Topic: Equally low compression on all 4 cylinders

[YotaJosh]

After driving my 20R with unknown mileage for 6 months, I decided to to a compression test.

Results:
#1 - 110 psi
#2 - 105 psi
#3 - 105 psi
#4 - 96 psi

So, that leads me to believe that my rings are probably worn, or all of my valve seats are worn and leaking.

I guess the low compression explains a few things I've experienced, such as hard starting, running hot, bad gas mileage, and still sluggish in 5th gear with 5.29's and 33's doing 65 on the interstate.

Time to start weighing the options...   

[MiniSimp]

Mine is:
#1 - 125
#2 - 130
#3 - 110
#4 - 80

If compression is low in one or more cylinders, you can isolate the problem to the valves or rings by squirting a little 30 weight motor oil into the cylinder through the spark plug hole and repeating the compression test. The oil temporarily seals the rings. If the readings are higher the second time around, it means the rings and/or cylinder is worn. No change in the compression readings tells you the cylinder has a bad valve.

With electronic testing, a computer analyzer "estimates" compression in each of the engine’s cylinders by measuring slight variations in engine cranking speed. The results correlate well with actual gauge readings and can be completed in a matter of minutes without having to remove any spark plugs. What’s more, the analyzer prints out the results of the compression test making it easy to see and compare the actual numbers.

[WHITE_TRASH]

Mini speaks the truth.  Put a squirt of oil (I use atf but anything will work) in each hole and try it again. 

[79coyotefrg]

After driving my 20R with unknown mileage for 6 months, I decided to to a compression test.

Results:
#1 - 110 psi
#2 - 105 psi
#3 - 105 psi
#4 - 96 psi

So, that leads me to believe that my rings are probably worn, or all of my valve seats are worn and leaking.

I guess the low compression explains a few things I've experienced, such as hard starting, running hot, bad gas mileage, and still sluggish in 5th gear with 5.29's and 33's doing 65 on the interstate.

Time to start weighing the options...   

22R Block   


BUT FIRST,   was the engine warm when you did the compression check??

[superyota]

i checked mine a few days ago and my results were


1-155psi
2-150
3-152
4-152

i remember checking it right after my breakin period after the motor was rebuilt and it was 180psi across all 4.  i guess 150 on average isn't bad though. 
hey mini, you said you had 80 in one cylinder.  don't  you have a miss?  i thought you needed something like at least 80 psi or maybe it was 85 psi to have fire on the cylinder.  maybe i'm wrong.

[MiniSimp]

hey mini, you said you had 80 in one cylinder.  don't  you have a miss?  i thought you needed something like at least 80 psi or maybe it was 85 psi to have fire on the cylinder.  maybe i'm wrong.

A miss? I'm lucky the damn thing still runs!

[superyota]

lol

[YotaJosh [OP]]

I tested 2 of them dry, then I remembered the oil trick. Put some oil in there and retested, and it may have jumped up 5 more, but nothing significant. I went ahead and tested the rest with oil.

And I tested it cold. Too many horror stories of stripping the plug holes in heated aluminum heads (I've already got one cross threaded hole from it's previous life).

My current options are:
a. run it till it dies
b. find a 22RE to freshen up and swap in there
c. find a 3RZ to swap in

I'm sticking with A until B or C fall in my lap.

[79coyotefrg]

 

[Jagdverband44]

The 20r head kind of sucks, so just get rid of it. I'll be happy to "recycle" it for you PM yo' Boy. 

[superyota]

i got a 22re i need to get rid of.  asking $300 for it.  let me know if your interested

[DeadlyPeace]

A miss? I'm lucky the damn thing still runs!

I'll say!

Normally your compression shouldn't be more then 10 PSI between cylinders.

[kneedownnate]

Mine is:
#1 - 125
#2 - 130
#3 - 110
#4 - 80

  I think toyota calls for rebuilding a n/a r series engine at 122-125 psi maybe 

[MiniSimp]

  I think toyota calls for rebuilding a n/a r series engine at 122-125 psi maybe 

That was after the rebuild in 2004. I think Toyota calls for a new motor if they ever saw mine.

[kneedownnate]

Yikes... I did a compression on the 91 at around 200,000 miles and they were all over 190 psi I think, and within 3lbs of each other. 

[79coyotefrg]