synthetic vs conventional?
Le Mans Master
Joined: Oct 2007
Posts: 7,453
Likes: 976
From: RI, Now Franklin/Nashville TN
First of all glad to hear that your problem was an exhaust leak which can be maddening to locate sometimes! I'm currently chasing an exhaust leak now for months on my 94 Mustang GT Convertible (29,000 miles) that I cannot locate definitively-I've tried everything.
As for the the original premise of the thread, that switching to synthetic oil possibly caused an immediate "knock" versus the prior conventional oil, well, like I have said a thousand times now, correct synthetic oils (NOT a 0W-20 with 800 PPM ZDDP, for example) do NOT cause the following mysteriously-"knocks," wiped lopes after a synthetic change on previous "good" cams after 100 miles, gasket leaks in engines that had previously sealed tight, low mileage engines with conventional oil that switch to a synthetic oil and mysteriously consume all or half of the oil in 400 miles without any obvious signs of leaks or burning, etc! Some of this stuff borders on the comical.
My advice to folks is to use a good correct quality oil (ZDDP), synthetic or conventional, in your older C3 engine and you are good to go. BUT let's stop trying to constantly blame correct synthetic or conventional oil for problems in 30-40 year old engines. If my 78 L-82 with 66,000 miles (more like 100,000 miles with 3.70 gears) suddenly wipes its cam, throws a rod, or generally implodes using Mobil 1 15W-50, I am not going to blame the oil when I know for fact that GM generally did not use the highest quality engine components in these engines back in the day and certainly did not put these motors together with the tightest tolerances possible. Are there cases where something strange could occur? Yes but rarely. The arguments are ridiculous, seriously!
As for the the original premise of the thread, that switching to synthetic oil possibly caused an immediate "knock" versus the prior conventional oil, well, like I have said a thousand times now, correct synthetic oils (NOT a 0W-20 with 800 PPM ZDDP, for example) do NOT cause the following mysteriously-"knocks," wiped lopes after a synthetic change on previous "good" cams after 100 miles, gasket leaks in engines that had previously sealed tight, low mileage engines with conventional oil that switch to a synthetic oil and mysteriously consume all or half of the oil in 400 miles without any obvious signs of leaks or burning, etc! Some of this stuff borders on the comical.
My advice to folks is to use a good correct quality oil (ZDDP), synthetic or conventional, in your older C3 engine and you are good to go. BUT let's stop trying to constantly blame correct synthetic or conventional oil for problems in 30-40 year old engines. If my 78 L-82 with 66,000 miles (more like 100,000 miles with 3.70 gears) suddenly wipes its cam, throws a rod, or generally implodes using Mobil 1 15W-50, I am not going to blame the oil when I know for fact that GM generally did not use the highest quality engine components in these engines back in the day and certainly did not put these motors together with the tightest tolerances possible. Are there cases where something strange could occur? Yes but rarely. The arguments are ridiculous, seriously!
Last edited by jb78L-82; May 4, 2013 at 07:34 AM.
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Or, how about this from Comp Cams (who would rather not warranty out camshafts):
http://www.compcams.com/Base/pdf/Fla...chBulletin.pdf
...which says:
"Another major factor in the increase of flat tappet camshaft failure is your favorite brand of engine oil. Simply put, today’s engine oil is just not the same as it used to be, thanks to ever tightening environmental regulations. The EPA has done a great job in reducing emissions and the effects of some of the ingredients found in traditional oils; however these changes in the oil have only made life tougher on your flat tappet camshaft. The lubricity of the oil and specifically the reduction of important anti-wear additives such as zinc and phosphorus, which help break-in and overall camshaft life, have been drastically reduced. In terms of oil selection, we recommend oil with the proper level of “ZDDP”, Zinc Dialkyl Dithiosphosphate additive fortification."
...or how about this from Crower Cams (one of the best):
http://www.crower.com/camshaft-installation
...which says (on pg. 6):
"BE AWARE! Flat tappet camshaft failure is a major problem for the fact that your favorite brand of engine oil is not what it used to be,..anti-wear ingrediants such as zinc and phosphorous have been dramatically reduced,.."
Last edited by 73, Dark Blue 454; May 5, 2013 at 11:12 PM.
