4.0 SOHC FoMoCo Re-Man Any Input? Original 300k engine timing chain noise, time for new engine?

[Dzrt1]

2003 Mazda B 4000 w/ 305000 miles, original owner, making timing chain noise.
Replaced tensioners but no improvement and deciding whether to just fix what's wrong (pull engine and replace timing chain cassettes) or give it a new motor?
It's been a good engine, never failed and no problems except for thermo housing(s). Want to keep the truck. Engine runs good except for timing chain rattle on startup, have stopped driving it to minimize the damage until I can fix it.

Anyone with knowledge of FoMoCo re-man engines (how good are they; where are they built, etc? or anyone who has used them) Would they be a top choice? I've found a few rebuilders who won't build the 4.0 sohc. Is going to the source the best move?
Thanks for all input.

 

[rusty ol ranger]

Id fix it and run it. It might go another 300k.

 

[Dzrt1]

Yeah, I like the way you think Rusty -

 

[gw33gp]

I rebuilt the cam timing chain system at around 250K miles. I have no regrets what-so-ever. I also installed a new oil pump at the same time.

 

[superj]

welcoem to the group. @Dzrt1

replacing hte timing chain stuff sounds cheaper and easier than buying and replacing hte engine. and since it runs good, minus noise, i would just do the timing stuff

 

[PetroleumJunkie412]

I rebuilt the cam timing chain system at around 250K miles. I have no regrets what-so-ever. I also installed a new oil pump at the same time.

What did you wind up using for a timing set?

 

[arlen.burroughs]

I am currently replacing the Left side cam chain cassette and sprockets, and main chain and sprockets. I am leaving the passenger side as is, since it wasn't the one that started making noise and I didn't want to have to pull the engine.

If it is just your driver's side front of the motor making noise, then you may want to do what I am doing, and replace it in the vehicle.

Biggest hurdles I've had so far:
- Get a fan puller tool. I tried to wrestle the dang thing off for an hour and finally gave in and got a fan puller tool overnighted via amazon.
- Harmonic balancer removal. Again, get a pulley puller tool. Also needed an AIR impact wrench to get the crank bolt off. My bauer impact driver did not budge it.
- Before removing any timing sprockets, put the engine in true TDC AND check the cams. I thought I was in TDC, but my cams were 180 degrees off (small section of cam end was up instead of down). Not a huge deal, but the special timing tools for making sure the motor is in sync didn't fit on quite right.

The smaller semi-circle should be at the bottom for the sync tool to fit properly on it, but since my crank key-way is at 12 o'clock and both cams are parallel to the head (like above) the motor is still in sync.

I thought about getting a remanufactured motor too, but opted for this as I will get the job done for $500 in parts (putting a new radiator, water pump, valve cover, and a few other things in as well).

I used this timing kit from RockAuto:

More Information for SKP SK90398SB

You'll want to check your motor for a balance shaft. Mine is a 4x4, but did not end up having a balance shaft. The only thing I noticed different is the lower crank sprocket is slightly deeper than what came with the kit for motors with balance shaft.

 

[gw33gp]

What did you wind up using for a timing set?

I used all OEM parts. I understand they are getting harder to find.

 

[gw33gp]

I am currently replacing the Left side cam chain cassette and sprockets, and main chain and sprockets. I am leaving the passenger side as is, since it wasn't the one that started making noise and I didn't want to have to pull the engine.

If it is just your driver's side front of the motor making noise, then you may want to do what I am doing, and replace it in the vehicle.

Biggest hurdles I've had so far:
- Get a fan puller tool. I tried to wrestle the dang thing off for an hour and finally gave in and got a fan puller tool overnighted via amazon.
- Harmonic balancer removal. Again, get a pulley puller tool. Also needed an AIR impact wrench to get the crank bolt off. My bauer impact driver did not budge it.
- Before removing any timing sprockets, put the engine in true TDC AND check the cams. I thought I was in TDC, but my cams were 180 degrees off (small section of cam end was up instead of down). Not a huge deal, but the special timing tools for making sure the motor is in sync didn't fit on quite right.
View attachment 94386
The smaller semi-circle should be at the bottom for the sync tool to fit properly on it, but since my crank key-way is at 12 o'clock and both cams are parallel to the head (like above) the motor is still in sync.

I thought about getting a remanufactured motor too, but opted for this as I will get the job done for $500 in parts (putting a new radiator, water pump, valve cover, and a few other things in as well).

While you are in there, be sure to replace the mechanical timing chain tensioner for the main crankshaft/jackshaft chain. My tensioner was totally broken off. The left and right cassettes were still intact but were getting brittle. I broke one of them when pulling it out.

 

[arlen.burroughs]

While you are in there, be sure to replace the mechanical timing chain tensioner for the main crankshaft/jackshaft chain. My tensioner was totally broken off. The left and right cassettes were still intact but were getting brittle. I broke one of them when pulling it out.

Are talking about this one?:

Yeah I got a full kit, so it will definitely get replaced.
I bought a kit for motors with balance shaft (thinking that all 4x4s had a balance shaft) only to be surprised when the timing cover came off that there was no balance shaft. I think the only difference (other than extra balance shaft parts) is the crank shaft sprocket was 1-2mm less deep than the stock sprocket. Can't tell if this was on purpose for the balance shaft, or slightly different because it isn't an OEM part.

Either way, I think I will re-use that lower crank shaft sprocket to be safe.

 

[gw33gp]

That looks like the one. I bought the stuff for the balance shaft too, only to find out I did not have one. Fortunately, they allowed me to return those parts for a refund. Someone told me only the early 4WD Explorers had the balance shaft. Some of the early 4WD 2001 Rangers may have had it.

I ran into that lower crank shaft sprocket issue too. I also re-used the original sprocket. The one that was sent to me did not line up properly. I am pretty certain what they sent me was for a balance shaft engine and I did not want to wait to get the right one. Mine was OEM.

 

[Dzrt1]

Wow-
thanks all for the info. I'm listening!

 

[DILLARD000]

...bought the stuff for the balance shaft too, only to find out I did not have one
...early 4WD Explorers had the balance shaft. Some of the early 4WD 2001 Rangers may have had it.

Good info in this thread, good pics.
Believe the easiest way to really confirm if a V6~4.0L~SOHC has a BalanceShaft or not,
is to drop the lower OilPan & look up thru the "Girdle"; the BalanceShaft if there, will be next to the OilPump.
Much easier than removing the front TimingCover.
BalanceShaft seems to have been randomly installed a couple of years in Explorer\Ranger\Sport\SportTrac,
as Ford engineers realized they weren't needed & assembly lines drew down inventory of pre-built engines.

View attachment 94400

 

[arlen.burroughs]

I've seen a couple different YouTubers saying that the balance shaft can safely be deleted.

 

[DILLARD000]

I've seen a couple different YouTubers saying that the balance shaft can safely be deleted.

Yep, next time I have the WaterPump\TimingCover off,
plan on removing the smaller BalanceChain, abandoning the BalanceShaft in place,
& hopefully get a couple of extra HorsePower.