84-85 Trucks & 4Runners 2nd gen pickups and 1st gen 4Runners with solid front axles

Low compression on Rebuild

Old Nov 7, 2009 | 06:02 AM
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From: Natchitoches, La
Low compression on Rebuild

I rebuilt a 1984 22R shortblock 3 weeks ago before I came back to work, and I went back with the same head, a stock 20R. Now I cranked it up before I came to work and it sounded great and ran very good, and had a compression test done on the cylinders a few days after I got to the rig and the readings are all around 110 PSI. standard size pistons, I know its a tall deck 22R block , but why the low compression readings
110 105 115 110 Thanks

Last edited by toyotabull; Nov 7, 2009 at 07:52 AM.
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Old Nov 8, 2009 | 10:42 AM
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After alot of hard thinking and playing 20?'s with my brother, I have figured out why it runs good but has low compression. Now there are 2 types of compression testers. #1 is the bolt in unit, dont have to worry about it leaking and getting a wrong reading, and then there is the one my brother used. The push in, yeah, the one with the rubber nipple that you press firmly into the spark plug hole. So I figured it out and he is not allowed to work on yotas again, and ill post the right readings when I get home Wednesday.
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Old Nov 8, 2009 | 05:05 PM
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you might have your rings backwards on the pistons
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Old Nov 9, 2009 | 09:33 AM
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From: Natchitoches, La
I hate to pull it down and check, but if I do then I'm putting a bigger set of pistons in there and sending everything back to the machine shop just in case. I'm out here on the drill ship right now catching about 20-30 foot waves from Ida, this thing is rocking.
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Old Nov 9, 2009 | 09:49 AM
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ya my freind just rebuilt an engine and that was his problem but ive also heard that if you put some money into the rebuild you can get the 22r to push 200hp .

ya i wouldnt want to be out there right now, i hope your rakin in the money for being there
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Old Nov 9, 2009 | 11:42 AM
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From: Natchitoches, La
Yeah, its not too bad out here, worst we have had is about a 30 foot wave but its slowing down. Back to the engine, all the rings were in marked packs from engnbldr, and unless they were packaged wrong (which i dont see happening) then Im gonna have to look into the cam setting, might be a tooth off. Ill let ya know when I get home wed. And the drill ship is 835 feet long by 125 feet wide, so its hard to rockit, but when it does!!
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Old Nov 19, 2009 | 01:48 PM
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So I got home last week and ran another compression check, and guess what, 110 115 110 110, put a little oil in each cylinder and ran a leak test, and the test came back good with minimal ring leakage, and still avg. of 110 psi on each cylinder. HELP?
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Old Nov 19, 2009 | 02:55 PM
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Do you have a screw in compression tester? Where did you buy the gauge and is it reading right? If the rings were in backwards there would be more leakage than that it be like about 60-80% leakage. Check you valve clearnances. Do the pistons come all the way up to the TDC postion? timing....
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Old Dec 3, 2009 | 09:56 PM
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the problem is the pistons, the ones i got were for the 85 motor and I didnt check the height when installed, so now I am going to pull the motor and have the block shaved and then have the head ported and polished.
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Old Dec 4, 2009 | 08:16 AM
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good luck on the rebuild

Last edited by herpestes; Dec 4, 2009 at 09:36 AM.
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