Strokin' Betsy

ScottR

ScottR

It's never done.
Joined
Mar 21, 2005
Location
Raleigh, NC
Betsy's Engine has gone strong for ~170K miles. It had a blown gasket so I am doing what any Jeep owner would do- time for an upgrade. Turning the 4.0L into a stroker. I am going to make it a 4.6L.

Parts:
4.0L Engine Block- Cylinders bored 0.030. Deck Milled 0.020
4.2L 3.895" stroke crank
4.0L Piston Rods
Keith Black UEM-IC944-030 pistons
CompCams 68-231-4 206/214 degree camshaft
New Timing Chain
High Flow Water Pump
New Oil Pump
Ford 24lb/hr injectors
Newer High Flow Intake
Compression Should be around 9.6

Here is the where the engine use to sit.
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Here is the engine block torn down. Taking it to the machine shop tomorrow.
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Original Air Intake
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Newer 4.0L Intake (runners are much smoother) that I bought from a buddy 4 years ago for $20. I guess now is a good time to install it. Just need to install the new Ford injectors and my throttle body, etc on to it.
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Last edited:
@ScottR
You going to use 4.0 rods or 4.2 rods?
 
jeepinmatt said:
@ScottR
You going to use 4.0 rods or 4.2 rods?
Click to expand...
I am using the stock 4.0 rods.

RHSCTJ said:
Pretty sure that part # is for the 4.0 6.125" rod. What head are you going to use?
Click to expand...
I am using a reman head that has GM valves- 1.94 Intake, 1.50 Exhaust, GM Performance valve springs.


Dropped everything off at Ashworth Performance in Fuquay earlier today. I am having them clean/check the block, bore the cylinders 0.030, mil the deck 0.020, install crank, pistons, camshaft bearings, balance engine.
Probably several weeks before I get it back.
 
ScottR said:
I am using the stock 4.0 rods.


I am using a reman head that has GM valves- 1.94 Intake, 1.50 Exhaust, GM Performance valve springs.


Dropped everything off at Ashworth Performance in Fuquay earlier today. I am having them clean/check the block, bore the cylinders 0.030, mil the deck 0.020, install crank, pistons, camshaft bearings, balance engine.
Probably several weeks before I get it back.
Click to expand...
If you are getting a "new" head I would try to get a 7120 cast number. I need to get motivated to finish putting mine together. I'm just kinda burnt out on the whole jeep.
 
What's the reason for going with a reman head? Because yours blew a head gasket and worried about cracks, warp, etc, or is there a performance advantage? Are the 1.94/1.50 valves larger than stock? I've done a few stock 4.0 rebuilds, but never paid that much attention. Not sure how much longer the engine in my ZJ is going to last, so I'm planning to make it a stroker when the time comes.
 
ScottR said:
I am using the stock 4.0 rods.
Click to expand...
Nice. Those pistons didn't exist when I did my stroker (just realized its been 11 years, wow!). If it ever gives out, I've still got my nice 4.0 rods ready to go back in.
 
BLarkin said:
What's the reason for going with a reman head? Because yours blew a head gasket and worried about cracks, warp, etc, or is there a performance advantage? Are the 1.94/1.50 valves larger than stock? I've done a few stock 4.0 rebuilds, but never paid that much attention. Not sure how much longer the engine in my ZJ is going to last, so I'm planning to make it a stroker when the time comes.
Click to expand...


I believe it was cost. Scott was telling me it was cheaper to get a new head with the right springs and bigger valves than it was to redo his original head.
 
Black Bear is right. With the cam I will be running the stock valve springs did not have enough lift. So, I would have to change them out for Mopar Performance valve springs, retainers and locks. Those came out to be $35.50 a valve. X 12 valves = $426. I found a reman head with appropriate springs and slightly larger valves (Intake 1.94 vs 1.91) for $420.
 
That's understandable, I would probably do the same thing. By the time you get the head checked and switch the springs and all, you would be crazy not to go that route.
 
ScottR said:
Black Bear is right. With the cam I will be running the stock valve springs did not have enough lift. So, I would have to change them out for Mopar Performance valve springs, retainers and locks. Those came out to be $35.50 a valve. X 12 valves = $426. I found a reman head with appropriate springs and slightly larger valves (Intake 1.94 vs 1.91) for $420.
Click to expand...

Is the head built to OEM specs (maybe for a later model year), or is it modified and offered turn-key as a "better than stock" head?
 
With the engine at the machine shop, I have a couple other things to take care of.

The poly engine mount bushings were shot- one of the sleeves fell out. So, I ordered new bushings from Rusty's. Installed-
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I transferred everything over to the highflow intake. Ford 24lb injectors, Fuel rail, bored throttle body, throttle body spacer, sensor, vacuum accessories. A couple of the vacuum items are in different locations so I will need to run longer rubber lines to them.
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Still waiting on my engine from the machine shop....

In the mean time. TheGriz picked up a Volvo electric fan for me and made a drop in aluminum flange to mount it to the stock shroud. Thanks for doing this!!! I stopped by his house today and we (he) welded up a couple aluminum pieces to fill in the shroud. Here it is all bolted together- it turned out great.

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I will hook the fan up to a thermostat switch to turn on automatically when needed.
 
I got the fan wired up. 12 volt switched power goes to temperature sensor then to relay on fan. Power is fed from the battery through a marine breaker that goes to the stock Volvo relays. I used weatherpak connecters on everything for a quick dependable hookup. The fan will kick on at 190 and go off at 175 degrees.
Temp sensor will be in the top radiator hose.
 
I finally got the engine back from Ashworth Performance- 5 weeks. The owner took me through the shop and showed me all the steps they took to do the job right. They are meticulous. I am looking forward to firing up this engine. Here is the engine back at home.
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I installed the oil pump, oil pan and gave it a fresh coat of paint.
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Here is the top of the engine with the new dished pistons and machined deck.
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I installed some of the accessories last night.
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Today, I installed the engine.
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Head installed. It has dual rate valve springs. I removed the inner springs for cam break in.
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Fail- the Fan that theGriz and I worked on will not work. It is too thick- not enough room between the radiator and engine. I moved it to the opposite side of the aluminum shroud and was able to slide it into place. However, there was only about an 1/8 of clearance between the fan and the engine. The fan is just too deep.

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So, I just installed the mechanical fan. I will be on the lookout for a thinner electric fan.
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Tomorrow, I should be able to get everything together and fire it for the first time. For Cam break in it will have to be run for ~25 minutes between 2000 and 3000 RPM. Then, I will put the inner valve springs back in.
 
Bad news- jeep won't run. It sputters and runs really rough- usually cuts off after a couple seconds. I really should be running the engine and getting the cam broke-in. Well that isn't happening. I got a fault code- P0202. So, trying to figure out why there is a problem with the second injector. Any input is appreciated.
 
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