Request confirmation on my conclusions on my 2F compresson numbers (1 Viewer)

[norsk]

[UPDATED] Request confirmation on my conclusions on my 2F compresson numbers

Head cast number 61040, 193k miles

Cyl....1st Reading.....2nd Reading....Wet Reading
1.......140................140.................150
2.......125................120.................130
3.......140................140.................150
4.......130................130.................135
5.......125................130.................138
6.......140................140.................150


I assume that since all cylinders went up abt 10psi under wet, that gain is caused by the oil rings gaining more "traction" in the oil.

Since there were no dramatic upticks in the low cylinders, I assume those low cylinder are caused by head losses, etc.

Therefore I assert my pending head swap should fix up those lower cylinder pressures. Do my thoughts follow the numbers?

Cyl 2 and 5 have had funny numbers now and in the pass. I think they are a growing concern

Thoughts?

thx from this site on the proper procedure to gather these numbers

doug t

 

[fliphkd778]

A head job couldn't hurt; but it can put stress on a weak bottom end. Then again, those numbers aren't awful either. Was the test performed pending a valve adjustment in the past?
The FSM lists 149 psi at 250 rpm as standard, the limit is 114.

 

[Spike Strip]

For a 200K motor, those numbers are fine.

Run a 15w-40 or 20w-50 engine oil.

 

[Cruiserdrew]

Those numbers look OK. Were the compression numbers obtained at altitude?

How does it run?

Are you sure you want to mess with it?

 

[Wile E Coyote]

Dry vs wet compr. readings are ripe with possibility for error. I would be happy to get your numbers above at 193k miles. To really know, a leakdown test would be more indicative of valves vs rings, vs, etc.

Note that those # will also be affected somewhat by the atmospheric pressure where u do the test. Your 5500 ft elevation is lowering your numbers.

 

[Drofen]

My thoughts too. Wish my numbers looked that good when I tested mine. Mine ended in a total rebuild...

 

[norsk]

Those numbers look OK. Were the compression numbers obtained at altitude?

How does it run?

Are you sure you want to mess with it?

A head job couldn't hurt; but it can put stress on a weak bottom end. Then again, those numbers aren't awful either. Was the test performed pending a valve adjustment in the past?
The FSM lists 149 psi at 250 rpm as standard, the limit is 114.

I got the truck at 189k and have not yet done a valve adjustment. I think my side cover PCV mount is plugged as well. Previously I found the cover to air cleaner hose full of oil foam and spilling into the air cleaner. From that I found NO PCV vacuum. Trace it to a very plugged PCV steel nipple from the intake mainfold. Cleaned that out and got great vacuum at PCV.

BUT.....I am still getting foam from the cover hose and smoke coming out, hence I don't think I have good air flow. Thus I think the PCV mount stem is plugged as well. Given that I believe I have sludge inside. HG is leaking at several places, as is the side cover.

I have 2nd head already rebuilt, but found too late it is the older 61030 head, not a 61040 that I have. Yet as per MarkW/Weak-link's suggestion shaving the head 0.100 inch would increase its CR. Both of them have or have had an old head shaved on a newer FJ60 2F block and did or are doing well. Therefore, I am going to swap it for now, and get my 61040 head rebuilt. This time with JimC's suggestion of SS SBC valves and new springs - but still need to know which springs to use.

Would like to put in the Delta CAM and new/reground lifters next time as well. Maybe when I put the 61040 head back on, and do new rings then as well w/o removing the block. (Saw post on that. New rings, new con bearings and the ARP con bolts. Future stuff for now.)

If I do have alot of sludge, what is the best way to clean it out inplace w/o a rebuild??

thanks for the info so far. And I am at 5535 ft in the Wasatch Mtns. Have desmogged, waiting for JimC's mod on my dizzy and air pump idler pulley (air is just cycle air on itself - air rail is disconnected), and waiting for Trollhole's new carb.

doug t

 

[norsk]

Dry vs wet compr. readings are ripe with possibility for error. I would be happy to get your numbers above at 193k miles. To really know, a leakdown test would be more indicative of valves vs rings, vs, etc.

Note that those # will also be affected somewhat by the atmospheric pressure where u do the test. Your 5500 ft elevation is lowering your numbers.

Okay, pls explain what/how a leakdown test is.

doug t

 

[Cruiserdrew]

For that altitude your numbers are not that out of line. Does it run OK?

Adjust your valves. That is free and way cheaper than a motor rebuild.

Having the head redone just can't be bad. So with unlimited cash and time on your hands, you should do it.

A leak down test is hard to do yourself, so maybe adjust the valves, repeat the compression test, and see where you are.

I would tolerate a running motor a long time before I'd dive in, just to dive in. I'm certain the 2F in my FJ40 is tired. But it still runs and starts at 11,000 feet so I don't worry about it. If I had no other projects, and was bored, and had no one to talk to, and the dog didn't want to go for a walk, I would consider doing a head job on that motor. So for, that has not happened.

 

[norsk]

For that altitude your numbers are not that out of line. Does it run OK?

Adjust your valves. That is free and way cheaper than a motor rebuild.

Having the head redone just can't be bad. So with unlimited cash and time on your hands, you should do it.

A leak down test is hard to do yourself, so maybe adjust the valves, repeat the compression test, and see where you are.

I would tolerate a running motor a long time before I'd dive in, just to dive in. I'm certain the 2F in my FJ40 is tired. But it still runs and starts at 11,000 feet so I don't worry about it. If I had no other projects, and was bored, and had no one to talk to, and the dog didn't want to go for a walk, I would consider doing a head job on that motor. So for, that has not happened.

runs ok, starts good, but on hills 35-40 mph gets old fast after doing 65-70 on the flat

I had a 10 psi gain on the dry to wet. I hear that 10-15 psi gain indicates troubled rings.

So what is a normal gain for a good engine between dry and wet tests?

caveofbob got 2-5 psi gain on his test. Is that what normal is?

doug t

 

[Nemesis Gnat]

I have compression envy

If it were me I'd let that one be, run it. For what it's worth, my numbers range from 130 to 35...

 

[LAMBCRUSHER]

A leakdown is the only way to REALLY know weather it's valves or cylinder/piston ring related.
When I did my wet test, mine jumped 20-25 on all but my # 2 which only gained about 18psi on the wet test. I think that 15% is the acceptable limit between your highest reading and your lowest reading. So based on your first battery of #s, 15 % less than 140 is 119. Even if we called it 10% you are still w/in 1psi of that. Those #s are not that bad. Valve adjustment?

 

[gdtrfb]

Dude, where are you, Kamas? running up and down parlys?, these things are tractor motors, not pavment rockets, our 87 runs from salt lake to park city bout 45 to 50 on a good day with a tail wind

besides, the journey thats the thing, not the destination!

 

[caveofbob]

valve adjustment then test again

I would do a valve adjustment first then test again. If the valve our to tight you would lose compression. just did my after asking the same question over at is it time to rebuild or not. at now it looks great
https://forum.ih8mud.com/60-series-wagons/349834-time-rebuild-not.html


caveofbob

 

[norsk]

I would do a valve adjustment first then test again. If the valve our to tight you would lose compression. just did my after asking the same question over at is it time to rebuild or not. at now it looks great
https://forum.ih8mud.com/60-series-wagons/349834-time-rebuild-not.html


caveofbob

yeah the adjustment is at the top of my list now, looking for a feeler gauge this lunch hour. Part of all of this is to gain "context" of what is "normal" and it is looking like I might have a normal 2f in there. But I think I might have a bunch of sludge in there though from other indications. Will find out when I pop the valve and side covers.

doug t

 

[norsk]

Well I did my valve adjustment this morning and most of the rockers needed to be loosened, while one was spot on and another needed tightening

New numbers in last column. All but #3 went UP in compression.

Cyl....1st Reading.....2nd Reading....Wet Reading.......Dry-After Valves Adjusted
1.......140................140.................150......................145
2.......125................120.................130......................141
3.......140................140.................150......................136
4.......130................130.................135......................145
5.......125................130.................138......................135
6.......140................140.................150......................145

So the valve adjustment did improve the compression of the cylinders and removes from my mind the need to rebuild the head at this time due to low compression number. They are now all under 10% difference between each other.

My spark plugs are black fouled on #2, 3 and 5. #1, 4, and 6 have the normal brown/tan color. I thought that usually indicated a carb issue, but since #2 and #5 were low compression before the adjustment I wonder if there is a connection. I will run for some miles and pull those spark plugs again and compare.

That then removes a head rebuild for awhile and changes my short TODO list to:

1) pull side cover and clean things up in there
2) Install JimC's recurved dizzy
3) Install Trollhole's carb
4) Acquire and install the 6-to-1 header

Other items come later.


Conditions inside the valve cover:

Inside the valve cover was some sludge but not everywhere. There were hard granules of carbon on the rocker arms, shaft and cover studs. These came off with wiping down with towels.

The vent hose from the cover to AC was yet again filled with carmel colored oil foam, whipped up like. I cleaned out that hose. I then checked the PCV 90 degree elbow by sticking a wire down into there and it came back up massively covered in the same oil foam. It took a dozen times to get alot of it out of there but more still in there. I assume that elbow is fully plugged since there is not a negative pressure at the valve cover to AC connection for the hose. The PCV vacuum was probably plugged for "years" before I cleaned out the vacuum tube on the intake manifold. This means that there has NOT been PCV flow for years on this rig. (I got it in May 2008)

So as mentioned, next thing to do is take the side cover off and clean things up a bit in there and make sure that elbow is completely clear. Would like to get my dizzy back and install it at the same time.

Thanks for all who replied. This really helped me learn and understand this truck. I hope this is of benefit to other "new" mudders

doug t

 

[gdtrfb]

thats cool glad the numbers came up, I still wonder if your in the valley or up on the hill
PS I have a new header I could part with if the price was right been in my storage shed for 2 years in the orignal box from man a fre

 

[norsk]

thats cool glad the numbers came up, I still wonder if your in the valley or up on the hill
PS I have a new header I could part with if the price was right been in my storage shed for 2 years in the orignal box from man a fre

is that the ceramic one listed at $450 or so plus the Y-pip at $140? If so their retail is bit too much for me, but it is a good looking header. What is your price?
Or is it the 6-to-1 model?

The JTOutfitters 6-in-1 I am looking at is $160 plus $40 shipping. So if it is the 6-to-1 and has all the parts, I would do the $160 price and save the shipping by picking it up face to face

my zip is 84032

Placed called Heber City UT in Heber Valley at 5535 feet per my GPS, near the Post Office

doug t

 

[norsk]

well, left this morning with a full tank and just got home from work and topped off the tank again.

51.7 miles, 1000 feet down in the morning, 1000 feet up at night.
3.50 gallons

14.8 mpg

my average for the past 2,226 miles has been 11.1 mpg

AND I had far more power. I left it in 4th coming up the hill. On a couple of the steeper hills, speed came down to 45 at 1800 rpm, but it kept climbing and didn't bog down like it has before. I am very surprised at the difference the adjustment made. I will need to keep measuring to see if it is consistent, but wow.

 

[caveofbob]

Nice to hear that your #'s went up and looks like your MPG did to