4.0 Engine Toast - Considering Stroking

[Knoxes]

Do you have a build thread or excel sheet with your coats? I'd love to see this

Build thread...

http://www.jeepstrokers.com/forum/viewt ... f=8&t=3391

Ah buggers, I can't figure out how to post the xls. Currently, I'm at ~1800, inlcuding the machine costs of 1K.

FYI - regarding the cam - the Melling MC1377 is the stock replacement for the 4.0 cam. You can find a Mopar replacement, but it's much more expensive.

[Knoxes]

Do you know of any pictures that shows this can pin setup?

Here's a pretty good thread on it...

http://www.jeepstrokers.com/forum/viewt ... f=5&t=2064

Here's the bolt, pin and spring

http://hescosc.com/shop.asp?action=deta ... 343&catId=

Or post #89 shows the difference between the two cam snouts and the pin & spring bolt.

http://www.forabodiesonly.com/mopar/sho ... 636&page=4

[CobraMarty]

Great thread, Thanks.

[mikalcarbine]

Great links, that helped understand it a lot. I called around a couple more places, definitely cheaper and I'll be visiting one or two of them next week.

Knoxes, I use google docs then click share to get a web link, give it a try it's free

[mikalcarbine]

So I'm toying around with the idea of just buying a remanufactured crank from NAPA vs the cost of cleaning up, polishing and potentially (likely due to rust) grinding my crankshaft. Most of the ones at NAPA are ~220 and some do/don't include a core. If I go down the NAPA route is there a particular model/year I want to aim for so my output flange and snout are most compatible? I called NAPA and they said a 5-7 day lead time is on for a 79' CJ5 crank but they had a few weird options, flat flange and one with a V-belt snout. It'd be awesome to pick up a 12CW but I highly doubt they'll have one

[honkysXJ]

The crank out of late 80's wrangler is for many the most desirable because its off a serpentine set up and has the short snout casting#3727 so its a bolt on crank ,no spacer or machining on the snout needed!
The one in your pictures appears to be the longer snout 4 wt. Crank ... If your already invested in it I'd recommend having the shop check it before buying another one, could just be flash rust on the journals and a polish will go along way,also if you get another re-man crank you'll still have to buy mains for your 4.0 block! Your decision of course but might be worth getting the shop to look at it!

[heavy equipment]

About cams: I used a stock camshaft from a '92 4.0. I read that it has enough overlap that EGR isn't needed. My 4.7L "poor man's stroker" is very satisfactory pulling a 13' travel trailer on long trips in the mountainous West. It pulls the hills faster than the 4.0L and still averages 14 mpg. Doing all the work except boring and valve grinding myself, it cost about the same as a generic rebuild of a 4.0L.

[Cheromaniac]

My 4.7L "poor man's stroker" is very satisfactory pulling a 13' travel trailer on long trips in the mountainous West.

Glad you like the "poor man's stroker". Maybe that'll finally silence the naysayers who've bashed my poor man's recipe and called it a disaster. Seems that my strong-running 72k miler wasn't good enough for them.

I used a stock camshaft from a '92 4.0. I read that it has enough overlap that EGR isn't needed.

The '91-'95 HO cam is exactly the same as the Renix cam but it seems that in the HO engine the cam timing was retarded a few degrees to reduce cylinder pressures at low rpm. This allowed the engine to run on 87 octane fuel without a knock sensor but it also raised the powerband higher up the rpm range.

[heavy equipment]

My knock sensor is connected. In Utah and Idaho I've been running 85 octane with no problems. I once built a 351 Cleveland Ford engine and put it in a camping van. I polished the combustion chambers and tops of pistons. I wanted to be able to run it on Mexican gas. I advanced the ignition timing so far it wouldn't start, but even then it ran well on poor gas and never knocked, even though it had no knock sensor.

[mikalcarbine]

Lot's to update on

I ended up picking up a used 4.0 for $350 to get me by while I stroke my original block. I figured I'd do all of the gaskets on the engine before dropping it in. While inside I checked the bearings, completely shot. The upper rod bearings were all copper. I started thinking about just refreshing the engine but one thing led to another and it seems like it'd cost over $1000 even to do it half assed, so now I'm back at square one

I found a new machine shop with much better pricing, here is what I'm looking at

Hot tank $65.00
Bore 0.030" and hone $210.00
Install Cam Bearings $60.00
Install Freeze Plugs $15.00

Crankshaft
Hot Tank included with grind
Magnaflux $45.00
Grind mains and rods to 0.010 $150.00
Chamfer oil holes included with grind
Balance rotating assembly $200.00

Connecting Rods
Hot Tank
Magnaflux
Resize bearing journals as needed $105.00
R&R and Instal Pistons $50.00

Intake/Exhaust Manifold
Check for flatness Free
Shave manifold $65/each

Cylinder Head
Magnaflux $35.00
Valve Steam Seals, Performance Valves, 3 angle valve job, assemble springs $275.00

Engine Assembly $700.00

The only thing I forgot to ask about was milling the block, either way this is already $900 cheaper than the other shop. This makes building my own stroker vs buying a Golen a little more attractive.

I might take a new path, a few more questions

1) How much performance does running a higher DCR/SCR give? I'm debating on doing a build for 91 octane, the price difference is only $5/tank fillup, if I can gain 10+HP it may be worth it

2) Any reason not to do a 4.7L instead of a 4.6L? The only difference I see is minimal extra machine work and a few parts

3) Would a piggyback system be required for a 4.6/4.7L? I'd like to run for a while without one and then add one if I'd like to tune everything

[mikalcarbine]

I've decided I'm going with this 4.7L build

Jeep 4.2L 3.895" stroke crank
Jeep 4.0L 6.125" rods
Keith-Black Silvolite UEM-IC944 +0.060" bore pistons
9.6:1 CR
CompCams 68-231-4 206/214 degree camshaft (still torn between 231 and 232)
CNC ported HO 1.91"/1.50" cylinder head
Mill block deck 0.020"
Mopar/Victor 0.043" head gasket
0.051" quench height
65mm over bore TB
Accel 26lb/hr injectors with stock 49psi FPR for '96 and later engines.

From what I gather the ideal quench is 0.045", when I try to use the calculator I'm getting something different from the recipe above. The stock deck clearance is 0.0215" so by milling it 0.020" it should be 0.0015" unless the wrist pin height of the IC944's is different (is it?). If I am right then I'll have a 9.87:1 SCR and 8.4:1 DCR with a 0.0445" quench. If I open up the combustion chambers on the head a little bit say to 60cc I can decrease my DCR to a nice 8:15:1

[Cheromaniac]

From what I gather the ideal quench is 0.045", when I try to use the calculator I'm getting something different from the recipe above. The stock deck clearance is 0.0215" so by milling it 0.020" it should be 0.0015" unless the wrist pin height of the IC944's is different (is it?). If I am right then I'll have a 9.87:1 SCR and 8.4:1 DCR with a 0.0445" quench. If I open up the combustion chambers on the head a little bit say to 60cc I can decrease my DCR to a nice 8:15:1

The stock deck clearance is based on the stock 4.0L crank's 3.411" stroke and the stock piston's 1.601" pin height. Your 258 crank has a 3.895" stroke and the IC944 pistons have a 1.353" pin height so that changes the results.

[mikalcarbine]

That makes sense now, based on those numbers the new deck clearance would be 0.0275" without milling the deck - the lower pin height adds 0.248" to deck clearance, longer stroke reduces this by 0.242", totaling 0.0215+0.248-0.242=0.0275", shave off 0.020 and the new deck clearance will be 0.0075

With this the SCR is 9.75:1 and DCR is 8.19:1 with quench of 0.0505", I'd probably open up the combustion chamber a little and get the DCR around 8:1, do these numbers look right?