.  The pent roof design, and some remaining squish around the cylinder, still allows good turbulence for fuel and air mixture.

    The workmanship on the machining is "pretty good" -- which is as good as I can get them in Thailand.  I went the extra mile and had them sanded and polished, in case I want to race on E85 some day (with it's low tolerance for pre-ignition). The valve seats will need to be redone.

    The very good Aeromotive A1000 fuel pump arrived at last, along with thse very scarce -10 fittings

    Chasing Issues

    For the last month I have been chasing issues related to the race 1UZ not idling below 3000 rpm.  "There MUST be an air leak" has been our guiding principle.  But . . . after taking off the entire intake track and checking EVERY place air could possibly be entering the engine we determined there was NO Fricking Way there could be air getting in.  Please do not suggest otherwise.  Yes, the throttle body is completely closed.  I said everywhere!

    We looked everywhere.  Nothing.  We came up with all kids of good sealing solutions.  Still a too-fast idle.

    Special aluminum washers were made to hold and seal the Subaru injectors in place and were checked on the running engine with soapy water, listened to with a tube, and every other means of detecting a leak.  No leak here.  So . . . .  what's up.  Our new working theory, based on the experience of several other racers here, is that the camshafts were not manufactured  with the indexing correct.  In other words, too much overlap is allowing the engine to pump air up into the intake manifold which in turn allows just enough air to run the motor.  It can happen, and has happened to a friend of mine here.  Kelford, I am sure, makes every effort to do good work, but they also assume that engines are put together by race engine builders who check the cams, index the cams, and dial in the cams.  We did not: we took them out of the box and installed them using the "locator pins and marks" that should have been right.  So now we mic the cams.