Jeep Wrangler Forum

Jeep Wrangler Forum (http://www.wranglerforum.com/)
-   TJ Tech Forum (http://www.wranglerforum.com/f210/)
-   -   Loading up (http://www.wranglerforum.com/f210/loading-up-625626.html)

Jeepboy89 04-03-2014 01:03 PM

Loading up
 
Ok so I just rebuilt my engine biggest comp cam and .30 pistons new oil pump and sending unit head totally reworked timing set but now it seems like the thing is loading up on fuel or it has to much back pressure. When I rap out in third the engine wants to bog out and backfire any ideas on what this could be. I'm running 93 octane in it as we'll. please help

UFOtestpilot 04-03-2014 01:05 PM

Backfire or after fire?

Jeepboy89 04-03-2014 01:07 PM

Seems like back fire what is the difference

UFOtestpilot 04-03-2014 01:47 PM

Back fire is in the intake or pre-combustion, afterfire is in the exhaust. The diagnosis and fixes differ for the two so the distinction can be important. The afterfire popping is usually an enriched condition.

Jeepboy89 04-03-2014 01:56 PM

It sounds like it's coming from the intake when it does it.

Jeepboy89 04-03-2014 01:57 PM

It sounds like it's coming from the intake when it does it. I was gonna try taking the muffler off and seeing if opening it up some would help

UFOtestpilot 04-03-2014 02:14 PM

Probably won't help at all. If it's backfire it's timing related. Since you can't tune the ECM if you aren't running stand alone engine management you likely have an overlap at your cam.

UFOtestpilot 04-03-2014 02:23 PM

Did you match the cam lift and duration to the intake and exhaust?

Jeepboy89 04-03-2014 02:27 PM

Not that I'm aware of. When we put the cam in it said to line the dots up pointing at eachother we did that and being as the valves are non adjustable how do you go about doing that.

UFOtestpilot 04-03-2014 02:34 PM

Mathematically in regards to lift and duration of the cam. Did you just pick the biggest cam you could get or something?

UnlimitedLJ04 04-03-2014 02:34 PM

Quote:

Originally Posted by Jeepboy89 (Post 9585282)
Not that I'm aware of. When we put the cam in it said to line the dots up pointing at eachother we did that and being as the valves are non adjustable how do you go about doing that.

you also do understand the cam needs to be matched to the valves, lifters, rockers and valve springs, right?

it's not like you just take the biggest cam you can find and shove it in the motor.

Quote:

Originally Posted by UFOtestpilot (Post 9585474)
Mathematically in regards to lift and duration of the cam. Did you just pick the biggest cam you could get or something?

sounds like that's exactly what he did. zero homework, buy some parts and jam it all together....

krisbman 04-03-2014 02:59 PM

Quote:

Originally Posted by UnlimitedLJ04 (Post 9585490)
you also do understand the cam needs to be matched to the valves, lifters, rockers and valve springs, right? it's not like you just take the biggest cam you can find and shove it in the motor. sounds like that's exactly what he did. zero homework, buy some parts and jam it all together....

Lol. Sounds like the guy who threw a huge single plane intake and a double pumper carb and wonders why his car is a huge turd out of the hole.

Jeepboy89 04-03-2014 03:31 PM

When I called and spoke to the guys at comp cams I told them that the motor was bored 30 over and that I wanted to change nothing in the head. They told me that the cam they were going to sell me was gonna work fine with the stock head. That's the only reason why I agreed to order the one I did. I have the numbers for lift and duration maybe someone can tell me if it's still good for a stock head or not.

Duration is
206
212
50 thousands
The intake valve is
.435
The exhaust valve is
.448
Lobe separation is
.113.

UFOtestpilot 04-03-2014 03:56 PM

They said this would work on stock valve springs? Are your valve springs in good shape? Are your valves seating properly? How many miles on the head?

Jeepboy89 04-03-2014 03:59 PM

The head had all ew springs put in reground seated and the only things I didn't change were the push rods and the rockers. Other than that the machine shop did all the cleaning up of the head and put it all back together. Other than those two things.

UFOtestpilot 04-03-2014 04:12 PM

What's your engine management? I'll let you know that we are outside of my Jeep experience, but still within the realm of my general automotive understanding, just to be clear.

UnlimitedLJ04 04-03-2014 04:17 PM

CompCams doesn't list a cam that meets those specs. http://www.compcams.com/catalog/COMP...2011_20-25.pdf

The only cam remotely close is 68-232-4, and that has significantly higher valve lift and requires Mopar Performance valve springs. If you have that cam, you may have actually wrecked components of the valvetrain at this point. Lots of people burn up cams and lifters in no time flat with improper assembly....

Also, was the timing advanced when installing the cam? How did you go about installing the cam position sensor? Was the motor at TDC?

Jeepboy89 04-03-2014 04:42 PM

I guess I'm gonna have to get ahold of comp cams and make sure the numbers are right and make sure they sold me the right cam. I timed it as if it were a distributed motor Tdc and then positioned the oil pump as stated in the book and then set the cam position sensor back in with the plug facing the back of the jeep


All times are GMT -5. The time now is 02:36 PM.


User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.