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RWyatt's "It's takin forever" Build Thread

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RWyatt's "It's takin forever" Build Thread

 
Old 08-14-2018, 05:58 PM
  #541  
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Good for what material of piston? don't Wiseco expand more than Supertech?
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Old 08-16-2018, 05:50 PM
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I have some slap in the morning, but my car burns zero oil and runs great. It is important to follow the piston manufacturer recommendations for wall clearance and ring gap. Not the ring manufacturer or mazda recommended specs.
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Old 08-16-2018, 05:51 PM
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I should probably add, for your specific pistons.
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Old 08-16-2018, 06:14 PM
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EDIT: sorry I'm reading this from a plane, below is not relevant if you've already checked. Carry on



Right. The Supertech instruction spec'd tighter clearances than the wiseco pistons I first used (which subsequently failed at ringland anyways knocking out my efr6258 back in 2014.) the coefficient of thermal expansion was different for the differing alloys used.

If he switched from Supertech to wiseco, he might need to mind those clearances. Grabbing numbers from my butt but if I recall anything Supertech recommends something on the order of 0.0028" where wiseco wants up to 0.004" or possibly more. Those pistons might expand in the bores more than the Supertech and would make for some amazing noises and pictures later.
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Old 08-17-2018, 06:25 AM
  #545  
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(Trying to) put this to rest...the original ST's were installed loose - looser than recommended. The machine shop that the block went to for that was less than desirable (as in, during the 2 month stay at the shop, the owner went out of town, let my block sit idle for 3 weeks, then jobbed the work out to a second shop where it sat for almost a month before I tracked him down and located my block). In the meantime, the specs got lost in the shuffle and the block got bored out to a "best guess". I ran it like that because I would have had to have the block bored to 40-over and order a whole new piston set - I didn't have that kind of coin at the time. I didn't have any piston slap with the ST's and didn't burn oil - so I left it...for 5 years.

Now, with the Wiseco's, they measured between .0035 and .0038 PWC after honing, Wiseco says .0035 is the right number so I trust that number. Now, if .004 or more is the right number, then...as psyber says, it might make for some amazing sounds and noises later.

Anyway...I spent the week (after work) doing some work on the head. Cleaning it, inspecting for damage on the valves and seats (and found some nicks in the dome of the combustion chambers of #3 & 4 where the damaged pistons were, and no marks on the valve seats or valve faces. That seemed VERY odd - I expected major carnage there - with bits of piston slapping around in the chamber...pero nada. So I cleaned out the carbon and the head's going back together tonight.

If all goes well, the engine will be back in the car by Sunday and we'll see how long before this one blows!
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Old 08-17-2018, 09:50 AM
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I used .035" on my Wiseco pistons and get no audible piston slap on cold start. I ran Wisecos for 8 years prior and piston slap didnt start until a couple years later when they started wearing a little bit.; Thats not the first time Ive seen someone post about broken supertech pistons in that same spot, I think the wiseco piston is just better and its stronger too.
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Old 08-21-2018, 10:50 AM
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Originally Posted by andyfloyd View Post
I used .035" on my Wiseco pistons and get no audible piston slap on cold start. I ran Wisecos for 8 years prior and piston slap didnt start until a couple years later when they started wearing a little bit.; Thats not the first time Ive seen someone post about broken supertech pistons in that same spot, I think the wiseco piston is just better and its stronger too.
Yeah, I thought that ST's were good - I hadn't hear anything like this either.

Anyway, the engin is 80% assembles;


I've got some AN hoses to re-do and a few things to tidy up. The new clutch plate went in, and the trans went back on last night. I plan to have the engine back in the car this Saturday.
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Old 12-28-2018, 09:45 AM
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It's been a long time since my last post so just to bring everything up to date;
- The engine went together well. Started up nicely and there was no discernible piston slap (so...put that question to rest in my mind).
- Break-in was un-eventful so I settled in to tweaking my tune for the new setup. All of the "likely suspects" got adjusted (VE, spark map, minor ASE and WUE tweaks, idle settings, etc...).

Then I had a semi-minor wiring catastrophe (foolishly was re-wiring a pair of 12v DC to USB supplies that were powering an in-dash tablet and a phone charger port with the battery still connected - touched the wrong wires together on an un-fused circuit...and the rest is history!). I released LOTS of "Magic Smoke", and torched my ancient Nexus 7 tablet (RIP "Old Faithful"). So I decided to use that as an opportunity to take out the dash and re-wire the whole kit-and-kaboodle, as well as make some "strategic modifications".

Up till then I had some severe heat-management issues behind the tablet install (which took up the space where the old radio/tape player was). It would get so hot in that small space that the battery in the tablet would stop charging (I even had to replace the original battery in the tablet). I resorted to putting some CPU fans inside the space behind the tablet to vent the hot air out. The fans were controlled by a digital switch connected to a temperature sensor that turned on the fans when the temp exceeded 95F - which it did quite often in the summer. It worked...just barely - because the fans weren't ducted and weren't properly oriented to exhaust the hot air properly.

With the dash out, I was able to re-think my heat problems and decided to put the fans inside the main duct to the eyeball vents in the dash and put in some additional air management from the exit of that duct, to the back of the tablet. That way, when the fan turns on, the heat is pulled from the tablet and into the duct and eventually gets vented into the cabin!
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Old 12-28-2018, 10:02 AM
  #549  
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Besides all of that HVAC work, I also have been dealing with a "smoking issue".

With the rebuild of the engine, I changed the size of the turbo oil-feed line from -3AN, to -4AN. At the time, I didn't think that made any difference...boy, was I wrong! Every morning, after a cold-soak, the car would smoke like a 60's-era ad executive. After things warmed up, everything was good. Obviously, I was over-oiling the bearing in my Churbo. So, I tried the "punched-out pop rivet in the oil feed fitting" trick. That helped, but not enough. So I purchased a fancy-schmancy oil feed fitting with replaceable jets (from Vibrant), and used the smallest jet size. That didn't work either. I think that the root-cause was that the bearing is so sloppy that it would leak when cold and would only seal when it got hot from thermal expansion.

What I needed was a way to stop the oil flow to the turbo when it was still hot prior to shutdown and then re-start the flow after the turbo heated up a bit.So I decided to go semi-low tech and put a solenoid in the turbo oil feed line, connected to a switch in the cabin. I also added an oil pressure switch to the outlet side of the solenoid so that I would know if the solenoid failed and there was no oil going to the turbo (it's a N/C solenoid). The output from the pressure switch goes to a LED that's right in my face so if the solenoid fails (or I forget to switch it on), I'll know.

Could I have reverted to a -3AN line? Yes, but I don't think the problem was with the bleed line, or the restrictions.I think the problem is in the el-cheapo turbo. So far, it all works like a champ - my car has become a non-smoker (and I'm so proud)!

My next challenge? Dealing with EAE!!
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