Jump to content


Photo

78 620, L20B foreign matter in combustion chamber.


  • Please log in to reply
337 replies to this topic

#21 Atikin9000

Atikin9000

    Advanced Member

  • Members
  • PipPipPip
  • 97 posts
  • Location:Ashland Oregon
  • Cars:1978 620 long bed.

Posted 22 September 2017 - 01:04 PM

I only had a minute to look over it this morning and upon further investigation, it looks like a valve seat and it's in one piece, turned it over by hand so the piston would drop and the ring stayed in one place looks like it's hanging off the valve, valve spring worked though, the supposed ring seems jammed hard now, tried to fish it out but it won't move and seems very whole to come out of the sprarkplug hole. Piston had some scaring.

When I have some time next I'll pull the head.

#22 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 69,433 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 22 September 2017 - 01:10 PM

Poop.


Posted Image

#23 Charlie69

Charlie69

    Senior Member

  • Senior Member
  • PipPipPipPipPip
  • 6,067 posts
  • Location:Tolleson, AZ
  • Cars:1966 520, 1985 720 ST King Cab, 1986 720 King Cab

Posted 22 September 2017 - 08:39 PM

Pull the head it could have scored the cylinder wall and or beat up the head and the piston.


Here is my build link:
http://community.rat...s-66-520-build/

 

Here is my 86 720 2WD King Cab Thread

http://community.rat...20-king-cab-dd/

 

Here is my 85 720 2WD King Cab ST Build Thread

http://community.rat...20-king-cab-st/

 

Here is my Photo Bucket Album Link:
http://http://s477.p...arlie69_Datsun/


#24 distributorguy

distributorguy

    Senior Member

  • Senior Member
  • PipPipPipPip
  • 1,069 posts
  • Location:Metropolis, MN
  • Cars:77 Datsun 620, 73 Datsun 620

Posted 26 September 2017 - 01:49 PM

"Will have" scored the piston, likely won't have touched the cylinder walls, definitely bent the valve, definitely beat up the head.  The piston may be fine, but the head is going to get expensive to repair.  Likely welding to get a seat to take after it released then pounded against the head every time the valve opened and closed.  You'll need someone who can weld aluminum AND has a Serdi head bench to cut the head for a new seat.  Valves are cheap.  



#25 Atikin9000

Atikin9000

    Advanced Member

  • Members
  • PipPipPip
  • 97 posts
  • Location:Ashland Oregon
  • Cars:1978 620 long bed.

Posted 30 September 2017 - 07:17 PM

https://imgur.com/a/zdm4M

Thought I'd share a small update.

#26 Atikin9000

Atikin9000

    Advanced Member

  • Members
  • PipPipPip
  • 97 posts
  • Location:Ashland Oregon
  • Cars:1978 620 long bed.

Posted 30 September 2017 - 07:24 PM

Also some pics of said truck.

https://imgur.com/a/eIU8J

#27 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 69,433 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 30 September 2017 - 07:30 PM

HMbYbw9.jpg


Posted Image

#28 flatcat19

flatcat19

    Back in Black

  • Senior Member
  • PipPipPipPipPipPipPipPipPipPip
  • 19,739 posts
  • Location:Tri-Cities, WA/PDX
  • Cars:Smaller. Better. Slower. Lower.

Posted 30 September 2017 - 11:33 PM

Is it in fact the seat?

You can't hang if your nuts haven't dropped...it's physics


#29 G-Duax

G-Duax

    prickly in San Antonio

  • Senior Member
  • PipPipPipPip
  • 776 posts
  • Location:San Antonio, The Republic of Texas
  • Cars:73 620 & 90 Toyota Cressida

Posted 01 October 2017 - 02:33 AM

Could be a guy with really fat fingers lost his gold wedding band....:)



#30 flatcat19

flatcat19

    Back in Black

  • Senior Member
  • PipPipPipPipPipPipPipPipPipPip
  • 19,739 posts
  • Location:Tri-Cities, WA/PDX
  • Cars:Smaller. Better. Slower. Lower.

Posted 01 October 2017 - 07:21 AM

Looks to me like the carb sucked something up in to the head.


But you showed a pic prior of something in he spark plug hole...so you have 2 foreign objects?

You can't hang if your nuts haven't dropped...it's physics


#31 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 69,433 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 01 October 2017 - 07:33 AM

The seat has dropped but caught on the larger valve width.

 

68corvair025.jpg

 

 

L head spark plug location points directly between both valves so seats are easily seen....

 

chamberMedium.jpg


Posted Image

#32 flatcat19

flatcat19

    Back in Black

  • Senior Member
  • PipPipPipPipPipPipPipPipPipPip
  • 19,739 posts
  • Location:Tri-Cities, WA/PDX
  • Cars:Smaller. Better. Slower. Lower.

Posted 01 October 2017 - 12:17 PM

Damn.

That's what I get for not clicking external links from Ratsun.

You can't hang if your nuts haven't dropped...it's physics


#33 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 69,433 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 01 October 2017 - 12:30 PM

I fucking hate links. (I hate PB too)

 

I know. Today I learned that Canadian football is actually American football even though we play on a longer wider field, have 3 downs and an extra player to make the game faster and more enjoyable. Canadian football (AKA American football) is closer to European football (AKA Soccer) Go figure...


Posted Image

#34 hang_510

hang_510

    too ol'skool

  • Senior Member
  • PipPipPipPipPip
  • 9,603 posts
  • Location:so.cal
  • Cars:71 2 door - LZ22 / 72 wagon - TBD

Posted 04 October 2017 - 10:32 PM

Today I learned that Canadian football is actually American football even though we play on a longer wider field.


Damn metric system.

"I can spend time working on the Dattos, or wasting money at the strip club. You make the call." :D


I'll put on chain mail and a dirt bike tire jock strap and drive it!!!!!


#35 distributorguy

distributorguy

    Senior Member

  • Senior Member
  • PipPipPipPip
  • 1,069 posts
  • Location:Metropolis, MN
  • Cars:77 Datsun 620, 73 Datsun 620

Posted 05 October 2017 - 05:01 AM

I see a bevel cut on that valve seat - not ok.  I also have to assume that's why the press fit was no good.  Whoever installed it deserves a kick in the nuts.  



#36 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 69,433 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 05 October 2017 - 05:08 AM


 
 

I know. Today I learned that Canadian football is actually American football even though we play on a longer wider field, have 3 downs and an extra player to make the game faster and more enjoyable. Canadian football (AKA American football) is closer to European football (AKA Soccer) Go figure...


Damn socialist system.


Posted Image

#37 Atikin9000

Atikin9000

    Advanced Member

  • Members
  • PipPipPip
  • 97 posts
  • Location:Ashland Oregon
  • Cars:1978 620 long bed.

Posted 15 October 2017 - 02:58 PM

Little update, sorry for the imgur link again.

https://imgur.com/a/Oj0A4

#38 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 69,433 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 15 October 2017 - 03:27 PM

bCNprpE.jpg

 

If you are precisely set at TDC without backing the crank counter clockwise, then this is good

.


Posted Image

#39 Atikin9000

Atikin9000

    Advanced Member

  • Members
  • PipPipPip
  • 97 posts
  • Location:Ashland Oregon
  • Cars:1978 620 long bed.

Posted 15 October 2017 - 03:38 PM

Yea but I bumped the bottom end on accident so there goes that out the window.

I went 10 and 2 on the compression stroke on #1.

#40 Atikin9000

Atikin9000

    Advanced Member

  • Members
  • PipPipPip
  • 97 posts
  • Location:Ashland Oregon
  • Cars:1978 620 long bed.

Posted 15 October 2017 - 03:42 PM

https://imgur.com/a/BOcDc

The timing mark on the block was way off.

It’s gonna have to get timed again I guess, because it’s looking like this head might not be repairable.