5kT perf. engine rebuild

[Todd Phenneger]

Ameer,

  I'll do my best to help out here. I just put a KH into a 4kq so I'm fairly familiar with it and the MC.  Read below.



  Ameer Antar <ameer at snet.net> wrote: 
So, my engine finally blew up. It was actually the hose to the heater 
valve, not the valve itself that broke. The engine overheated and when I 
poured water into the tank, I heard a scary thud from the engine. The next 
day, I looked into the hole and it was flooded w/ water. So is it likely 
the head is cracked, or could it be a blown gasket? Should I get a new head 
or can cracks be fixed?  You cant really answer this untill you pull the head.  It could of just warped the head causing gasket to leak or you could of cracked it.  Either way though, just remember that an overheated engine is VERY hot.  ANd hot metal doesn't like suddenly getting cold water dumped on it.  So next time (as I'm sure youve now realized) its best to wait 1/2 hour and then add the water. :-)
Compression tests showed the rings were in OK shape. Should I overbore? If 
so, I was told by Rod at TPC that oversize pistons can only be ordered 
through the dealer. In that case, it'll be cheaper to have them custom 
made. You can get forged ones for $120 a piston. Forged pistons would be 
nice anyway as I'd like to warm up the engine a little more. My KH engine 
has a few limitations in it b/c of the control system. The ECU is not 
programmable, so I'm stuck w/ it, unless I convert the whole engine bay 
over to '86-'88 5kT design. This means, my boost is limited to .4 bar, 
unless I use an aquarium valve, which I don't wanna do. I'd like to 
actually increase the compression a little, which would affect the 
performance throughout all ranges, not just at top end using higher boost. 
I have a ratio of 8.3:1 right now. How much could I get just from skimming 
the head? I could have the pistons machined w/ a smaller dish. Would a 
ratio of 8.6:1 be reasonably safe? Since my ECU can't be programmed, I was 
thinking of just retarding timing a few degrees. Can I do this just by 
turning the dist.? Please recommend any other good mods, that will warm 
things up a little. Thanks for the tips...
 First, I'd say that your PROBABLY  ok with the pistons in there.  BUt check the gaps and make sure.  If it needs it then replace them.  BUt if not I"d leave it alond and concentrate on the upper 1/2 of the engine.  WHen you get the head re-built, or replaced, port and polish it and have the 40mm valves installed.  This will free up breathing and help turbo lag.  THen as you said you can skim it a bit to raise compression.  On my KH I did this and it raised it to about 8.8:1.    FYI thats the same as the Euro version of the KH.     Now, as for ECU's, you can fairly easily add a Mac-10/11 to the car.  THere are only a couple wires that are different.  If memory serves a few have to be swapped and thats it.  THen you can get custom code written for your car.  Otherwise to retard timing you'd need an ur-q flywheel or have the Hall Pin on yours moved.  Read    RB PITA (unless you pulling tranny anyhow but I think the newer ECU is a better option)  BUT, to get more boost out of your engine, its fairly easy to do so if you dont mind bypassing the safegaurds.  (Donning Firesuit now).  I did this in the 4ktq but of course you HAVE to watch the boost gauge and it is a little risky but many have done this with no problems.  BUt as some will say, all it takes is once. :-)  So, my recomendations.  Rebuild and modify head, get a good Exhaust for the car (free breathing with free flow Cat) raise compression a tiny bit if you really want, and add the Mac-10/11 ECU with custom code.   OH, and get a Cam for it to help that engine breath at higher RPM.   My KH dies at about 5,800.   I want it to pull to 6,500. :-)l8r 

Todd Phenneger
    83' ur-q (awaiting a 20vt)
    84' 4ktq  fun but I'm sick of CIS.


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