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Discussion Starter #1
Hi guys,
I finally got around to pulling my valve cover today for a visual inspection of the cam shafts.
They appear to be perfectly smooth, no scoring, ridges. I rolled the car in fifth gear so I could look at multiple views/angles.

Having looked at many 911 camshafts over the years (all lobes are very shiny), the Lotus cam shaft lobes are nice and shiny and some
of them are kind of half shiny and half a darker black/dark gray color. All super smooth, just odd color.

Is that normal?

Thanks.,
Henry
'07 Exige S
1261854
1261855
1261853
 

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Is there a definitive guide to which models and years of production were affected by the flaw?
No. It's still very much a debate as to why it happens.

San
 

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No. It's still very much a debate as to why it happens.

San
This is really odd to read. There can be 3 reasons why this problem occurs.

1. Insufficient lubrication- The oil used does not have the ability to prevent metal on metal contact.
2. No lubrication- The lubrication system fails to provide lubricant at the right position to the camshaft to again prevent metal on metal contact.
3. Camshaft metallurgy- The camshaft's metallurgy is not performing as designed.

The lubricant industry conducts failure mode analyses every single day. I work in the industrial lubricant business so cannot really speculate on automotive applications but I have seen first hand the intense efforts that are put into solving lubrication problems. It is half our business.

Any reasonably skilled automotive lubrication engineer could trouble shoot this problem and determine the cause.

Why has Lotus not done this?
 

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This is really odd to read. There can be 3 reasons why this problem occurs.

1. Insufficient lubrication- The oil used does not have the ability to prevent metal on metal contact.
2. No lubrication- The lubrication system fails to provide lubricant at the right position to the camshaft to again prevent metal on metal contact.
3. Camshaft metallurgy- The camshaft's metallurgy is not performing as designed.

The lubricant industry conducts failure mode analyses every single day. I work in the industrial lubricant business so cannot really speculate on automotive applications but I have seen first hand the intense efforts that are put into solving lubrication problems. It is half our business.

Any reasonably skilled automotive lubrication engineer could trouble shoot this problem and determine the cause.

Why has Lotus not done this?
Your points #1 and #2 can have any multitude of root causes. Personally, I subscribe to the overcooling theory which yields your point #1. Toyotas with the 2zz don't seem to have the wiping issue we have in the Lotus, so the extra coolers are the biggest difference in the oil's eyes.
 

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Your points #1 and #2 can have any multitude of root causes. Personally, I subscribe to the overcooling theory which yields your point #1. Toyotas with the 2zz don't seem to have the wiping issue we have in the Lotus, so the extra coolers are the biggest difference in the oil's eyes.
Switching to a lower grade viscosity oil should rectify the problem in this case then.
 

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Switching to a lower grade viscosity oil should rectify the problem in this case then.
I prefer blocking the oil coolers when I am not driving hard. I created foam plugs that I could pop in and out as needed, and I watched my oil temps. On track, the oil gets pretty hot, so running a lighter viscosity would not be a one-size-fits-all solution.
 

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Your points #1 and #2 can have any multitude of root causes. Personally, I subscribe to the overcooling theory which yields your point #1. Toyotas with the 2zz don't seem to have the wiping issue we have in the Lotus, so the extra coolers are the biggest difference in the oil's eyes.
I agree. People not waiting the 20-30 minutes after coolant is fully up to temperature before using cam switchover.

Switching to a lower grade viscosity oil should rectify the problem in this case then.
Nope. Pls see my reply an inch or so up.
 

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Plural of Lotus is Lotus
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I bought an 05 with a suspect cam and replaced it with OEM (Toyota). I didn't last 5K miles. I then installed a hardened version of the cam from MonkeyWrench. Same profile, just harder. I ALSO installed a Mishimoto sandwich plate and 200 degree thermostat to help the oil get warmer BEFORE heading up to the coolers and circulting back. I ALSO installed baffeled oil pan, oil temp/pressure sensors and gauge. Since doing all this and a 2019 of maybe 6 track days, cams are smooth as glass. I did measure the oil temp when water temp gets to 160 (this is the point at which the car will let you jump on the 2nd cam) and it was way too cold.

Warm oil (that circulates properly) is your friend. As mentioned above, don't mess with the viscosity - Just wait until the oil is warm enough (say 180 degrees or so). 20 minutes should do it.
 

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This valuable info. Thanks, JF.
 

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I bought an 05 with a suspect cam and replaced it with OEM (Toyota). I didn't last 5K miles. I then installed a hardened version of the cam from MonkeyWrench. Same profile, just harder. I ALSO installed a Mishimoto sandwich plate and 200 degree thermostat to help the oil get warmer BEFORE heading up to the coolers and circulting back. I ALSO installed baffeled oil pan, oil temp/pressure sensors and gauge. Since doing all this and a 2019 of maybe 6 track days, cams are smooth as glass. I did measure the oil temp when water temp gets to 160 (this is the point at which the car will let you jump on the 2nd cam) and it was way too cold.

Warm oil (that circulated properly) is your friend. As mentioned above, don't mess with the viscosity - Just wait until the oil is warm enough (say 180 degrees or so). 20 minutes should do it.
I completely agree about oil needing to be warm enough before using the second cam. Cold oil means higher viscosity, more internal pressure drop and less flow to the cams.

@JFHughes08088 Thank you very much for the info on the sandwich plate. I checked MW's site and the Mishimoto site for the thermostatic plate. Mishi lists one for Subie and Nissan applications, but nothing for Toyota. Any chance you have the PN?

Many thanks,
Dan Wise
 

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Plural of Lotus is Lotus
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Having looked at many 911 camshafts over the years (all lobes are very shiny), the Lotus cam shaft lobes are nice and shiny and some of them are kind of half shiny and half a darker black/dark gray color. All super smooth, just odd color.

Is that normal?
The dull gray color is an anti-corrosion coating applied to the camshafts at the factory. Where you see shiny metal is where the coating has been worn away. It is 100% normal.
 

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This

and this
Thanks so much, JF,
So this plate replaces the existing plate. Correct?

Dan
 

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Discussion Starter #17
@StressCraxx - I am using the identical Mishimotot sandwich plate. You need to purchase new fitting that the oil lines thread in to.
Contact ExigeGus - he sells the fittings
 

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Discussion Starter #18
The dull gray color is an anti-corrosion coating applied to the camshafts at the factory. Where you see shiny metal is where the coating has been worn away. It is 100% normal.
Ok, great, thanks for letting me know.
 

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Thanks so much, JF,
So this plate replaces the existing plate. Correct?

Dan

When you purchase the 200 degree oil thermostat, make sure to test it, the first one they send me was a 185 degree one, no good for this use.
 

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...what henry said. Exigegus has the fitting to go from the oil cooler lines into the plate.
 
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