a little off for some groups: 1989 Mazda 626 clacking from top of engine
in [Toyota]
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From: Hachiroku ハチロク on 5 Apr 2007 19:00 On Wed, 04 Apr 2007 21:32:23 -0700, Michael Pardee wrote: > "Hachiroku ????" <Trueno(a)AE86.gts> wrote in message > news:JYiQh.8917$IY4.8369(a)trndny03... >> I'm crossing this to Honda and Toyota because there are some sharp >> individuals in these groups, and also in the Ford group since this is a >> common engine among Fords, IIRC. >> >> The problem: 1989 Mazda 626. Over the course of the winter, occasionally >> on cold days the engine would clack from just under the valve cover. >> Since I seem to recall seeing somewhere that this engine has hydraulic >> lifters of some sort, it just seemed that allowing the engine to warm >> and circulate oil would cause this to stop as the lifters (or whatever!) >> responded to the rise in oil pressure. It always worked, and when it >> didn't, I would check the oil, add 2/3 3/4 of a quart, and be done with >> it. >> >> Saturday the oil was down less than 1/4 from the Full on the dipstick. >> Since it's getting an oil change in about 500 miles, I let it go. >> >> This morning I had to make a trip about 30-35 miles one way. When I >> returned home I noticed the engine was making a louder noise than usual, >> and when I went to investigate it was the clacking noise from under the >> Valver Cover. I shut the car off and let it cool. >> >> Before I left the house later, I added 2/3 of a quart of Castrol >> Synthetic (the closest bottle of oil I had) and started it. I let it run >> for a while but the clacking continued. I added about 1/3 quart of >> Marvel Mystery and let it run till warm and the noise never went away. >> After parking the car for about 2.5 hours, when I started it up the >> clacking was still there. I drove home still clacking, but quieter. >> >> The partiulars: this is the 2.0L 12-vavle engine, OHC, new timing belt >> <3,000 miles ago, fuel injected. It's going to get parked in 1-3 weeks >> when I take my Supra out of winter storage. Any ideas about what it is >> or what I should look for? If I find the Haynes I will be able to answer >> more questions concerning the motor. It looks good and runs great, even >> with the clacking. >> >> >> > I don't have much experience with hydraulic lifters, but the one time I > had to replace some I replaced them all. Replacing them isn't without > risk, since the cam lobes were fitted to the originals and now they're > pushing a whole new set, but the buzz was that if one or more were > collapsed the others were in similar shape. I got rid of the car for other > reasons a few months later. > > I was advised any attempted repair is temporary. Maybe that would have > been good enough for a few months :-( > > Mike Hmmm...excuse me if I seem a bit ignorant here. What this car has is Hydraulic Lash Adjusters (HLAs). It is at the end of the rocker and pushes the shims over the valves down to open the valves. (Um, what's the difference between this and a hydraulic lifter...?) You can replace them without removing the rocker shafts, but I have seen a couple write ups that say they don't go bad for no reason, and the reason is usually that the holes that feed the oil to the HLAs are plugged. So, it is possible to clean the HLAs and the holes feeding them oil. I guess I'll investigate when I park the Mazda and put the Supra on the road...! |