4.6L Stroker, "Low Buck Low CR"

Project vehicle blogs or "mod diary" specific threads only.. Pics encouraged!!
Retlaw01XJ
Movin on up ^
Movin on up ^
Posts: 307
Joined: November 23rd, 2011, 10:40 pm
Stroker Displacement: 4.6
Vehicle Year: 2001
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: 4.6L Stroker, "Low Buck Low CR"

Post by Retlaw01XJ »

That's close to the build I did last winter. Went with stock valve springs and a milder Crower 44243 cam.
Cut the deck 0.020" for a deck clearance of 0.013" and a resulting CR of 9.35:1.
Dynamic CR is 7.72. I've been using 89 octane for the 2,000 miles I put on it. I get occasional ping when it's cold and I push it past 70% throttle, it's ping free otherwise.

The 9.6 CR listed in the recipe is higher than I experienced. Someone mentioned deck heights varied between some years, mine is a 2001.
Dino's cam page has specs for a wide selection of cams, check it out:
http://www.angelfire.com/my/fan/Jeep4.0Camshafts.htm
Walt K
Eastern Pa
2001 Cherokee 4.6 stroker 90 day build
Buick GS's and Saab turbos for other days...
Lil Dutchman
Where's the "any" key?
Where's the "any" key?
Posts: 22
Joined: September 14th, 2012, 9:34 am
Stroker Displacement: Low Buck 4.6
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Warrenton, VA

Re: 4.6L Stroker, "Low Buck Low CR"

Post by Lil Dutchman »

So what did you do differently? The last recipe that I posted had only 0.020" off the deck yet it quoted a 9.6: CR. Is it the fact that you used a mild Crower that ended up reducing CR? I thought piston cc and the and head volume affected CR. Well, either way, after your post and a couple others, I think I'll be looking into using a Crower cam.

The pistons just arrived, after speaking with my machinist, I was steered away from thermally coated pistons and he recommended Icon pistons. So I picked up Icon IC944-30 pistons and ring set. Now I'm just waiting for the connecting rod bolts to arrive before dropping everything off at the shop where they may beginning working on the beast.

Image
Image
Image
Retlaw01XJ
Movin on up ^
Movin on up ^
Posts: 307
Joined: November 23rd, 2011, 10:40 pm
Stroker Displacement: 4.6
Vehicle Year: 2001
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: 4.6L Stroker, "Low Buck Low CR"

Post by Retlaw01XJ »

Those pistons sure are beauties!
Be sure the shop checks to see if the small end of the rod clears the underside of the piston. Most need a little material taken off the end of the rod.
I don't know what measurements KB used to get their 9.6:1 advertised CR. Their deck height must be different than what I got. My pistons were 0.013- 0.014" down after the deck was cut 0.020". Chambers were about 58 cc after polishing and valve job. 0.043" head gasket thickness.
Walt K
Eastern Pa
2001 Cherokee 4.6 stroker 90 day build
Buick GS's and Saab turbos for other days...
Lil Dutchman
Where's the "any" key?
Where's the "any" key?
Posts: 22
Joined: September 14th, 2012, 9:34 am
Stroker Displacement: Low Buck 4.6
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Warrenton, VA

Re: 4.6L Stroker, "Low Buck Low CR"

Post by Lil Dutchman »

Well, I finally found time to swing by the machinist to drop everything off. I was wondering why he needed everything (pistons, rings and connecting rod bolts) before he started boring, I thought that was something you can just knockout right away. He explained that not every piston is manufactured perfect and that they vary a little from one piston to another. I guess some places whats called "blind boring", where they bore what ever size you want without checking the pistons first. But this practice apparently can lead to a list of issues, some of which are unnecessary noise and wear.

I'm sure majority of you guys/girls on this site already know this, but if you're like me and you didn't, now you know. I forgot to ask but I'm guessing the next step would be to check the quench and decide how mush is coming off the deck?
User avatar
SilverXJ
Global Moderator
Global Moderator
Posts: 5789
Joined: February 14th, 2008, 7:14 am
Stroker Displacement: 4.6L
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Radford, Va

Re: 4.6L Stroker, "Low Buck Low CR"

Post by SilverXJ »

Lil Dutchman wrote:Well, I finally found time to swing by the machinist to drop everything off. I was wondering why he needed everything (pistons, rings and connecting rod bolts) before he started boring, I thought that was something you can just knockout right away. He explained that not every piston is manufactured perfect and that they vary a little from one piston to another. I guess some places whats called "blind boring", where they bore what ever size you want without checking the pistons first.
That is correct. Any good machinist will need the pistons first to correctly bore the block and set piston to wall clearance. If anyone finds a machinist that doesn't need the pistons grab your stuff and run.
I forgot to ask but I'm guessing the next step would be to check the quench and decide how mush is coming off the deck?
The machinist will need to mock up the block with bearings, crank, pistons and rods to decide on how much to take off and set your quench. Again, there are variables between crank throws, rod length and piston pin heights. Before the final cleaning your or him may want to go through and clean up the oil drain back holes in the lifter valley and head.
Lil Dutchman
Where's the "any" key?
Where's the "any" key?
Posts: 22
Joined: September 14th, 2012, 9:34 am
Stroker Displacement: Low Buck 4.6
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Warrenton, VA

Re: 4.6L Stroker, "Low Buck Low CR"

Post by Lil Dutchman »

I just picked up a K&N cold air intake for pretty cheap and starting to question if it was the smartest decision. I just read that the K&N filters actual allow fine dust to enter through the filter into the cylinders, so I have a couple questions questions:

Is this true and is it something that I need to worry about? I could understand it being an issue is I lived in a dry climate like out west, but here in VA, I don't see that much dust (other than dry dirt trails).

Should I sell the intake and stick with the stock intake or just upgrade the filter to an Afe "dry" filter?

And if I stick with the cold air intake, is there any thing I can do about that whistling sound?
User avatar
SilverXJ
Global Moderator
Global Moderator
Posts: 5789
Joined: February 14th, 2008, 7:14 am
Stroker Displacement: 4.6L
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Radford, Va

Re: 4.6L Stroker, "Low Buck Low CR"

Post by SilverXJ »

I wouldn't worry about it too much. Most of our vehicles have had K&Ns and are will over 150,000 miles. Some above 200,000 miles. I switched to an Amsoil cone filter because I wasn't fond of oiling anymore and it should filter better.

We haven't had an engine failure while running a K&N.
shawnxj
I love this board
I love this board
Posts: 413
Joined: March 30th, 2009, 7:30 pm
Vehicle Year: 1988
Vehicle Make: jeep
Vehicle Model: cherokee
Location: portland, tx

Re: 4.6L Stroker, "Low Buck Low CR"

Post by shawnxj »

i've had a k&n on my truck for the last 280,000+ miles...still runs like a raped ape
Lil Dutchman
Where's the "any" key?
Where's the "any" key?
Posts: 22
Joined: September 14th, 2012, 9:34 am
Stroker Displacement: Low Buck 4.6
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Warrenton, VA

Re: 4.6L Stroker, "Low Buck Low CR"

Post by Lil Dutchman »

Sold! I'm keeping it, plus for $80 bucks, I can't really go wrong. I threw it on the other day and I noticed a small difference, nothing too dramatic. But I'm sure it'll be needed later on.

While I'm waiting on the machine shop, I started reading up how to bore out your own throttle body, and like they say, "an idle mind is a dangerous mind". I was originally planning on purchasing one from Leigh Performance http://www.strokedjeep.com/ because I heard great revews, but after coming across this site http://jeep-xj.info/HowtoTBboring.htm I figured that I first try my luck with what I have.

Here's the TB off the donor engine
Image

Just based from the soot, you can see how much needs to come off, I decided to stick with the size of the gasket which is 62mm
ImageImage

I threw an old milling bit into the drill press, set the height just above the highest point of the butterfly valve, and went to town... slowly (TB fully disassembled)
Image

I didn't go the full 62mm, I noticed that as I was starting to dig into the body so I backed off and stuck with 60mm. A little light sanding and buffing and the ridge would disappear.
ImageImageImage

Ever since my wife and I picked up the Jeep, she's been slowly getting into the mechanical side of things. So I had her put the TB back together (ended up painting the body)
ImageImageImage

Man what an improvement!!! If I would had done this a while ago, I might not have decided to stroke the motor because what a difference! It's as if I just lit a match under its @ss. If my Jeeps driving this great with these two improvements, I can't wait to see what the strokers going to be like. I might try fully boring the other TB to 62mm and see what thats like, that would require me to fab a larger valve. I highly recommend this upgrade, either buying or doing it yourself. Now I'm on the lookout for a 99+ intake manifold.
Lil Dutchman
Where's the "any" key?
Where's the "any" key?
Posts: 22
Joined: September 14th, 2012, 9:34 am
Stroker Displacement: Low Buck 4.6
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Warrenton, VA

Re: 4.6L Stroker, "Low Buck Low CR"

Post by Lil Dutchman »

It's been a while since my last post, my machinist had me on the back burner, not too big of a deal since I'm not in a rush. The block has been bored, the head has received a valve job and the crankshaft was ground. And that's where the problem was discovered. I guess the crankshaft sat so long at the shop that a rust pocket developed, so bad that it was going to require too much grinding. So I spent a couple weeks figurin out what my next step was going to be.

I decided to purchase a remanufactured crank from Autozone, $180 plus $40 core, which came with matching main bearings. It just came in and looks great, I just hope I got the right one. I went with an '87 Jeep wrangler 4.2 crank because of the shorter nose, that way I don't have to worry about a spacer. After a lot of reading, I didn't understand the true benefit of the extra counterweights.

Image

I'll be dropping it off at the shop on Monday to have the assembly balanced and I guess start looking for camshafts. I'm thinking about going with a Crower, being that I can keep my stock valve springs. Something with a powerband from 1500-4500 RPM's. Thoughts?
User avatar
SilverXJ
Global Moderator
Global Moderator
Posts: 5789
Joined: February 14th, 2008, 7:14 am
Stroker Displacement: 4.6L
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Radford, Va

Re: 4.6L Stroker, "Low Buck Low CR"

Post by SilverXJ »

You are pretty limited with cam selection using stock springs. But it also depends on what you are after.

What was that crank ground down to?
Lil Dutchman
Where's the "any" key?
Where's the "any" key?
Posts: 22
Joined: September 14th, 2012, 9:34 am
Stroker Displacement: Low Buck 4.6
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Warrenton, VA

Re: 4.6L Stroker, "Low Buck Low CR"

Post by Lil Dutchman »

I'm not too sure as to what the cranks ground to, I'll have it checked. And I'm going for a daily driver/offroading. More daily driver though, I haven't been doing too much offroading lately, and my wife's tired of me breaking parts. I guess the biggest thing is that my not trying to build a racer or break the bank.
Retlaw01XJ
Movin on up ^
Movin on up ^
Posts: 307
Joined: November 23rd, 2011, 10:40 pm
Stroker Displacement: 4.6
Vehicle Year: 2001
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: 4.6L Stroker, "Low Buck Low CR"

Post by Retlaw01XJ »

Nice work on the throttle body! That's a mod I still have to do. It's great that your wife is interested too.
I went with the Crower 44243. It's a little bigger than stock but smaller than the popular Comp 231 or 232 grinds.
Couple of reasons I went with it:
- it doesn't require another $300 for valve springs and retainers
- the slightly 'larger than stock' specs would feed the extra cubes of the stroker.
- with 194/204 duration it keeps the exhaust open longer for mid and hi-end performance, but still has an early closing intake valve to keep the dynamic compression higher for good low end.
- there aren't many other choices that can use the stock springs.
- It performed very well on Dyno 2003 engine simulations (if they are even accurate?) compared to other cams.
It runs well, but I honestly can't compare it to anything else. I bought my XJ with a noisy engine, and never drove it more than on/off the trailer! I am impressed with the daily driver torque of the 4.6... I barely have to push the gas pedal to get up the rolling hills around here.
Walt K
Eastern Pa
2001 Cherokee 4.6 stroker 90 day build
Buick GS's and Saab turbos for other days...
homebrew
Posts: 1
Joined: April 20th, 2012, 9:09 pm
Vehicle Year: 1993
Vehicle Make: jeep
Vehicle Model: yj

Re: 4.6L Stroker, "Low Buck Low CR"

Post by homebrew »

i had my thottle body bored out to 62mm at a school called boces in upstate ny.they have a machining course and will do it for a small donation.i made the butterfly valve out of sheet aluminium that i got from the hardware store.i also had them make me a throttle body spacer.it was a great inprovement in throttle reponse and power.
Lil Dutchman
Where's the "any" key?
Where's the "any" key?
Posts: 22
Joined: September 14th, 2012, 9:34 am
Stroker Displacement: Low Buck 4.6
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Warrenton, VA

Re: 4.6L Stroker, "Low Buck Low CR"

Post by Lil Dutchman »

Picking a cam with the proper springs/retainers is more difficult than I thought. Still on the fence about the Crower 44243, but I recently started looking at the Lunati 63500, if I knew what springs I should run with, I might go with it. I like the increased range of RPM's compared to the Crower. I don't know what the cranks ground to.

Image
Post Reply

Who is online

Users browsing this forum: Ahrefs [Bot] and 21 guests