'51 8N question

[Eman85]

Bring the piston to TDC and place a straight edge across the block and see where the piston top and shiny spot is in relation to the deck surface of the block.

 

[boler76]

I'd be very curious to see a picture of that. Not sure what you have for oversized pistons - a few options were used when the liners were pulled. Is the domed top crowned that much?

yes the oversized pistons are domed and there is a slight depression in the top center and they are shiny around edge of this depression, I have yet to try it but have reinstalled head after making a crater in head to align with piston top?? Thanks

 

[Duner Wi]

I use modeling clay to come up with clearances on piston tops.

 

[boler76]

I'd be very curious to see a picture of that. Not sure what you have for oversized pistons - a few options were used when the liners were pulled. Is the domed top crowned that much?

well that wasnt the fix as after relieving the head the noise still is there when engine is warmed up to thermistat setting at 160-180, I am hoping the re done crank was done to specs as I just put it in with bearings supplied, now i will plastigage it?? Kind of late if thats the problem

 

[DanielW]

well that wasnt the fix as after relieving the head the noise still is there when engine is warmed up to thermistat setting at 160-180, I am hoping the re done crank was done to specs as I just put it in with bearings supplied, now i will plastigage it?? Kind of late if thats the problem

Hmm. I think a mechanic's stethoscope and and narrowing down the source is the next step at this point. No point taking a guess and throwing parts at it without knowing where it's coming from. Could be something very simple. Fan belt getting lose when warm/pliable and slipping? Fan hitting the shroud? Both not uncommon on N's. Can you post a quick video showing the sound?

 

[soaked]

Hi boler76,
Does the sharp sound, sound like a crankshaft hitting an oil pump pick up tube?

 

[boler76]

Hi boler76,
Does the sharp sound, sound like a crankshaft hitting an oil pump pick up tube?

YES and what I have found so far is that the pick up tube was too close to the bottom of the pan and when the pan is off everything looks normal but when pan is put on it pushed the pick up tube so it just contacted the crank, I have replaced the pick up tube with one that is configured to miss and am hoping that the noise will not be there when I get it back together GOOD Call Soaked thanks

 

[soaked]

Sure hope the new one clears!!
I came across a post with this info from John Smith a while back

Edit to include:
Found the threads this was posted to, there are more details on the tube fitment

B

Thread '51 8N Oil Pick up tube Alignment'

Apr 16, 2016

Due to a loose Oil pickup tube on a recently purchased 51 8n,I have begun the process of repair. However once I dropped the pan and inspected the situation there was not only not a screen at the pick up but the pickup wont come close to aligning with the drain plug hole. Is there a posibility that sometime in this tractors past a wrong tube was installed and not even attached securly to the pump? What should I do ? Help my 1st tractor.

• BobMsc
• Replies: 23
• Forum: Ford 9N, 2N & 8N