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Discussion Starter #1
is it even possible to have that low a compression in each cylinder and still run? o_O just did a dry test 2day out of curiosity and they came back 45/45/33/45 front to back respectively, i cranked each one for about 10secs hoping theyd go higher. any info on this?
 

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Fully charged battery? All plugs removed? Throttle open? :huh:

Warm you should see 160+. Cold MAYBE a little less.

Have you messed with the valve timing?

Does it run / exhaust smoke HEAVY?

What year, what engine?

Is the tester known good?
 

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Discussion Starter #3
tester is good, maybe because i didnt have all the plugs out, i did em 1 at a time and throttle closed. barely smokes mainly on cold start then down to nothing. 87 samurai 5speed with the original 1.3L, maybe ill just check it again when i get the chance, to me it just didnt seem right to be that low and still driveable. thnx for the response
 

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Also, if they still read low after you pull the plugs, put a teaspoon of oil in and see if the reading goes up. If it does, it's your rings. If not, it's probably valves.
 

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Discussion Starter #5
will try that as well, didnt have any oil on hand so couldnt try that at the time. could be y it feels gutless even with the "high performance" cam i just put in over the summer, i thought i wasted money on a cam and rockers. if its time for a rebuild should i do the 1.6 8v? i want to keep it carbed (less hassle IMO) or rebuild the 1.3 to the max like my original intention was i.e. high comp pistons, bored .40, and head work. either motor im doing 100% new everything when the time comes. just dont know what all performance options the 1.6 8v has compared to the 1.3 aside from the same stuff in the head.
 

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Discussion Starter #6
no good, pulled the plugs, fully warmed up, and WOT it pumped up to 75/75/80/75 front to back, tried with the clutch in and out to alleviate friction to turn over faster, on and off the gas but nothing worked, still couldnt do the wet test since im broke and cant buy any oil (thought about using the blowby oil but no catch can >.<). guess its just time for a rebuild both top and bottom, atleast shes still running (which im surprised)
 

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I'm surprised its starting with figures that low, but at least they are even which says its worn equally. You cranked it until the gauge stopped rising obviously?
WOT clutch in, fully charged battery is correct method, so no probs there.

With compressions that low, it will be noticeably down on power, does it idle ok? How much oil does it use? how bad is the blowby? Thats the big indicator, if its got oily blowby, its looking like dead rings.
Engines never cease to amaze me when they can run and sound so nice and be so worn internally.
 

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Discussion Starter #8
it runs fine, i never drove a 60hp vehicle b4 so idont what it should feel like but it is sluggish. yes i cranked even after it stopped in hopes of it rising more. battery is charged, it spins its brains out lol its the fastest cranking vehicle ive had. i did notice the swooshes are barely noticeable when i cranked it without the plugs, my previous cars had a really noticeable compression sound. im surprised myself but could be y i have to downshift into 3rd and rev the piss out of it to go up a minor hill on the road...as for blowby its just a small puddle by the oil cap which is the 2 prong cap (got a screw on type from the yard just havent installed it yet) i havent had to put oil in it since maybe april this year. idles fine once warmed up sometimes a little choppy but sits around 800rpms. im gunna have to get a vid of the comp. check and driving it around just to prove this thing is weird lol
 

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full throttle? no throttle? For running a compression test, NONE of that matters. You should have your coil UNPLUGGED, as well as your plugs unplugged. A compression test doesn't care about throttle, as it only has to do with the position of the valves being closed, and the piston rising to compress the chamber.

Depending on who you talk to, will determine what you hear as proper temperature for running the test. For me, full op temp makes the most sense as that's when the metal is going to be expanded and have the most accurate tolerances.

I haven't run a test on my Zuk yet, so I haven't looked into specs, but 160 sounds about right. 45? Not so much!

Sometimes carbon can build up on the rings, causing them to not expand. Here is a FREE way to try and clean that out. (A lot of short trips also contributes to this build up....a good ol' road trip can also help to clean it out!)

Get a small cup. With kids around, we always have kiddy cups in plentiful supply...but figure about 8-10 ounces. Fill it with water. Yup! Regular old tap water.
Get the engine to operating temperature. Take off the carburetor bonnet so you can access the carb direct.
With the engine running, and revving to about 2500 RPM, trickle water into the carb slowly. It will bog the engine down. Pace the trickle so that it doesn't kill the engine. Trickle, pause....trickle, pause.
By the time you empty the cup, you should notice that the engine is probably running a lot smoother. If carbon deposits were causing compression issues, a new compression test should show some improvement.

Another option...

RESTORE:

This stuff WORKS! It's not a permanent fix, you have to do it with each oil change, but it does work.

Run a leak down test too. It can tell you if your rings are bad, or if your valves aren't sealing or what ever.

Hope this helps.
 
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