JustChou Posted June 18, 2004 Share Posted June 18, 2004 Hello all, I'm proud to say that I've now joined the ranks of Z owners, having picked up a 260Z a few days ago for a project car. In the process of trying to decide whether I should attempt to get the car running with the L26 in it, I decided to do a compression check, and got some strange results that I'm hoping you can help me interpret. As measured from the radiator, they're as follows: 132 - 120 - 150 - 136 - 135 - 124 - radiator> Now, they seem fairlyl in the zone, save the freakishly high compression in cylender 4. Now, I don't know whether that means that cylender four is healthy while the rest are crapping out, or if there's something wrong with No. 4. The other strange indicator is that the engine doesn't turn over smoothly - it seems to "stall" every time cylender 3 is compressed. It makes a sound like...whiirr cachunk whiiiiiir cachunk (pardon my terrible iforum onomonopia). In addition to that, I'm not sure how exactly to do a compression check - do I crank the motor several times over (which usually gives me increased compression with every turn, then it tapers off) or just once? Thanks for any help you may be able to provide. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 18, 2004 Share Posted June 18, 2004 Warm the car up. Pull the spark plugs. Put the compression tester in each hole, turn it over until the compression readings don't get any higher (usually about 5 compression strokes or so). When you've checked that way, you can squirt 2 squirts of oil into each cylinder and check again. If the numbers jump up a lot, then you have some piston rings which aren't doing their job. Your initial numbers don't look that good. You want them all to be really even, and yours were all over the place. Quote Link to comment Share on other sites More sharing options...
JustChou Posted June 18, 2004 Author Share Posted June 18, 2004 Well, I can't really warm the car up - it is currently lacking carbs and a distributor. Any input on the strange cranking sound? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 18, 2004 Share Posted June 18, 2004 Could be anything. Broken tooth on the flywheel would be my first guess. Even if you can't warm the car up, you can still do the oil test and see if the numbers jump. If they jump a lot, then it probably needs new rings. Test results would be more accurate from a warm engine though. Quote Link to comment Share on other sites More sharing options...
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