Jeep Strokers

Over the summer I built a 4.6 stroker since the head gasket went in my Cherokee and I was feeling more confident after building a 4.0 for my Comanche. (4.0, 30 over, comp cam, 7120 head, 99+ intake, 62mm TB and 4 hole injectors) that thing felt amazing after the rebuild it gets pretty good and shocks most people who ride in it or drive it. Anywho, the Cherokee being lifted and all was feeling like a slug comparatively. I built the 4.6 using the clegg stage 1 kit with stage 1 cam. I can hardly tell a difference between the fresh 4.6 and the blown headgasket 200k mile 4.0. There’s a little better performance, but nothing to write home about. It’s a 1999 with an 0630 head, new stock valve springs, 784 injectors, 62mm TB. From that combination is there anything glaring that I’m doing wrong/could gain performance from. At this point I’ve contemplated pulling the motor and doing a TDI swap or a stock 4.0 with the same cam as the Comanche because it honestly feels like it’s got more power. (Granted it is stock height, 2wd, small tires and stick shift). Point is, this thing is a pig. I don’t know if I put something together wrong or wrong combination of parts or I missed something in my research, but I don’t know where to look and I don’t have any buddies that know anything about motors.

Oh as far as performance goes, with 4.56 gears, 35” mtrs at street pressure it cannot spin the tires on pavement. I’ve seen Cherokees on 33s with stock gears spin tires on pavement.

Does the engine run rough, stumble, misfire, run too hot, or is hard to start?
Pull the plugs and check their color.
Check your catalytic converter by bashing it with your fist to see if it rattles. A clogged cat will definitely reduce performance.

You might want to try a custom tune from flyin Ryan.

Cheromaniac wrote: ↑February 7th, 2020, 11:07 pm Does the engine run rough, stumble, misfire, run too hot, or is hard to start?
Pull the plugs and check their color.
Check your catalytic converter by bashing it with your fist to see if it rattles. A clogged cat will definitely reduce performance.

The engine seems to run fine, no misfiring, no stumble, no hard start. It seems to run a hair warmer than the 4.0, but the temperatures are not uncontrollable. Highest it got was about 230, but that was because the electric fan was having connection issues and it was not run at 230 long, and was shut off, connection fixed and cooled back down to just over 210 ( usually about 215 reading from an obd2 scanner). I am typing this on the computer, but have the pictures of the plugs on my phone so I will upload those in a bit, I'm not sure what to look for when it comes to plugs. I haven't quite learned that science yet. There are no cats on the jeep. It has a stock style manifold, 2.25" front pipe (to match the manifold), then at the crossover it goes to 2.5" with a flowmaster super 44 and out the back of the jeep.

dwg86 wrote: ↑February 8th, 2020, 7:29 am You might want to try a custom tune from flyin Ryan.

I would love to get a custom tune done, but before that I would like to make sure I am getting the most out of it that I can as it sits. Also, I would hate to do a tune with some underlying issue and it end up being a waste and needing redone or something. Everyone just speaks of how crazy the improvement is even without a tune so I have to feel as if I'm missing something.

Here is a picture of both sides of all 6 plugs, and 3 plugs that seemed interesting because of the brown spot on them, but again I don’t know how to read plugs so I’m not sure what I’m looking at or looking for in them. All plugs were around .035-.037 gap. RC12ECC plugs. Not sure if I should use a different plug in them or not.

How long have you run this engine? I'm assuming you have completed a break in procedure for the cam and rings, have you changed the plugs since then? Either way, how many miles would you say are on these plugs?

In a properly running engine, the whole insulator on the plug should be a light tan color, kinda like the color of the tip of a couple of your plugs in the photos you supplied. Looks like you may be running lean my friend. Do you happen to have a wideband installed? If not, thatd be a great spot to start.

Mike B wrote: ↑February 8th, 2020, 12:33 pm How long have you run this engine? I'm assuming you have completed a break in procedure for the cam and rings, have you changed the plugs since then? Either way, how many miles would you say are on these plugs?

In a properly running engine, the whole insulator on the plug should be a light tan color, kinda like the color of the tip of a couple of your plugs in the photos you supplied. Looks like you may be running lean my friend. Do you happen to have a wideband installed? If not, thatd be a great spot to start.

The engine and spark plugs have 1500-2000 miles on them, I don't remember exactly and I am away from the jeep at the moment. The cam break in was done on first start up, and have not changed plugs since the build. I have a wideband installed near the factory o2 sensor and it reads low 12 range under hard throttle and hovers around 14.7 while driving. The leanest I have seen on the gauge while driving was 15.1. I don't have anything to log/save data from it, so I typically just glance at it when I get a chance. Should I change to a different injector with a different flow? I got these injectors in 2015 "cleaned and rebuilt" I just got what was recommended on the forums for a 4 hole injector. Maybe some are leaking or something causing a few cylinders to be more rich of a mixture than others?

Wide band numbers seem to be in the correct range. When you got the kit from clegg did you end up getting the 24lb injectors? I dont see any mention made of that, perhaps if you have the standard 4 hole replacements installed right now, switching to the 24lb injectors may make the difference you're seeking. Maybe not though since it seems to be getting enough fuel based on the wideband readings.

The plugs look OK to me, and the yellowish tinge could be from a fuel additive. Nothing wrong with the A/F mixture. If anything it's a tad rich under hard throttle but acceptable.
It may just be a case of the engine needing a few more miles under its belt to loosen up.

Mike B wrote: ↑February 8th, 2020, 1:58 pm Wide band numbers seem to be in the correct range. When you got the kit from clegg did you end up getting the 24lb injectors? I dont see any mention made of that, perhaps if you have the standard 4 hole replacements installed right now, switching to the 24lb injectors may make the difference you're seeking. Maybe not though since it seems to be getting enough fuel based on the wideband readings.

According to the quick google search I did (very dangerous thing trusting a quick google search), the injectors I have are 24.4 lb/hr.

Cheromaniac wrote: ↑February 8th, 2020, 2:01 pm The plugs look OK to me, and the yellowish tinge could be from a fuel additive. Nothing wrong with the A/F mixture. If anything it's a tad rich under hard throttle but acceptable.
It may just be a case of the engine needing a few more miles under its belt to loosen up.

I figured around 2000 would be plenty for it to have loosened up. I’m wondering if maybe the distributor may be a little off. The data sheet I have for my cam doesn’t mention timing advance or retard built in, but I know with my Comanche it had some running issues and I ended up cutting the ears off and indexing it like mentioned in cruisers mostly renix tips. I’m just confused because going from a 200k mile motor to a fresh motor should be a noticeable gain, and then the numbers claimed by clegg using this combination there’s no way it wouldn’t be a huge difference. I wish I knew someone semi local with a stroker that could take it for a spin around the block and say yeah that’s about how mine feels or woah there’s something wrong.

Your distributor may indeed be very slightly off, causing the injector pulse to be out of synch with the spark. Since the required adjustment is very small, you may only need to notch rather than cut off one of the ears.

http://www.angelfire.com/my/fan/dist_index.html

Might be a good idea to view the wave sync before changing anything.