Author Topic: The official mileage vs. compression thread  (Read 11608 times)

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Gnarly4X

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Re: The official mileage vs. compression thread
« Reply #30 on: Jun 25, 2017, 11:34:17 AM »
Carbon browning is only on one side -- I tried to photograph the brownest side on each one.

How is your oil consumption?  Do you see any blue exhaust smoke?

Gnarls.
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

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Re: The official mileage vs. compression thread
« Reply #31 on: Jun 25, 2017, 11:54:19 AM »
The way I see it, oil burning is good. Keeps things lubricated ;)

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Gnarly4X

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Re: The official mileage vs. compression thread
« Reply #32 on: Jun 25, 2017, 01:23:21 PM »


The way I see it, oil burning is good. Keeps things lubricated ;)

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LOL.... That's like saying... engine ping is good... you know the spark plugs are firing!!  :ha_ha:


Gnarls.  :rofl:
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

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Re: The official mileage vs. compression thread
« Reply #33 on: Jun 25, 2017, 01:43:59 PM »
LOL.... That's like saying... engine ping is good... you know the spark plugs are firing!!  :ha_ha:


Gnarls.  :rofl:
The way I've seen it, if your engine burns oil and it doesn't get worse, just keep up on it. That's what I do.

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emsvitil

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Re: The official mileage vs. compression thread
« Reply #34 on: Jun 25, 2017, 04:34:31 PM »
1986 22RE stock cam

166314.5 miles

Current miles 173903.4

Did this a several years ago in June, so temp would have been between 70-80F @ 98ft above MSL


1:    189 psi   3% leakdown
2:    188        2%
3:    190        5%
4:    186        3%


1 Qt oil about every 2000 miles.
« Last Edit: Jun 25, 2017, 05:43:26 PM by emsvitil »
Ed
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22RE  W56B
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Lewis Hein [OP]

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Re: The official mileage vs. compression thread
« Reply #35 on: Jun 25, 2017, 04:45:56 PM »
How is your oil consumption?  Do you see any blue exhaust smoke?

This is actually a very complicated question to answer. I never saw any trace of blue exhaust until this morning (more on that below). Even oil consumption is hard to answer. Since I have owned it, it has lost at least a quart every 1000 miles, but up until I did a new valve cover gasket a couple weeks ago, there was significant leakage out from the valve cover. I have not driven enough since the new gasket and accompanying oil change to measure oil consumption.

About blue smoke: I never, ever had any until this morning. A couple days ago I parked the truck with the nose pointing uphill for the first time ever. Then this morning, I started the motor to warm it up for my compression test, and got an enormous cloud of thick blue exhaust -- classic oil smoke. It thinned out and stopped after about a half a minute. I can only conclude that when it's pointed downhill, the oil can drain into the oil pan better, and otherwise it drips slowly past the valve guides???

Lewis

Lewis Hein [OP]

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Re: The official mileage vs. compression thread
« Reply #36 on: Jun 25, 2017, 04:48:08 PM »
1986 22RE stock cam

166314.5 miles

Current miles 173903.4

Did this a several years ago in June, so temp would have been between 70-80F @ 98ft above MSL


1:    189 psi   3% leakdown
2:    188        2%
3:    190        5%
4:    186        3%

Thanks!

Lewis Hein [OP]

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Re: The official mileage vs. compression thread
« Reply #37 on: Jun 25, 2017, 05:03:25 PM »
An important piece of info you do need is if it's mated to an auto or manual tranny. I say that because my 89 22re was mated to an auto, had 210k miles and 175 as it's compression reading

At what elevation?

Thanks

Mudder

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Re: The official mileage vs. compression thread
« Reply #38 on: Jun 25, 2017, 07:31:23 PM »
100' above sea level.

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Re: The official mileage vs. compression thread
« Reply #39 on: Jun 25, 2017, 11:49:37 PM »
The way I've seen it, if your engine burns oil and it doesn't get worse, just keep up on it. That's what I do.

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Yep.  I mean, what's the alternative - spend a bunch of money and time to rebuild an engine that runs fine but just uses a little oil?  How much oil could you buy for what the rebuild would cost?  LOL...  As long as it's not fouling plugs or pinging like crazy under load, who cares if it burns a little oil?
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Gnarly4X

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Re: The official mileage vs. compression thread
« Reply #40 on: Jun 26, 2017, 04:34:19 AM »
Yep.  I mean, what's the alternative - spend a bunch of money and time to rebuild an engine that runs fine but just uses a little oil?  How much oil could you buy for what the rebuild would cost?  LOL...  As long as it's not fouling plugs or pinging like crazy under load, who cares if it burns a little oil?

I agree.  The gasoline ICE is designed to burn gas, not oil.  And, the more oil it burns the less power it makes.  But… every vehicle I’ve owned used/burned oil.  I think the issue for us is what is “excessive” or “too much”, and what do we do about it?                                                                                                                                                                   

My 1985 22R did not leak oil or blow smoke, but it did burn about 1 quart of oil every 3,000 +/- 100 miles. Sometimes it would burn a half a quart in less than 500 miles.  A round trip to Lake Havasu City and back is about 7 ½  hours drive time and 480 miles.  It’s 98% freeway and I drive 80 MPH.

I drive about 20K miles per year.  IF my 22 burned 1 quart every 2K miles that would be 10 quarts a year, or about $40 to $100 per year, depending on the oil I used.  Checking the oil level and keeping it up every 6 weeks or so would bother me, but as said, it’s way cheaper and easier than having to do an engine rebuild!

If my 22 starting burning 1 quart about every 1,000 miles, I'd be concerned and start looking seriously at my options.

Oil burning issues have been around since the ICE was invented, and still going on.  Apparently BMW and Subaru have issues with excessive oil burning, and there is, or was, a class action lawsuit against the car makers.

Gnarls.
« Last Edit: Jun 26, 2017, 04:45:12 AM by Gnarly4X »
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

Gnarly4X

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Re: The official mileage vs. compression thread
« Reply #41 on: Jun 27, 2017, 04:59:41 AM »
Just thinking out loud...

The most meaningful analysis of collected data is to start with a benchmark.

For a rebuilt engine, the compression reading right after firing and initial start up.   Then again at 500 miles. Then again perhaps 5,000 miles.  After that 20K mile intervals.

For engines with mileage, check and date stamp initial reading, then check again at 10K or 20K intervals.  Of course for some vehicles that are trail rigs only, mileage advance may be very slow over time.

Gnarls.
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

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Re: The official mileage vs. compression thread
« Reply #42 on: Jun 27, 2017, 12:46:08 PM »
Hit the nail on the head. Both my truck and my Jeep (08 Wrangler) burn oil. The Wrangler is much worse, I didn't check it for awhile and ended up adding 3 quarts. Crazy how bad it can get.

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Lewis Hein [OP]

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Re: The official mileage vs. compression thread
« Reply #43 on: Jun 27, 2017, 01:42:46 PM »
Just thinking out loud...

The most meaningful analysis of collected data is to start with a benchmark.

For a rebuilt engine, the compression reading right after firing and initial start up.   Then again at 500 miles. Then again perhaps 5,000 miles.  After that 20K mile intervals.

For engines with mileage, check and date stamp initial reading, then check again at 10K or 20K intervals.  Of course for some vehicles that are trail rigs only, mileage advance may be very slow over time.

Agreed. This means that I need a Toyota with a freshly rebuilt engine. Actually, since we don't like small sample sizes, I need about 10-20 brand new Toyotas for each engine I want to test...



Gnarly4X

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Re: The official mileage vs. compression thread
« Reply #44 on: Jun 28, 2017, 01:58:11 PM »
....The Wrangler is much worse, I didn't check it for awhile and ended up adding 3 quarts. Crazy how bad it can get.


The rapid loss of oil is an issue with excessive oil-burning engines!  In my past, I've pulled the dipstick more than once on an engine and found the oil level just touching the bottom of the stick!!  :yikes: 

Time goes by quickly and we don't always keep track of the "check-that-oil" duty cycle. :smack:

Gnarls.
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

Snowtoy

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Re: The official mileage vs. compression thread
« Reply #45 on: Jul 18, 2017, 11:00:52 AM »
Some comp. #'s from the rigs that have passed through my hands, and I kept info on.
                         #1      #2    #3     #4
'84 22r/325k      149     154   149    151
'84 22re/175k    160     161   158    163
'84 22re/277k    170     170   170    170 Rebuild w/510 miles
'85 22r/307k      144     147   145    146
'86 22r/257k      153     150   151    150
'86 22r/137k      167     168   167    166 Rebuild w/370 miles
'86 22er/158k    170     171   169    168
'87 22r/235k      162     160   161    163
'88 22re/197k    160     164   165    162
'91 22re/219k    175     175   175    175 Rebuild w/10k miles

Comp. #'s were taken cold.
Valves set cold-.007 intake, .011 exhaust.
Altitude 1547ft.

 



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Re: The official mileage vs. compression thread
« Reply #46 on: Jul 18, 2017, 02:09:25 PM »
1982 22r with 168k miles. 140 in all 4.

Gnarly4X

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Re: The official mileage vs. compression thread
« Reply #47 on: Jul 18, 2017, 02:44:19 PM »
Some comp. #'s from the rigs that have passed through my hands, and I kept info on.
                         #1      #2    #3     #4
'84 22r/325k      149     154   149    151
'84 22re/175k    160     161   158    163
'84 22re/277k    170     170   170    170 Rebuild w/510 miles
'85 22r/307k      144     147   145    146
'86 22r/257k      153     150   151    150
'86 22r/137k      167     168   167    166 Rebuild w/370 miles
'86 22er/158k    170     171   169    168
'87 22r/235k      162     160   161    163
'88 22re/197k    160     164   165    162
'91 22re/219k    175     175   175    175 Rebuild w/10k miles

Comp. #'s were taken cold.
Valves set cold-.007 intake, .011 exhaust.
Altitude 1547ft.

 





This is good poo-poo!!!  :thumbs:

Gnarls.  :D
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

Gnarly4X

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Re: The official mileage vs. compression thread
« Reply #48 on: Jul 18, 2017, 02:45:31 PM »
1982 22r with 168k miles. 140 in all 4.

This is good poo-poo too!  :gap:

Gnarls.
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

Lewis Hein [OP]

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Re: The official mileage vs. compression thread
« Reply #49 on: Jul 18, 2017, 07:54:06 PM »
Nice! Thank you, Snowtoy.

This may be enough for me to make a plot. But that will have to wait until the end of the week probably.

Lewis

Lewis Hein [OP]

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Re: The official mileage vs. compression thread
« Reply #50 on: Jul 23, 2017, 04:42:27 PM »
1982 22r with 168k miles. 140 in all 4.

At what elevation?

Lewis Hein [OP]

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Re: The official mileage vs. compression thread
« Reply #51 on: Jul 28, 2017, 08:01:40 PM »
OK, here is a long overdue plot and analysis. First the model table for a simple linear regression:

                 Estimate      Std.Error      t value     Pr(>|t|)
Intercept    181.284      5.3158         34.1029   <1e-11
Miles          -5.2371e-5  2.54297e-5  -2.05944  0.0639

And a pretty picture:


After correcting for elevation (but not engine temperature), we see that our engines seem to lose 5 +/- 7 PSI every 100k.

Comments? Arguments? Argue and comment below...

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Re: The official mileage vs. compression thread
« Reply #52 on: Jul 29, 2017, 04:15:04 AM »
Hey Lewis,

Cool tech!!  :beerchug:

Gnarls.  :greengrin:..... x .014572391 pomp/stink.
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

Lewis Hein [OP]

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Re: The official mileage vs. compression thread
« Reply #53 on: Jul 29, 2017, 04:54:52 AM »
Reversing the linear regression, we can use a compression test to estimate mileage:

                    Estimate     Std.Error     t value     Pr(>|t|)
Intercept       1.09235e6  4.44428e5  2.45788   0.0318
Compression  -5313.55    2580.1        -2.05944  0.0639

Thus, my '85 probably has somewhere around 189000+/-7000 miles on the engine. This may be consistent with the condition of the timing chain guides.

Lewis

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Re: The official mileage vs. compression thread
« Reply #54 on: Jul 29, 2017, 06:50:05 AM »
Reversing the linear regression, we can use a compression test to estimate mileage:

                    Estimate     Std.Error     t value     Pr(>|t|)
Intercept       1.09235e6  4.44428e5  2.45788   0.0318
Compression  -5313.55    2580.1        -2.05944  0.0639

Thus, my '85 probably has somewhere around 180000+/-7000 miles on the engine. This may be consistent with the condition of the timing chain guides.

 Lewis

Timing chain guides.... :D

If they are the stock plastic type.. they most likely will fail between 80,000 and 100,000 miles.  The metal guides may go to 180,000?  :blah:

Gnarls... just a tad of "pomp" added for squish. :gap:

1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

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Re: The official mileage vs. compression thread
« Reply #55 on: Jul 29, 2017, 07:47:09 AM »
Timing chain guides.... :D

If they are the stock plastic type.. they most likely will fail between 80,000 and 100,000 miles.  The metal guides may go to 180,000?  :blah:

OK, here's what I did on timing chain guides.

Based on some research, I estimated the average life of the plastic timing chain guides to be 120,000 miles. Let us call this one Timing Chain Unit, or TCU.

Now, when I took a squiz under the valve cover, the (plastic) timing chain guides look like they may have had 1/3 of their life used. The evidence of the unsealed and badly done valve cover gasket, sloppy oil pan gasket, and clearance-free valves suggests that someone was monkeying around inside this engine. Maybe they replaced the timing chain??

Thus, I place the miles on this engine at N+1/3 TCU, for some integer N. Is N 0? Maybe, but I doubt it. Based on the compression numbers, I think it likely that N=1. Combining these numbers gives me between 150k and 200k on the engine. The linear regression alone says 189k +/- 7k.

Lewis

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Re: The official mileage vs. compression thread
« Reply #56 on: Jul 30, 2017, 07:42:39 PM »
22r stock block 180 000km/110 000 mi
20r head milled 0.015"
250' elevation
stock cam

Did the compression test with 3 different gauges, engine hot, no fuel in the bowls.

Equus gauge: 161 - 165 - 160 - 153
1977 milton inc: 149 - 150 - 145 - 138
No name made in usa: 167 - 170 - 167 - 160

Gnarly4X

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Re: The official mileage vs. compression thread
« Reply #57 on: Jul 31, 2017, 03:08:44 AM »
...
Did the compression test with 3 different gauges, engine hot, no fuel in the bowls.

Equus gauge: 161 - 165 - 160 - 153
1977 milton inc: 149 - 150 - 145 - 138
No name made in usa: 167 - 170 - 167 - 160

Hey Gillesdetrail,

Geezz... that is some interesting results. The difference in the test gauge readings is surprising.  :yikes:

I vote for "MADE IN THE USA"!! :usa:

That data could mathematically skew Lewis's calculus.  It's been many years since my statistics classes and did any calculus, but I believe it may add another correlation factor "r"?  :dunno:

Gnarls.... :blah:
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

emsvitil

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Re: The official mileage vs. compression thread
« Reply #58 on: Jul 31, 2017, 04:14:25 AM »
Looks like the variance is more in the test equipment........
Ed
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86 SR5 XtraCab
22RE  W56B
31x10.50R15

Lewis Hein [OP]

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Re: The official mileage vs. compression thread
« Reply #59 on: Jul 31, 2017, 04:14:48 AM »
Hey guys,

These are very interesting results about comparing gauges.

First, an observation. My regression model explains only ~28% of the variability in the data from this thread (R^2=.278), leaving the source of 72% of it unknown, but guessable. This is actually pretty good, at least for the sorts of regressions I normally do. But it's also a valuable number to bear in mind.

That remaining unexplained 72% is probably a combination of driving habits, driving conditions, transmission type, maintenance, variation at the factory, and dozens of other things, probably including what compression gauge was used. My model assumes that there is an underlying process

Compression  = a+(b*Miles)+otherStuff.

a is the compression when it's brand new; b is the rate at which that goes down, in PSI/mile. otherStuff is the sum of everything that affects compression readings that is not miles driven, i.e. everything on the list above and more. Even in the presence of large amounts of otherStuff, we can get accurate estimates of a b if (and only if) otherStuff meets certain reasonable assumptions: It must be symmetrically distributed with mean zero and complete independence between engines.

In less technical terms, we are assuming that otherStuff is just as likely to make the compression reading higher as lower, and that what otherStuff is for kneedownnate's engine does not affect what it is for, say, Mudder's (or anyone else's) engine. I have my doubts about whether the first assumption is exactly true; but it's probably close enough to get meaningful results.

In re compression gauges: Mine is a NAPA brand gauge, but it came with a real short adapter that made it impossible to get tight in the head -- I had to buy a pipe nipple and coupling before I could tighten it up. The pipe nipple definitely affects my readings, but not as much as a leak!

Did the compression test with 3 different gauges, engine hot, no fuel in the bowls.

Equus gauge: 161 - 165 - 160 - 153
1977 milton inc: 149 - 150 - 145 - 138
No name made in usa: 167 - 170 - 167 - 160



I am intrigued by these differences between gauges. What order did you do the tests in?

 
 
 
 
 

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