Until you get the valve out and inspect the seat for any roughness and pitting, you won't know. If the exhaust valve has been leaking for some time, the seat may be damaged (burned or pitted). Normally lapping is all that is required unless the problem has existed for a while. These are pretty good engines and hold up well.
94 Sundance Exhaust Valve Replacement / Lapping
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Our 94 Sundance @ 225,000 on its 2nd engine was beginning to overheat. Like many of my 2.2/2.5L Mopars I felt it was time to replace the head gasket/thermostat and timing belt. The head is off and I have found one of the exhaust vlaves to be burned or chipped with enough metal missing to prevent sealing on the valve seat. I used to have a box of good used I & E valves from 2.2/2.5's I have worked on over the years but regret that I gave them away. Our local supplier had one on their shelf and I;ll consider myself lucky seeing these engines are dwindling with limited supplies available.
I would like to replace this valve with the new one but need advice on preparing the valve seat. I have a lapping tool and compond to prepare the seat surface to imporve sealing and heat transfer.
Your advice on technique would be appreciated.
Thanks in advance
Alderfrove
I would like to replace this valve with the new one but need advice on preparing the valve seat. I have a lapping tool and compond to prepare the seat surface to imporve sealing and heat transfer.
Your advice on technique would be appreciated.
Thanks in advance
Alderfrove
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I recently had the heads of my 92 Ranger 3.0 off, and decided to lap the valves, clean them, new stem seals among other things. I used a lap stick, that POS suction cup thing about twice and gave up on it. So to speed up the process I applied some compound the the valve, dropped it in the head, attached a cordless drill to the other end....gently and got-er-done. When seats are freshly machined and valves are new it's not necessary to lap them. Once I have the springs in I will pour a liquid in the port to see if the valves leak excessively, the liquid should hold a few seconds at least.
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The valve seat appeared good. I applied the grinding compound to both replacement valves and seats and used a drill both clock and counter clockwise. Cleaned surfaces and reassembled with new Gasket. New timing belt + water pump installed on this 2.5L. Hopefully she'll run well. This car is simple in design and handles beautifully. No reason why it can't continue through the years. IF further issues persisit not I'll buy a complete 2.2L longblock from the wreckers with good compression for $200 and go from there.
These were very well designed and built engines for their time and that is why I continue to hold on to mine. The simplicity makes it so easy and inexpensive to maintain these that I continue delay updating to newer models. It seems like every year I think about just getting rid of my EEKs, but then I realize that the basic function of getting around reliably is still there.... plus I see many people getting 300,000 mile + without having to touch the engine bottom. The only time I had to get into the engine was just for a headgasket change. If the previous owner(s) changed the oil regularly and didn't let it overheat or get low on oil, you should have a pretty reliable and good running vehicle. Keep us posted.
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260 Posts
Thanks John!
IT seems that this vehicle was well maintained by an elderly owner who over the years could afford to regularly care for her car's needs. There is no way of knowing but it seems that the oil was changed regularly as per stickers on windshield. The interior is as clean as it was the day she bought the car.
The suspect valves were replaced and seats lapped. Compression is restored with a smooth idle. The head had no more than 0.002" variation in trueness. Vehcile runs well, however when I replaced the ALT belt with a new PRESTONE brand belt,there was a loud squeal. Water test confirmed belt issue so belt dressing was sparingly added and all is normal.
I like the simplicity of these engines and their fuel economy still is impressive today. Perhaps we'll get another 7 years from this car.
I fought for years with my alt belt, every year it would begin to scream around december when the temp dropped, eventually I had to replace it. Somewhere on this forum I was told about overtightening the tensioner would put the alteranator pulley out of alignment, and to replace the alt bushings. I did that, replaced the tensioner due to the rubber part was shot, and got it just tight enough and it has been on there about 4 years. Now on occasion when the headlights are on and blower is on full it will chirp a bit but not to bad. What a really stupid design!
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12,300 Posts
Chirping is either a loose or worn belt, or a pulley out of alignment. I never use belt dressing, it covers up the real problem. You can have a pulley off less than 1/8" from the plane of the other pulleys on that belt, and it will chirp. Fine-tuning the alignment has always fixed this problem for me.
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260 Posts
The old belt had factory cuts in the alt drive belt which appear like dashes instead of a steady series of parallel lines. The new belt , which squeals, is esgined with continuous lines.
The alt was not changed. How does one adjust the sleeve so that the pully is in alignment with the others?
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12,300 Posts
You install new bushings and you tap the metal insert collar sideways, that the pivot bolt rides through, to get the correct lateral adjustment. It takes several iterations before you get it right.
I replaced my bushings (why did they put bushings here anyway?) then I turn headlights on and blower on full I adjust tension as tight as it will allow before it chirps, and it isn't very tight. On humid mornings it might still chirp with lights and blower on full but it isn't too bad.
Does anybody make a solid metal bushing? never seen and engine with such a setup.
Does anybody make a solid metal bushing? never seen and engine with such a setup.
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6,102 Posts
Additionally, I would look at the fuel system itself as the reason for the burning valves. Kind of in an era where injectors or TBI is on the car, if injectors, get them cleaned. At this date and time, with EFI per cylinder, if everything is working properly, valves don't burn, they only seem to burn when injectors aren't equally shooting fuel.
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