Simple/Budget Stroker Build 2000 WJ 4.0 to 4.5

[bratcop]

I am not trying to bump the cost of your build up...but for my money (especially if I am paying someone to deck the block anyway) I would zero deck it. I tried the numbers with a zero deck and you end up with .042 quench, SCR 9.69, DCR 8.03. Besides, when you ask for a zero deck, typically it will only be zero on the highest piston and can vary anywhere from .000 to .006 across the six pistons, giving a slightly wider quench. I really like DCR 8.03:1 with a .04x quench. It can't cost more to zero deck than it does to deck .010, can it? And I know 9 (so far) that it will run on pump gas 87 octane at 500 feet above sealevel

Bratcop

[SilverXJ]

Silver, I have an 01 with 4.0 and it definately has a knock sensor. It is attached directly to the block above and behind the CPS on the right side of the engine.

Sorry, that is not a knock sensor. I don't recall what it is but my 00 XJ has it too. It is a square plastic body sensor with a sheet metal mounting tab at an angle. I also check both the 2004 WJ 4.0L FSM and parts manual and both don't list a knock sensor for the 4.0L.

Edit: That is the ignition capacitor. 56041889AA

[rradford9]

Bratcop, I was trying to keep from having to take my block to a machine shop. They are few and far between around here, and the local ones are extremely slow. The change that I made in the quench height was from using the 802 piston, which has a .007" taller pin height, therefore making the deck height .0145 instead of .0215 like Mcgardiner noted.

[SilverXJ]

Either way you will have to take the block to a machine stop to have the bores cleaned up. And unless you have a piston pin press I don't see how you would get the pistons on the rods. As much as I would like to see someone put together a stroker without a machine shop I don't think it is a good idea.

[bratcop]

It would seem to me a machine shop would be a must, but if you are trying to avoid one, then decking the block is definately out of the question...

Silver, I do believe we are talking about the same sensor...and I still think it is a knock sensor.
Check out this page...http://www.wjjeeps.com/engine.htm. It states there is one on this engine. If that is not a knock sensor, then what on god's earth is it? It obviously isn't a oil/temp/pressure sensor of any type...I believe it can only be a knock sensor. Besides, I found a torque spec for it in my Chilton/Haynes manual (I know that isn't a FSM, but they are usually pretty close.

Here is where you can order one...
http://www.bestvalueautoparts.com/ShopB ... 54&mode=PA

Bratcop

[SilverXJ]

Silver, I do believe we are talking about the same sensor...and I still think it is a knock sensor.
Check out this page...http://www.wjjeeps.com/engine.htm. It states there is one on this engine. If that is not a knock sensor, then what on god's earth is it?

Bratcop

Does it look like this: http://images.wrenchead.com/smartpages/ ... height=300
That is what the knock sensor usually looks like.

What you have is the ignition capacitor, not really a sensor. Frequently part sources list incorrect parts. I know I found one place that had a V8 as an option for the XJ and another one that would sell you coil springs for the rear.

And as I said, the 2004 Factory service manual and the 2004 factory parts manual list no knock sensors for the 4.0L

[Mgardiner1]

The renix era had knock sensors. My 91 does not have a knock sensor, and i am not aware if they re-introduced it with OBD2. They very well may have so they could get individual cylinder misfire codes.

[rradford9]

I'll make some calls on Monday to check on a few machine shops in the area. I can't remember if I mentioned it or not, but I'm not the one actually doing the labor on the motor. This is the first engine I've been inside, so I'm learning as much as I can. My friend, Chris, is the engine builder. He's been building hi-po motors for ~20 years and got into jeeps after doing the drag strip scene for a long time (he's raced on the TV show Pinks). He has built too many engines for me to count, but this is his first time building a stroked 4.0. He's got a large press in his shop, would that suffice to press the pistons on the rods, or is a special type of press needed?

Also, he has a Flex bore cylinder honing brush, which looked like this.

Like I said, my first motor, so I'm trying to get as many opinions as possible. Am I safe going this route?

[SilverXJ]

They very well may have so they could get individual cylinder misfire codes.

They didn't. IIRC the misfire codes come from the CPS sensor.

[SilverXJ]

I'll make some calls on Monday to check on a few machine shops in the area. I can't remember if I mentioned it or not, but I'm not the one actually doing the labor on the motor. This is the first engine I've been inside, so I'm learning as much as I can. My friend, Chris, is the engine builder. He's been building hi-po motors for ~20 years and got into jeeps after doing the drag strip scene for a long time (he's raced on the TV show Pinks). He has built too many engines for me to count, but this is his first time building a stroked 4.0. He's got a large press in his shop, would that suffice to press the pistons on the rods, or is a special type of press needed?

Also, he has a Flex bore cylinder honing brush, which looked like this.

Like I said, my first motor, so I'm trying to get as many opinions as possible. Am I safe going this route?

I think you need a special fixture to hold the piston while pressing.

As for if you are safe just honing... I wouldn't do it.. especially since this is your daily driver. You could spend money on pistons and other parts and a short while later have to re do it again. What you are wanting to do (i.e. just a home with the brush) is just a stop gap short term fix. As the bore wears, it wears unevenly often developing into an eggs shape. While rehoning it and installing new rings and pistons may hold for a while it will eventually fail.

[Mgardiner1]

They very well may have so they could get individual cylinder misfire codes.

They didn't. IIRC the misfire codes come from the CPS sensor.

The cam and crank sensors of course would tell the location. How does it know if the cylinder "misfired" without some kind of sensor to "listen" to combustion? i don't know either way, but would love to learn!

[rradford9]

Ok, trying to do some hypotheticals in case I take it to the machine shop and they say that I need to bore the cylinders...so here's my question before I start calling shops tomorrow...if I go .030 over and don't deck the block that will give me a quench between .052 and .057 (depending on actual crushed height of the VR thin head gasket) and a DCR of 7.9:1 to 8.0:1. After doing some searching it looks like that would be good on mid-grade, and maybe even regular.

Can I still use the OEM WJ fuel injectors and stock cam with that setup? IIRC the WJ uses 22.5lb/hr injectors and 49psi fuel pressure.

[rradford9]

Silver, I do believe we are talking about the same sensor...and I still think it is a knock sensor.
Check out this page...http://www.wjjeeps.com/engine.htm. It states there is one on this engine. If that is not a knock sensor, then what on god's earth is it?

Bratcop

Actually, wjjeeps says there is NOT a knock sensor on the WJ's. If you look at the knock sensor row and the 4.0 column it says (none).


Also think I finally figured out how to properly use the CR calc. Went back and read Dino's site (for like the 10th time). Finally figured out the deck clearance with the 4.2L rods, 4.2L crank, and 1.592" Piston Pin height. Ran the calculator again with .038" deck clearance, 18cc's piston dish and .043" head gasket. That yields a SCR of 9.25:1, DCR 7.96:1 and quench of .081". I know this is way off from the quench height you guys are pointing me towards, but its better than that in Dino's 4.5L simple stroker recipe so I see no reason for it not to work. Everything has been ordered, so now its just waiting for parts to come it. I'm sending my TB and pistons to Oletshot for some work. Hopefully we can have it running by next weekend.

[SilverXJ]

Err..ok.. that is too weird. It said one yesterday and the day before... now it says none.

You really should go with a tighter quench. While you will increase the compression (usually more power) you will also reduce the chance to detonate.

[bratcop]

This is mostly for SilverXJ.

My sincerest apologies, you are correct and I am wrong. The '01 has no knock sensor. I emailed the guy that posted the knock sensor info on wjjeeps.com and inquired where he'd found that info. He acknowledged it was a mistake and changed it. Since that was one of my only sources, I must be wrong. Seriously, thanks for the education. It is truly a sincere apology, I should have never doubted one the experts on here.

Thanks again.

Bratcop