# engine rebuild questions



## enti7y (Sep 12, 2008)

First off, i had a knocking in my engine come to find out it was all of my main bearings, and my rod bearings, got all sizes for each bearing set and made sure i have the perfect set for my engine, all piston rings were changed, head was surfaced, hot tanked, and checked for pressure. we have everything back together on th engine stand except we are stuck. 

The FSM doesn't say enough about timing. In order to keep in time there has to be oil pressure, everything is set TDC and the engine is tight. BUT are we able to spin the crank without having the timing going out if we have the engine sealed up, and filled with oil? 

This is the KA24DE. If anyone knows more about it please inform me. We are getting ready to drop the engine in the bay this weekend coming up, and we need to know weather or not we have to hold the tensioners while we crank the engine up the first time or weather it can jsut be cranked without losing timing. and having to be pulled apart again.


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## rogoman (Dec 16, 2004)

Think about it; every time an engine is cranked to be started up, there is no oil pressure initially for the tensioner to activate, so don't worry about, the timing will not jump.


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## enti7y (Sep 12, 2008)

So, there isn't a way i can spin the cran a couple times on the stand to make sure everything is smooth without having the timing jump? does it have to be running? i'm just trying to be able to turn it over a few times on the stand to make sure nothing else comes up before i try to crank it for real.


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## rogoman (Dec 16, 2004)

You're getting way too paranoid about this issue. Look! I've done compression tests on KA24 motors which involves spinning the motor without starting it; measured/set valve lifter clearances by turning the motor by hand many times. All this without any worry of cam timing jumping. If you don't believe me, go ask any auto mechanic.


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## enti7y (Sep 12, 2008)

*spun and fail*

we spun the engine 4 times and all 4 times it jumped timing on us. any other possibilities why?


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## rogoman (Dec 16, 2004)

Make sure the chain guides are installed correctly. It's also possible that the cam timing is way off so that when you're turning the crank, a piston is up and stopping a cam from turning; this might cause the chain to jump teeth.


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## enti7y (Sep 12, 2008)

*get me nowhere*

the last reply got me nowhere.. what i'm trying to ask.. i'll be a little more specific. 

The tensioners are held by oil pressure. when you take apart those tensioners they lose the pressure they had in them. So, when i'm assembling the timing chain setup, and i have those installed.. they have not near enough pressure to keep the chain tight causing it to jump timing.. is there a certain way other than with a screwdriver to hold the chain in place when cranking it for the first time? i know once it's fired up once it will hold the oil pressure even when it's shut off. just the initial startup.

help please..


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## Trippen (Feb 21, 2006)

Ok first things first...If the chain isnt relatively tight then you have an issue right off the bat. The lower chain that goes from the crank to the center cam gear should be tight enough to not to "Jump" timming. If your worried about oil pressure to start off with prime the pump(look up priming oil pumps KA24de). What your seeing I think in the jumping of timming is natural. In other words One complete revolution of the motor on the stand the chain marks WILL NOT LINE UP. This is normal and its not jumping timing. It is because of the amount of teeth and Gears. I went through this my first time too. Now quite a few KA motor builds under my belt including my beast of a KA-t(see signature) I can agree with Rogo completely. And yes it still weirds me out but I now know its normal. I know it seems weird that they dont line up again but all is good. They will if you spin the motor a few hundered times. And they dont jump timming. Just an illusion. AT TDC you should still see the cam and crank gear marks the same but not the chain marks. Make sure you look at the lobes of the cams they should be almost pointing to the right and left sides of the motor for piston 1. Ill try to post a pic. The only thing if you feel your chain is too loose then your chain tensioner is missing its spring this should firmly press against the chain , Or your chain is stretched or the wrong one. Hope this helps and shoot me an IM if you need further help on here or KA-t.org or TexasNissans.com I am the same on all of them. 
Peace 
Rick


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## Trippen (Feb 21, 2006)

Ok this is all set up right. Minus the front covers...My dirty azz in the pic..Buddies motor...Fun was had by all in 100deg Austin weather for 3 days in his dads drive way...but all is good. Look at the marks in the 2nd pics...2nd picture this was prior to one full turn..this was from my motor build...Off one tooth intentionally by the way.


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