I just got through putting timing chain, timing cover, steel guides, new piston rings, rod bearings and bigger camshaft. The cam is a 257/268 adv. duration, .416/.430" adv. lift made my clevite. After putting all this back together and the cam in, my gas milage has gone down to nothing. I was getting around 11 mpg, and I do realize with the setup I have that I'm not going to get very good milage to begin with. Now I can drive around 7-10 miles going to work and watch my gauge move down.

I was wondering if anyone else has done this type of setup and had the same experience? I just don't see that it should have gotten this bad. Maybe I should wait and let my engine break in a little more, but I don't see that making much of a difference.

 

i dunnno man, i had that same cam in my old yota, with headwork, and a .060 overbore, exhaust and the works, and i never saw below 17 with stock tires, i got 15 with 32's and a full bed of tools for setin up firework stands,

mabey its just you?
wade

 

you may need to degree your cam in and make sure your spark timing is right for that cam.as in more advance.if its EFI you may can play with the a/f ratio by turning the clock in your air flow meter.this is complicated and dangerous its easily damaged.use no silicone it,s fumes will eat the meter circuits!

 

yes look at you cam timing ... may be heads up is not what that cam needs. call the mfgr they may have a quick answer.but if the cam is designed to be 110 deg centerline etc then you need to degree it

 

good ideas.... thanks

 

If your mileage was 11 before, and you put a bigger cam in, you should keep in mind that the purpose of a bigger cam IS to get MORE gas and air into the cylinders, so your gas mileage will suffer. Any time you increase the duration, you increase the air delivery, and thus the computer adds more gas to keep the mixture the same (or near). It's the sole purpose of a bigger cam, and thus the drop in mileage.

On another note, like the other guys mentioned, you may need a bit of tuning to perfect it, but if you were getting 11mpg before, I wouldn't expect to get any better than 9-10 after, at best. Just some advice from a fairly experienced engine builder... :-)

Take care and good luck!

 

How the heck were you getting 11 before? I can't get down to 11 even playing on the dunes! The worst tankful I ever got (that I can remember) with the 22re (33s and 4.88s) was about 14, I got 19-20 every single day real world driving, and 22 or better on highway trips. And I drove it hard - you have to, it's only a 22re...

 

I'm gonna switch back to my stock cam this weekend and start over from there. I think I need an O2 sensor and fuel filter. That'll be a start.

thanks for all the input

 

serious... i beat the crap out of my truck, its a 4x2 wit ha stick and 31s wtih 3.07 gears... i get 17 real mpg on average....