attn hainz, timing question with pictures

[Braden]

ok so im sure this is as simple as moving the chain up a tooth, and it makes sens in my head but i just want to double check thins timing chain setup. here is the problem, i have lined up the dots with the bright chain links on both sprockets, engine is at tdc ompression, now why in the hell is the groove in the cam sprocket showing that it is advanced, its probably just off by one tooth, but in the hainz video it shows the chain on the sprocket as one tooth different than mine, the timing mark isnt in the center of the bright link its off to one side or the other correct? if you look at the pictures it seems as though the cam sprocket needs to be moved one tooth counter-clock wise thus aligning the marks, but then that would put the bright link on the chain just to the right of the number 2 timing dot, and the crank sprocket still on the dot, this is what is confusing me, i guessz i need to disregard the links and strictly go by the marks.

 

check my work here guys as i would rather be 100% sure before i go and fuck something up

[Braden]

bump, the day is wasting away

[Braden]

do you guys think the reason it could be like that is because too much metal was removed from the bottom of the head when it was belt milled??

[datzenmike]

Remove the sprocket and turn clockwise untill the #3 hole is beside the bright link. This will advance the cam 4 degrees and move the V closer to the horizontal etch mark.If the chain isn't stretched or the sprocket worn then the head must have been milled down. Measure from the valve cover gasket surface down to the engine surface gasket... stock un-milled head thickness is 4.248"

 

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[datzenmike]

Hey, is this the head those assholes belt sanded??? Grrrrrr.

[Bleach]

Attn Hainz, I dropped off a 4-speed transmission and some points distributors on your front lawn! haha :lol:

[datzenmike]

:rofl: He'll find them next time he cuts the lawn looking for a fuel pump.

[Braden]

well mike here is what moving it to number 3 did

now let me say this while its fresh on my mind. if i disregard the bright links on the timing chain and use only the v notch in the cam sprocket (which has to be correct because of the dowel on the end of the cam) in theory if the engine is at tdc compression stroke and if the v notch in the cam sprocket is lined up with the notch in the camshaft bracket then the engine should be timed assuming that the chain is is tight and there is less that one link slack in the tight side ,(depending on wether or not i used number 1 2 or 3 on the cam sprocket).

does that sound correct? ive typed this message 3 f ing times because i keep being interrupted :angry: :angry: :angry:

[Braden]

on a side note the chain is a factory chain with less than 3k miles on it and so is the sprocket the only thing not oem is the cam. also i re measured the head and it is 4.248-4.247" so it cant be out of spec, one thing i did notice is when i disassembled the engine is that the bright links on the chain were on the backside not on the front like they should be, im assuming that when my grandfather assembled it years ago that he used the theory that i described above

[Braden]

the more i think about the more it seems as though the cahin is simply stretched causing it to be off

[datzenmike]

One link on the chain is 9 degrees. Nissan figures that that is too much adjustment for mere chain wear so they use the 1, 2, 3 holes which give 4 degrees adjustment.

 

'Yes as long as the v and the mark are close it doesn't mater how you did it, the motor is cam timed.

[Braden]

so should i use the numner 2 or 3 hole? i am guessing 2

[datzenmike]

 

Looks like the #3 dot is above the bright link here.

 

 

Let's see.. The sprocket is locked to the cam by a dowel pin so when the V is on the horizontal etch mark the cam is timed for TDC on the crank.

 

Moving the sprocket ahead by one link will move the cam about 9 degrees or a little over two etch mark widths. This is likely way too much adjustment for the average L motor chain stretch/wear.

 

Nissan provided at least one adjustment hole for the cam dowel that is only 4 degrees retarded or about the width of the etch mark. This is good for the average L motor.

 

Having said all this... It doesn't matter how many links are between the two sprockets, or what hole your are using as long as the crank is at TDC and the cam sprocket V is just below the horizontal etch mark The cam is timed!.

 

I don't know why your motor is so strange, but in the pictire above it looks to be perfectly timed.

 

some things to check.

 

Has the block been decked? This would be like plaining the head down and would effectively lengthen the chain.

Assume nothing and check TDC on the crank. Could it be off somehow? Has the key holding the small crank sprocket come loose, fallen out when assembled??

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[Braden]

i guess iull thow this sucker back together

[datzenmike]

 

This looks perfect to me. Don't fuck with it.

 

The only problem I have is why it is out so much. As I said, can you check if the crank is not at TDC for any reason, don't assume anything. Don't forget one degree out on the crank is 2 degrees out on the cam so a small amount is twice that on the cam.

 

Maybe Hainz will chime in when he gets back from church this morning.

 

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[Braden]

since i have the head on how will i check to make certian it is still at tdc? i put it at tdc and havent messed with it and when i look through the plug hole it looks as if it as at the very top. i would rather check to make sure, like you said it is wierd, the head still measures good and they did deck the block but probably 5 thousandths or less, it could be a combo of strethced chain and decked block. but like you said it doesnt matter how many links as long as the v notch is lined up and as long as the engine is at tdc.

[datzenmike]

Yes, good enough for now. When you get the timing cover and crank pulley back on later see if the timing mark on the pulley is at TDC. If not just block the chain and re position the cam sprocket. Weird though.

[Braden]

Yes, good enough for now. When you get the timing cover and crank pulley back on later see if the timing mark on the pulley is at TDC. If not just block the chain and re position the cam sprocket. Weird though.

so shouldnt i be able to put the crank pulley on right now and verigy it is at tdc? the more i think about it being at tdc the more i want to check it.

[datzenmike]

Sure, slip the timing cover on first as it has the timing scale on it. No need for gaskets yet, just a couple of bolts to hold in place and slip the pulley on to the woodruf key and see where the notch on the pulley is in relation to the TDC 0 mark is.

[Braden]

ok i verified that the engine is at tdc compression, i put the chain on and the closest i could get to aligning the v notch is barely to the left or retarted (on the number 3 hole). here is what i am going to go with, just someone please verify that it will be ok to run the cam on the number 3 sprocket hole???? i know 2 would be ok but im not to sure about the 3 hole

[datzenmike]

Roll with the #3, after all you can always change it back later. #3 looks closest to perfect.

[banzai510(hainz)]

Sorry I dont have computer access all the time.

But you need to take your time.

Honestly I never seen this happen before where you put the brite link on the dimples and its off that much. In your 1st set of photos. Usually if you use the brite link its pretty much self centers,You sure you didnt have a wrong chain? like a L16/18 chain on a L20? But I would think if you had the shorter chain it would be hard to get it one the lower crank sprocket.

 

I myself have a assoretment of sprockets and would swap the top one just to see if they come out different.

But going by your last photos that Mike helped you out looks like your fine. Nothing wrong going to #3 sprocket position. Matter of fact I think it would be better since you have that long dur cam in there in the 1st place.

 

another note I would see if you could push that tensioner in a little more. adjsut the slack side guide as much as possible to get that done. other wise I think your fine on this set up

[datzenmike]

You and the widow were in church.

[Braden]

i went with the number 3, i guess we will see how it works pretty soon.

[banzai510(hainz)]

long as you got the oil pump primed with oil/valve lash and distributor shaft is lined up it will fire. long as the carb and dizzy works.

 

if possible prime up the carbs if you have a manual fuel pump. pour oil over rockers and timming chain

tighten up that tensioner so it more IN