Engine options
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Freshman User
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Engine options
Hi guys and gals. New to forum but not my truck, in need of engine options. Some back ground on my truck, 02 Screw FX4 with a 4.6 and 320k miles. Lost oil pressure driving from work one day went to mechanic and he recommended a new motor with install for 4500 bucks ( out of my budget with 2 in college). So I am looking for a used motor. Would it be worth the effort and HP gains to swap in a non-pi block and use my pi heads and intake? My current engine is a Windsor with an 8 bolt crank. Are the flex plates the same diameter between the 6 and 8 bolt cranks? Will the ECM work properly? Thanks in advance for your help
Lead Driver
Joined: Sep 2006
Posts: 7,907
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Romeo engine had 6 hole flex plate.
They should both be the same otherwise to fit the 4r70w transmission.
PI heads on a non PI Windsor block will raise the compression ratio to about 10.5 to 1.
This should offer more torque across the whole RPM range.
The possible issue is the gas Octane you use on the higher compression may not be 87 but the next higher Octanes available.
The PCM should run the motor ok but for the spark advance curve that might be a too aggressive unless you use higher Octane gas.
You will find that out once you get on the road and listen for Pinging.
Only other way around this is a Tuner to make timing changes, then your driving the cost of the project up.
Good luck.
They should both be the same otherwise to fit the 4r70w transmission.
PI heads on a non PI Windsor block will raise the compression ratio to about 10.5 to 1.
This should offer more torque across the whole RPM range.
The possible issue is the gas Octane you use on the higher compression may not be 87 but the next higher Octanes available.
The PCM should run the motor ok but for the spark advance curve that might be a too aggressive unless you use higher Octane gas.
You will find that out once you get on the road and listen for Pinging.
Only other way around this is a Tuner to make timing changes, then your driving the cost of the project up.
Good luck.
Thread Starter
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Freshman User
Joined: Oct 2017
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Thanks Bluegrass, octane shouldn’t be a problem as we have 91 here. Still want a tune to maximize the performance. The easiest solution would be to rebuild my block, but it spun a bearing and lost the thrust washer in the process doing damage to the crank, bearing journal and the back plate. Need to get it out and decide which way to go
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
A non PI engine should be a bolt in.
They all use the same 4r70 transmission 'overall'
The difference is ignition.
Look at the ignition on the engine your considering.
One has two coil packs, your original has 8 coils over plugs.
The harness and PCM are different to operate each type.
One addresses the coil packs, the other fires each of 8 coils separately.
.
Comment:
These trucks have a dummy oil gauge such that you can't tell when your oil pressure is 'going' low from the dash over time until it boots you in the pants.
I run a full time oil pressure gauge for many years and watch it many times during each drive cycle.
At 274xxx miles the idle pressure is still 25 psi hot and runs at 50 psi at normal road speeds. Cold starts runs up to over 70 psi depending on the ambient temperature. These pressures are stock values in the manual.
.
You had no chance to save your motor under the stock circumstances.
Its hard to see how yours went so fast unless you let it run low to long such that it went into starvation.
The sole purpose of lube oil is to keep sliding/rubbing part apart a few thousand's of an inch and keep the surfaces cool from the flow so the lube does not break down from over heating.
Good luck.
They all use the same 4r70 transmission 'overall'
The difference is ignition.
Look at the ignition on the engine your considering.
One has two coil packs, your original has 8 coils over plugs.
The harness and PCM are different to operate each type.
One addresses the coil packs, the other fires each of 8 coils separately.
.
Comment:
These trucks have a dummy oil gauge such that you can't tell when your oil pressure is 'going' low from the dash over time until it boots you in the pants.
I run a full time oil pressure gauge for many years and watch it many times during each drive cycle.
At 274xxx miles the idle pressure is still 25 psi hot and runs at 50 psi at normal road speeds. Cold starts runs up to over 70 psi depending on the ambient temperature. These pressures are stock values in the manual.
.
You had no chance to save your motor under the stock circumstances.
Its hard to see how yours went so fast unless you let it run low to long such that it went into starvation.
The sole purpose of lube oil is to keep sliding/rubbing part apart a few thousand's of an inch and keep the surfaces cool from the flow so the lube does not break down from over heating.
Good luck.
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Freshman User
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I believe my engine starved for oil, when I dropped the pan the pickup tube was full of aluminum shavings. Replaced the oil pump and the tensioner, cleaned it all up and put it back together. Ran it for about 2 weeks ( 12 miles round trip ). Noticed an oil spots underneath it and found the oil pan was leaking, I had failed to put RTV in the rear plate junction. Got a new gasket and dropped the pan and found the thrust washer in the pan and more metal shavings. Truck is nice and straight and everything works just a lot of miles.
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
Put a reman short block assembly in it.
You have to disassemble the motor anyway.
Its trough to pull out a whole motor so take the intake and heads off so the short block comes out easy then reassemble in reverse order.
Good luck.
You have to disassemble the motor anyway.
Its trough to pull out a whole motor so take the intake and heads off so the short block comes out easy then reassemble in reverse order.
Good luck.
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