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94 Mazda 626, unexpected pressure in engine
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Norder
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Jun 12, 2011, 1:22 AM
Post #1 of 20
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94 Mazda 626, unexpected pressure in engine
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I have a 94 Mazda 626, either ES or LX model, with the 2.5L V6 KL-DE engine, according to what research I've done on it, and what I saw posted on this site, it isn't an interference type engine. With that understanding I have been going about trying to replace my timing belt. It seized when one of the regular idler? pulley's bent off alignment and the belt chewed into the plastic casing as I was attempting to start the car and/or right after it started and I tried to back up. After much hassle with many a frozen bolt, I finally got it all removed and was ready to align the camshafts to TDC #1. It is a DOHC motor and my problem is when I attempted to rotate the front camshaft (side-mounted engine) that is connected to the distributor, pressure built up against the ratchet I was using. I had already removed the spark plugs. It rotated between a quarter and a half turn before the pressure built until I couldn't turn it further without fear of breaking something, and when released it spun back into place as if it had been a wound spring. Someone suggested the pistons needed to be in neutral position and perhaps they were contacting when I attempted to rotate the camshaft, but it didn't stop the rotation as if hitting something but acted as if I were fighting against a high tension spring. With the spark plugs out, it was my understanding the pressure wouldn't build. The crankshaft is at the marking for TDC #1 already. The camshafts need to be before I can install a new belt, any help would be greatly appreciated.
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Hammer Time
Ultimate Carjunky
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Jun 12, 2011, 4:46 AM
Post #2 of 20
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Re: 94 Mazda 626, unexpected pressure in engine
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That's just the valve pressure sliding off high cam,........ completely normal.
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Norder
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Jun 12, 2011, 6:01 PM
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Re: 94 Mazda 626, unexpected pressure in engine
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That is a relief to hear, but in that case how do I proceed to align the camshafts? Do I need to release that pressure somehow? If I attempt to force it the camshaft simply rotates back to where it was and the pressure is fairly extreme so how would I make it not counter-rotate so it can be aligned? Thanks for the quick response btw.
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Hammer Time
Ultimate Carjunky
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Jun 12, 2011, 6:04 PM
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Re: 94 Mazda 626, unexpected pressure in engine
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Welcome to my world. They make tools to hold the gears in place but that's part of doing a timing belt, dealing with stuff like that.
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Norder
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Jun 12, 2011, 10:35 PM
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Re: 94 Mazda 626, unexpected pressure in engine
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Any advice then? Will forcing it to turn past that pressure be a problem? Currently it won't even turn halfway before that pressure is damned near solid, and instructions in repair manual suggest breaker bar but I need to know if I will cause damage forcing it. How would I even rotate the entire engine twice once the timing belt is installed to test the timing mark alignment as the manual instructs if the camshafts don't rotate really?
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Hammer Time
Ultimate Carjunky
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Jun 13, 2011, 3:05 AM
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Re: 94 Mazda 626, unexpected pressure in engine
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My advice is to give this job to a professional. You don't have sufficient experience with timing belts and may end up doing damage to something.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Norder
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Jun 13, 2011, 11:40 AM
Post #7 of 20
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Re: 94 Mazda 626, unexpected pressure in engine
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I knew that from the beginning when I embarked on attempting to replace the timing belt. Had six different mechanics flake on me and the car itself isn't worth sinking any more real money into. If I cannot manage this repair myself then the car is going to pick-n-pull as it's been a real money pit. Or some sort of scrap yard. Please reconsider some of my questions or point me to someone who will because a professional is no longer an option.
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Hammer Time
Ultimate Carjunky
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Jun 13, 2011, 12:31 PM
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Re: 94 Mazda 626, unexpected pressure in engine
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Aligning a timing belt is something that comes with practice and experience. Not something I can type to you.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Norder
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Jun 13, 2011, 12:45 PM
Post #9 of 20
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Re: 94 Mazda 626, unexpected pressure in engine
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I have clear instructions in my repair manual and as far as actually aligning the belt I believe that the markings should be enough. There's just the problem of the camshafts not turning. If this is normal pressure then can I remove the valve cover and do something to release that pressure so the camshafts will simply rotate as I wish? If not then am I to force it to rotate with a breaker bar and use a helper tool to hold it in position once I do, and will the cams forcefully rotate the engine once I install the new belt and remove the piston holder? I've done some research and can find no one mentioning this problem whatsoever besides a warning of not letting the cam and crank move independently of each other which was impossible since the timing belt was seized and had to be removed beforehand. I don't need help or an explanation about how to do timing belts, just addressing this one issue with the camshafts and I can deal with the results and/or consequences. I have to try, or else six grand of what I've put into this car turns into two-hundred bucks scrap.
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Tom Greenleaf
Ultimate Carjunky
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Jun 14, 2011, 12:53 AM
Post #10 of 20
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Re: 94 Mazda 626, unexpected pressure in engine
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What are you? The King of the run on sentence? Have you been to school at all?
T
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Norder
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Jun 14, 2011, 3:52 AM
Post #11 of 20
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Re: 94 Mazda 626, unexpected pressure in engine
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I don't know, maybe it has something to do with the total lack of information in any response I've received past the first. Perhaps by going over points, repeatedly, in different ways, will get some better response than 'you can't jackass'. Which is all Hammer Time has for me so far. I'd really rather a lack of responses than anything but the info I'm asking for. Thanks for your interest.
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Hammer Time
Ultimate Carjunky
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Jun 14, 2011, 5:41 AM
Post #12 of 20
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Re: 94 Mazda 626, unexpected pressure in engine
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Don't shoot the messenger if you don't want to hear the truth. You don't know what you're doing and shouldn't be messing with it.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Tom Greenleaf
Ultimate Carjunky
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Jun 14, 2011, 9:09 AM
Post #13 of 20
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Re: 94 Mazda 626, unexpected pressure in engine
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Norder - sorry from me. You are as welcome here as anyone and I'll leave it to Hammer to keep me in line. Smile bros,
Tom
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Norder
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Jun 14, 2011, 1:12 PM
Post #14 of 20
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Re: 94 Mazda 626, unexpected pressure in engine
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Thanks Tom, and no problem, it's just frustration over the vehicle. I knew from the beginning that there was a high chance I wouldn't be able to replace the timing belt. Or I'd make it worse. Still, I would have paid a pretty penny to find out what I have on my own. If I just understood how to deal with the cam pressure I feel that I could finish the job considering how far along I came. The repair is a simple matter of removing a broken off bolt for the idler pulley. Took me a week to get the belt off nearly, mostly due to lack of the proper tools. Telling me I shouldn't be doing this isn't helpful since I'm telling you it will be scrapped otherwise. If I mess the car up, I am in no worse position than I am right now, about to sell it to pick-n-pull. You don't have to explain if you don't want to, but hell I see people answering such general questions online as 'how to change a timing belt' and they actually get some responses. I just want the cam pressure resolutions.
(This post was edited by Norder on Jun 14, 2011, 1:17 PM)
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Hammer Time
Ultimate Carjunky
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Jun 14, 2011, 1:41 PM
Post #15 of 20
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Re: 94 Mazda 626, unexpected pressure in engine
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You have already been told on 2 different sights that is normal and you just have to deal with it. When the cam lobe tries to open the valve, the spring pressure pushes back.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Norder
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Jun 14, 2011, 2:32 PM
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Re: 94 Mazda 626, unexpected pressure in engine
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Back to useful discussion, thank you. I spoke to a mechanic who runs his own shop locally and he thought the pressure was more than it ought to be from my descriptions. If this is normal pressure, even though it becomes almost impossible to turn it using a ratchet, then it sounds like I just use a breaker bar to push past it. In other folks instructions they mentioned attaching a couple open wrenches to the camshafts and clamping them together to prevent movement. The more I read though, the more it seems the pressure is more than it should be. Might I be on TDC exhaust stroke instead of compression and that is causing the piston to valve pressure? The pressure is so great that I believe turning the crankshaft after belt installation won't turn the camshafts accordingly. The resistance on the crank is less than the cam. Shall I 360 degree the crankshaft and try the cams again? Even people who have done multiple timing belts don't seem to know, they say the pressure shouldn't be so great.
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Hammer Time
Ultimate Carjunky
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Jun 14, 2011, 2:47 PM
Post #17 of 20
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Re: 94 Mazda 626, unexpected pressure in engine
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If it's spongy pressure, it's normal. If you hit anything solid, there is a problem.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Norder
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Jun 14, 2011, 3:06 PM
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Re: 94 Mazda 626, unexpected pressure in engine
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Thanks. I spoke to a Mazda tech and he confirmed what you said about that pressure. He did have a suggestion however, if I removed the valve cover and use a wrench inside as opposed to turning it with the camshaft bolt then I can successfully rotate the camshaft without snapping anything. He said if I attempted to rotate it using the camshaft bolt past that pressure that I would cause damage. I am going to get that cover off now, but if this advice sounds solid to you I would appreciate confirmation and the specific portion of the camshaft that I should rotate with the wrench. If you don't know then I'll research further.
(This post was edited by Norder on Jun 14, 2011, 3:07 PM)
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Hammer Time
Ultimate Carjunky
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Jun 14, 2011, 3:10 PM
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Re: 94 Mazda 626, unexpected pressure in engine
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That's a lot of extra work and probably not necessary. There will be a square spot on the cam that you can slip an open end wrench if you do take that route. Moving the cam isn't your big problem. It's trying to hold it in place while installing the belt. You'll end up pretty frustrated.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Norder
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Jun 14, 2011, 4:09 PM
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Re: 94 Mazda 626, unexpected pressure in engine
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I found the square on the camshaft itself about 1/3 of the way in from the cam pulley. It's the only one so I assume that is it. I'm thinking of removing the air intake so I can get the back valve cover as well, since the rear camshaft has the same built up pressure. That is more work, where as removing the front valve cover was simple. What if I use two open wrenches and clamp them together as others suggested? Someone even said zip ties but somehow I doubt that will hold. Still worried about forcing past that pressure. Maybe it won't be so intense at the square. I keep thinking I'm going to cause piston/valve damage if I force it but it's non-interference so should be alright by the way you keep telling me it's all normal. About to move forward with the repair so any info on those points would help a lot. More work doesn't concern me, being successful or finding out it's time to scrap the heap are my only goals.
I've seen multiple suggestions of a bolt or proper sized drill bit inserted in a specific area will also lock the cams in place.
(This post was edited by Norder on Jun 14, 2011, 7:14 PM)
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