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Discussion Starter #1
I inspected my 22k mile cams for the first time today. I've had the Elise for a year and a half but this is the first time I've been inside the valve cover. The intake cam lobes have more of a visual indication of wear compared to the exhaust but no ridges or clear removal of material which was a big relief. On the exhaust side, one of the lobes looks like it had a bit of debris get caught between slipper and lobe at some point but the scratch is only on the closed-valve portion of the cam profile.

One odd thing that I noticed is that the wear on the exhaust cam is perfectly centered on the lobes but the intake is not. It's not consistent between lobes and they are all generally shifted toward one side of the lobe. I remember seeing this on another member's cam pictures as well. I know there are manufacturing and assembly tolerances but I was surprised to see the slipper wear so close to the edge of the lobe on cylinder #4.

I also took the opportunity to replace my lift bolts and was surprised to see the amount of wear after so few miles.

Cylinder 1:
1254816


Cylinder 2 (the odd pattern at the tip of the lobe is the mark from my finger in the oil film):
1254817


Cylinder 3:
1254818


Cylinder 4:
1254819


Lift bolts:
1254820


Overall:
1254821

1254822
 

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I'm just a stitch over 30k and have to yet to personally pull the valve cover. That'll probably be a spring task. The only thing that makes me think I may have something to concern myself with is that after I'm up to temp, there's a slight audible tapping/ticking. Only when it's warm though :/ might as well replace the lift bolts when I do get around to it though. Nice post. Thanks.
 

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Thanks for the post. Do you have a link to the lift bolts?

They're cheap, seems like a really easy preventative item that should be done every few years.
 

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Discussion Starter #5
I have yet to find a good explanation of what exactly lift bolts do. All I have seen says they are a wear item and wear faster when on lift (high speed cam lobe). There is clearly something rotating around them as evidenced by the wear marks. They are easy to replace with the valve cover off. Just remove them and install new ones.

I also replaced the valve cover gasket since re-using 15 year old rubber didn't seem smart as well as the o-ring that seals the oil squirter tube on the valve cover into the feed in the head.

Toyota P/N's:
Lift bolts (2 required): 90105-06293
Valve cover gasket (1 required): 11213-88600
o-ring (1 required): 96741-19009

Under $20 for everything. Like TachItUp said, the lift bolts were less than a buck a piece and the Celica guys seems to recommend replacing them every few oil changes. If they break, they're a pain to get out.
 

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I have yet to find a good explanation of what exactly lift bolts do.
The lift bolts hold the rocker arm shaft in place. The saft essentially floats. The lift bolts hold it so it does not rotate. There is an oil passage through the middle of the shaft and holes that line up with the rockers. Because the shaft floats, vibration causes the wear on the lift bolts.
 

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I have yet to find a good explanation of what exactly lift bolts do. All I have seen says they are a wear item and wear faster when on lift (high speed cam lobe). There is clearly something rotating around them as evidenced by the wear marks. They are easy to replace with the valve cover off. Just remove them and install new ones.
People call them 'lift bolts' but all they are doing is locking the rocker tube in place. More like a set screw/dowel. The wear comes from the rocker arm tube moving back and forth as the rockers go up and down. When they break that whole tube can turn and it either blocks off the oil to the second cam plunger (so its delayed or on partial cylinders) or it turns enough to physically jam the plunger.

It probably depends on the tolerance at the start (same with cam lobe wear). My bolts looked perfectly fine at 35k miles but I changed them anyway.

Your cam lobes dont look bad. I have one lobe that has a streak like yours. Its more of a colour blemish than a scrape. Ive checked it multiple times over 8kmiles and it hasnt changed. If you cant feel any ridges youre probably ok.
 

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I have yet to find a good explanation of what exactly lift bolts do. All I have seen says they are a wear item and wear faster when on lift (high speed cam lobe). There is clearly something rotating around them as evidenced by the wear marks. They are easy to replace with the valve cover off. Just remove them and install new ones.

I also replaced the valve cover gasket since re-using 15 year old rubber didn't seem smart as well as the o-ring that seals the oil squirter tube on the valve cover into the feed in the head.

Toyota P/N's:
Lift bolts (2 required): 90105-06293
Valve cover gasket (1 required): 11213-88600
o-ring (1 required): 96741-19009

Under $20 for everything. Like TachItUp said, the lift bolts were less than a buck a piece and the Celica guys seems to recommend replacing them every few oil changes. If they break, they're a pain to get out.
Thanks for the link. Where do you get the rest of the parts for under $20.00. A no brainer for that price.
 

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Discussion Starter #9
I bought them online from a Toyota dealership online. There's a bunch of places that sell the parts so just find one with the best price and shipping, or see if a local Toyota dealer has good pricing on them. Those are the only 3 parts you need to do a valve cover removal, cam inspection, and lift bolt replacement.
 
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