Low compression in number one and number four cylinders

Tiny
NICKMALLI
  • MEMBER
  • 2001 HONDA CIVIC
  • 1.7L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 255,000 MILES
Hi, just getting into my project car listed above it is a coupe. No spark in one and number four cylinders, and compression test reads:
#1- 90.
#2-140.
#3-140.
#4-30.
I am planning on replacing the spark plugs but still have to deal with compression. Car is in time. Now about to move to the head gasket and inspect camshaft lobes. Just wondering if an entire rebuild is needed or if I can get it firing right and rebuild the head gasket and replace any damaged components. Thanks
Friday, March 30th, 2018 AT 7:23 PM

3 Replies

Tiny
STEVE W.
  • MECHANIC
  • 13,413 POSTS
First thing I would do would be a wet compression test. Just squirt some oil into the cylinders and see what you get. I would probably run a leak down test as well, that would give you an idea if it is bad intake or exhaust valves. Then pull the head off. Being it is one and number four I would guess it lost a couple valves or they are sticking open just enough to cause problems.
If the compression does not come up with the added oil and you find leakage at those cylinders through the valves I would say doing the head over would get it to run.

However, as the engine has that high mileage on it I would probably opt to go through it or drop in a re-manufactured engine. Simply to repair any wear that it has.
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Friday, March 30th, 2018 AT 9:17 PM
Tiny
NICKMALLI
  • MEMBER
  • 2 POSTS
Okay thank you very much! I could not access air compressor or leak valve today so instead lifted the rocker arm assembly to inspect the camshaft lobes. They look great but some metal shavings right by where the bolts hold the assembly on. I am just assuming already on rebuilding the head anyways so now I will proceed with pulling all of the exterior engine components, in order to access to head. The car is TDC on compression one. Any advice before proceeding?
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Saturday, March 31st, 2018 AT 4:29 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,413 POSTS
Take lots of pictures of the hoses, brackets and such. If you have not torn one apart before things can get interesting when you go to assemble them. Make sure you have a good manual for it.
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Saturday, March 31st, 2018 AT 11:51 PM

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