Discussion:
nissan h25ka

hey guys iv got this old truck from the 80's always been a good runner. lately its been losing power and im not entirerly sure why. idels good but under load its gutless. I did a commpression test this morning and iv 100/75/75/175 lbs across the cylinders.. cant find any specs on it without paying an arm and a leg for a ebay manual. was hoping some one might be abel to help me out. I need specs on cylinder compression and valve gap distance. any info would be greatly appreciated.
  • Posted 10 Jun 2022 02:55
  • By Savageone
  • joined 20 Nov'18 - 5 messages
  • Michigan, United States
Showing items 1 - 2 of 2 results.
Hey Scott thanks for the response.. I guessed and gapped them at 15 thou, it did quite it down a bit but didn't do much for power. Besides the low compression I'm starting to think the timing chain jumped a tooth. The adjustment on the distributor is all the way to one side and if you move it even slightly it won't run at all. I'm thinking the tensioner failed and the chain slipped.
  • Posted 11 Jun 2022 21:54
  • By Savageone
  • joined 20 Nov'18 - 5 messages
  • Michigan, United States
Sounds like this truck might need a valve job with compression like that. Just to let you know it takes 90psi just to get a spark plug to fire and that is very low compression the motet should have approx 150psi or more in each cylinder and be close in compression to each other with less than ten percent difference in cylinders. l believe the valve lash is 15 thousands intake and exhaust hope this helps.
  • Posted 11 Jun 2022 12:17
  • By Scott_
  • joined 16 May'21 - 306 messages
  • Pennsylvania, United States
Scott

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