98ZJ 4.6L Stroker Build

[purple_jeep]

Hi All,

A few weeks back my engine started to make a bad noise so first thing I checked was the valve train which seemed to be ok then a week later I pulled the oil pan to discover chunks of piston two in the pan . At this point I could have just pulled the head and changed the piston with the engine still in the car. Decided instead to pull it out strip it down and stroke it! Good choice as during the strip down I found 3 more pistons with pretty bad cracks.

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This will be my first engine build and my plan atm is as follows:

Machine Work:
Jet Clean Parts....................$165
Magnaflux Block...................$Lost the price :p
Magnaflux Head...................$Lost the price :p
Bore and Hone Block.............$125
Assemble Rods and Pistons......$40
Valve Job..........................$125
Magnaflux Rods...................$40
Deck Block to 0...................$115
Balance rods and rotating.......$130
Resize Rods........................$90
Grind/Polish and shotpeen......$79
Install Cam Bearings..............$60
Check Line Hone..................$50

Parts:
Icon/Keith Black IC944 Forged Jeep Stroker Pistons 0.030" oversize
Hastings Moly Rings
SCAT 9-4.2L-3895
Clevite Rod Bearings
Clevite P-Series Main Bearings MS704P10
Clevite Camshaft Bearings SH1980S
Fel-Pro CS81693 Conversion Set
Fel-Pro HS9076PT3 Head Set
Cloyes C-3041 Timing Set
Melling M81A
Comp Cams High Energy™, 252H: Cam & Lifters CL68-200-4
Sealed Power 381-8084 - Sealed Power Freeze Plugs
ARP Rod Bolt Kit 146-6001
ARP Head Bolts
Stock replacement Springs
ACCEL 120330 Distributor Cap
ACCEL 130330 Distributor Rotor
Champion RC12LYC
Amsoil SAE 10W-30 Signature Series 100% Synthetic ATM1G-EA
AMSOIL Antifreeze and Engine Coolant ANT1G-EA
AMSOIL Ea Oil Filters EAO42-EA

Total should land right around $3K

I plan to degree in the Cam and also use plastigauge on all bearings.

This should give me the following compression Ratios:
Sea Level - SCR 9.47, DCR 8.27
Tucson (2300 ft) - SCR 9.01, DCR 7.81

Do these numbers mean I can run normal pump gas in Tucson (where I live) and higher?
Cam is the only thing that still concerns me but it was mentioned in another site and the owner of the machine shop says thats what they have used in the past in 4.0 strokers.

Thoughts??? Comments?

Cheers

Chris

[SilverXJ]

You should be able to run regular or midgrade.

You don't want to run that particular Amsoil in this engine. I would run the Z-ROD 10w-30 (ZRT) or the Premium Protection 10W-40 (AMO) http://www.syntheticwarehouse.com/broch ... Tappet.pdf

For some reason I am blanking on the usual Champion plug number for strokers. You should run a colder heat range than stock.

[purple_jeep]

I will plan on running midgrade then, if I go down to sea level will I need to run higher octane? the Compression ratio to octane is something I have yet to see clearly explained

Well thats good news on the oil as I already have 2 gallons of 10W40 Premium Protection in the garage as that was what I was running prior to this rebuild. I thought I should switch back to stock 10W30 since everything would be nice and tight now but I was wondering what to do with the oil I have left. Your comment makes it much easier!

Those are the stock plugs I listed everyone says to stay with that brand and specific part number on the stock jeep for a stroker should I stay with the same line and just a colder heat range?

One more question, I currently have a totally stock cooling system (will be adding the cooler for the transmission oil) with the stock thermostat should I be going to a 180 degree thermostat?

Cheers

Chris

[purple_jeep]

Also decided to return the Cloyes C-3041 Timing Set (stock replacement) and get the JP performance set you used in your build (I've read your whole thread and Muad'Dib's) so I can adjust timing if required and its double roller.

Cheers

Chris

[purple_jeep]

Progress is been made, just picked up everything from the Machine shop. They said the Scat crank was 30g out on the balance so I am glad I got the rotating assembly balanced.

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Block will be painted this weekend.

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Hone job looks good, they decked the block to zero deck clearance

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And everything else!

Rods were shotpeened polished and weight balanced, new ARP bolts and resized.

This weekend I will be checking all the clearances with plastigauge and getting everything ready to build during the week.

Few Questions:

• 1. For checking the main bearings with plastigauge do I install all the upper bearings, place the crankshaft on them and then install the caps/lower bearings one at a time (removing as I move to the next one)?
  2. What Thermostat should I use for this build? 180degree? Robert Shaw or another brand?
  3. SilverXJ, in your thread you mentioned possibly removing the plastic tensioning pad for the roller chain? Did you?
  4. I have ARP rod bolts and ARP head bolts is it worth getting ARP main bolts or am I ok using the original ones?

Cheers

Chris

[HuggyBear]

If you want to run the main girdle, you will need to use the original main bolts (or new stock ones). ARP does not provide bolts or studs with the stand offs for the girdle.

[purple_jeep]

Yup just saw that!

Stock main bolts it is

Cheers

Chris

[SilverXJ]

1. For checking the main bearings with plastigauge do I install all the upper bearings, place the crankshaft on them and then install the caps/lower bearings one at a time (removing as I move to the next one)?

Doesn't matter. It might be better to do them one at a time in case you accidentally rotate the crank. If you do you only mess one up. Remember, no lube when checking clearances.

2. What Thermostat should I use for this build? 180degree? Robert Shaw or another brand?

195* unless you have a reason for a 180*. RS are good but I think they are not sold under Mr. Gasket.

3. SilverXJ, in your thread you mentioned possibly removing the plastic tensioning pad for the roller chain? Did you?

It is advisable with a double roller chain. It also adds tension tot he tension side of the chain, effectively advancing the timing a bit.

[purple_jeep]

Well I spent much of yesterday checking clearances.

Piston Rings all checked out both side clearance and gap clearance. Also bought a ring expander and put the rings on the pistons with the gaps alternating 180 deg around the pin centerline.

I checked the clearance on the Main Bearings and they all seem to be between .0025" and .0030". Spec calls for .0010" to .0025" with an ideal of .0020" looks like i need undersized bearings . Before I go beat up the machine shop for new bearings can you guys tell me if the following procedure is ok for measuring the clearance? Also tomorrow I will have the machinist at work measure the crankshaft journals with a micrometer.

• 1. Starting with an empty block
  2. Install all upper bearings dry after making sure everything is clean
  3. Place crankshaft on bearings
  4. Install all lower bearings in caps after making sure everything is clean
  5. Install caps on block torque all main bolts to 80ft.lbs
  6. Remove cap and lower bearing for bearing to be checked
  7. Place plastigauge on crankshaft journal full width
  8. Reinstall bearing cap and bearing and torque to 80ftlbs
  9. Remove bearing cap and bearing and measure plastigauge
  10. Clean off plastigauge and reinstall cap and lower bearing
  11. Repeat 6-10 for each bearing

So I had everything torqued down for checking each bearing one at a time. I have read you should shim the caps on each side of the bearing to be checked I think but I am not sure if that was for checking in the car?

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I also prepared the engine for paint and it is currently drying after a coat of primer followed by some gloss black

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Cheers

Chris

[purple_jeep]

Hi All,

After taking the block and crank to the machine shop and having them measuring with a micrometer it looks like the clearance is between .0025 and .0027 but the only option for .001 undersized bearings is Mopar at $40 list per pair! (online at $15 per pair but I want to build and install this long weekend.) The shop also mentions that for higher performance motors they usually run larger tolerances on the main bearings?

Any comments on this?

Cheers

Chris

[Retlaw01XJ]

The Scat crank I used was a little undersized as well. I wasn't happy about that. Couple of us here had that issue.
I went with the Mopar 0.001" undersized bearings. Cost was somewhere around $150 for all, the thrust bearing was most expensive. Final clearance was 0.018- 0.020", just right for the stock type oil pump. Won't need a hi-volume pump with this setup.
I don't like excessive clearance on a street engine..... you end up with low idle pressure and a lot of oil being thrown around inside.

BTW, you have a nice clean shop. Looks like you do nice work!

[purple_jeep]

Thanks!

Yeah to get the bearings by this weekend I would need to get them from the dealer and they want $40 per set for the mains and I didn't ask about the thrust so all up over $300.

Online I can get the mains for $16 ea and the thrust for $28 but then I will have to wait for them to be delivered before I can install the engine.... Ohh the decisions :p

I already have the stock Melling oil pump so I don't want to have to use the high flow one.

Cheers

Chris

[Retlaw01XJ]

My 0.001 bearings were $165 for the set from the dealer, full list price. Here's the thread I posted in Jan 2012:
http://www.jeepstrokers.com/forum/viewt ... =undersize

Just checked the pricing online, 83507080-AB is $21 list. You're getting $40?
Thrust is 83507086-AB, now $37.50 list.

If you can buy them through a local shop, they should get a discount. Even my local NAPA can get dealer parts for 10% off list.

[purple_jeep]

I ended up ordering them from a vendor on JeepForum (Kolak) about the price you paid. I will have them next week so this weekend will be spent cleaning some more, touching up the paint and changing my Torque Converter seals.

Best to do it right rather than regret it later.

Cheers

Chris

[purple_jeep]

Well another busy weekend! Not that much done on the stroker other than some painting.

Then I worked on changing the torque converter seal and the pump gasket.

I pulled the torque converter off and then pulled the pump out of the transmission to replace the seals but I have to wait till Wed for the parts store to get the seals in.

First thing was to tighten the front band which was alot easier to get to from the top over the bell housing instead of going from underneath as you would have to with the engine in place.

Had to fabricate a pair of slide hammers to get the pump out. Made them from some 5/16" threaded rod, lock nut, two fender washers, steel pipe nipple and two steel pipe caps drilled for the threaded rod.

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When I pulled the pump out all the oil came out so looks like I am doing an oil change on the Transmission also.

At this point is there any reason to change the torque converter? It looks fine but I would hate to have to get to it again later?

Cheers

Chris