Valve Train Explosion

[CDW6212R]

hi Tekreck - I am pretty new to the 4.0 SOHC so I don’t know exactly what the timing cassette is. Obviously, its the timing chain / belt, but I’ve never heard it referred to as a cassette…. I‘m pretty much a vintage Oldsmobile big block guy. My first guess was a timing chain because it was an immediate issue, not like you would hear a noise getting worse over time. Just don’t understand why an oil change would trigger that….
I guess my big thing is figuring out if it ws a goof on the part of the oil change place, or just as John said “coincidence”.

The problem is most likely an unfortunate coincidence.

The SOHC has OHC chains which ride on a plastic guide, that parts assembly is called the timing cassette. There is one in the front as well as the back. There is a traditional appearing timing chain, but it has a chain guide made of a plastic, plus a tensioner with very thin steel pieces to apply pressure to the main chain.

 

[Turdle]

You might try another filter. Just for giggles. The new one could be defective , it's been reported here before.

 

[Jimmy Sport]

The problem is most likely an unfortunate coincidence.

The SOHC has OHC chains which ride on a plastic guide, that parts assembly is called the timing cassette. There is one in the front as well as the back. There is a traditional appearing timing chain, but it has a chain guide made of a plastic, plus a tensioner with very thin steel pieces to apply pressure to the main chain.
View attachment 434066

Why didn't the OHV engines come with similar crappy guides? My OHV went over 200K miles and never had a problem. Luckily, I had the truck for many years before finding this forum and hearing about all the issues with the SOHC guides. This was the one time in my life where everything went right without me knowing something could have went wrong.

 

[Argentimage]

The problem is most likely an unfortunate coincidence.

The SOHC has OHC chains which ride on a plastic guide, that parts assembly is called the timing cassette. There is one in the front as well as the back. There is a traditional appearing timing chain, but it has a chain guide made of a plastic, plus a tensioner with very thin steel pieces to apply pressure to the main chain.
View attachment 434066

I am also looking for guidance - anyone know who does this timing chain repair in Metro "detroit" Michigan?

FWIW I used valvoline synthetic for 200k, changed oil myself at no more than 4000miles, usually 3-3500.
June this noise started and it getting worse daily.

 

[TimothyPaul]

Hi Everyone - so the mechanic I took the car to pulled the intake. He said it was the sludge build up, and it damaged the timing guide assemblies, which in turn damaged the left head.

So I am trying to decide, do I rebuild the engine, or swap it with a junkyard engine. I think a remanufactured engine is way too pricey for a 20-year-old vehicle. Also he wants $1500 for the labor to do a R&R. The vehicle is in ok shape.... needs some minor maintenance like swap bar bushings, etc.... Or my third thought is to bring it back here, and part it out.

If I do a junk yard engine, the mechanic said because its a four-whel drive, I am limited on motors I can use, but I thought all the 4.0 SOHC engines used the same block assembly.

 

[410Fortune]

synthetic oil in sohc engines ONLY!!!!!!!!!!!!!!!!!!!!!!!
Using conventional over and over is not helping the life of this engine

not all states will dispose of tires for free at the dump, many states like CO and CA charge for each tire
Here in Idaho I am allowed 3 yards of "trash/debris, one mattress and two tires per day (no wheels)"
We pay $180 a year for dump fee (all taxpayers)

The poil change might not have helped your engine but it is not likely the "trigger" unless they used a defective filter and/or you experienced a loss of oil pressure before the timing cassette failed

These engines have 5 timing chains.........nylon guides and hydraulic tensioners. In these engines oil changes on time and using full synthetic is a MUST
To repair the passenger side "cassette" the chain is at the rear of the passenger head and the engine must come out
Other repairs to the main chain, tensioner or drivers cassette can be done in the vehicle

they are also interference engines so if the timing chain lets go the piston will slam into the valves

this engine was used in MANY ford vehicles finding a good low mile replacement can be done
do some research first!!

 

[TimothyPaul]

Hi All - first, thank you all for your insight so far.

Question - several people have mentioned failure of the oil filter. I have never had this happen, what would I look for to see if the filter failed ?

 

[Turdle]

Hi All - first, thank you all for your insight so far.

Question - several people have mentioned failure of the oil filter. I have never had this happen, what would I look for to see if the filter failed ?

Just replace it. If there is blockage the symptoms will change. You'll loose about a quart of oil so be prepared.

 

[CDW6212R]

Virtually any SOHC 4.0 will swap into your truck, ignore the references to a 4WD or not. You would have to reuse most of the external parts outside the engine, but the main engine does swap.

With the mechanic mentioning sludge under the intake, I'd want to see the lower oil pan soon, see how that looks.

 

[TimothyPaul]

Just replace it. If there is blockage the symptoms will change. You'll loose about a quart of oil so be prepared.

Can’t do that Jon, the motor is blown…. I am trying to isolate if a oil filter failure is the cause of the motor blowing up

 

[Lee's Automotive]

Can’t do that Jon, the motor is blown…. I am trying to isolate if a oil filter failure is the cause of the motor blowing up

Did it lock up?

 

[410Fortune]

Why didn't the OHV engines come with similar crappy guides?

Pushrods!!!!

BIG difference between a pushrod engine (camshaft under the heads) using lifters and pushrods to move the rocker arms, a single beefy timing chain to turn the cam off of the crank

SOHC = overhead cam, the cam is over the valves, no more pushrods. This results in less rotating mass which is more efficient and makes more power. However you now have guides and chains to turn each cam........

I own pushrod engines myself, 4.0 OHV, 5.0 OHV, and 7.3 OHV I never have and never will own a 4.0 SOHC vehicle, simply because I do not have to. The small v6 auto transmissions also help with this decision.
4.0 OHV, 5.0 do not have these problems

 

[Argentimage]

Pushrods!!!!

BIG difference between a pushrod engine (camshaft under the heads) using lifters and pushrods to move the rocker arms, a single beefy timing chain to turn the cam off of the crank

SOHC = overhead cam, the cam is over the valves, no more pushrods. This results in less rotating mass which is more efficient and makes more power. However you now have guides and chains to turn each cam........

I own pushrod engines myself, 4.0 OHV, 5.0 OHV, and 7.3 OHV I never have and never will own a 4.0 SOHC vehicle, simply because I do not have to. The small v6 auto transmissions also help with this decision.
4.0 OHV, 5.0 do not have these problems

Especially the Fix Or Repair Daily v6 trany

Still looking for the timing chain changer in Michigan...

Don't have engine pull capability

 

[410Fortune]

if the timing went and the piston hit the valves then you need more then just a "timing chain redo" you will also need the heads re worked
This is why many of us would rather just replace the engine with a known good one

 

[thatunknownguy87]

Ciao Group - looking for a little direction. Took my car to have oil changed and new tires. Drove out of service center’s lot to my house ( approx 2 miles) picked up my trailer, drove another two miles to my warehouse and the upper half of my engine blew up. :-(. 115K miles on it and engine was perfect before oil change. Roughly been about 4-5K miles since last change with a synthetic blend. Don’t really use the vehicle much, its just my utility vehicle for Home Depot runs, etc….

I haven’t pull anything apart yet, posted video so you can hear the noise. It is much much louder in person….
Anone have thoughts ?

I've had this happen on my '99 4.0 SOHC. I changed out my driver's side timing chain tensioner with a Cloyes tensioner and as soon as I started the engine, the tensioner exploded causing the timing cassettes to explode. Unfortunately, I bent 3 valves, so the engine was scrapped. Your engine sounds exactly like mine did. It'll start up, but won't idle. Pull your valve cover on the driver's side and check out the cassette and tensioner. This is 100% your issue.

 

[410Fortune]

you can also look through the oil fill cap and get a good eye on the drivers upper tensioner and guide

 

[Josh P]

Plenty of low mileage 4.0L engines in the junk yards and $1,500 labor to swap it out is a fair price. I'd find one out of a mustang with under 80k miles. I see them for around $1k to $1,200 at the yards here in Phoenix.

 

[hunterwolf]

i am not sure where you are located,, years ago, over here, the scrap yards would do the change out at a very good price,, with a warranty, personality, i would take it afterward, to a good shop to make sure everything was perfect.
good luck...

 

[thatunknownguy87]

Plenty of low mileage 4.0L engines in the junk yards and $1,500 labor to swap it out is a fair price. I'd find one out of a mustang with under 80k miles. I see them for around $1k to $1,200 at the yards here in Phoenix.

I would look on Facebook Marketplace. They have shops out there that pull engines and sell them. I found a low mileage engine that had the timing job recently done for $500. They used a Melling kit which is what I recommend. Stay away from Cloyes tensioners. Use Ford oil filters and good FULL SYNTHETIC oil only. I'm using Amsoil.

 

[Argentimage]

I would look on Facebook Marketplace. They have shops out there that pull engines and sell them. I found a low mileage engine that had the timing job recently done for $500. They used a Melling kit which is what I recommend. Stay away from Cloyes tensioners. Use Ford oil filters and good FULL SYNTHETIC oil only. I'm using Amsoil.

I always use synthetic since they invented it.
What tool - not ebay - do you use to find junk yard engines?
Nothing on fleebay anywhere near SE Michigan, and what I do see is closer to 3000$ and the rebuild of one is quoted at $3500