Just wanted to post a quick update and lessons learned.
I have replaced the intake camshaft and the 4 rockers. The flat-tappets on the rockers were badly worn as I expected based on how wiped the camshaft was. The rollers were OK. Valve lash was in fact out of spec (too tight). I re-shimmed it to spec. The car is now back on the road, runs smooth.
Having done extensive research on the topic, I place 90% of the blame on the government for needlessly regulating out ZDDP from motor oil formulations and 10% of the blame on the out-of-spec valve lash. Some of you commented on my oil change interval. The only 2 times I exceeded 9,000 miles was when I was driving round-trips from NY to TX. Easy miles, not using lift. Oil change intervals were not a factor here.
Going forward I will be mixing in a quart of Valvoline VR-1 (high zinc formulation) at every oil change, as well as 3oz of Rislone ZDDP additive. Based on my research, the catalytic converter poisoning argument against ZDDP is greatly exaggerated, if not completely false.
Lessons learned: 1) Never trust the government. 2) Modern motor oils (API SM, SN and newer) do not provide adequate protection against wear in high performance, high-revving engines, especially when equipped with flat-tappet camshafts.
Analysis of ZDDP content and thermal decomposition in motor oils
AMSoil engineer explaining importance of ZDDP additives (@13:27)
Old vs New rocker (note the badly worn pad on the left)
View attachment 84177
New intake camshaft in
View attachment 84178
All buttoned up
View attachment 84179
Just wanted to post a quick update and lessons learned.
I have replaced the intake camshaft and the 4 rockers. The flat-tappets on the rockers were badly worn as I expected based on how wiped the camshaft was. The rollers were OK. Valve lash was in fact out of spec (too tight). I re-shimmed it to spec. The car is now back on the road, runs smooth.
Having done extensive research on the topic, I place 90% of the blame on the government for needlessly regulating out ZDDP from motor oil formulations and 10% of the blame on the out-of-spec valve lash. Some of you commented on my oil change interval. The only 2 times I exceeded 9,000 miles was when I was driving round-trips from NY to TX. Easy miles, not using lift. Oil change intervals were not a factor here.
Going forward I will be mixing in a quart of Valvoline VR-1 (high zinc formulation) at every oil change, as well as 3oz of Rislone ZDDP additive. Based on my research, the catalytic converter poisoning argument against ZDDP is greatly exaggerated, if not completely false.
Lessons learned: 1) Never trust the government. 2) Modern motor oils (API SM, SN and newer) do not provide adequate protection against wear in high performance, high-revving engines, especially when equipped with flat-tappet camshafts.
Analysis of ZDDP content and thermal decomposition in motor oils
AMSoil engineer explaining importance of ZDDP additives (@13:27)
Old vs New rocker (note the badly worn pad on the left)
View attachment 84177
New intake camshaft in
View attachment 84178
All buttoned up
View attachment 84179
It´s a Toyota it cant be anything wrong with a part in the car so it has to be the oilYou admit you found the valves were too tight, which you have been told causes the wear, and yet you are still blaming the oil???
Talk about being willfully ignorant!
Technically, this engine is made by Yamaha, sold as Toyota 2ZZ-GE. See attached image of the timing chain cover with the Yamaha logo. All cars break, including Toyotas of course. I replaced many parts on the car over the years but this particular wear issue is something that shouldn't have happened with regular synthetic oil changes.It´s a Toyota it cant be anything wrong with a part in the car so it has to be the oil
I stand by my conclusions. 1-line responses using"lol" as arguments have zero weight.Lol Engine fails…blame government
In all I spent 30+ hours repairing this (including all the related jobs as mentioned) and probably just as much time doing research on the lubrication challenges in high-revving performance engines post the 2004 govt-mandated ZDDP reduction regulation fiasco. High levels of zinc/phosphorus additives used to be common in all synthetic oils before that. So it's hard to blame Yamaha/Toyota. They designed the engine in the late 90's based on the lubricants of the time which all had good levels of ZDDP wear protection.You admit you found the valves were too tight, which you have been told causes the wear, and yet you are still blaming the oil???
How far out of spec? And was every cam lobe that was damaged out of spec?Valve lash was in fact out of spec (too tight). I re-shimmed it to spec.
Spec on the intake is 0.08-0.18 mm. All 4 high-profile cam lobes looked equally wiped to me as did the pads on the rockers. All the low-profile cam lobes were fine with no visible/palpable wear, no wear on the rocker rollers either. After installing the new camshaft, on two cylinders I was able to slide in the 0.04 mm feeler gauge easily but the 0.06 mm was tight. The other two cylinders were below 0.04 mm.How far out of spec? And was every cam lobe that was damaged out of spec?
But did you measure the valve clearance on the old damaged cam before disassembly? Measuring after putting the new cam in tells nothing about what the clearance was on the setup before disassembly.Spec on the intake is 0.08-0.18 mm. All 4 high-profile cam lobes looked equally wiped to me as did the pads on the rockers. All the low-profile cam lobes were fine with no visible/palpable wear, no wear on the rocker rollers either. After installing the new camshaft, on two cylinders I was able to slide in the 0.04 mm feeler gauge easily but the 0.06 mm was tight. The other two cylinders were below 0.04 mm.
I re-shimmed with 0.16 mm as the target. After reassembly I measured between 0.10 mm and 0.14 mm on all 4.
Partially. With old camshaft:But did you measure the valve clearance on the old damaged cam before disassembly? Measuring after putting the new cam in tells nothing about what the clearance was on the setup before disassembly.
0.06 mm is only 0.002 inch. Are the valve clearance specs that tight on these engines?Partially. With old camshaft:
0.00 mm on #1
0.06 mm on #2
In spite of #2 being close to spec the high-profile cam and rocker pad wear was as bad as it was on #1.
Yes! 0.08-0.18 mm on intake side. Like I said, high-strung princess. But makes 100HP/liter of displacement.0.06 mm is only 0.002 inch. Are the valve clearance specs that tight on these engines?
Lol what? Synthetic oil can prevent issues regarding material/engineering/design/valve adjustment issues?Technically, this engine is made by Yamaha, sold as Toyota 2ZZ-GE. See attached image of the timing chain cover with the Yamaha logo. All cars break, including Toyotas of course. I replaced many parts on the car over the years but this particular wear issue is something that shouldn't have happened with regular synthetic oil changes.
I stand by my conclusions. 1-line responses using"lol" as arguments have zero weight.
In all I spent 30+ hours repairing this (including all the related jobs as mentioned) and probably just as much time doing research on the lubrication challenges in high-revving performance engines post the 2004 govt-mandated ZDDP reduction regulation fiasco. High levels of zinc/phosphorus additives used to be common in all synthetic oils before that. So it's hard to blame Yamaha/Toyota. They designed the engine in the late 90's based on the lubricants of the time which all had good levels of ZDDP wear protection.
Many Lotus/Toyota owners with the 2ZZ-GE have found that the intake camshaft wipes even when the valve adjustment is within specs. I doubt 3-4 hundreds of a millimeter would've made a noticeable difference. In lift mode with the high cam profiles engaged, the 2ZZ-GE is simply a high-revving, high-strung princess that needs a lot of wear protection that modern "street use" 5W-30 synthetics sadly cannot provide. The labels on post-2004 passenger car synthetic oils should include a warning: "Not suitable for performance engines with flat-tappets." I had no idea until I found out the hard way.
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