1998 4.0 ohv motor rebuild

[Grego50]

I have a 2000 Ford Ranger 4.0 that I would like to build a new motor for. Today I picked up a doner motor off a 1998 and I am going to get it mounted on a engine stand.
During this planning stage, what upgrades should I be considering for power and longevity of my new motor. Any help would be appreciated.
Thanks, Greg.

 

[poker4me007]

Depends how much you want to spend...A few things i'd definitely do is replace all the gaskets, oil pan, valve cover ect.. plus your rear crank seal...also i'd replace the valve seals...Put in a new oil pump...To know what else you may want to replace while it's out would depends on how many miles on the motor and how it ran ,did it use oil? ect...

 

[Grego50]

This will be a full rebuild. After tear down, off to the machine shop.

 

[roscoe 0202]

I would port in the bowl area under the valve if you can remove a valve look how restrictive it is there don't know how much power gain but would it would be able to feel increase in seat of pants.
roscoe
ps rebuilt mine all stock except for port work haven't got it running yet still wiring bII for the swap.

 

[96eb96]

I know there are nice headers for the OHV, I forget the brand. This place has some nice upgrades too:
Tom Morana Racing Engines

Pushrods and lifters wear on these motors because of poor oiling, good to check them out before reinstall.

Heads are prone to cracking, make sure they are checked well. There are inexpensive heavy duty heads on ebay.

 

[bigred4x4]

Updated hd Heads for sure, also don't cheap on the gaskets especially head gaskets and get a quality brand name oil pump, also new lifters, push rods and rockers would be nice as the originals tend to develope a tick, sky is the limit really just depends on your wallet,a machine shop or a few measuring tools will let you know what is in spec and what needs to be machined, like rods, crank, block, etc... Get good bearings like clevite or federal Mogul,MLS head gaskets are a little better than graphite,

Some tips for the rebuild are.....

Good luck finding stock rod bolts the ARP high performance bolts for the 302/289 work perfectly in the 4.0.

If you re use the stock heads at least lap the valves and replace seals, clean combustion chamber,

Pay attention to chain and sprocket set up with a 98 you should be good but my 95 engine had mixed parts due to being a transitional year.

My engine wasn't too bad to rebuild but I did hit a few snags here and there that the hanes manual didn't cover or mention.

Also the CPS needs a tool to reinstall the drive gear and sensor make positive that your using the correct one because if you rent it from Auto zone it comes with like 5 different tools in the box,

 

[bigred4x4]

Rebuilding The Ford 4.0L Pushrod V6 - Engine Builder Magazine


Here is a very interesting article about the 4.0

 

[Grego50]

Good stuff, thanks too all that replied!
Greg

 

[96eb96]

This guy is a professional diesel engine tech, pretty through series on a top end 4.0 OHV job. (There are a few vids).

 

[Grego50]

The motor that I purchased has the EGR setup that I believe was for California smog emissions crap. Since I already have the wiring harness, correct computer, left exhaust manifold and upper intake manifold, I do not see any issues. Both the blocks are 8 digit x vin models.
Is there anything else Cali lib gov did to these motors?

 

[96eb96]

Rangers had EGR deletes, because they are a truck(different emission standard) and there were improvements made to the 98 heads(the exhaust is narrower to increase velocity). The difference is a plug in the exhaust and intake. Not sure about Explorers. Beyond that everything is in the PCM software. Any OHV should work.

 

[Grego50]

Update:
Both heads had cracks in them. I did plan on replacing with stronger aftermarket anyways because of that problem with these year motors. Heads Up machine shop is only 5 miles from my house and they have casts in stock. It takes them 3 business days to machine them out and instal parts. All rod and main bearings were in spec, confirmed with plastigauge, crank was still very shinny and nice. Cam measured within factory service manual specs. I will probably pick up a mild delta reground cam with a bit more lift, when I go down to drop off my rocker assembly’s for exchange. Nice having them only 15 miles from my house. Piston bore’s showed very little wear, I should be able to get by with light machining. Been looking at a set of JBA headers, has anyone used a set of these and would recommend?
Greg

 

[Spudhut]

This is going to be a good thread. Subscribed!

 

[96eb96]

The OHV bottom end is pretty indestructible. The machine shop here said they don't usually touch them, even after very high miles. He said he remembers one Ranger delivery truck with like 600K and it just needed heads and was back on the road in a few days. There is an old cash for clunkers video where OHV runs 7 minutes, the last minute minus a rod that smashed thru the oil pan and all the coolant bleeding out. Pretty sad.

 

[roscoe 0202]

go to king cyl heads 294 each complete new.
roscoe