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Papay

Is this a 4K or 5K head?

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Listed as .2 for intake and .3 for exhaust (cold).  I got them set yesterday with no trouble.  I used a little bit different method to compress the lifters:  since getting all 8 pushrods located on the rocker ball was a bit tricky, I dialed out the clearance before the rocker stands were fully seated, and before the head was fully torqued.  My logic was to let the head bolts do the work.  Then I went around one by one and backed them off to the proper clearance.  My recollection of previous hydro engines though, is that there was zero lash adjustment.  Then again, that was an Oldsmobile. 

In the pics you can see #1 with the exhaust valve compressed.  Rocker geometry seems fine to me, but I'd like to get extra eyes on this.  In the other pic you can see my pistons, which were not the dished type I was expecting.  I cleaned most of the gunk off and ran a wire wheel through the top of the bores just checking for cracks and ridges.   Didn't find any.  Block seems to be in good shape, I gotta say Toyota impresses me (this being my first one). 

IMG_2147.jpg

IMG_2146.jpg

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Yeah, that looks fine to me.  You should be driving it around for Christmas!

They look like flat-top pistons, the dish in a typical 5K is deeper-

https://www.rollaclub.com/board/topic/73806-5k-head-identification/page/2/

That's why you have an inserted combustion chamber, as those dished pistons are the combustion chamber and the head for them is basically flat.

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Def interesting how Toyota seems to have provided different combinations in different markets.  These pistons have a slight concavity, so I wouldn't call them flat per-se.  But as you say, seems to be designed to work with the dished head.  Now other 5k's in the AU/NZ market seem to have been build with dished pistons and a flat top head I guess.  

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Drove to the exhaust shop this morning with an open exhaust.  Had tried unsuccessfully to get a downpipe made before the dual plane exhaust manifold was installed, but they had to use a good bit of guess work, resulting in the pipe pointing out to the side about 30 degrees haha.  The chop jobs done here on exhausts are frightening to look at, so this particular setup is just temporary.  Now I'm onto drawing up a flange to get it laser cut in stainless.  Gonna order the proper sized stainless pipe sections and maybe weld it up myself for better results. 

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Mission accomplished!  Engine is butter smooth, all the chuffing is gone, along with the random surges and hiccups.  Quiet, powerful, wow I'm stoked!  

Huge thanks for the words of advice and recommendations. 

 

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We have taken a few trips that were 2-3 hours duration, and the van has been flawless.  Plenty of passing power, and incredibly smooth pull at low RPM in 3rd or even 4th. Now I'm excited to move ahead with the dual electric fans and hopefully ditch the clutch fan.  Combined with the future exhaust system I have in mind, I'm looking forward to actually being able to hear the engine instead of the fan.  

Today I re-torqued all the critical bolts, the manifolds had all loosened a bit.  Reset the rocker clearance, which had all tightened a bit, wasn't expecting that.  Plugs look really good except for #4 had oil on it (which has been ever since I've owned the van).  Have enjoyed the cooler running temps, and have not added a drop of water after the initial run-in fill.  I'm going to cleanse the system now and go back to coolant, and reinstall the thermostat.  Before the new head, it was losing so much water there was no point wasting money on coolant, and the thermostat would get too much scale to function properly.

Incidentally, the VLT ceramic paint is holding up really nicely on the manifolds.  First time I have used the stuff.  Wife wasn't thrilled about baking parts in the oven, think I may need to get my own oven in the shop....

 

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Electric fans are great!  The lack of noise is very noticeable.  We always just use one, never a problem, although all the cars have the new alloy radiators in.

The rockers tighten up as the valves settle in, and the manifold bolts often need a little wind-up after running for a bit. All sounds good!

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