Friday, July 12, 2013

sr20 comp

Time to do a compression test on the sr2o. I realize I was in country for this purchase, and would have liked to do it before transferring money, but it was a logistical nightmare to simply get the car delivered while I was in town to receive it. I expressed my want of a compression test to the previous owner, and he said he got it done, providing pictures of the test, numbers of which between 13o and 14o.

This seemed a little low to me, not to mention the previous owner completely missed the point of me asking to witness said test. I believe the FSM calls for 125 min before needing a rebuild, but at least the numbers were within 1o% or so of each other. This is more than I would get from an engine importer, and if you are going to stretch the truth, at least give better numbers. The engine was seemingly running well, no smoke, rattles, leaks, or vibs.




Remove the strut tower bar.



Remove the spark plug cover.









Remove the spark plug boots.

I quickly realized at this point that the short 3/8" extension won't reach the spark plugs and that I would have to make a parts store run.


Put strut tower nuts back on.


Place spark plug boot and cover bolts, and strut bar, inside car.



Go to Halfords.



At this point I got frustrated. My local Halfords, the only parts store in London, did not have any long 3/8" extensions in stock. They had a few as part of larger socket kits, but the only ones left were 6oGBP or more. There were others that were marked down half price, but of course these were out of stock as well.

I had to postpone the compression test yet another day. I went into work the following day and a longer than normal one was provided.





The plugs were a little wetter than I expected, but the tips looked OK.





One interesting part of the plug removal was the fact they were extremely tight. I've always installed plugs by hand until they bottom out, then a light twist with the socket to secure them. These plugs were so tight that I almost needed a breaker bar on the socket wrench to break them loose. I don't remember my suspension bolts being torqued that much. Maybe whoever changed the plugs last did it with the engine hot, and of course I was removing them cold to perform the compression test. If this was the case the head may have tightened down excessively around the plugs as it cooled. This still doesn't excuse the amount of force that was needed, they still would have been over torqued while warm. It's lucky nothing cracked.

Oh wait.











The ceramic of cylinder three plug cracked and chipped. It was contained inside the spark plug socket, so nothing fell into the engine cylinder and it obviously happened upon removal not installation, but surprised me nonetheless when removing the plug from the socket.

I was impressed the engine had HKS brand spark plugs in it. I never even knew HKS made spark plugs. That's like buying a Ferrari air freshener. I looked them up online and they are available here in the UK, but for 19GBP (about 3oUSD). That's one hell of a spark. 

Back to the compression test.


Unplug cam angle sensor and place the long wire out of harms way, ie away from the fan.




Locate fuel pump fuse of an s14a within the inside fuse box near the driver's side kick panel, and remove.

Screw tester into cylinder 1. Push the gas pedal down all the way, opening the throttle, and hold. Turn ignition to "on", then to "start" and hold, cranking about 1o times. Jot down cylinder number and pressure, take clear evidentiary photo, press schrader valve on gauge to release pressure, resetting to 0. Unscrew tester from cylinder 1.

Repeat 3x on remaining cylinders.







Better numbers than provided before purchase, and with a cold engine. When does that ever happen?! 7.8 % between the highest and lowest cylinders, average psi of 146.3. Hopefully the previously owner didn't actually waste 6o quid on a compression test from a shop prior to dropping the car off. Making a quick excuse that he paid cash, thus no receipt and only pictures of some red top engine getting tested is more likely.

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