Fix Harmonic Balancer or new engine

[rydrew55]

I'm starting a new thread, as I have decided to buy the 98 XLT with a broken harmonic balancer. Picking it up tonight.

Before I decide to replace the engine, which I am fully prepared to do, how can I determine if the problem is a cracked crankshaft or just the harmonic balancer.

As far as I can tell after searching many posts here, there are 3 possibilities.

1. Crankshaft is cracked. Take the engine to a machine shop to replace the lower end (crank, bearings etc.)

2. Harmonic balancer or bolt failure. Figure out a way to extract whatever is left from the bolt and replace.

3. Stop looking for a cheap solution and just get a salvage motor.

I am picking up the truck tonight, and will look at it a little closer. I'm ready to do the new motor, but thought I would seek advice before comitting to that solution.

Any opinions or suggestions would be appreciated.
Thanks,
rydrew55

 

[2000StreetRod]

which engine?

Did you determine if it has the SOHC or OHV V6 engine?

I would determine the engine symptoms before replacing or repairing the engine.

There could be a lot of reasons for noises coming from the engine.

 

[rydrew55]

It is a sohc.
Not running,so no idea it there are any noises.
Only going by the previous owner who said it ran ok b4 the balancer broke off.
Now I am just trying to decide if there are any options besides a new engine.

 

[rydrew55]

I should have been more clear, sorry.
I have given up on the Navajo with the ohv.
I am buying a 98 with a broken off harmonic balancer.
Will try to fix or buy a new salvage sohc engine.
RIP 93 Navajo. May just sell it for parts (good motor and tranny.

 

[2000StreetRod]

timing chain failure

It's more likely to be a timing chain related failure. Balancer and crankshaft failure is uncommon with the SOHC V6 but timing chain slippage is common. A 98 model would be about the right age for failure. Performing a compression test will usually tell. If all of the cylinders on one bank have low compression then its usually from a slipped or broken timing chain.

 

[rydrew55]

OK, thanks. I will check tonight.
But he said the HB was cracked right off.

 

[Runnin'OnEmpty]

Sounds like the crankshaft snout has broken off.
This is a more common problem with the 4.0 than
it should be; both on the OHV and SOHC.
Do a search and
lots of posts on this problem will show up.

There are two choices, one is to replace the engine,
other is to replace the crankshaft. The engine will
have to be removed regardless of which you choose.

An easy way to verify is to remove the serpentine belt
and then see if the harmonic balancer will easily turn, or
perhaps can be pulled off by hand.....

 

[rydrew55]

Verdict....cracked crankshaft. I have it in my hand. The snout broke off flush with the HB.
I have a picture, but I don't know how to attach it.
Anyway, looks like I'll need a motor, which I was prepared for. Before I buy one, I'll probably bring this one to a machine shop to get a price on a bottom end rebuild.
The engine pull will start in a week or 2.
thanks for all the advice so far.
Rydrew55

 

[2000StreetRod]

What a shame!

I've heard about the crankshaft snout breaking on large block high rpm V8s on dragsters but didn't know that it can happen on a stock SOHC V6. Does the balancer have a balance hole in it? If not, it may be a cheap aftermarket balancer. An out of balance balancer can destroy a crankshaft. You may want to check everything that connects to the serpentine belt for balance and good bearings.

 

[rydrew55]

I've heard about the crankshaft snout breaking on large block high rpm V8s on dragsters but didn't know that it can happen on a stock SOHC V6. Does the balancer have a balance hole in it? If not, it may be a cheap aftermarket balancer. An out of balance balancer can destroy a crankshaft. You may want to check everything that connects to the serpentine belt for balance and good bearings.

Actually, not that rare. Several posts here and info on other sites. I don't think it happens a lot, but it does seem to be an issues with these motors.
It is a stock HB, and the CS cracked flush with the balancer. No other visible damage, but maybe it's too subtle to see with the naked eye.

Now it's a choice to put in a new crank and bearings (assuming good compression-need to check) or a salvage motor with 131k miles. Full rebuild might get expensive.

Anyone care to offer a suggestion on what you would do? Of course a full rebuild is best if $ no object. It's a 98 XLT, leather, real good body and interior. Truck and motor have 161k miles. Tranny is newish according to previous owner, but can't confirm. I never drove it. Bought it with the busted motor pretty cheap. Project "EX" (plorer).

All advice welcome.

Thanks,
rydrew55

 

[2000StreetRod]

repair or salvage?

A salvage engine with 131,000 miles could easily have broken timing chain guides and primary tensioner. I would not install it without checking first which means pulling the valve covers and front timing cover. The same is true for your current engine with the broken crank.

If it were me doing my own work, only paying for parts, and not in a hurry to get the vehicle running I would check the compression, pull the engine and inspect the timing chain components. If they're not failed and the compression was good then I would pull the pan, cradle and replace the crank (without pulling the heads) and front and rear main seals. If the compression was bad it could be from worn rings, glazed cylinders, burned valves, broken valve springs, blown head gasket, or slipped timing chain. In that case, I would purchase the salvage engine.

 

[ranger7ltr]

I pulled heads to change a gasket and found a bad pair of cylinders...

I have no idea this was a problem before pulling the heads since the engine had run great the 20k I had driven it...So I looked at options and found a remanufactured Motorcraft shortblock for my 4 liter ohv engine...

I already had new aftermarket heads so the shortblock was not a costly prospect... After getting the shortblock and pulling the old shortblock, it was a matter of just replacing parts on the shortblock...

If the original engine was running well before the crankshaft broke you could just replace the crankshaft...And if the truck is 2wd you could remove the crankshaft with the engine in the truck...Probably not the best solution but a possibility...

In hindsight, and since i have a V8 that I could have used, I should have gone with the original plan when I bought this truck and pulled the v6 and installed my v8... I would have had to buy a v8 tranny and deal with the pats issue with the new PCM and wiring harness...But a v8 conversion could be really cool too!!

 

[rydrew55]

2000 StreetRod,

Sounds like very good advice. I will proceed as you suggest starting with the compression check. I can do that now as the motor still turns with the battery. Then I will remove the engine using your thread "1 SOHC V6 Engine Removal Procedure"



which by the way was one of the best how to's I've ever seen. I have been a member of several other forums and this thread was top 10 for me. I have learned how to spot common problems and perform several complicated repairs by working on these various forums. My Catera is a 2000 with 190k on the clock (bought it with 25k) and it looks and runs cherry thanks to the help I got at Catera Owners at Yahoo. Serious Explorations is obviously a great forum too and I look forward to working with you folks.

Thanks a bunch.
rydrew55

 

[2000StreetRod]

V8 Sport 1st Choice

. . . In hindsight, and since i have a V8 that I could have used, I should have gone with the original plan when I bought this truck and pulled the v6 and installed my v8... I would have had to buy a v8 tranny and deal with the pats issue with the new PCM and wiring harness...But a v8 conversion could be really cool too!!

A 2000 Sport with V8 and 4R70W would have been my first choice but wasn't available. I still am tempted off and on to do the upgrade. More so now that I've given up on the future 2000 Mustang GT purchase because of strain on the knees when exiting the vehicle.

 

[rydrew55]

Engine Swap for 98 Explorer

2000 StreetRod,

Sounds like very good advice. I will proceed as you suggest starting with the compression check. I can do that now as the motor still turns with the battery. Then I will remove the engine using your thread "1 SOHC V6 Engine Removal Procedure"



which by the way was one of the best how to's I've ever seen. I have been a member of several other forums and this thread was top 10 for me. I have learned how to spot common problems and perform several complicated repairs by working on these various forums. My Catera is a 2000 with 190k on the clock (bought it with 25k) and it looks and runs cherry thanks to the help I got at Catera Owners at Yahoo. Serious Explorations is obviously a great forum too and I look forward to working with you folks.

Thanks a bunch.
rydrew55

Thanks again.
Parts for the rebuild were expensive ($235 just for the crank) and I would still have a motor with 160k miles.
I have decided to try and find a newer motor 2002+ with less miles and swap out the components (fuel rails, sensors etc). Everything I found for a 97-01had 130k or more miles. So I figure it's better to find something newer with less miles, better timing stuff, and swap out the components to work in my 98.
I will start a fresh thread for the swap and include a reference back to this one for anyone who wants to see how this all started.
Thanks again for all the help.
rydrew55

 

[2000StreetRod]

returnless fuel system?

I believe 1998 was the year Ford changed from a return fuel system to a returnless one. If so, you could have either depending on when your vehicle was manufactured. The return fuel system has a fuel pressure regulator mounted on the fuel rail and a fuel line that allows excess fuel to return to the tank. The returnless system has a fuel pressure damper on the rail and the fuel pressure regulator is mounted in the tank. The pressures of the two systems is significantly different and the PCM may be programmed accordingly. Try to determine which fuel system you have.

Also, I believe the 2002+ engines have a plug where the crankcase breather is installed on your engine. You will have to remove the plug (similar to a freeze plug) to install the breather. The photo below shows the breather (large black object under wiring loom).

 

[liquidbeef]

Good you posted the pic, I was having a hard time trying to locate the breather without actually looking at it personally.