Just replaced timing chain, but noisy lifters/rockers.. Now what??
I am working on a 1992 NIssan Stanza GXE for my son. The car has 190,000 miles on it and is in decent shape. I got it from my brother, who said the car wouldn't go over 45 MPH. My son and I test drove the car on the highway and got it running up to 65 MPH, although the car seemed to surge. On the way home from the test drive, the car just cut off. Upon further checking, it sounded like the timing chain slipped and the pistons where smacking the valves. Sure enough, upon teardown, the valves were bent and the timing chain plastic guides were broken up, allowing the chain to flop and jump.
Anyway, we put in a new chain set with steel backed rails, crank seal and had new valves & seals installed in the heads. Upon re-assembly, the car fired right up, however, the lifters/rocker arm assemblies are making quite a racket. Since the valves were bent good, should I replace the lifters/rocker arm assemblies or does it take quite a while (more than 5 minutes) for them to pump up?
I'm not positive but I think your rockers should be ok since it is running alright (except for the noise). The noise your hearing is likely from air that has got into the rockers. If you had the rockers off the engine they can drain of oil and fill with air. This will cause the rocker noise. Especially if they were turned on their side. I have read that to get the air out you need to run the engine for about ten to twenty minutes at around 1000 rpm.. During this time the rockers will make the ticking sound. Gradually during this time the noise will subside as the rockers are purged of air.
I'm looking at replacing the timing chain on my 90 stanza (KA24E engine). If you have the KA24E did you have to lower the engine some to get the timing cover off? Also, how did you hold the crankshaft pulley to remove the nut?
Macc, you are right about the KA24 rockers. They did purge of air after driving the car around the block. All seems well now.
As for removing the timing cover, that job is a lot of work. I've been doing car work for years, so I have an in-garage lift, screw-jacks and plenty of air tools. I'm essentially setup like a auto shop. The lower pulley bolt was removed with an 1/2" air impact wrench, so I didn't need anything to hold the pulley. If you have to do it without an impact wrench, pick up a strap wrench (used by plumbers) to hold the pulley while removing the center bolt with a 1/2" drive breaker bar and socket.
I had to lower the motor to get the timing cover off by removing the motor mount closest to the cover. Don't forget to remove the oil pan, as it must come off to remove the front cover (the oil pump pickup is bolted to the front cover and to the engine). This job takes a lot of time and a lot of parts must be removed to get the front cover off (A/C compressor & bracket, P/S pump, motor mount and bracket, engine stiffner brackets & trans converter cover to get to rear oil pan bolts, etc.).
Macc, you are right about the KA24 rockers. They did purge of air after driving the car around the block. All seems well now.
As for removing the timing cover, that job is a lot of work. I've been doing car work for years, so I have an in-garage lift, screw-jacks and plenty of air tools. I'm essentially setup like a auto shop. The lower pulley bolt was removed with an 1/2" air impact wrench, so I didn't need anything to hold the pulley. If you have to do it without an impact wrench, pick up a strap wrench (used by plumbers) to hold the pulley while removing the center bolt with a 1/2" drive breaker bar and socket.
I had to lower the motor to get the timing cover off by removing the motor mount closest to the cover. Don't forget to remove the oil pan, as it must come off to remove the front cover (the oil pump pickup is bolted to the front cover and to the engine). This job takes a lot of time and a lot of parts must be removed to get the front cover off (A/C compressor & bracket, P/S pump, motor mount and bracket, engine stiffner brackets & trans converter cover to get to rear oil pan bolts, etc.).
Hope this helps..
I just recently replaced the chain/guide/tensioners/oil pump cover/oil pan/motor mount in my 1990 XE. The job is very time consuming and many many components need to be removed. I followed the Haines (Hayes?) manual. Read and re-read all the sections regarding timing cover removal. There are 10 bolts that hold the timing cover on, a few of which are not visible, the worst of which is up behind the rear of the motor near the valve cover and it is behind the p.s. pump. I had all but the driver's side motor mount taken off and supported the entire engine on the air conditioining compressor bracket (rest of the mounts, oil pan were off). Exhaust must be dropped, center member removed and sway bar removed to drop the oil pan. Also note that the Haines manual calls out far too much torque for the oil pan bolts so when you put a new gasket in and put your permatex on the lip of the oil pan cover, just snug everything up evenly and carefully (this takes time), but do not follow torque recommendations in Haines manual as you will force the gasket to squeeze out everywhere.
I was able to get timing cover off by jacking the engine up a bit, then down a bit as needed to get clearance to all the bolts holding it on. You can get the timing cover off w/o removing a/c compressor bracket if you use a die grinder and grind away part of the boss that the tensioner bolt for the compressor belt rides in. It's just one less thing to remove.
Carefully organize and catalog all fasteners removed so you know where they go and that you put them all back in upon reassembly.
The cast aluminum oil pump cover, which is inside the timing cover, was cracked due to the timing chain tensioner breakage. Inspect the pump cover carefully, because you don't want to reassemble everything and find out there is no oil pressure because all the oil pisses through the cover rather than up into the oil galleys as needed.
Also, if you live in a cold climate, very thoroughly clean the oil pan inside and out after removal (looking for debris on the inside and removing sludgey build-ups) and verify that there is nothing more than surface rust on it, especially where the exhaust passes under it. My pan was rotting, yes rotting, in this area which necessitated a pan replacement from local junk yard. Clean, prime, and paint it, if you can.
I am sure there is more, but you are no doubt tired of reading my babble. If you have more questions, please don't hesitate to ask.
Tim
__________________
Tim the diesel man
1990 Stanza 206k miles...make that 212k..214k...237k
Thanks for the information atomicDog and isb360! I replaced my cam over the weekend due to a crack near the cam gear. Upon examining the timing chain I do have a few more questions. Exactly how do you tell if the timing chain is good or bad? Mine has not broke. The chain links, gears, guides etc. all look ok. But here is what draws my suspicion/uncertainty. To install the cam I rotated the crank by hand to set the engine to TDC. At that point I checked the chain tension on both sides and it looked good (less than 1/4" of deflection). After cam installation I rotated the crank again by hand to make sure there was no binding etc. before starting the engine. At this point I checked the chain again and it had alot of slack on the non-tensioner guide side (way over an inch, maybe 2). I then rotated the crank by hand some more and the slack disappeared on both sides. It's almost seems that if the crank turns slightly back (opposite its' normal direction), maybe from some piston compression, the chain develops slack. Any ideas on what is going on here. Why would the slack appear then disappear when turning the engine by hand. Could the spring in the tensioner be hiding a stretched chain when the engine is turned by hand the proper direction. Yet, if the engine kicks back ever so slightly, could the tightening of the chain on the tensioner side push the tensioner in some and result in alot of slack on the non-tensioner side. Sort of lost and confused here. Any thoughts are welcomed! Does it sound like the chain is simply stretched/bad?
Macc, has the chain, tensioners and chain rails ever been replaced on this motor and how many miles does the motor have on it? The motor sounds like it has several miles on it and your description sounds a bit confusing. If you are unsure of the timing components history, I personally would replace them, as my motor (Ka24) had 190,500 miles on it and when it jumped timing, it bent all of the valves. Timing chains do stretch over time and tensioners wear. The timing components for this motor aren't very expensive and are readily available, however, it is a lot of work to install them.
As I told my son when we embarked on this project, to me, it's better to do the job right the first time than to do the same (or related) job twice!!
The chain rides over the cam sprocket on the top, down the right side is the plastic, yes plastic, guide, down to the oil pump/crank sprocket, and up the left side to the spring-loaded tensioning mechanism. Not only will the chain stretch over time forcing the spring and guide to do extra work to maintain chain tightness, but this increases wear on all the components.
The mode of failure in my car was the disintegration of the plastic guide. Some of the pieces fell into the oil pan, others got caught between the chain and the crank sprocket which ended up breaking the cast aluminum oil pump cover.
Springs wear out, plastic guides are essentially sacrificial items, and chains stretch. We know these are interference engines and I know I was lucky not to have trashed the top end of the engine when the guide broke. It is definitely worth changing the chain/sprockets/guides/tensioner if you have over 150k miles -- for peace of mind if not something else.
It is a b!tch of a job which might explain why the parts are not very expensive, but it's worth it.
Tim
__________________
Tim the diesel man
1990 Stanza 206k miles...make that 212k..214k...237k
Thanks for the response atomicDog and isb360. I know the previous owner. He had nissan change the timing components at about 60K. The car now has 120K. I figure at that mileage it would be wise to change it anyway just to be on the safe side. What I am curious about is whether it needs to be done immediately. As I posted earlier, when I turned the engine by hand, sometimes the chain was fairly tight (on both sides). Then at other times, if I turned it some more, it was rather loose (on the non-tensioner guide side). I'm not sure why it was doing this, maybe the spring in the tensioner is hiding the chain slack sometimes and revealing it at others. What I'm looking for is a surefire way to determine how much slack there is in the chain (maybe push in on the tensioner?). If ya"ll have any ideas let me know! Out of curiosity, when ya'll put the new chain on, how much slack did it have without the tensioner acting on it, maybe this will give me a clue? Once again, thanks for any help!
Macc, I know of no way to verify if the chain is good and won't fail in the near future. If it were me, I'd want to pull it down myself and verify what is truly under the timing cover and put new components in for longevity's sake. Hopefully, the right side (facing the front of the motor) chain rail was replaced before with the redesigned, metal reinforced chain rail. Out of curiosity, do you know what caused your cam to crack?
atomicDog I don't know for sure what caused it to crack. I guess it depends on exactly what that cam gear peg is for. Is it solely for aligning the cam gear, preventing the cam gear from rotating on the cam, or both. Since the missing chip is right where the cam gear peg is and the crack originates from there I can only guess two things, depending on the purpose of that peg. One, if the peg is for solely for alignment and the cam gear bolt was ever so slightly loose (even though I didn't notice it when removing it), and it let some of the cam gear's torque act on the peg, then the force on the peg must have started a fracture. I find this scenario hard to believe in that I would think that if the cam gear bolt was slightly loose allowing the gear to move it would have sheared off that peg rather quickly Second, If the peg is for both alignment and anti-rotation then there must have been either a fault (metal fatigue etc.) or the design is is inherently weak. Who knows!!!
If you don't mind let me ask you a few questions about your replacement.
(1) When you put the new chain on roughly how much slack (deflection) did it have?
(2) Is the main reason for lowering the engine to give you room for removing the timing cover off of the crank (I've read that there is not enough room to remove it because of the car's body)?
(3) Is there any gasket (or parts of such) used on the cover or do you only use liquid gasket (other than the crank seal)?
(4) How did you handle the head gasket above the timing cover? Where you able to use the original? Did you have to cut that piece out and fabricate a new section?
(5) On the oil pump is there any seal/gasket that I out to go ahead and replace?
(6) Finally, did you go with genuine nissan parts or auto store? What's your thoughts on this?
If you don't mind let me ask you a few questions about your replacement.
(1) When you put the new chain on roughly how much slack (deflection) did it have?
(2) Is the main reason for lowering the engine to give you room for removing the timing cover off of the crank (I've read that there is not enough room to remove it because of the car's body)?
(3) Is there any gasket (or parts of such) used on the cover or do you only use liquid gasket (other than the crank seal)?
(4) How did you handle the head gasket above the timing cover? Where you able to use the original? Did you have to cut that piece out and fabricate a new section?
(5) On the oil pump is there any seal/gasket that I out to go ahead and replace?
(6) Finally, did you go with genuine nissan parts or auto store? What's your thoughts on this?
Thanks in advance for any help!!!!
Answers (IMHO)...
1) Chain had lots of slack until I put the tensioning assembly in and then it was tight. I could make it deflect, but that was exercising the tensioner. Since the engine only turns one direction, my guess is that when you crank the engine manually the "wrong" way, something in the tensioning/guide system is sticking/catching/binding and causing it to appear as though there is slack. The X-factor is the plastic guide....hard to tell when it's fatigued and going to break
2) Yes, I needed to raise the engine slightly (5-6" maybe) to get at some of the components/bolts, and lower the engine slightly to get at the rest of the components. Front pass side frame rail and suspension bits get in the way. You will find only one position that you can have the engine in where you can extract the timing cover. Of course prying the cover off isn't so bad...it's trying to line it up and get it seated back in place (there are dowel locating pins) without wiping all the permatex off that is the tricky part. Also, if you have a/c, you can grind away part of the compressor belt tensioner boss to avoid having to unbolt it and remove it. It was the only sturdy thing left under there to jack the engine with, so removing it would have been tough. THe cover is cast aluminum, so pry it evenly and gently with as wide of an object as possible to prevent galling the aluminum.
3) permatex only on the cover. the top of the timing cover seals to the head gasket and the bottom seals to the oil pan gasket. If you end up taking the oil pump off/apart from the timing cover, be sure to pack every nook and cranny of it back again with vaseline to prime it. Also, there is what appears to be an oil pressure regulating spring assembly which slips in on an angle from the front of the motor and must be removed prior to removing the timing cover. Don't lose the spring. The plunger for this assembly can be removed with a small automotive magnet.
4) Head gasket is metal composite and the cover peeled away from it nicely. The head gasket kind of dangled in a cantilevered position over the edge of the block until I put the timing cover back on. There is no cylinder pressure over this part of the gasket anyhow...it's just containing oil.
5) If you don't have to take apart the oil pump, there is nothing to replace. It's driven off the crank. I would recommend just taking a peek inside of it to make sure there is no debris in there or that the pump gears are not damaged or destroyed -- now is the time to do it.
6) I bought the chain/tensioner/guide/sprocket kit from ACME for $150 or so. I also bought Moog sway bar end links from ACME (these were rusted to sh!t and needed to be replaced) as well as front center engine mount (also destroyed from age) from ACME as well as the valve cover gasket and oil pan gasket. The only thing I got from Nissan was the oil pump cover which is a dealer only item. THe replacement oil pan is a dealer only item too, so if you can find one in a junk yard...if needed, go for it.
Hope that helps.
Tim
__________________
Tim the diesel man
1990 Stanza 206k miles...make that 212k..214k...237k
If you don't mind let me ask you a few questions about your replacement.
(1) When you put the new chain on roughly how much slack (deflection) did it have?
(2) Is the main reason for lowering the engine to give you room for removing the timing cover off of the crank (I've read that there is not enough room to remove it because of the car's body)?
(3) Is there any gasket (or parts of such) used on the cover or do you only use liquid gasket (other than the crank seal)?
(4) How did you handle the head gasket above the timing cover? Where you able to use the original? Did you have to cut that piece out and fabricate a new section?
(5) On the oil pump is there any seal/gasket that I out to go ahead and replace?
(6) Finally, did you go with genuine nissan parts or auto store? What's your thoughts on this?
Thanks in advance for any help!!!!
1. My chain had plenty of slack, as the plastic guide broke and allowed the chain to somply flop around, causing timing to jump and bending of all of the valves, as this is truly an interference motor!! The flopping chain also did some damage to the back of the timing cover, however, I reused the cover as the damage was relatively minor.
2. The main reason for lowering the motor is to remove & replace the timing cover. Also, you need to lower the car to remove the power steering pump pulley, too. This car is very tight for working space.
3. RTV is the only sealer available for the front cover. Even Nissan doesn't make a gasket for it, nor does the aftermarket.
4. You should be able to reuse your head gasket at the cover. In my case, I installed a new head gasket, as I had to remove the head to repair the bent valves.
5. I did not dis-assemble the oil pump. It worked fine before, so all I did was thoroughly clean the cover with varsol and shot plenty of it into the oil pump to clean it up.
6. All parts were non-dealer (stealer). The timing chain set (tensioner, chain, chain rails, O-rings, crank seal, misc. gaskets) was $71. Engine teardown gasket set was $60. I needed that for the head gasket. I found that it didn't include an oil pan gasket, which must be purchased seperately. Fel-Pro makes an oil pan gasket, as Nissan calls for this to be RTV.
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