Compression Test on Donor Engine (Need some opinions))
05-20-2017, 10:21 AM
#1
Registered User
Thread Starter
Compression Test on Donor Engine (Need some opinions))
Hey guys, I need some ideas, thoughts, advice or just plain ole comments on the compression test data I'm getting from my 2000 model 3.4 donor engine.
Here's a little background on my project.
I have a nice 89 4runner 3VZE that still runs like a champ. It has some oil leaks, the valve seals leak, and, overall, I just don't trust it enough to live up to my future expectations for the truck. I purchased a wrecked, but not bad wrecked, 2000 4Runner SR5 about 7 months ago. It had probably been sitting for 6 months prior to that but it had 150K on it and ran good all the way into that ditch that ended it.
I brought it home and completely disassembled it. Removed all wiring without even cutting one single wire just to say I did it, swapped the running gear into my 02 because the 00 had a locker and 4.30 gears and set aside everything else including the engine and transmission. The entire powertrain looks like it's three years old. Everything is in order. I have been putting my swap off for the longest while I read, prep, test, etc, but am moving forward a little faster at this point.
Last night I bolted up a starter and bell housing, wired me up a circuit with a push button and started compression testing. Specs on my circuit are a gigantic marine battery that is new and two 4' leads made from an old set of 8G jumper cables. That's all the big wire I had. Crimped on big copper ends and started testing.
Here are some results.Cylinder:Test 1Test 2Test 3Test 4Test 51901259014215531301251455120150212015041151256212 215210Test one was very sluggish. Probably from not running in a year.Test two seemed to be better. Readings seemed to rise in comparison to test one as I tested each additional cylinder. Like engine oiling up.Also possible that I tested cylinder 3 in place of 1 and got that higher reading. It's late.Test three showed 90 again in number one. Added a few drops of oil and immediately tested. Much higher now. Could be junk on cylinder wall.Test four showed much higher reading in number one but did not test others as I had an epiphany, or however you spell that.Throttle body was still taped off and butterfly closed.Test five showed a quick jump to 155 in cylinder 1. Need to test 6.Cylinder 6 still tests slightly over 200 in all tests tonight. Need to find out why.
So the issue I'm concerned about is the high reading on number 6. Any thoughts on that?
Lastly, I quit testing last night because I thought maybe I should get some thoughts on even doing a test like this. Should I have oiled up each cylinder before hand? Should I oil them up before I retest today? I bought some Lucas upper cylinder lube today. I was thinking of using it but wanted to hear what you guys think and how much to put in each hole.
I know this is long winded but wanted to give all of the detail I had. Thanks for your help.
Here's a little background on my project.
I have a nice 89 4runner 3VZE that still runs like a champ. It has some oil leaks, the valve seals leak, and, overall, I just don't trust it enough to live up to my future expectations for the truck. I purchased a wrecked, but not bad wrecked, 2000 4Runner SR5 about 7 months ago. It had probably been sitting for 6 months prior to that but it had 150K on it and ran good all the way into that ditch that ended it.
I brought it home and completely disassembled it. Removed all wiring without even cutting one single wire just to say I did it, swapped the running gear into my 02 because the 00 had a locker and 4.30 gears and set aside everything else including the engine and transmission. The entire powertrain looks like it's three years old. Everything is in order. I have been putting my swap off for the longest while I read, prep, test, etc, but am moving forward a little faster at this point.
Last night I bolted up a starter and bell housing, wired me up a circuit with a push button and started compression testing. Specs on my circuit are a gigantic marine battery that is new and two 4' leads made from an old set of 8G jumper cables. That's all the big wire I had. Crimped on big copper ends and started testing.
Here are some results.Cylinder:Test 1Test 2Test 3Test 4Test 51901259014215531301251455120150212015041151256212 215210Test one was very sluggish. Probably from not running in a year.Test two seemed to be better. Readings seemed to rise in comparison to test one as I tested each additional cylinder. Like engine oiling up.Also possible that I tested cylinder 3 in place of 1 and got that higher reading. It's late.Test three showed 90 again in number one. Added a few drops of oil and immediately tested. Much higher now. Could be junk on cylinder wall.Test four showed much higher reading in number one but did not test others as I had an epiphany, or however you spell that.Throttle body was still taped off and butterfly closed.Test five showed a quick jump to 155 in cylinder 1. Need to test 6.Cylinder 6 still tests slightly over 200 in all tests tonight. Need to find out why.
So the issue I'm concerned about is the high reading on number 6. Any thoughts on that?
Lastly, I quit testing last night because I thought maybe I should get some thoughts on even doing a test like this. Should I have oiled up each cylinder before hand? Should I oil them up before I retest today? I bought some Lucas upper cylinder lube today. I was thinking of using it but wanted to hear what you guys think and how much to put in each hole.
I know this is long winded but wanted to give all of the detail I had. Thanks for your help.
05-20-2017, 07:46 PM
#4
Registered User
Thread Starter
Ha! Man that's super weird. I copied and pasted from my excel sheet and it looked good in the preview. Stand by for something you all can read.
Never mind. It won't let me type them in in like I'm looking at them. I'll post a pic of my sheet.
Test one was very sluggish. Probably from not running in a year.Test two seemed to be better. Readings seemed to rise in comparison to test one as I tested each additional cylinder. Like engine oiling up.Also possible that I tested cylinder 3 in place of 1 and got that higher reading. It's late.Test three showed 90 again in number one. Added a few drops of oil and immediately tested. Much higher now. Could be junk on cylinder wall.Test four showed much higher reading in number one but did not test others as I had an epiphany, or however you spell that.Throttle body was still taped off and butterfly closed.Test five showed a quick jump to 155 in cylinder 1. Need to test 6.Cylinder 6 still tests slightly over 200 in all tests tonight. Need to find out why.
So the issue I'm concerned about is the high reading on number 6. Any thoughts on that?
Forgive my sloppy work. Usually I am strictly scientific and thorough with my tests. I was just fooling around with it last night and wanted to get some feedback before I did my official checkup on the engine. Thanks again.
Never mind. It won't let me type them in in like I'm looking at them. I'll post a pic of my sheet.
Test one was very sluggish. Probably from not running in a year.Test two seemed to be better. Readings seemed to rise in comparison to test one as I tested each additional cylinder. Like engine oiling up.Also possible that I tested cylinder 3 in place of 1 and got that higher reading. It's late.Test three showed 90 again in number one. Added a few drops of oil and immediately tested. Much higher now. Could be junk on cylinder wall.Test four showed much higher reading in number one but did not test others as I had an epiphany, or however you spell that.Throttle body was still taped off and butterfly closed.Test five showed a quick jump to 155 in cylinder 1. Need to test 6.Cylinder 6 still tests slightly over 200 in all tests tonight. Need to find out why.
So the issue I'm concerned about is the high reading on number 6. Any thoughts on that?
Forgive my sloppy work. Usually I am strictly scientific and thorough with my tests. I was just fooling around with it last night and wanted to get some feedback before I did my official checkup on the engine. Thanks again.
05-20-2017, 10:56 PM
#5
Registered User
1/2 an oz seems like too much oil, just put a capful or 2
run your tests again, your ˟˟˟˟s all over the place
per the FSM I believe 175+ is the ideal range, 145 on the low end, ideally 15psi or less diff between cylinders
run your tests again, your ˟˟˟˟s all over the place
per the FSM I believe 175+ is the ideal range, 145 on the low end, ideally 15psi or less diff between cylinders
05-21-2017, 12:24 PM
#6
Registered User
Thread Starter
That's what I'll do. I think the months sitting up is what is causing the numbers to look strange. They seem to get better each time I turned it over. I'll add a cap full of oil in each and run them again this evening. I'll post up some numbers in a readable format afterward.
Still, the 200+ reading in #6 has me a little puzzled. Not sure why that one is so far up there.
Still, the 200+ reading in #6 has me a little puzzled. Not sure why that one is so far up there.
05-21-2017, 02:03 PM
#7
Registered User
Very difficult to get good numbers from an engine that has not been run recently.
Carbon and other deposits sometimes swell with time and moisture, causing different sorts if inaccuracies.
From what you've got, and the fact the numbers are going up I think your engine is a good one.
I'd check the valve lash, but the non-running deposit issue might make for inaccuracies, showing larger lash than true because a valve might not close perfectly. If any show tight, they're likely to actually be tight.
Carbon and other deposits sometimes swell with time and moisture, causing different sorts if inaccuracies.
From what you've got, and the fact the numbers are going up I think your engine is a good one.
I'd check the valve lash, but the non-running deposit issue might make for inaccuracies, showing larger lash than true because a valve might not close perfectly. If any show tight, they're likely to actually be tight.
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05-21-2017, 02:19 PM
#8
Registered User
Thread Starter
Very difficult to get good numbers from an engine that has not been run recently.
Carbon and other deposits sometimes swell with time and moisture, causing different sorts if inaccuracies.
From what you've got, and the fact the numbers are going up I think your engine is a good one.
I'd check the valve lash, but the non-running deposit issue might make for inaccuracies, showing larger lash than true because a valve might not close perfectly. If any show tight, they're likely to actually be tight.
Carbon and other deposits sometimes swell with time and moisture, causing different sorts if inaccuracies.
From what you've got, and the fact the numbers are going up I think your engine is a good one.
I'd check the valve lash, but the non-running deposit issue might make for inaccuracies, showing larger lash than true because a valve might not close perfectly. If any show tight, they're likely to actually be tight.
1. 225
3. 180
5. 160
2. 160
4. 235
6. 230
My starter circuit is being run off of a deep cycle battery with 8g cables. It turns pretty slow. If I hold on to the button, most of them will continue to climb little by little but I don't want to damage my starter. I'm sure the valves that weren't completely seated or completely open when it was killed for the last time have a buildup of oil sludge in their seats. I wish I had a dyno I could run it on and run some sea foam through the top end.
I'm just trying to see what all I am going to need to do to it before I stab it in my 4Runner. I was debating on even pulling the valve covers but I'm pretty well set on it now so I can check and adjust the valves.
At any rate, I'm going to let her cool off and then run the tests again. Thanks for the reply.
05-23-2017, 04:55 PM
#9
Registered User
Thread Starter
I finally got me some useful readings. After waiting a day, I came back and ran my tests again. This time I did them quickly, one after the other. I got more weird readings on the first three and then got an even 220 on the last three. I immediately retested the first three and got 220, 220 and 225. The high readings don't bother me due to no exhaust being hooked up and gunk in the heads and cylinders from not being heated up for a year. I'm ready to move forward now.
I do think I'll take it down to the valves and adjust them before I install it. Just not sure how accurate my adjustment job can be with sludge that will be in the valve train from sitting up. I still want to take a peak and install new valve cover gaskets.
I do think I'll take it down to the valves and adjust them before I install it. Just not sure how accurate my adjustment job can be with sludge that will be in the valve train from sitting up. I still want to take a peak and install new valve cover gaskets.
