4.6L Stroker, "Low Buck Low CR"

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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

4.6L Stroker, "Low Buck Low CR"

Post by Lil Dutchman »

I feel like this is over my head but I'm still going to try, I have a 1998 Wrangler and I'm tired of the sluggish features that came with it. I did a little reading (a lot of reading) and the more I read, the more lost I started to feel so I said F it, and took the plunge. One way to learn is by trying, and hopefully I don't waste too much money in the mean time.

I found a donor motor out of a '97 Wrangler on craiglist for $200. The guys I bought it from started with doing a V8 swap and has now decided to rebuild everything from the ground up. Here's his write up http://www.jeepforum.com/forum/f22/97-t ... d-1407123/.

Thanks to Dino, I think I'm going with the "low buck, low CR" build, but I'm still unsure. The main thing driving this build is that I still wish to have an incredible Jeep while still using 87 octane. This is what I'm thinking of going with this recipe:

4.6L Low-buck, low CR "rockcrawler"

Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Silvolite UEM-2229 +0.030" bore pistons
Increase piston dish volume to 30cc
8.75:1 CR
CompCams 68-115-4 192/200 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Mill block deck 0.035"
Mopar/Victor 0.043" head gasket
0.058" quench height
Ford 24lb/hr injectors for '87-'95 engines, Accel 24lb/hr injectors for '96-'04 engines, '98 Chevy LS1 25.2lb/hr injectors for '05-'06 engines
240hp @ 4700rpm, 315lbft @ 3000rpm

I started shopping around for machine shops and felt pretty comfortable with the first one I came across. Started explaining what I was looking for to the head guy and he mentioned that he had a 4.0L block, 4.0L head, 4.2 L crank, and 4.2L rods in the back that he'd sell me. Unfortunately the block and head were a little older than the one I picked up so my father and I started breaking ours down.

Being that the donor motor was from Jersey, there seemed to be a lot of rust and a lot of concern. Brought it to the shop where they had the same concerns but they said it still looked pretty good. I guess a little extra time in the hot tank before checking for any cracks or abnormalities. Once its out, I'll be sitting down with them and come up with a plan of attack.

If anyone as advice/suggestions, I'm open to them. I'll post pics once I figure it out.
TR1Hemi
Making Progress
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Posts: 84
Joined: August 23rd, 2012, 3:33 am
Vehicle Year: 1997
Vehicle Make: Jeep
Vehicle Model: Cherokee

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

Post by TR1Hemi »

I am just starting my build also, I have done engine swaps, rear end swaps, a Dana 44 rebuild with all new gears, and bearings, but not an engine, so maybe we can keep in touch as we build them. I am building a 1998 block, 1995 7120 head, 1980 12cwt 4.2 crank, 1980 4.2 rods, 1999up intake, undecided about cam, Lunati 500/7000, Comp 235-4, or Lunati 501/7001. The biggest thing that I have seen that need to be addressed is the unmachined part of the oil pump mounting surface, if going with an HV pump, making sure you either pick the right valve springs, or machine the valve spring seat for 1.800" springs, keeping an eye on comp ratio, and getting 24lb injectors, other than that it is straight forward, and there are fixes for most, if not all, small issues.
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 »

Great, thanks for the advice, I had no idea that there was additional machine work for a HV pump. Good job on finding a 12cwt, but being that the shop already had a 4.2L crank/rods, I couldn't say no. Ended up with the 4cwt with long nose, so I guess I'm gonna need to have the shop make a spacer for the nose as well.
Bring her home
Image
Quick pic of the heavy rust on the header side
ImageImage
Doesn't look too bad on this side
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My dad lending a hand
Image

Camera battery died, so I'm out of photos. I'll be better when parts come back from the shop
Last edited by Lil Dutchman on September 17th, 2012, 8:17 am, edited 5 times in total.
dwg86
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Posts: 1201
Joined: February 13th, 2008, 6:20 pm
Stroker Displacement: 4.6
Vehicle Year: 2003
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Atlanta, Ga

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

Post by dwg86 »

Don't go too low buck and expect good results or huge hp gains.

From what I've read on here of other's experiences and building my own stroker, if you don't want your engine to ping (detonate), keep your quench tight (.040-.060). My quench was .043 with 9.25 Static compression ratio (SCR), and 7.8 Dynamic compression ratio (DCR). I had no problems running 87 octane. I feel like I could have gone 9.5-9.8 SCR 8.0-8.3 dcr and ran 87-89 gas. I think I would have been happier with the performance from the higher comp ratio.

If you cut your block to get a tighter quech, you will need new push rods, adustable valve train or rocker shims to adjust you valves.

Stock valve springs are only good for .450 valve lift. If you are going over .450 lift on your cam, make sure you budget for mopar valve springs and retainers, or install small block chevy valves and pick almost any spring you want. I bought 1.94/1.50 undercut, stainless SBC valves on ebay. I used retainers that install the valve springs .050 higher. That makes the sbc valves install at the same hight as stock springs (or pretty darn close). You can the pick almost any spring/retainer combo you want. I think I payed around $100.00 for the springs. That is the way it is with the 4.0 valves...not many options. Also, do not buy a complete kit from comp cams with springs and retainers, the springs and retainers won't fit a 4.0. They are designed for a 258.

Because of reading about stock, or single row roller timing chain failures, I would run a double roller chain. They aren't that much more expensive than a stock chain (depending on which one you buy).
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 now you have me rethinking the entire recipe, I was already on the fence with the "Low Buck, Low CR" and "Poormans" stroker, and now you have me looking at the "Low Buck" with the 9.6:1CR

Jeep 4.2L 3.895" stroke crank
Jeep 4.0L 6.125" rods
Keith Black UEM-IC944-030 pistons
9.6:1 CR
CompCams 68-231-4 206/214 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Mill block deck 0.020"
Mopar/Victor 0.043" head gasket
0.050" quench height
Ford 24lb/hr injectors with adjustable FPR or MAP adjuster for '87-'95 engines, Ford 24lb/hr injectors for '96-'04 engines, '99-'00 Chevy LS1 26.2lb/hr injectors for '05-'06 engines
264hp @ 4900rpm, 324lbft @ 3500rpm

It has the increased CR along with a tighter quench height than original plan. I just don't want to have to use high test, I already have one car that requires it.

I heard about Comps springs and lifters not working, but I'm glad you reminded me, so I can come back to it when I start working on them.
dwg86
Donator
Donator
Posts: 1201
Joined: February 13th, 2008, 6:20 pm
Stroker Displacement: 4.6
Vehicle Year: 2003
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Atlanta, Ga

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

Post by dwg86 »

Check out http://www.bulltear.com . They make custom stroker pistons any size, comp ratio (cc dish) and compression distance (for quench). They cost $429.00. I think this is cheaper than kieth black pistons, and you can have them custom made for your engine.
TR1Hemi
Making Progress
Making Progress
Posts: 84
Joined: August 23rd, 2012, 3:33 am
Vehicle Year: 1997
Vehicle Make: Jeep
Vehicle Model: Cherokee

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

Post by TR1Hemi »

I wouldn't call it an extra machining step, you can fix it your self, with a dremel, a small amount of the unmachined ridge needs be be removed so the bigger HV pump will sit flat, I am rethinking my pump choice, is it really needed, and may cause more wear to the dizzy gear. But I have already removed the ridge on my block. I need to call the machine shop and see if my head is done.
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 »

dwg86 wrote:Check out http://www.bulltear.com . They make custom stroker pistons any size, comp ratio (cc dish) and compression distance (for quench). They cost $429.00. I think this is cheaper than kieth black pistons, and you can have them custom made for your engine.
Thats awesome!!! I'll definitely give them call after I speak with the machinist. Speaking of which, I need to call them tomorrow to find out how everythings looking from the hot tank. I hope they don't do anything on their own like resurfacing the deck or head without calling me first. (slight moment of panic)
TR1Hemi wrote:I wouldn't call it an extra machining step, you can fix it your self, with a dremel, a small amount of the unmachined ridge needs be be removed so the bigger HV pump will sit flat, I am rethinking my pump choice, is it really needed, and may cause more wear to the dizzy gear. But I have already removed the ridge on my block. I need to call the machine shop and see if my head is done.
I was originally planning on running a HV pump, but after doing some additional reading, I don't think its really needed. I'm probably going to stick with the stock pump. I don't think having it would hurt, I just don't think the benefits out weight the costs.
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SilverXJ
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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 »

TR1Hemi wrote:I wouldn't call it an extra machining step, you can fix it your self, with a dremel, a small amount of the unmachined ridge needs be be removed so the bigger HV pump will sit flat,
Depending on the block/pump it may be necessary with any oil pump, not just the HV. The ridge interfered on a standard melling pump on mine.
TR1Hemi
Making Progress
Making Progress
Posts: 84
Joined: August 23rd, 2012, 3:33 am
Vehicle Year: 1997
Vehicle Make: Jeep
Vehicle Model: Cherokee

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

Post by TR1Hemi »

SilverXJ wrote:
TR1Hemi wrote:I wouldn't call it an extra machining step, you can fix it your self, with a dremel, a small amount of the unmachined ridge needs be be removed so the bigger HV pump will sit flat,
Depending on the block/pump it may be necessary with any oil pump, not just the HV. The ridge interfered on a standard melling pump on mine.
Wow, first I have heard of that one, kinda makes you wonder WTH the factory was thinking huh?
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 swung by the shop today and dang does that block look awesome. Everything checked out great, no more rust, no cracks, the head was cleaned and magna-fluxed and everything checked out great. (No pics because I was too excited to see how great it looked - idiot!). My guy mentioned that there was a light tapering in the cylinders and that he would recommend at least 0.030 bore, perfect! I brought the the crank caps, bolts and girdle so he can start working his magic. And thanks to dwg86's comments, I ran the "low buck" stroker recipe by the machinist and he thought it would work fine with regular fuel, as long as I stay away from crap fuel like at 7-11. This raises the compression ratio from 8.75 ("Low Buck, Low CR") to 9.6 ("Low Buck Stroker"), and providing what appears an additional 24 hp at the flywheel. Getting pretty excited at this point.
TR1Hemi
Making Progress
Making Progress
Posts: 84
Joined: August 23rd, 2012, 3:33 am
Vehicle Year: 1997
Vehicle Make: Jeep
Vehicle Model: Cherokee

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

Post by TR1Hemi »

Sounding good! Picked up my head from local NAPA machine shop, after sinking the valves and my chamber work I ended up with 68cc chambers! He also sank the spring seats, combined with the sinking of the valves I got a 1.8" spring height. Gunna post some pics over on my build thread.
dwg86
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Posts: 1201
Joined: February 13th, 2008, 6:20 pm
Stroker Displacement: 4.6
Vehicle Year: 2003
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Atlanta, Ga

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

Post by dwg86 »

What springs are you useing? What are your closed and open pressures?
TR1Hemi
Making Progress
Making Progress
Posts: 84
Joined: August 23rd, 2012, 3:33 am
Vehicle Year: 1997
Vehicle Make: Jeep
Vehicle Model: Cherokee

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

Post by TR1Hemi »

I think you were asking me, havent decided on a cam yet, I would rather only have to install it once. But the spring selection will be unlimited by going 1.8".
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 »

Ok, I just want to be sure that I'm going with the right build. I was originally looking at the "low budget, Low Cr" build with a 8.75 cr, but after dwg86 mentioned that I could go higher with the CR, so I started leaning toward the:

4.6L low-buck stroker
Jeep 4.2L 3.895" stroke crank
Jeep 4.0L 6.125" rods
Keith Black UEM-IC944-030 pistons
9.6:1 CR
CompCams 68-231-4 206/214 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Mill block deck 0.020"
Mopar/Victor 0.043" head gasket
0.050" quench height
Ford 24lb/hr injectors with adjustable FPR or MAP adjuster for '87-'95 engines, Ford 24lb/hr injectors for '96-'04 engines, '99-'00 Chevy LS1 26.2lb/hr injectors for '05-'06 engines
264hp @ 4900rpm, 324lbft @ 3500rpm

Has anyone built this set up or has any knowledge as to whether or not I'll have issues running standard fuel? And does anyone have any recommendations for cam options? I haven't heard great things about Compcams.
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