Gutless 4.7 stroker

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YJCorbyn
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Posts: 20
Joined: October 8th, 2017, 7:16 am
Stroker Displacement: 4.7
Vehicle Year: 1988
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Utah

Gutless 4.7 stroker

Post by YJCorbyn »

For a little background I built the stroker 3 years ago then I bought a house and had my first kid so long story short I just got it up and running after some wiring issues.

I used a 4.0 block and connecting rods with a 4.2 crank,hesco rvob6 cam, hesco FPR, 30lb/hr injectors, a 62mm throttle body, 7120 port/polished head. I can’t for the life of me remember what pistons I went with.. but I know I ordered a set of KB944-60 but they didn’t work for some reason and my machine shop ordered a similar set that would. I also can’t remeber what valve springs I used but I talked to hesco and ordered what they recommended for there cam. When I built the motor I followed the medium buck 4.7 build sheet from this site but it has changed since I built my motor. http://www.jeep4.0performance.4mg.com/stroker.html

Now that you know what’s done to the motor here’s my problem..... it will fire right up but sounds really rough at idle and has no power. I checked for misifires and found that I can pull the spark plug wires or fuel injector plug on cylinders 3 and 4 without any change. Then I checked for spark and power to the injectors and I have both. Next I did a compression check on cyl. 3,4,5 and all were close to 180psi (cold).

I’m not sure if I need to maybe advance timing or maybe the injector timing is off but there is something definitely wrong. I have an air fuel gauge and it’s running around 14.5-15.5 with the FPR set at 47psi.

Hopefully you guys can help me get this figured out. I would really appreciate it!
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Cheromaniac
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Re: Gutless 4.7 stroker

Post by Cheromaniac »

Did you check if the distributor is indexed correctly?
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
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YJCorbyn
Where's the "any" key?
Where's the "any" key?
Posts: 20
Joined: October 8th, 2017, 7:16 am
Stroker Displacement: 4.7
Vehicle Year: 1988
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Utah

Re: Gutless 4.7 stroker

Post by YJCorbyn »

I did about a year ago but I will check it again tonight when I get home from work just to be sure.
YJCorbyn
Where's the "any" key?
Where's the "any" key?
Posts: 20
Joined: October 8th, 2017, 7:16 am
Stroker Displacement: 4.7
Vehicle Year: 1988
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Utah

Re: Gutless 4.7 stroker

Post by YJCorbyn »

Well I checked the timing and It was retarted pretty far so I moved it a tooth advanced but it wouldn’t start... Then I moved it a tooth back and it barely ran so I tried moving it back to the original spot and couldn’t find the sweet spot. So tomorrow after work I’ll put #1cyl at TDC and drop the dist. back in the right spot but this time I’ll cut the mounting point off so I can manually time the motor with a vacuum gauge.
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SkylinesSuck
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Vehicle Model: Wrangler
Location: Northern VA

Re: Gutless 4.7 stroker

Post by SkylinesSuck »

Clocking the dizzy won't effect timing. It only effects injector timing. Get it on the right tooth though. That will change the timing!
YJCorbyn
Where's the "any" key?
Where's the "any" key?
Posts: 20
Joined: October 8th, 2017, 7:16 am
Stroker Displacement: 4.7
Vehicle Year: 1988
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Utah

Re: Gutless 4.7 stroker

Post by YJCorbyn »

SkylinesSuck wrote:Clocking the dizzy won't effect timing. It only effects injector timing. Get it on the right tooth though. That will change the timing!
Good to know! I assumed it would be like older motors that you would turn the dizzy to time.

Is there a way to check injector timing or will the ECM just set it correctly? I’ve heard of guys cutting the dizzy mount off and using a clamp to fine tune strikers... I just always assumed it was timing.
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SkylinesSuck
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Location: Northern VA

Re: Gutless 4.7 stroker

Post by SkylinesSuck »

You will need to do that, yes. Dino had instructions in his sure.
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Cheromaniac
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Re: Gutless 4.7 stroker

Post by Cheromaniac »

YJCorbyn
Where's the "any" key?
Where's the "any" key?
Posts: 20
Joined: October 8th, 2017, 7:16 am
Stroker Displacement: 4.7
Vehicle Year: 1988
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Utah

Re: Gutless 4.7 stroker

Post by YJCorbyn »

Great! Thank you!i will get this done then report back on how it runs.
jsawduste
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Joined: February 28th, 2008, 3:13 am
Stroker Displacement: 4.9
Location: Michigan

Re: Gutless 4.7 stroker

Post by jsawduste »

Dino`s link while helpful may not be "correct" for your application.

The dist. needs to be indexed as shown in his link as a baseline. This gets the parts playing nice together.

Depending on the advance/retard ground into the cam. Or the advance/retard you degreed the cam with the cam timing set the dist. may have to be rotated slightly from the fixed position the tab/bolt provides.

Baseline as Dino says.
Mark the position of the dist and remove the tab.
At idle rotate the dist CW/CCW to find the sweet spot. The engine will tell you where it wants to be.
Tighten the hold down clamp.

My personal engine I run the cam 4 degrees advanced to bring the power curve down a bit. The dist. is rotated a few degrees away from where the tab/bolt would have been.
Life is good.
lazyxj
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Re: Gutless 4.7 stroker

Post by lazyxj »

Setting the cam synchronizer can make a big difference in drivability, as mentioned above. Having it out of proper range can also set P300 misfire and other codes. Had this same problem on the first 4.0 I rebuilt, it was a shock that a one minute adjustment could make such a big difference.
30-lb injectors may be too big for your engine, probably should be in the 24-27-lb range.
Do you have a ported head?
YJCorbyn
Where's the "any" key?
Where's the "any" key?
Posts: 20
Joined: October 8th, 2017, 7:16 am
Stroker Displacement: 4.7
Vehicle Year: 1988
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Utah

Re: Gutless 4.7 stroker

Post by YJCorbyn »

jsawduste wrote:Dino`s link while helpful may not be "correct" for your application.

The dist. needs to be indexed as shown in his link as a baseline. This gets the parts playing nice together.

Depending on the advance/retard ground into the cam. Or the advance/retard you degreed the cam with the cam timing set the dist. may have to be rotated slightly from the fixed position the tab/bolt provides.

Baseline as Dino says.
Mark the position of the dist and remove the tab.
At idle rotate the dist CW/CCW to find the sweet spot. The engine will tell you where it wants to be.
Tighten the hold down clamp.

My personal engine I run the cam 4 degrees advanced to bring the power curve down a bit. The dist. is rotated a few degrees away from where the tab/bolt would have been.
Life is good.

Thanks for the help! I think I talked to you over on JF and on the phone when I was originally building the motor.

I can’t remember how I degreed the cam but I know I did when I switched to the RVOB6 cam. If I need to I can re degree the cam so I know where it’s at.
YJCorbyn
Where's the "any" key?
Where's the "any" key?
Posts: 20
Joined: October 8th, 2017, 7:16 am
Stroker Displacement: 4.7
Vehicle Year: 1988
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Utah

Re: Gutless 4.7 stroker

Post by YJCorbyn »

lazyxj wrote:Setting the cam synchronizer can make a big difference in drivability, as mentioned above. Having it out of proper range can also set P300 misfire and other codes. Had this same problem on the first 4.0 I rebuilt, it was a shock that a one minute adjustment could make such a big difference.
30-lb injectors may be too big for your engine, probably should be in the 24-27-lb range.
Do you have a ported head?
What air fuel ratio do these strokers like to run at? I just assumed 14.7 is what they ran at like other motors.

I do have a potted and polished head
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SkylinesSuck
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Stroker Displacement: 4.6L
Vehicle Year: 1998
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Vehicle Model: Wrangler
Location: Northern VA

Re: Gutless 4.7 stroker

Post by SkylinesSuck »

14.7 is a lite throttle and idle air/fuel ratio. Your narrow band closed loop factory system should keep it there by itself. WOT should be much richer. Ballpark 13'ish.
YJCorbyn
Where's the "any" key?
Where's the "any" key?
Posts: 20
Joined: October 8th, 2017, 7:16 am
Stroker Displacement: 4.7
Vehicle Year: 1988
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Utah

Re: Gutless 4.7 stroker

Post by YJCorbyn »

Well tonight I tried to re time it using Dino’s link. I did everything to the T and it won’t start. Both valves were closed I even hooked my compression gauge up to make sure it was on the compression stroke.

Here is a picture with the rotor set like his instructions say. The black sharpie mark is where the #1 plug terminal is.

Image

And here is a picture with it retarted one tooth.. still wouldn’t start.

Image

I’m not sure how I had it running before I didn’t do anything different when I timed it.
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