Converting a roller cam to a more reliable flat Tappet cam...yes it's a thing
- Thread starter Krooser
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Cartel
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what a nightmare. Imagine the bill for that
Well, that would seem to shoot a bit of a hole in conventional wisdom. My brother just spent $7200 for Mercedes to replace one failed camshaft in a newer Merc SUV. Why can no one seem to supply a cam and lifters/followers that is dead-on reliable anymore?
70ChargerRT
Well-Known Member
My buddy is a Master Mechanic at a huge big 3 dealership. He is seeing very few of these failures. The ones that have failed has seen extended oil use and the wrong oil used like using conventional 15/40. Use 10w30 syn. Diesel oil. Temps below 0 use 5w40. Change oil at 5k mile max. He’s seen plenty 300k+ mile trucks in for maintenance, zero issues. He still says less issues with Ram Diesel trucks vs GM and Ford except for the 68rfe transmission.
My Brother said the recommended oil change intervals on the Mercedes is 15,000 miles and he commented that he’s suspicious that might have been the cause of the cam failure. But no way to know for sure now.
70ChargerRT
Well-Known Member
On on our GLC 300 AMG Benz it’s 10k miles but Ill change it every 5k even though it doesn’t even have 10k on it.
70ChargerRT
Well-Known Member
My wife is still beating up the 15 Grand Cherokee 3.6 Pentastar. Getting ready to hit 200k miles only replaced a Filter housing, plugs and a Thermostat. 5w20 Conventional 5w20. Wouldn’t give us nothing on trade-in so we just kept it.
bobsgtx
Well-Known Member
In my years as a government(low bid) fleet mechanic the bean counters would look at Total Cost of Ownership numbers on what they would buy. I would see manufacturers extend oil change intervals to compete against each other. Marked police cars would average 50k miles a year and sold when they had 100k or over( usually 2 years). I remember when they went from 5k oil changes to 7.5k oil changes to save money.
Cartel
Member
when I was towing, my boss would change the filter but leave the oil till next go around. I didnt like it but it wasnt my job to
MoparLeo
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Oil does not break down. The additives do. The oil just gets dirty and carbureted engines would let excess fuel past the rings and contaminate the oil.
They used to sell oil fiters that had a "pill" inside that contained the additives that were worn out. You woud just change the filter between oil changes.
Modern engines with fuel injection dont dirty the oil like the older engine do/did. The oil is much better quality today and some synthetic oil formualtions can go much longer without changing.
Another reason for extended oil change times and oil monitors is to help decrease the consumption of oil and the disposal of millions of gallons of waste oil every year.
Roller lifters genrally have different rates of lift acceleration based on the profile of the cam lobe. Not all non-roller lifters can properly follow the profiles without excessive wear of the lifter and lobe
They used to sell oil fiters that had a "pill" inside that contained the additives that were worn out. You woud just change the filter between oil changes.
Modern engines with fuel injection dont dirty the oil like the older engine do/did. The oil is much better quality today and some synthetic oil formualtions can go much longer without changing.
Another reason for extended oil change times and oil monitors is to help decrease the consumption of oil and the disposal of millions of gallons of waste oil every year.
Roller lifters genrally have different rates of lift acceleration based on the profile of the cam lobe. Not all non-roller lifters can properly follow the profiles without excessive wear of the lifter and lobe
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