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Discussion Starter #1
Hey guys, im on my way to installing a 91+ exhaust cam into a my 90 FWD. Now, Im not sure whether or not 91 and 92 are different than 93's and 94's but I really dont even know for sure if they are different and I dont have the time to wait around for a 93+ exhaust cam to show up. Unless if anyone has one for sale that they would like to sell :cool:

Anyways, that being said, I would like to take the shortcut in installing the cam. Meaning, I dont want to remove the timing belt. I know to use zip ties and vice grips to hold the belt to the cam gear, and I will also have someone else helping to make sure nothing gets screwed up or anything.

Now, my question is, is there a specific spot where I should line up the cam gear? Secondly, wont some of the exhaust valves be open while removing the cam? How will they stay open while removing the old cam and installing the new one? Finally, wont the timing belt loose some of its tension when the cam gear has no cam on it? What precautions should I take to insure that nothing screws up? Lastly, how long will this take approximatly?

My car is due shortly for a timing belt, but I dont have the finances set up right now to do it at this time. :)

Oh yea and one last thing, I will be sure to write a nice detailed review of this mod and if it is effective or not. Stay tuned... :cool:

Thanks for the time,
Nomie
 

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To be honest with you, I dont thinnk I have ever heard of someone doing a cam swap while leaving the cam gear in the car. Ide like to see hear how this is done. Im definatley not saying it cant be. Like you said, I dont see how the came gear will stay in place, or even how you're going to remove the cam from the gear while still in the head.
 

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I tried it with out removing the timing belt. went ok till I tried to put the cam gear on to the cam. With all the tension on the belt I couldnt maneuver the gear to get it on.

I ended up just using my timing belt tool and compressing the tensioner down to give me slack in the belt. Got the gear on the cam with the belt on it.

So it can be done, but I would do it expecting you may need to remove the timing belt.
 

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sbiggi said:
...timing belt tool and compressing the tensioner down to give me slack in the belt. ....
thats how it is done.... you need to have the compression tool for the tensioner...

and no there is no change from the mid 91 manufacture date on to the late 94 manufacture date that i know of... cant say anything about the pre may 91 manufacture date cam...
 

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Discussion Starter #5
These are the part number from CAPS for M/T cars:

03/89-06/90 Intake: MD128974, Exhaust: MD128969
07/90-on Intake: MD128974, Exhaust: MD128973

So the exhaust cam is definitely different on the 90 cars.

Instances from people who have 90 cams vs. others:

You're correct the 1990 cams do begin to "drop off" after 5K. My car had most of the same setup as yours. March 1990 build date. I too had to shift a 6.5K to maintain power levels. 5th gear was always weak too. Even with a Big16G.

I never changed my cams but, rode in a car with a similar mods. two differences though, web cams (546/547) and TMO ECU upgrade. Holy crap. big difference. Very lumpy idle from the cams.

Im just getting so excited reading all of this stuff...I hope I dont expect too much out of the exhaust cam. :D

Nomie
 

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I tried this as well and failed.. I know it has been done a lot of times but to me it seems now it would have been easier to do it the regular way.

My screw up apparently happened while loosening the sprocket bolts. Those suckers were tight. We had to put a pipe on a 12" breaker bar.. Both cams/sprockets jumped a couple of theeth in the process and were off after the smog cleared.

Another PITA is using that tensioner tool. The Mitsu one is expensive. RRE has their own version for $10. Cover it completely with antiseaze. If that thing breaks while being in there you are fu*ed. You 'll have to take all apart and drill it out otherwise it will keep on pushing on the tensioner arm and your engine will stay inoperable untill you remove it.

As far as what marks to align, it is better to read a t-belt job in some manual than for us to explain. If you do happen to do it the short way, then you gotta worry only about sprockets' marks for them to be on the same plane as centers of sprocket bolts while being at their closest point; three o'clock for exhaust and nine for intake as you look from the timing side.

Do NOT forget to bleed the lifters or you 'll bend some valves.
 
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