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1997 Ranger 4.0 OHV Rebuild question


97rangershmazda

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Hi, I'm new here, I have a 1994 Mazda B4000 in which I'm rebuilding a 1997 Ranger engine for. It's a 4.0 SOHC with OHV. My question is do I need to worry about where TDC is of I'm replacing both heads with brand new ones? I should just be able to turn the crank shaft until I see the pistons at TDC and put the new heads on correct? Any help is much obliged. Just was wondering before I pull these old heads off.

P.S. I have one more quick question, will the manual transmission from my 1994 B4000 4.0 OHV engine bolt up and work with this 1997 Ranger engine? Thanks so much for any help and stay safe out there in these troubling times...

Regards,
Matthew
 

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Rock Auto 5% Discount Code: 70D65189E6D8FF: January 5th, 2022

RonD

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Welcome to TRS :)

You are working on two 4.0l OHV engines, drop the SOHC(overhead cams) that's a different engine, only 2001 and up Rangers used the 4.0l SOHC engines

You can bolt the heads to the OHV engine regardless of piston positions
All the valves will be closed until Rocker assembly is added

Yes, the 1994 manual trans will work on any 1990-2000 Ranger 4.0l engine, its an M5OD-R1(M5R1) trans it has ATF inside not gear oil, just FYI
It has 3 rubber plugs at the top back of shifter housing, they like to dry out and leak, check them

The Flywheel from the 1994 4.0l will not work on the 1997 4.0l, in 1997 Ford changed the 4.0l Crank to an 8 bolt version, 1990-1996 used 6 bolt
So if the 1997 didn't come with a flywheel you will need to buy one
Also change the rear main seal when flywheel is off


Some info on rebuilding 4.0l OHV here: https://www.therangerstation.com/tech_library/40rebuild.shtml
 
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97rangershmazda

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Thanks for the reply, that some really good info and I really appreciate it. I got the heads off and I'm wondering if it's a good idea to do a leak down test, to test the rings since I already have it down this far? Any recommendations on what I should use for a leak down test? Thanks again for the info and thanks for the link.
 

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97rangershmazda

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Also thank you for the clarification on the OHV vs SOHC.
 

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97rangermazda:

You need to know that if you are installing 97 4.0 ohv heads on a 94 4.0 ohv bottom end you will be increasing the compression approximately 1.0 whole point; resulting in a 10:1 (ish) compression ratio engine vs the stock 9:1. You should only use premium fuel in this set up.

Also, your 97 heads may be a 98TM casting which has the smaller, more round exhaust ports. Post a pic of the 97 head exhaust ports so that you know what you'll be dealing with.

Are you doing anything with the valve train or just reusing the 94 or the 97's push rods/rockers?

I highly recommend having your valve guides measured prior to reassembly. If yours are anywhere as worn as mine were, your rebuild will drink oil and suffer on overall performance.
 

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One heads up, you have a CAM sensor and synchro tower on the 1997, seen in 1st picture above, your 1994 computer doesn't use/need that, and the bushings on these were a know issue, more so on the 3.0l
The lower 1/2 of this synchro is the Oil Pump Drive, an important part, lol

Your 1994 will just have the Oil Pump Drive, so swap it over to the 1997, one less thing to go wrong :)

Leak down test is done with heads on, with air pressure, not sure any fluid "leak down" would tell you much
You can test the valves in the heads that way, with water
The 4.0l OHV bottom end, bearings and rings, held up pretty well, 400k miles is not unexpected

If you were going to change the bearings then you would just change the rings

If you have the oil pan off then changing the oil pump is not an expensive thing to do, and of course a new oil pan gasket, these like to leak, on any engine, lol
 

97rangershmazda

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So I'm pulling the 94 4.0 engine out. The guy I got the engine from gave me, Engine, Wiring harness, flywheel, so I bought new heads for the 97 block which it is. Shoulda clarified that sorry.
 

97rangershmazda

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I think I did make one mistake though, I bought a head gasket kit for a 94 and I think the block is different is it not? So I'm going to probably have to order another for. A 97..
 

97rangershmazda

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97rangermazda:

You need to know that if you are installing 97 4.0 ohv heads on a 94 4.0 ohv bottom end you will be increasing the compression approximately 1.0 whole point; resulting in a 10:1 (ish) compression ratio engine vs the stock 9:1. You should only use premium fuel in this set up.

Also, your 97 heads may be a 98TM casting which has the smaller, more round exhaust ports. Post a pic of the 97 head exhaust ports so that you know what you'll be dealing with.

Are you doing anything with the valve train or just reusing the 94 or the 97's push rods/rockers?

I highly recommend having your valve guides measured prior to reassembly. If yours are anywhere as worn as mine were, your rebuild will drink oil and suffer on overall performance.
The engine came out of a 1997 ford ranger that I'm rebuilding and putting into my 1994 Mazda B4000 in place of the 94 engine that's in it.
 

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RonD

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I don't think it would matter for the head gaskets, but I would get 1997 gasket set/kit if possible
Also new head bolts, they can't be reused
 

gaz

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97rangerhmazda:

OK, now I understand; your installing the 97 4.0L into you 94 B4000 after it's rebuilt.

Three things I would incorporate:

1) new oil pump
2) new timing set
3) new water pump

I recommend considering:

a) rocker tip hardening/socket insert treatment, by Delta Cam of Tacoma Washington.
b) adjustable push rods by Smith Brother's, custom to YOUR engine.
c) taper hone your stock throttle body to 64mm; this will result in an increase of 3 hp across the RPM band.

I am currently rebuilding a 94, 4.0L with all of these and several other improvements. On paper it is expected to make over 29 mpg at normal legal highway speed and develope maximum 242hp/321tq at the crank. So depending on your performance goals, there is room for improvement.
 
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I changed the thread title to avoid future confusion.
 


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