cam wiping early catch: what to do? - Page 2 - LotusTalk - The Lotus Cars Community
 2Likes
Reply
 
LinkBack Thread Tools Display Modes
post #21 of 34 (permalink) Old 02-20-2018, 03:05 PM
Registered User
 
Join Date: Nov 2017
Location: Arizona
Posts: 254
Nice data log....and when I got my Elise I immediately put a temp gauge in place that made me modify the system....I was rarely seeing 160 degree oil even on warm days. I just, upon suggestion from some here, put a different 185 thermostat sandwich plate in place...now I am normally 195-205.

I suspect (I've never looked at mine) that there are numerous Elise's with that same type/kind of wear motoring about without issue (street) as I think I see wear but the glare/reflection can deceive the eye.

If you do replace I'd go with a stock grind but harder (Rockwell measured) cam from someone like Monkeywrench...for some piece of mind.

Cool thread.
Reiver is offline  
Sponsored Links
Advertisement
 
post #22 of 34 (permalink) Old 11-19-2018, 03:55 PM Thread Starter
Registered User
 
Obeisance's Avatar
 
Join Date: Oct 2014
Location: SE MI
Posts: 562
This year my datalogging setup worked (although I did not drive as much as past years).

This log includes removal of oil cooling loop via the Toyota oil filter union.

It looks like I can reach higher oil temps without the cooling loop hooked up. However, the temperature of the oil never really stabilizes. I guess it shifts a lot with applied heat load; this is similar to other users' ( @cyow5 ) observation that oil temps rise fast when the engine is run hard if flow through the oil coolers are blocked. I can also see some heat displaced to the coolant system (as a high temperature tail).

At this point, it does not look like I drive hard enough to merit having the nice, higher-temp thermostat oil sandwich plate- I'm simply not adding enough heat to the oil. On the other hand, it would be nice to have a more stable oil temp (similar to the coolant temperature stability)- I can see how the Laminova would benefit both warmup of oil (to the water temp level) and temperature stability.

I can also see the time that it takes to reach peak temperatures increase compared to the log with the coolers active. I guess the heat delivery rate is probably similar, but the peak temperature is higher, so time to reach peak temps is a bit longer.

I have not looked at my camshaft wear yet this year to see how it's progressing.
Attached Images
     
Obeisance is offline  
post #23 of 34 (permalink) Old 11-19-2018, 04:48 PM
Nein Kinder
 
Glen's Avatar
 
Join Date: Feb 2011
Location: Golden, Colo.
Posts: 1,568
@Obeisance - I realize youíve been running a damaged camshaft for some time, but no one has mentioned an important fact about the materials involved. The camshaft is surface-hardened, so once you bust through the hard layer, the metal-to-metal interface will wear rapidly and dump metal particles into your engine oiling system. If youíve detected damage to the camshaft - especially the nose which sees very high pressures - you are most likely dumping metal particles into your engine oil. Itís an understatement to say thatís not recommended.

Glen

2011 Lotus Elise SC
Glen is offline  
 
post #24 of 34 (permalink) Old 11-20-2018, 03:04 AM Thread Starter
Registered User
 
Obeisance's Avatar
 
Join Date: Oct 2014
Location: SE MI
Posts: 562
yeah, i hadn't thought of that.

i also don't really know anything about this camshaft's hardening treatment- if it's a bake-in-CO2-carbonization or a coating, then it would certainly be a thin layer. But i thought that some steels that don't need large plasticity are hardened via a heat-and-quench to martensite process (whixh i expect to be homogeneous).

in any case, based on the wear pattern (smeared metal and missing material), I'm inclined to believe that the hardening is only surface deep.

on the other hand, what are the chances that a cam that's worn through the hard layer will begin to work harden in the softer layer and recover some resilience?

early in this experiment, i was close to buying a $200 Vickers indenter tip from ebay so that i could check hardness at various worn and unworn parts of the cam in situ (i figured i could get by with a usb microscope since the Vickers measurement is simple). maybe i should revisit this idea..

I'm still not inclined to rush into changing the camshaft, but maybe i should check other parameters like cylinder compression more often.
Obeisance is offline  
post #25 of 34 (permalink) Old 11-20-2018, 05:30 AM
Nein Kinder
 
Glen's Avatar
 
Join Date: Feb 2011
Location: Golden, Colo.
Posts: 1,568
Here is a random article about camshaft hardening: CPG Nation / Camshaft Heat Treatment. It echoes what Iíve read elsewhere . .. most camshafts have some variable depth of surface hardening with a soft core. The latter keeps thing flexible enough to avoid fracture, while the hard surface provides wear resistance. For an analog, this is exactly how a twist drill is engineered.

Some hardening treatments have a fairly substantial depth while others are very thin. Based on the number of cam wiping reports, Iíd guess the Toyota cam surface hardening method produced a very thin layer.

Glen

2011 Lotus Elise SC
Glen is offline  
post #26 of 34 (permalink) Old 11-20-2018, 06:26 AM
Registered User
 
cyow5's Avatar
 
Join Date: Mar 2013
Location: NoVa
Posts: 3,837
Quote:
Originally Posted by Glen View Post
Here is a random article about camshaft hardening: CPG Nation / Camshaft Heat Treatment. It echoes what Iíve read elsewhere . .. most camshafts have some variable depth of surface hardening with a soft core. The latter keeps thing flexible enough to avoid fracture, while the hard surface provides wear resistance. For an analog, this is exactly how a twist drill is engineered.

Some hardening treatments have a fairly substantial depth while others are very thin. Based on the number of cam wiping reports, Iíd guess the Toyota cam surface hardening method produced a very thin layer.

Glen
These layers are actually visible to the naked eye (oftentimes) so we just need someone with a band saw and an old cam to slice one down the middle of the big lobe. You can also then run a hardness test on both the surface and the interior to figure out if it is below average or not.

"Lots Of Trouble; Usually Serious"
cyow5 is online now  
post #27 of 34 (permalink) Old 11-20-2018, 06:27 AM
Registered User
 
cyow5's Avatar
 
Join Date: Mar 2013
Location: NoVa
Posts: 3,837
Quote:
Originally Posted by Obeisance View Post

I'm still not inclined to rush into changing the camshaft, but maybe i should check other parameters like cylinder compression more often.
Cylinder compression won't tell you anything about the big lobe's health. I will hint though that removing the valve cover becomes a little over a 5 minute job with an electric drill/screwdriver...

"Lots Of Trouble; Usually Serious"
cyow5 is online now  
post #28 of 34 (permalink) Old 11-20-2018, 06:34 AM Thread Starter
Registered User
 
Obeisance's Avatar
 
Join Date: Oct 2014
Location: SE MI
Posts: 562
Quote:
Originally Posted by cyow5 View Post
Cylinder compression won't tell you anything about the big lobe's health.
i was guessing that if i have lots of little metal bits floating in the oil that wear surfaces like bearings, bushings and the cylinder walls would age faster. thus, i'd expect to see compression decrease abnormally if my prolonged run with a worn cam is exacerbating wear in other parts of the engine. maybe this is too much of a leap in logic, though.

i am aware of how easy it is to remove the cover on top of the engine too; i need to keep after this so that i can document better how the wear on the camshaft progresses over time.
Obeisance is offline  
post #29 of 34 (permalink) Old 11-20-2018, 06:55 AM
Nein Kinder
 
Glen's Avatar
 
Join Date: Feb 2011
Location: Golden, Colo.
Posts: 1,568
Quote:
Originally Posted by Obeisance View Post
. . . i need to keep after this so that i can document better how the wear on the camshaft progresses over time.
Don't take any of my comments as discouraging you. If you're willing to risk damage to your engine in the name of science (and I don't really know how big that risk is), lots of people will be interested in the data.

I can empathize with your inclination in this matter. In the 1980's, I had a Porsche 924 with an inline four cylinder. Porsche sourced the cast iron block from an Audi truck engine, then built an aluminum head with a single overhead camshaft. The engine kept eating cams about every 15,000 miles or so. I tried several different brands of lifters, camshafts, oils, filters and so on. I even sought out cams with different hardening techniques. I got really good at replacing the camshaft in a short amount of time. Looking back, I definitely had an oiling problem, but engineering an oiling change then wasn't in the realm of possibilities. So I took to monitoring the camshaft and replacing it when I thought the rate of metal removal was approaching damage-inducing levels.

I'm no expert in what damage would occur from metal coming off the camshaft lobes (or followers), but I suspect rings might get fouled, main bearings could take a hit and aluminum cylinder walls could get scored. You might consider running a magnetic drain plug to see if large chips are ending up in the sump. As someone else suggested, a series of oil analyses would be the gold standard.

Glen

2011 Lotus Elise SC
Glen is offline  
post #30 of 34 (permalink) Old 11-20-2018, 06:59 AM
Registered User
 
cyow5's Avatar
 
Join Date: Mar 2013
Location: NoVa
Posts: 3,837
Quote:
Originally Posted by Glen View Post

I'm no expert in what damage would occur from metal coming off the camshaft lobes (or followers), but I suspect rings might get fouled, main bearings could take a hit and aluminum cylinder walls could get scored. You might consider running a magnetic drain plug to see if large chips are ending up in the sump. As someone else suggested, a series of oil analyses would be the gold standard.

Glen
Adding more guesses, I would suspect that you'd have catastrophic cam/lifter failure by the time the wear gets to the point where internal components start to take notice of it. Oil analysis is far better at spotting a dangerous trend before any mechanic signs, especially if you send of sample periodically and build up a decent data set.

"Lots Of Trouble; Usually Serious"
cyow5 is online now  
post #31 of 34 (permalink) Old 11-20-2018, 07:03 AM
Registered User
 
Crazy05's Avatar
 
Join Date: Sep 2018
Location: Apple Valley, CA
Posts: 161
Quote:
Originally Posted by Ob917 View Post
You drove a year without going over 6000 rpm? Wow lots of self restraint. I can't even make it to work without doing that. Nice informative post, thanks.
Same here, Everytime I drive it I rev the hell out of it. after 3 years and 110k miles I still havent checked the cams.
Crazy05 is offline  
post #32 of 34 (permalink) Old 11-20-2018, 08:20 AM
Registered User
 
Join Date: Aug 2018
Location: Central Virginia
Posts: 340
Garage
Quote:
Originally Posted by Obeisance View Post
This year my datalogging setup worked (although I did not drive as much as past years).

This log includes removal of oil cooling loop via the Toyota oil filter union.

It looks like I can reach higher oil temps without the cooling loop hooked up. However, the temperature of the oil never really stabilizes. I guess it shifts a lot with applied heat load; this is similar to other users' ( @cyow5 ) observation that oil temps rise fast when the engine is run hard if flow through the oil coolers are blocked. I can also see some heat displaced to the coolant system (as a high temperature tail).

At this point, it does not look like I drive hard enough to merit having the nice, higher-temp thermostat oil sandwich plate- I'm simply not adding enough heat to the oil. On the other hand, it would be nice to have a more stable oil temp (similar to the coolant temperature stability)- I can see how the Laminova would benefit both warmup of oil (to the water temp level) and temperature stability.

I can also see the time that it takes to reach peak temperatures increase compared to the log with the coolers active. I guess the heat delivery rate is probably similar, but the peak temperature is higher, so time to reach peak temps is a bit longer.

I have not looked at my camshaft wear yet this year to see how it's progressing.
Points worth noting:
1. automotive engines are not designed around the assumption that oil temperature will be constant when the engine is operating. Neither are engine oils. A minimum desirable engine oil temperature is about 85 C to decrease water and fuel dilution of the oil. Continuous operating temperatures as high as 110 C are fine, and brief excursions to 120 C are beneficial if you want to get rid of diluents. Most street driven cars have trouble maintaining oil temps above 85 C in winter. An oil to water cooler (as fitted to EU spec 111Rs) can help with this.

2. All mass produced camshafts I know of are made of a mild iron with a carburized case hardening applied after grinding the lobe profile. This is because mild iron is easy to grind and also because it copes with shock loads (like camshafts experience as they bounce valves open and closed). As others have noted, once the case hardening is worn through, you have mild iron rubbing against fairly hard steel followers and wear accelerates.

What's probably saving you on the high speed cams of a 2ZZ-GE is that the big cams aren't engaged very often, particularly on a mildly driven street car. I'm curious to see what your wear looks like this year.

I have a parts 5S-FE I can steal the oil-water sandwich cooler from. That'll be going on my Elise this winter.
steelypip is offline  
post #33 of 34 (permalink) Old 11-20-2018, 08:56 AM
Nein Kinder
 
Glen's Avatar
 
Join Date: Feb 2011
Location: Golden, Colo.
Posts: 1,568
Quote:
Originally Posted by steelypip View Post
. . .
An oil to water cooler (as fitted to EU spec 111Rs) can help with this.
. . .
If the coolant is only 10į F cooler than the oil, there will be very little cooling going on. OEM’s typically fit these for their heater properties . . . getting the engine up to operating temp quickly reduces emissions. I try to call them water-to-oil heat exchangers or more simply, oil heaters.

Glen

2011 Lotus Elise SC

Last edited by Glen; 11-20-2018 at 11:33 AM. Reason: chg their to there
Glen is offline  
post #34 of 34 (permalink) Old 11-20-2018, 09:39 AM
Registered User
 
Join Date: Aug 2018
Location: Central Virginia
Posts: 340
Garage
Quote:
Originally Posted by Glen View Post
If the coolant is only 10į F cooler than the oil, their will be very little cooling going on. OEMís typically fit these for their heater properties . . . getting the engine up to operating temp quickly reduces emissions. I try to call them water-to-oil heat exchangers or more simply, oil heaters.

Glen
Yup. And that's what most normally aspirated OEM street car installations seem to use it for. Two examples I know of:

ST184 Toyota Celica: keep the oil warm in an under-worked 5S-FE. Also makes the engine unkillable on track days (if rather slow).
P71 (police interceptor) Ford Crown Vic: keep the oil warm when idling for long periods in cold temperatures - common in police and taxi use.

In my air cooled engine experience, I've found oil temperature to correlate more with BMEP than anything else - basically, the hotter the pistons get, the more heat goes into the oil.

In the case of the 2ZZ-GE Elise, we have problems in both extremes: The engine is very lightly loaded - it came in small minivans (Toyota Matrix), and even in a Celica it's pushing around a car with 1/3 more frontal area and 500 lbs more curb weight than an Elige. That makes an Elise slow to warm up. On the other end of the scale, Lotus drivers persist in taking their cars on race tracks, which means that the engine is making 100% of available power something like 50% of the time.

An oil cooler that heats the oil when it's cooler than the water, and cools it when hotter is exactly what we need. That's also what Lotus put on the original 111R. For some reason, they decided that the USA was like the Persian gulf and race cars in its oil cooling requirements.

Street driven US Eliges would have been much better served with the same package UK/EU Eliges came with.
steelypip is offline  
Sponsored Links
Advertisement
 
Reply

  LotusTalk - The Lotus Cars Community > Lotus Discussions > Maintenance and Repairs.

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the LotusTalk - The Lotus Cars Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 2 (0 members and 2 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome