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Got a big problem need help and thoughts

Old Apr 25, 2008 | 03:15 AM
  #1  
classiccarsrule85's Avatar
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Default Got a big problem need help and thoughts

Ok well my friend junk sunk a good amount of cash into a motor rebuild which included taking a head the stock 1993 civic dx motor due to a piston through the block and placing that head on a D15b8 bottom end...

I dont know the details of what went on in the process of building it he said he just changed all the gaskets as well as belts and said he made sure the timing was correct.

So here is the problem as far as I can tell from 3-4hrs of tinkering with it....

Symptoms
-Wont idle under 2k and it wont truely idle it is iratic in that is wont stay truley put on 2k but wont go past 3k in its spurt.

-When you move the rotor farther back it becomes a little better/ quieter....forward louder worse

-When you push the throttle it hesitates and will not rev at all sorta bogs then stays at 2k

-One of his friends tried moving it to show me it went past 2k since he did the work on it and well it sorta did then back fired loud.....

My thoughts on it
-Timings off first thing that came into my mind

-Vaccum leak?

-a bad Sensor somewhere....

Looking for some help on this matter id really like to help him out alot and any helpful hints to how i can solve this problem would be greatly appreciated.

P.s. one of my other friends has a stock dx motor with a blown head should he get that instead and just transfer all the new stuff over to that and buy another head gasket set..????
rahter than mess with this motor combo[/align]
He already put alot of time and money into this car to make it run and well its not going to well so i am unsure if he wants to pay to much more so please let me know what you guys think on this matter.
Thank you
John[/align]
 
Old Apr 25, 2008 | 06:12 AM
  #2  
mk378's Avatar
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Default RE: Got a big problem need help and thoughts

He's basically replaced the block, and the head and the rest of the car is still from the original 16 valve, right? That shouldn't affect anything I think all the 1500cc bottom ends are exactly the same.

Check the valve timing very carefully. Make sure you're using the right mark on the crank end. You use the little dot on the cam timing belt sprocket, not the keyway in the crankshaft. Also you can verify TDC by putting a rod into the #1 spark plug hole to feel the top of the piston. The spark timing must be set with a light. But the engine should run better than that over a wide range of spark timing. You need to warm up the engine and jumper the test connector to set the spark timing.

Make sure all 4 cylinders are firing. Spark plug wires in the wrong order for example. Or damaged valves.
 
Old Apr 25, 2008 | 08:58 AM
  #3  
mk378's Avatar
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Default RE: Got a big problem need help and thoughts

Thinking about it more, the little recesses in the top of the pistons to make room for the valves are going to be different for a 16 valve versus an 8 valve engine. That will be bad for your valves.
 
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