DIY Engine Rebuild - Part XIII (13) - It would be part 13 eh?
#21
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From: Vancouver, BC
Bang On!
Originally Posted by Brave Heart
180 degrees out
Bang on! (no pun intended). I mistakenly timing both cams perfectly but had a brain fart (a big one at that) and forgot that the right is 180 degrees from the left, e.e its on the opposite cycle of the crankshaft. Don't forget that the cams turn at half the speed of the crankshaft so every total turn of the crankshaft is 1/2 turn on the cams.
There is no problem with valves hitting pistons etc. since the cams are timed correctly for the wong side of the 4 cycle combustion cycle. It means for example that piston 4 spark plug is firing on the exhaust stroke and both piston 1 and 4 are in compression at the same time...which makes a very difficult obstacle for the starter to get over. Notice the sound of the starter...wooosh and then it grinds a halt, woosh/halt. The engine turns over nice and easy on one side since ALL the pistons are somewhere on the exhaust cycle but the next rotation of the crankshaft is a real bear...all the pistons are in some type of compression...
I do feel like an idiot posting this but I thought it would be good to show that problems do occur...
Stay posted for what happens next!
#25
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From: Vancouver, BC
Originally Posted by epj993
So how did you figure it out Mike? Review your pictures and docs? Wake up screaming?
1 - The engine was a bit lumpy when I turned it over on the stand, but i thought that was normal cam pressure.
2 - The engine was lumpy with the starer turning it over and the plugs in.
3 - The starter would turn the engine over just fine without the plugs in (no compression). I did this several times in order to circulate the oil and build up the oil pressure (2+bar!) before starting.
4 - The starter could barely turn the engine over only at specific spots of rotation (or so it appeared).
It problem looks obvous to me now and I am totally impressed how fast you guys solved the puzzle (faster than me...it took me about an hour) but with it beingt late a night and with lots of fatigue (my final summary post will deal with hours and costs) it was totally depressing at the time...
Cheers,
Mike
Last edited by Mike J; 04-02-2006 at 09:02 PM.
#26
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From: Vancouver, BC
Originally Posted by C4S_fan
I couldn't believe Mike figured it out... I think if I were him, I would have handled this a lot worse...
#28
A little late to the festivities, but I would have guessed compression as well. Your video sounded like our 4WD Kubota Diesel tractor years ago - yank on a decompression **** when it was severely cold outside in order to allow the starter to spin the engine easier.
Sorry for the delay - you'll have it running smoothly in short order. I think that's guaranteed!
Andreas
Sorry for the delay - you'll have it running smoothly in short order. I think that's guaranteed!
Andreas