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SOHC - 2.3L & 2.5L Lima Engines Discussions and Topics specific to the Lima 4 cylinder engines

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  #1  
Old 05-16-2016
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Icon4 VERY Low Compression, misfire!

2001 ford ranger XLT 2.5L
Hey everyone, so I was driving home and the truck started misfiring like crazy, I barely make it home and it says misfire in cylinder 3. I take the intake manifold off and change all 8 spark plugs with motor craft single platinum fine wire plugs gapped appropriately. I changed the spark plug wires and my idle air control valve as it was going bad. I start it up and it runs exactly the same. I then proceeded to do a compression test on the passenger side spark plug holes. it read like this, cylinder 1 140psi, CYLINDER 2 50 PSI, Cylinder 3 50PSI, Cylinder 4 120 PSI. I assume it could be the following, stuck valves, Bad rings, Hole in pistons,crack in head, or maybe a bad head gasket? ( because cylinders 2 and 3 are beside each other with no compression?) Its upsetting and I really need the truck running for my lawn business so I might have to go to a shop. I was just wanting to know everyone's thoughts. the truck runs but like crap. Does NOT smoke at all out of tailpipe or anywhere, I have not drove it since i parked it sunday. It is not low on antifreeze.
thank you for any input and help
Brandon
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Old 05-17-2016
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Blown head gasket and possible cracked head.

someone will need to drain all the fluids ( oil and coolant ) remove the cylinder head and send it out to be inspected and repaired valve job machining etc.

You will want to find the reason for the failure,fix the overheating problem if it was overheating.

Do not just go by the dash temperature gauge to determine if it was overheating.

I would plan on pressure testing the cooling system even if you claim the overflow was or is full. ( before taking the engine apart )
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Old 05-17-2016
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2001 2.5l is the Lima engine, last year in Rangers, it is a good engine.

Not a ring issue or holes in pistons.

Adjacent cylinder low pressure is almost always head gasket issue, but 50psi would have to be a pretty big leak

You can put #2 or #3 at Top Dead center then apply compressed air to that cylinder and listen, with a hose, in the other cylinder for escaping air.
Also listen at exhaust and intake for escaping air, i.e. burnt exhaust valve or intake valve issue

You can pull off valve cover and see what valve train looks like, the rockers can fail, only partially opening valves or hold it open a bit.
Also you can 'tulip' intake valves on these engines, with rockers off a tulipped valve stem will sit higher than the other valve stems
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Old 05-24-2016
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RonD, I blew air into cylinder 2, and I put a rubber hose on cylinder 3 and i am fairly certain it was going into cylinder 3 from cylinder 2, how would you recommend to ensure I am getting cylinder 2 at TDC? around here at smaller shops they want $1100 to do a head gasket without sending the head out to get pressure checked and etc. So looks like I will be attempting to do this job. Any tips and details for doing a head gasket? Any places that you know of that I can ship my head to, in order to get it pressure checked? Thanks
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Old 05-25-2016
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I use a wood dowel, pencil size, or smaller, in spark plug hole to see when a piston, other than #1, is at TDC.
But on a 4cyl #1 and #4 are both at TDC when timing mark is at 0deg
And #2 and #3 are at TDC 180deg from that, so if you put a mark on the opposite side of crank pulley and put that new mark at 0deg then 2/3 will be at TDC on that mark.


2.5l Lima engine is a SOHC(single over head cam), so head gasket replacement is fairly straight forward.

Most of the work is just "wrench work" no special knowledge is required.
Take lots of pictures and label wires and hoses as you go.

Metric wrenches and sockets are needed

You may need a special head bolt socket, not sure on the 2.5l.

Machine shop should be under $100 to clean($20), surface($25) and pressure test($40) a 4cyl head.
This can take 2 days, so get head to shop as soon as possible, so they can get it into their schedule.
If you get a head gasket kit, with all needed gaskets, it will come with new valve guide seals, if you take these seals to the machine shop with the head they will usually install them free or for $10.
You can rent/get a valve spring compressor and do this yourself after you get the head back from the shop.

You need to remove the Cam from the head before it goes to the shop, bearing caps should be labelled already, marks, if you don't see any marks then label then yourself, then need to go back on in the same place, then pull out the lower 1/2 of the bearing in the head side and keep it with that cap and bearing, cam bearings should be fine to reuse, just look at them

You will also need a torque wrench for reassembly which you can rent

You will need the head gasket set, new head bolts(old ones can't be reused), new coolant, and oil + filter.
Don't drain the old oil out until head is off and you have clean the block surface, bits will fall down into the oil drain passages and into the oil pan, these will come out when oil is drained.

Many also install a new water pump and thermostat while engine is disassembled.
Timing belt is good for 80k miles, up to you whether or not to change this.

Reassembly requires some specific knowledge, head bolt torque specs and pattern to tighten, also intake and exhaust manifolds have torque specs and patterns for best seating.
Cam, AUX and Crank timing is straight forward there are marks on the 3 gears.

Crank pulley can be hard to remove on these engines, bolt is often 80-100ft/lbs torque.
You can use starter motor to assist bolt removal.
Tackle this job fairly early, if not first, in the project.
You may need to rent a puller to get pulley off after bolt is removed.

If you have a fan clutch, mechanical radiator fan, then remove this before the crank pulley.

You should be fine doing this project, loads of info and help on the net and here at this site

Last edited by RonD; 05-25-2016 at 10:11 AM.
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Old 05-26-2016
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RonD thank you for all the help, I spent a few hours yesterday and then some hours today starting the teardown process, All the rocker arms and valves seem to be working correctly. The valve train looks very clean for 130K miles, The original owner must have kept up on oil changes. I am down to the Headbolts now. I am unsure how to remove the timing belt, I know the tensioner has a bolt that you must loosen up and then there is a special tool to move the tensioner. Any ideas on how to move the tensioner without the tool? Im really wanting to get the head off soon. The Headbolts are a normal size 13mm so the only thing holding me back is the timing belt LOL I have everything else unhooked and unfastened.
Thanks again!
Brandon
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Old 05-26-2016
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Here are some pictures. I have an impact so hopefully the crank pulley will come off easy. I plan to take that when i figure out the timing belt tensioner
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VERY Low Compression, misfire!-img_3064.jpg   VERY Low Compression, misfire!-img_3067.jpg   VERY Low Compression, misfire!-img_3068.jpg  
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Old 05-26-2016
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I have used a pry bar between tensioner pivot and pulley.
Loosen bolt
Pry pulley with belt on it to the left and tighten bolt so it holds.
Belt should now have enough slack to remove.

Removing the crank pulley and then the belt guide(looks like a large washer) makes removing the belt much easier, there is no "lip" on the crank gear.
Don't forget to put belt guide back on or timing belt WILL "walk" itself off after running a bit


May need wheel puller to get off crank pulley/balancer

Last edited by RonD; 05-26-2016 at 02:50 PM.
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  #9  
Old 05-26-2016
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Ron,
I finally got it apart today, It does appear that the head gasket blew in between those two cylinders. I have attached the pictures to show you. My impact was not strong enough to get the crank pulley off. I have already taken the head off. How do you advise me to get the pulley off now? I should have taken it off first like you mentioned but I got ahead of myself. I plan to call the local machine shop tomorrow and get my head scheduled for service. It has been a stressful but also a neat feeling doing the work myself
thanks again
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VERY Low Compression, misfire!-img_3071.jpg   VERY Low Compression, misfire!-img_3072.jpg  
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Old 05-26-2016
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Yes, that would be a blown head gasket.

Is it a manual trans?

Or automatic?

You will need correct socket, deep or very short extension and a breaker bar or socket wrench than can handle torque.

Get a long tube that fits on breaker bar and have at it, leverage baby you need leverage, lol.
I got a 4ft piece of pre-made threaded pipe at hardware store that fit over my breaker bar and also socket, doesn't have to be a snug fit, but does need to be long enough to give you the leverage to break loose the bolt.

1ft/lb of torque is 1 pound of pressure place on a 12" socket handle.
2ft/lb could be 2 pounds of pressure at 12" or 1 pound pressure at 24"(2 feet)

So say that bolt is on with 150ft/lb torque
You need 150lbs at 1ft or 30lb at 5ft
Leverage.

If you have an automatic it makes it a bit harder, because crank will just spin.
If engine was together then you could use starter motor.
You can use the pistons, put cut 2x4s on their wide sides into #1 and #4 cylinders pistons should be down a bit, put head back on and use 2 bolts to hold head down at both ends, snug is fine.
turn crank until 2x4s hit head, now try to break lose the bolt.
2x4 are wood so won't hurt piston or head and they spread out the contact area so won't stress out piston surface.
Piston, rod and crank handle A LOT MORE than even 200ft/lbs of pressure when cylinder fires


Good work so far, yes good feeling doing and learning new stuff.
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Old 06-02-2016
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Ron, It is a manual trans. I had a buddy of mine bring over his air compressor and his impact. My compressor is only 3 gallons lol but surprisingly it does very well for things like removing lug nuts and other bolts. We did get the bolt out of the crank pulley, unfortunately I am going to have to get a puller, the pulley was not going to budge. I am heading to the parts store now to rent a puller and get all my parts and gaskets. I just picked the head up today after work and it looks great, everything tested good and she is all clean. The head was one heavy SOB. Do you think I will need to put RTV on the thermostat housing or do you think the thermostat gasket will seal good enough to prevent a coolant leak there, it never leaked before but i am curious? I am also going to use a tiny bit of sensor safe oil RTV on the oil pressure sensor and the timing belt tensioner spring bolt do you think this is ok. reassembly should begin tomorrow night after work.
Thanks for the help
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Old 06-03-2016
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If thermostat housing uses a rubber O-ring then no RTV would be needed, if a paper gasket is used then I would put RTV on the housing side and apply gasket, leaving head/intake side bare.
Block, intake, and head surfaces tend to stay flat and clean up fairly well so you will get a good seal with paper gaskets.
Parts that attach to block, intake, and head can be warped or have other defects which might benefit from a bit of RTV, it also holds the gasket in place while installing the part.
But it is a judgement call.

1 wire senders, like coolant temp sender or oil pressure sender, use the threads as the ground for the circuit, using sealant on senders is fine just leave a few threads at the bottom bare for a good ground to engine.

2 wire sensors don't used engine as a ground
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Old 06-18-2016
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Ron, I finished up the truck a little over a week ago. Seems to be running good. I want to thank you for all your help, I really appreciate it. You have helped me out tons and I know you help others out as well. Just wanted to say you made the process a lot easier. I sure missed driving the ranger haha. Take care and I'm sure I'll see you around
Thank you,
Brandon
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Old 06-18-2016
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Thanks for the update, good work

And thanks for the thanks :)
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