Okay here is my problem. I bought forged pistons/ rods for my motor…It’s a JDM Dohc ZC. The pistons are standard bore. I installed new rod bearings, new main bearings, new thrust washer. Basically new internals. I did not bore or hone the motor. Now when everything is put back together and I try to turn the crank by hand its turns normal then whenever any 2 pistons for example: #1 and #3 are at TDC it get real hard to turn. I have the head on but the timing belt is not on. So besides the obvious question of what is the problem. I have a few more questions 1. Will it prevent the engine from starting? 2. Will it go away or get worse. Also my friend told me that when the motor ages the bottom gets cupped sorta like “U” is there any truth to this…I took my time and was carefull

 

Your piston is hitting a open valve, thats the extra resistance you'r feeling.

1. no timing belt = no start. Set your timing, and install the belt and you should have no problems.

2. see #1

 

u tried rolling it over by hand with no timing belt on and u wonder y there is issues? man its the pistons hitting/binding up on the valves. get that timing belt on before u break something

 

OKay It was doing this before the head was put on.....So how is that a valve?<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Drip Pan &raquo;</TD></TR><TR><TD CLASS="quote">Your piston is hitting a open valve, thats the extra resistance you'r feeling.

1. no timing belt = no start. Set your timing, and install the belt and you should have no problems.

2. see #1</TD></TR></TABLE><TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 001020 &raquo;</TD></TR><TR><TD CLASS="quote">Okay here is my problem. I bought forged pistons/ rods for my motor…It’s a JDM Dohc ZC. The pistons are standard bore. I installed new rod bearings, new main bearings, new thrust washer. Basically new internals. I did not bore or hone the motor. Now when everything is put back together and I try to turn the crank by hand its turns normal then whenever any 2 pistons for example: #1 and #3 are at TDC it get real hard to turn. I have the head on but the timing belt is not on. So besides the obvious question of what is the problem. I have a few more questions 1. Will it prevent the engine from starting? 2. Will it go away or get worse. Also my friend told me that when the motor ages the bottom gets cupped sorta like “U” is there any truth to this…I took my time and was carefull

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<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 001020 &raquo;</TD></TR><TR><TD CLASS="quote">Okay here is my problem. I bought forged pistons/ rods for my motor…It’s a JDM Dohc ZC. The pistons are standard bore. I installed new rod bearings, new main bearings, new thrust washer. Basically new internals. I did not bore or hone the motor. Now when everything is put back together and I try to turn the crank by hand its turns normal then whenever any 2 pistons for example: #1 and #3 are at TDC it get real hard to turn. I have the head on but the timing belt is not on. So besides the obvious question of what is the problem. I have a few more questions 1. Will it prevent the engine from starting? 2. Will it go away or get worse. Also my friend told me that when the motor ages the bottom gets cupped sorta like “U” is there any truth to this…I took my time and was carefull

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You said the head is on - are cams lined up for TDC?

 

yeas

 

SO ARE THERE ANY ANSWERS TO THE QUESTIONS?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 001020 &raquo;</TD></TR><TR><TD CLASS="quote">SO ARE THERE ANY ANSWERS TO THE QUESTIONS?</TD></TR></TABLE>

If the head is on, you are hitting a valve, if the head is off you might want to check everything. You might be causing a binding situation somewher ein your bottom end.


Did you use assembly lube?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Drip Pan &raquo;</TD></TR><TR><TD CLASS="quote">

If the head is on, you are hitting a valve, if the head is off you might want to check everything. You might be causing a binding situation somewher ein your bottom end.


Did you use assembly lube?</TD></TR></TABLE>
i USED OIL ON THE BEARING FACES/ MAIN/ ROD/ THRUST WASHER, i USED ASSEMBLY LUBE ON THE STUDS ON THE PISTON..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 001020 &raquo;</TD></TR><TR><TD CLASS="quote">
i USED OIL ON THE BEARING FACES/ MAIN/ ROD/ THRUST WASHER, i USED ASSEMBLY LUBE ON THE STUDS ON THE PISTON..</TD></TR></TABLE>

So the head it on, with no timing belt?

 

I just thought of something, did you notch th ebottom of your cylinder walls? I had the same problem with my D-16Y8, you might have to grind a notch so they have the proper clearance.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 001020 &raquo;</TD></TR><TR><TD CLASS="quote">Okay here is my problem. I bought forged pistons/ rods for my motor…It’s a JDM Dohc ZC. The pistons are standard bore. I installed new rod bearings, new main bearings, new thrust washer. Basically new internals. I did not bore or hone the motor. Now when everything is put back together and I try to turn the crank by hand its turns normal then whenever any 2 pistons for example: #1 and #3 are at TDC it get real hard to turn. I have the head on but the timing belt is not on. So besides the obvious question of what is the problem. I have a few more questions 1. Will it prevent the engine from starting? 2. Will it go away or get worse. Also my friend told me that when the motor ages the bottom gets cupped sorta like “U” is there any truth to this…I took my time and was carefull

</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by senpai &raquo;</TD></TR><TR><TD CLASS="quote">

You said the head is on - are cams lined up for TDC?</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 001020 &raquo;</TD></TR><TR><TD CLASS="quote">yeas</TD></TR></TABLE>

is the ******* head on or not? if it is u answered ur own question by telling us the timing belt isnt on and it is binding up when the pistons are at TDC against the valves

**** for this post

 

CRXiFIED U ARE A DICK HEAD..If u read what I posted and did not have ur ego up ur *** u would have heard like Drip Pan read when I said that It was doing it before I put the HEAD on..again let me explain it so there are no confusions....when I put the internals in at first I did not put the head on...I turned the crank by hand and when any 2 pistons were tdc it was hard to turn.....I realized that I was missing some parts at first..When I put all the parts in it bacame a little easier but it still get kinda stiff when any 2 pistons are at TDC..I have the head on now but I AM NOT SPINNING IT ........Any way Drip Pan You are right I think thats what the problem is because at the bottom of the cilinder wall there are two little is a little notch made by the pistons skirt...nothing crazy but 2 n both sides about a little smaller than half of an Inch....

 

wait, you said your building a motor but not having the bore checked for roundness, and not having it honed? whats wrong with this picture!?