Bored my Renix TB today

I haven’t had much time to spend on my MJ the resent months, but today I just have to do something…..and decided to bore the TB, (did it on my YJ long time ago with good results)

The stock 52 mm bore.

Don’t have any sophisticated machines so I’m using hand tools..

Started to grind

Then I used this..don’t know the English word :)

Finished with a hone tool

Modify the butterfly-shaft

Making new butterfly

The new 59-60mm butterfly compare to the 52mm

Modified the fine adjustment Idle screw

Extended the TV cable bracket

Ready for installation :)

Looks good!! GREAT JOB on the pics and write up! You should post this in the tech articles section!!!!

Let us know if you find any differences!

I put a 62mm on my TJ and found quite a difference, but I also noticed the intake had an even larger hole where the TB mounted. I am not sure this is the case with a renex intake.

Good luck,

CW

I bored my Renix TB also, but I used a Ford Explorer butterfly, worked almost perfect. Had to move the holes a bit but it worked.

Definate improvement in High rpm, low revs didnt seem to help too much, but at 4500 to 5000K it revs much easier.

Hi again, went away to England on Monday morning (working in UK now) so I didn’t get time to post how it turned out.

However, I installed it, adjusted the TPS with a digital Voltmeter and fired the engine…..it idle to high, around 15-1600 rpm, (I expected this to happen but hoped the idle stepper motor were able to compensate for the not perfect butterfly sealing)

So I removed the TB and took out the butterfly and did some accurate grinding in order to seal off better,

Here how I grind it...

Now it sealed perfect, and installed the TB again, adjusted the butterfly stop screw, so the edge on butterfly didn’t rest against the TB wall. Adjusted the TPS again, and fired up the engine, and finally adjusted the Fine Adjust Idle Screw until the engine idle smut at ca. 800 rpm.

Took it for a test drive…and I think it rev faster when I hit the pedal in all rpm’s….. definitely at higher rpm’s.

According to my knowledge the AW4 trans works as it should, when going 50-60 mph in 4th and give it light pedal it downshift to 3rd, if I floor it, it shift down to 2nd (in Power mode)…then I feel the old MJ is pretty fast :-D

Some time ago I did have problems with the trans lock up, but after fixing the brake switch the trans lock-up as it should.

When I’m home again I will run an AFR analyze using an Innovate LM-1 Digital Air/Fuel Ratio Meter in order to see how the Air Fuel Ratio is through the rpm range, to see if it’s running lean in WOT conditions due to the increased air supply.

The exhaust manifold and down pipe is stock, but after the flange it is a 3”with only a small 3” muffler (mean sound)

I will replace the stock Renix 18, 6 lb/hr (39psi) injectors with the HO 21 lb/hr (39psi) injectors and see how the Renix engine will work with bigger injectors :?:

It’s fun and interesting to work and play with the old MJ and it cost me nothing, to bore the throttle body was pure recreation, the HO injectors was left after going bigger on the YJ, and the AFR analyzer I already have.

Have also a K&N cone filter lying around, so I may test this out as well, here in Norway the emissions for pre -91 cars is easy to pass so I have nothing to fear in that matter.

The 'new' 39psi/21.0lb/hr HO injectors vs the stock 39psi/18.6lb/hr injectors.

Fuel rail

Fuel rail installed, next is to remove the air filter box and connected vac lines

All Gone..

New cone-filter set up, used an 80mm tube, and made a Y connection to connect the fresh air supply to the crankcase, and the evaporator canister.

It’s good to get rid of all the vacuum lines to the stock filter box.....rerouted the vac lines to/from EGR solenoid.

Will fabricate a combine heat shield/bracket for the cone filter.

Have not run an AFR analyze yet (can’t find the extension cable to the wideband O2 sensor :( )

But I can definitely feel more power, when accelerating from stand-still the wheels slips when giving full pedal, can also feel slipping when shifting from 1 to 2….was not able to do that before :)

Love this old MJ :-D

Looks GREAT!!

Where did you aquire the 80mm tube???

CW

Looks GREAT!!

 

Where did you aquire the 80mm tube???

 

CW

He,he..it’s made of a thick paper roll( to keep drawings, posters etc. in), it’s was just for testing.

However, today I made the heat shield box, and replaced the paper tube with a 3” steel tube (from a galvanized exhaust tube)

The heat shield, I made of a steel shelf.. I use what I can find around me :)

Here is the shelf…cutting the top cover.

3” bent steel tube, installing new nipples.

Put a cover on the top.

This modification cost me nothing and was fun to do, and I’m 100% satisfied with the increase in power :-D

My future short term plans is to put on new rims/tires, I have no time (will start building a new house this spring) to re-gear, do a lift and put on big tires, so I will run with the stock 3,55 gears and 31” tires.

Yesterday I got 5 cheap 10x15 rims, and now I’m checking prices on tires,

10,5” wide tires will be to narrow on 10” rims, or :?:

So, I’m checking prices on BFG M/T 325/60/15 meats ( 30.4”x12.8”) …low and wide.

Any opinions how M/T-325/60/15 will look/work on the Comanche :?: :?: