Have to scrape the gaskets off? Replace them normally?

Jake

 

You can use the gaskets if you have them, but RTV works just as well.

 

I disagree about lack of mileage improvement. I run synthetic in the front and rear, and dex 6 in the TC...as big as my truck is my avg is 12.7mpg. I actually saw almost a full mpg improvement as a result.

In fact, a friend of mine has a shortbox, regular cab with 35s and a 5 inch lift, 360 like mine and he avgs 9-10mpg, I avg 12-13. The difference (we run the same type of tires and he runs 4.56 while I run 4.88 even though I am two inches taller) I think it's a decent comparison because he is forever running the cheapest oils he can find and I run all synthetics. Mobil1 Extended Performance 5W30, Mystik ATF+4, Mystik Dexron VI, Valvoline 75W90 full synthetic.

To get around the gunk problem known to synthetic users, I run SAE30 DETERGENT motor oil for 1000 miles every July. If you wonder how well it works, I did a cam swap recently and most of engine didn't even have varnish on it.

 

Nope. Just the gears could be the difference there. And you give no information on other possible differences either. (body style, driving style, how much freeway driving either of you do, etc.)

Synthetics are NOT going to give you that big of a difference in fuel economy.

If you want to do a REAL test, Monitor your fuel consumption for year, then switch to all dino lubricants, and do the same thing. THAT information I would lend more credibility to.

 

I did that actually. I keep a log using a fuel log app on my phone. I have a record for the last few years of my fuel use. A crying shame how MUCH fuel but nonetheless. As for differences, same bodystyle, his truck is shorter and lighter than mine, we drive about the same mix of freeway/in town, same number of miles to work, same times of day (Wanna guess we work at the same place?) He cheaps out I don't. This isn't to say my truck might be in better overall shape, not to mention I have a recently rebuilt transmission and a precision converter. There ARE factors there. Even my fuel log reflects the improvements a rebuilt transmission made. I also keep track of fuel use through a ScanGaugeII device, logging every fillup (it self corrects when you do that).

And I am not disagreeing with you on principal, it's just given specific situations, like highway driving, towing on a regular basis...synthetic gear oil is a cut above dino.

I improve a FULL MPG over dino oil front to back. More in very cold WI weather. In reality though, over his truck mine is probably in better shape even though I have more miles. Now with the new cam, any further testing is completely out the window. And no, I don't have enough tank fill ups on the new cam to say if it's affected mileage one way or the other.

 

The cam may actually help....

I purposely do NOT track my fuel usage. It would be far too depressing.

 

I track mine for business reasons, read: taxes. And I must say...the truck feels "new" with this cam...it woke up something inside it I never thought it had.

 

These things are woefully underpowered from the factory.

 

Now there is an accurate statement if I have ever seen one.... underpowered, and STILL get horrid gas mileage.... Probably because of the wimpy trans they put behind it.

 

All I'm saying about synthetic is I have noticed better mileage in two vehicles. The HHR I spoke of and a 77 chevy 3/4t two wheel drive I used to own and that one was a four speed standard.
Until recently I never thought about the benefit but as the 77 showed me in the early 90's the HHR has shown me again.
I drive 70 miles round trip daily to work.
The 1.89 mpg average for just an engine oil change is worth it to me.
Costs me $40 for oil and filter.