RCP Phx
NAXJA Forum User
- Location
- Phoenix,Az
No, they should spin freely but generally it's hardly noticable(as in a couple RPM)!
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Cherokee XJ RENIX 1990 - low power, bad mpg, problem with ignition and timing
- Thread starter szachmat
- Start date
No, they should spin freely but generally it's hardly noticable(as in a couple RPM)!
"And the push rods should not turn just be in one position?"
Engines, with hydraulic lifters, are typically designed so that the center of the lifter is offset from the center of width of the camshaft lobe. So as the camshaft lobe rotates it slowly spins the hydraulic lifter to maintain uniform wear on both the lifter and camshaft lobe. If the center of the lifter rode on the center of the width of the camshaft lobe, the lifter/pushrod would not rotate as it rides the camshaft lobe.
Likewise, if the lifter's preload is excessive; the pushrod rotation becomes more noticeable and the wear, between lifter and camshaft lobe, may increase. Also,EXCESSIVE lifter preload may cause some lifters to act like solid lifters, and bend pushrods, while other lifters act like hydraulic lifters. Likewise, excessive preload causes camshaft lobe wear which is why we want to measure the lobe lift of each camshaft lobe.
You should learn how to set the preload on each hydraulic lifter. There is a specific procedure for that.
Best regards,
CJR
Engines, with hydraulic lifters, are typically designed so that the center of the lifter is offset from the center of width of the camshaft lobe. So as the camshaft lobe rotates it slowly spins the hydraulic lifter to maintain uniform wear on both the lifter and camshaft lobe. If the center of the lifter rode on the center of the width of the camshaft lobe, the lifter/pushrod would not rotate as it rides the camshaft lobe.
Likewise, if the lifter's preload is excessive; the pushrod rotation becomes more noticeable and the wear, between lifter and camshaft lobe, may increase. Also,EXCESSIVE lifter preload may cause some lifters to act like solid lifters, and bend pushrods, while other lifters act like hydraulic lifters. Likewise, excessive preload causes camshaft lobe wear which is why we want to measure the lobe lift of each camshaft lobe.
You should learn how to set the preload on each hydraulic lifter. There is a specific procedure for that.
Best regards,
CJR
I personally like Mobil and Rotella T5 & T6 oils for my XJs. I've also used Castrol oil (half standard oil+ half synthetic oil) in the past and reached 384,000 miles on my 88XJ before rebuilding/modifying the engine because of a broken cast-iron piston ring. Replaced cast-iron piston rings with ductile iron ones. I know of 4.0L XJs in my area that were still running well, with original engines, at 500,000 miles(info source: My local Jeep Service Manager).
Best regards,
Best regards,
Castrol doesn't have a good opinion here in Poland. Mostly because it's very popular and there's alot of fake oils. Same with Mobil, easy to buy fake one.
I have done few oil changes in BMW 740 with N62 engine - they bring their own oil - Castrol edge professional 5W30 and every time the old oil is RED. Dark red colour.
I have never used castrol in my cars, but i used alot of mobil, 5W50 mostly on my bimmers. Was great in my 523i, but i have noticed oil consumption on my 540i. I have changed to Valvoline all climate, and oil consumption was gone.
Rotella - never heard of it. Probably almost impossible to get in Poland.
Back to engine topic - i assume my engine is just worn out. And that's the cause of lack of power and fuel consumption.
Mileage isn't big, and it's originaly from germany where they have pretty restricted inspections every 2 years, but the last 6 years, previous owner used in only to carry woods from the forrest. To fix this engine i would need to do is as CJR suggest - completely rebuild it. It will be too expensive for me and it would take few months. That's why I want to swap this engine for another - used one. I know i can buy engine with same or even worse condition (had this situation few times) but ill take the risk.
I'll buy mopar engine(block+head, rest will leave mine), as I read, to only difference is the location of engine temp sensor on the engine head.
I have done few oil changes in BMW 740 with N62 engine - they bring their own oil - Castrol edge professional 5W30 and every time the old oil is RED. Dark red colour.
I have never used castrol in my cars, but i used alot of mobil, 5W50 mostly on my bimmers. Was great in my 523i, but i have noticed oil consumption on my 540i. I have changed to Valvoline all climate, and oil consumption was gone.
Rotella - never heard of it. Probably almost impossible to get in Poland.
Back to engine topic - i assume my engine is just worn out. And that's the cause of lack of power and fuel consumption.
Mileage isn't big, and it's originaly from germany where they have pretty restricted inspections every 2 years, but the last 6 years, previous owner used in only to carry woods from the forrest. To fix this engine i would need to do is as CJR suggest - completely rebuild it. It will be too expensive for me and it would take few months. That's why I want to swap this engine for another - used one. I know i can buy engine with same or even worse condition (had this situation few times) but ill take the risk.
I'll buy mopar engine(block+head, rest will leave mine), as I read, to only difference is the location of engine temp sensor on the engine head.
szachmat ,
A complete rebuild, i.e. rebore cylinders, replace pistons, balance rotating assembly, replace camshaft/bearings,main bearing, regrind crankshaft, align-bore, rebuild/resurface head, etc., can get expensive. But if you do a thorough diagnosis on this engine, you may be able to just replace some damaged parts, i.e. lifters,camshaft, and maybe some main bearings, gaskets, etc.. Also, if your cylinder bores are half decent you can hand-hone your cylinders and replace the piston rings. That would not be too expensive and could get the engine running again. If you find some major problem, that can't be corrected, at least you've increased your knowledge level. So far, you've thrown a lot of parts at this engine without determining what the problem is. You need to do more investigating/testing/measurings to increase your skill/knowledge level. Likewise, you need to learn how to properly time your camshaft to the crankshaft . Throwing parts at another risky engine will not increase your skill level.
Best regards,
CJR
A complete rebuild, i.e. rebore cylinders, replace pistons, balance rotating assembly, replace camshaft/bearings,main bearing, regrind crankshaft, align-bore, rebuild/resurface head, etc., can get expensive. But if you do a thorough diagnosis on this engine, you may be able to just replace some damaged parts, i.e. lifters,camshaft, and maybe some main bearings, gaskets, etc.. Also, if your cylinder bores are half decent you can hand-hone your cylinders and replace the piston rings. That would not be too expensive and could get the engine running again. If you find some major problem, that can't be corrected, at least you've increased your knowledge level. So far, you've thrown a lot of parts at this engine without determining what the problem is. You need to do more investigating/testing/measurings to increase your skill/knowledge level. Likewise, you need to learn how to properly time your camshaft to the crankshaft . Throwing parts at another risky engine will not increase your skill level.
Best regards,
CJR
- Location
- NJ, U.S.A.
The Rotella oils are made by Shell, if that helps any.
Yeah, i have googled it, but it's not popular in Poland.
We mostly use just shell helix.
I have started to disassembly my engine. Started with manifolds.
Still not sure what to do. Thing is, that parts for jeep are not so common and cheap here as in the US. set of new gaskets for bottom and upper part of the engine new bearings, piston rings, lifter parts will cost me around 3 times price of an used engine.
We mostly use just shell helix.
I have started to disassembly my engine. Started with manifolds.
Still not sure what to do. Thing is, that parts for jeep are not so common and cheap here as in the US. set of new gaskets for bottom and upper part of the engine new bearings, piston rings, lifter parts will cost me around 3 times price of an used engine.
- Location
- San Diego
I’ll be watching this closely. My MPG is also pretty bad. Lucky to get 15 highway. I average less than 10. And it’s constantly shifting from 3-4 on the highway due to it needing like half throttle to maintain highway speeds. But I also have lots of blowby so I know it’s worn. Curious to see how this ends up
I hope you get help here, but at this stage i think, that even if ill fix my Jeep, i won't be able to tell what was real problem.
For example, my exhaust manifold had cracks + as you can see in the picture below, there was exhaust gases escaping on the middle part. This is how it looks after about 5 mins of grinding by rotating machine.
Middle part was burnt on the sides. I grinded it more, to get flat surface.
One guy told me he had cracks on exhaust manifold in mopar and it helped for him with power and bad mpg.
https://photos.app.goo.gl/hREgYx4UFc4yGPRk8
And this is first look on my valves.
https://photos.app.goo.gl/QqWEvtSMybYXaU479
For me, the all look equal, exhaust valves are maybe too much burnt, but i'm not sure. Its 30 years old engine..
https://photos.app.goo.gl/QqWEvtSMybYXaU479
https://photos.app.goo.gl/kpgemoV8dFmH5S879
Next, ill remove head and see the cylinders, and lifters.
What online shop with jeep parts can you suggest guys?
I think ill rather order most of parts from US (rock auto maybe?).
They are more expensive if i add shipping to Poland, but at least i have a better choice with brands, not only NTY and Crown...
I looked at your photos. There appears to be some type of heavy grey build-up in the head exhaust ports. The grey built-up color, in the exhaust port is a different color than the typically expected tan color build-up on the exhaust valve stem. Am I seeing this properly? Is this grey color, in the photo, actually representative of the real head?
Best regards,
CJR
Best regards,
CJR
- Location
- San Diego
I know my sensors are good as I have the REM monitor to see the values of all the sensors in real time. I double checked my fuel pressure yesterday. 32psi with vacuum to regulator, 39 unplugged. I’ve pretty much accepted it’s worn rings or something. Mine shift fine and passes smog no problem.
1990JeepXJ,
Your rings may be OK, but stuck closed in the piston grooves. Something inexpensive to try to free up the stuck piston rings. Pull the plugs and spray a whole can of Gumout equally in all cylinders. Let set overnight, replace plugs and fire it up. You'll get a little white smoke and it will clear up. The rings will now be free to work as they're supposed to work. The Gumout will drain into the crankcase and evaporate. This technique works the best for me as it puts 100% solvent on the rings and is better than some solvent added to the oil where it's diluted to 5% or 10% solvent strength before it gets to the rings.
Best regards,
CJR
Your rings may be OK, but stuck closed in the piston grooves. Something inexpensive to try to free up the stuck piston rings. Pull the plugs and spray a whole can of Gumout equally in all cylinders. Let set overnight, replace plugs and fire it up. You'll get a little white smoke and it will clear up. The rings will now be free to work as they're supposed to work. The Gumout will drain into the crankcase and evaporate. This technique works the best for me as it puts 100% solvent on the rings and is better than some solvent added to the oil where it's diluted to 5% or 10% solvent strength before it gets to the rings.
Best regards,
CJR
Rockers, rods, lifters and valve head out of engine.
New photos here:
https://photos.app.goo.gl/bFvUHtGWvEhxvc368
The head gasket had black parts/spots mostly between cylinder 2-3 and 3-4.
I think the hone on the cylinders is ok, it's vissible and you can feel it under finger.
Push rods are worn out i'm sure. You can even see on a few that they are shorter than the others = rocker arms are worn out too.
The lifters have some cracks, and on most of them the edge is very sharp.
Pistons 1-4 looks nice for me, but 5 and 6 have some different, like they would burn oil?
Based on this I'm also 99% sure i need to replace my camshaft.
Do you guys see anything i missed?
Any suggestions?
Btw, do you think this is still original head gasket? Or was it replaced?
New photos here:
https://photos.app.goo.gl/bFvUHtGWvEhxvc368
The head gasket had black parts/spots mostly between cylinder 2-3 and 3-4.
I think the hone on the cylinders is ok, it's vissible and you can feel it under finger.
Push rods are worn out i'm sure. You can even see on a few that they are shorter than the others = rocker arms are worn out too.
The lifters have some cracks, and on most of them the edge is very sharp.
Pistons 1-4 looks nice for me, but 5 and 6 have some different, like they would burn oil?
Based on this I'm also 99% sure i need to replace my camshaft.
Do you guys see anything i missed?
Any suggestions?
Btw, do you think this is still original head gasket? Or was it replaced?
Good job on the photos. Not good on the cracked lifters. Cylinders look half decent. To me it looks good for a new cam, lifters, pushrods, and a new head gasket. You'll need to set the preload on the lifters properly and you should be good to go. This looks like a minimal rebuild to me. The head gasket needs to be installed correctly and I can offer some help there. Likewise, I'll give you the procedure for setting the lifter preload properly. You should have this engine running well in a short length of time. Also, while the head is off, spray GumOut into each cylinder to free any stuck-closed piston rings.
Best regards.
CJR
Best regards.
CJR
What about rocker arms and head bolts? For bolts I have found 1 set in poland, but it looks different, and i'm not sure if it will fit.
Mine are for 6 point (hex) ~17mm socket.
The one i found are for 12 point 13mm socket.
https://www.usauta.pl/index.php?cPath=3:53:1301&pID=14707
Great
I'll let you know when I will get all the parts, and prepare my valve head.
I want to resurface it.
What kind of product exactly?
I cannot buy any of gumout products in Poland.
I wanted to pour there engine flush or maybe a diesel fuel?
Btw, what can you say about new camshaft from CROWN automotive?
IF i will order parts in Poland i can choose only between NTY, and CROWN...
1. Rocker arms seem to last forever and are inexpensive. If you think you need new stock ones then get them. Likewise, replace the pushrods with the new cam and lifters.
2. I'd stay away from torque-to-yield head bolts that can only be used once and then must be discarded. Older XJs had reusable head bolts. ARP head bolts are excellent and reusable if you can get them over there.
3. GumOut is a carb cleaner which has two solvents; one for oil residues and one for lacquers which are present in gasoline. Check out carb cleaners available there and try them.
4. Definitely have the head resurfaced. If you remove the valves, before resurfacing, mark the valves/springs/keepers/locks for each cylinder and its valves. Likewise, hand-relap the valves to their seats. If you recut the head valve seats, locate the head seats close to the outer circumference of the valves. Reason? As the valves heat-up and expand in diameter the head's seat contact area, on the valve, will move inward towards the valve stem. If the head seat is cut too close to the inner diameter of the valve, the seat can move off the valve as the valve thermally expands and combustion gases will leak by the valve seats.
5. Typically, companies buy camshafts from cam grinders and rebrand them. I haven't used Crown cams but would expect them to be OK. I've only used Chevy, Crane, Comp, and Edelbrock cams and have had stock Jeep cams reground to custom durations and lifts.
Best regards,
CJR
2. I'd stay away from torque-to-yield head bolts that can only be used once and then must be discarded. Older XJs had reusable head bolts. ARP head bolts are excellent and reusable if you can get them over there.
3. GumOut is a carb cleaner which has two solvents; one for oil residues and one for lacquers which are present in gasoline. Check out carb cleaners available there and try them.
4. Definitely have the head resurfaced. If you remove the valves, before resurfacing, mark the valves/springs/keepers/locks for each cylinder and its valves. Likewise, hand-relap the valves to their seats. If you recut the head valve seats, locate the head seats close to the outer circumference of the valves. Reason? As the valves heat-up and expand in diameter the head's seat contact area, on the valve, will move inward towards the valve stem. If the head seat is cut too close to the inner diameter of the valve, the seat can move off the valve as the valve thermally expands and combustion gases will leak by the valve seats.
5. Typically, companies buy camshafts from cam grinders and rebrand them. I haven't used Crown cams but would expect them to be OK. I've only used Chevy, Crane, Comp, and Edelbrock cams and have had stock Jeep cams reground to custom durations and lifts.
Best regards,
CJR
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