At 275K miles, replace head or just put in a new long block?

[BadaBingM3]

So I've got what I call "valve chatter" coming from the driver side head valve train. I'm 90% certain. At around 2,500+ rpm at about half or partial throttle climbing a slight hill or surpassing traffic, I get what sounds like metallic chatter and fluctuates with throttle input. At full throttle, sound is suppressed by the pressure but will manifest at high rpm's. So with that said, the engine has 275,900 miles. I've done a hell of a lot of work to the engine over the last 10 years of ownership to keep it going so my question to make a decision on is, 1.) If I swap the head for a new one, should I do both heads? 2.) Just drop a new engine long-block and call it good. Time/money not the question. Rather, is it worth trying to swap out a head at those many miles? I do plan on keeping it for a long time more also and it does see a lot of 4wheeling, daily driver, and towing at times. Also, who would you all recommend I get my long-block from, besides the dealership where I'll be pealed alive like an orange. lol! I was thinking rockauto. Their long-block is $1,820. Is it a Ford re-manufactured and just as solid? Here is their link to it: 1999 FORD EXPLORER 4.0L V6 OHV Long Block | RockAuto Thanks for the advise fella's. RB

 

[C420sailor]

I’d figure out what’s going on first. Valve noise sounds like a valvetrain issue to me, rather than a cylinder head issue. Pull the valve cover and inspect.

If it’s in fact a top end issue on an OHV engine with good compression, little to no oil usage, etc...I’d fix it. If you had a SOHC I’d say swap it.

 

[BadaBingM3]

I’d figure out what’s going on first. Valve noise sounds like a valvetrain issue to me, rather than a cylinder head issue. Pull the valve cover and inspect.

If it’s in fact a top end issue on an OHV engine with good compression, little to no oil usage, etc...I’d fix it. If you had a SOHC I’d say swap it.

Thanks for that input. yeah tough choice because at this point, I've done enough work on this engine (passenger side rocker arms, lower intake manifold leak, water pump, that taking one head off, I'm thinking I'm going to have to pull off so much crap, might as well just drop a new engine in it. I'm not certain I can even find anything wrong if I pull the valve cover off. Everything might seem tight but under dynamic running pressure, it manifest itself.

 

[RickOTR]

If it's a SOHC engine, those lash adjusters fail often. Seems like I have to replace them every 125k miles or so. I remember replacing the rocker arms on my 91 Explorer around 175k miles. Remember though that both 4.0L engines are known for carbon fouling on the pistons which have a similar noise. Drive it around town a few days keeping rpms around 3000, that allows the carbon to burn off in the combustion chamber. I think you'll see the difference.

 

[C420sailor]

Is it your daily driver? If not, and if you want to swap the engine, drive it until it blows up—get your $$$ worth out of the current engine.

 

[BadaBingM3]

If it's a SOHC engine, those lash adjusters fail often. Seems like I have to replace them every 125k miles or so. I remember replacing the rocker arms on my 91 Explorer around 175k miles. Remember though that both 4.0L engines are known for carbon fouling on the pistons which have a similar noise. Drive it around town a few days keeping rpms around 3000, that allows the carbon to burn off in the combustion chamber. I think you'll see the difference.

That's interesting. I did not know about the carbon build up. I wish I had a good in-car sound video. I tried but hard to hear. But I think and leaning towards that it's a chatter. I've never had experience with such chatter before on any engine. Just a gut feeling though.

 

[BadaBingM3]

Is it your daily driver? If not, and if you want to swap the engine, drive it until it blows up—get your $$$ worth out of the current engine.

I know right? Problem is I do a lot of 4wheeling in the Nevada interior and up north. Far, far away from any humans. lol! That is where I likely will blow that engine and be stranded for days. Especially on a long hunt.

 

[masospaghetti]

Sounds like you probably have some worn valvetrain components (rockers and pushrods, or maybe a lifter). The issue may not be your head at all. You can inspect your valvetrain just by pulling the valve covers on both sides but be warned the driver's side does take a bit of work. Once the covers are off, 3 bolts will take the rocker shaft off of the head. You can easily inspect the parts for wear at that point or even replace them.

You can't diagnose or replace the lifters without removing the lower intake. If you don't see obvious issues with the rockers or pushrods, you can go ahead and pull the lower intake and check the lifters. If everything up to this point seems fine, then you can decide to pull the head. EDIT: you'll have to pull the heads to replace a bad lifter. Changing all 12 as preventative maintenance may be a good idea, but it's not cheap - each lifter is $30-40. I didn't replace mine.

I had the exact same question as you do about a year ago. My truck had 255,000 miles. In my case, I was burning coolant so I suspected a a cracked head, so I went ahead and bought two new heads. One was cracked, one was OK. I also looked at that Ford "longblock" on Rockauto. I believe it's labeled incorrectly and it's actually a short block (!) without heads. Tasca Ford has it listed as such. Short Block - Ford (F87Z-6006-ARM) | TascaParts.com

I didn't have an easy way to replace an entire motor in my garage, so I went with heads instead of a longblock replacement. So far I am happy with the results.

 

[koda2000]

I've never owned an OHV 4.0L, but don't the heads have to be removed to replace the lifters. I seem to recall reading this here in the past. If true, what a PITA. I also recall reading that the OHV 4.0L has a timing chain tensioner. I wonder if this (or a worn timing chain) could cause noise?

BTW - I just got finished rebuilding my 4.0L SOHC's V6 engine, which had over 200K on it. The OHV and SOHC appear to utilize the same engine blocks, which is a very durable unit. My 212K engine cylinders were still perfect and didn't even show any ring-ridge wear. This despite indications that the previous owner neglected normal maintenance. I found I didn't need to touch my long block. I just replaced the oil pump and engine seals. My SOHC heads were trash and had to be replaced along with all the timing components.

 

[koda2000]

I've never owned an OHV 4.0L, but don't the heads have to be removed to replace the lifters. I seem to recall reading this here in the past. If true, what a PITA. I also recall reading that the OHV 4.0L has a timing chain tensioner. I wonder if this (or a worn timing chain) could cause noise?

BTW - I just got finished rebuilding my 4.0L SOHC's V6 engine, which had over 200K on it. The OHV and SOHC appear to utilize the same engine blocks, which is a very durable unit. My 212K engine cylinders were still perfect and didn't even show any ring-ridge wear. This despite indications that the previous owner neglected normal maintenance. I found I didn't need to touch my long block. I just replaced the oil pump and engine seals. My SOHC heads were trash and had to be replaced along with all the timing components.

bump

 

[masospaghetti]

I've never owned an OHV 4.0L, but don't the heads have to be removed to replace the lifters. I seem to recall reading this here in the past. If true, what a PITA. I also recall reading that the OHV 4.0L has a timing chain tensioner. I wonder if this (or a worn timing chain) could cause noise?

BTW - I just got finished rebuilding my 4.0L SOHC's V6 engine, which had over 200K on it. The OHV and SOHC appear to utilize the same engine blocks, which is a very durable unit. My 212K engine cylinders were still perfect and didn't even show any ring-ridge wear. This despite indications that the previous owner neglected normal maintenance. I found I didn't need to touch my long block. I just replaced the oil pump and engine seals. My SOHC heads were trash and had to be replaced along with all the timing components.

Yes you're right, for some reason I thought they could be done with the lower intakes removed but now I realize that's not true. One of the bad designs of the OHV.

The OHV does have a single chain tensioner on the front side of the motor. Not a bad idea to check, but it will require removal of the water pump, harmonic balancer, and timing cover to check.

 

[BadaBingM3]

I've never owned an OHV 4.0L, but don't the heads have to be removed to replace the lifters. I seem to recall reading this here in the past. If true, what a PITA. I also recall reading that the OHV 4.0L has a timing chain tensioner. I wonder if this (or a worn timing chain) could cause noise?

BTW - I just got finished rebuilding my 4.0L SOHC's V6 engine, which had over 200K on it. The OHV and SOHC appear to utilize the same engine blocks, which is a very durable unit. My 212K engine cylinders were still perfect and didn't even show any ring-ridge wear. This despite indications that the previous owner neglected normal maintenance. I found I didn't need to touch my long block. I just replaced the oil pump and engine seals. My SOHC heads were trash and had to be replaced along with all the timing components.

Yes they do. I already had to pull the rocker arms off the passenger side few years back as one blew off the rail. Was a PITA!

 

[BadaBingM3]

Yes you're right, for some reason I thought they could be done with the lower intakes removed but now I realize that's not true. One of the bad designs of the OHV.

The OHV does have a single chain tensioner on the front side of the motor. Not a bad idea to check, but it will require removal of the water pump, harmonic balancer, and timing cover to check.

I replaced the chain two years ago when one of the exhaust valve rocker arm on the passenger side blew off the rod while at higher rpm's on the highway. I'm pretty much committed now into going with a new long block from powertrain and just rebuild the entire damn thing at this point.

 

[Gazios]

BadaBingM3:

I am going through a similar situation. I bought a "turn-key" 94Ranger's 4.0 ohv to use in my BII. Because I need years of solid use I decided to inspect inside before I dropped it in.

It wasn't all bad overall but I am lucky I did. It needed a valve job job horribly, the bottom had been bored to 0.5mm over, the cylinders and pistons look great. I am completing the inspection by pulling the cam and crank to measure for wear.

Here is what I did:

- multi angle performance valve job to TM98 spec heads.
- flow bench port/polished the heads +intakes.
- new dual springs for the machist's recommended custom cam grind.
- 2.9l adjustable rockers with free float rocker arm spacers.
- custom reground cam from Portland Cam Grinders of Washington.
- Mahle flat top 01 SOHC pistons/rings.
- Cloyes timing set.
- Gates water pump.
- Melling oil pump, disassemble, deburred, polished and port matched.
- all new Mahle/Clevitte bearings.
- ARP connecting rod bolts/nuts.
- new gaskets + seals.
- plugs, wires, air+oil filters.
- JBA 2.9L Headers with "H" pipe.
- Stage8 locking header bolts.
- bored stock T/B to 64mm.
-custom 2¼" dual Borla Turbo (ProXs) exhaust.
- new stock Ford lifters.
- 01 SOHC 2 piece oil pan with built in girdle.
- Hypertech Stage 1 PCM.

BETTER THAN NEW! I was able to accomplish all this for under $2,400.

 

[Gazios]

BadaBingM3:

I am going through a similar situation. I bought a "turn-key" 94Ranger's 4.0 ohv to use in my BII. Because I need years of solid use I decided to inspect inside before I dropped it in.

It wasn't all bad overall but I am lucky I did. It needed a valve job job horribly, the bottom had been bored to 0.5mm over, the cylinders and pistons look great. I am completing the inspection by pulling the cam and crank to measure for wear.

Here is what I did:

- multi angle performance valve job to TM98 spec heads.
- flow bench port/polished the heads +intakes.
- new dual springs for the machist's recommended custom cam grind.
- 2.9l adjustable rockers with free float rocker arm spacers.
- custom reground cam from Portland Cam Grinders of Washington.
- Mahle flat top 01 SOHC pistons/rings.
- Cloyes timing set.
- Gates water pump.
- Melling oil pump, disassemble, deburred, polished and port matched.
- all new Mahle/Clevitte bearings.
- ARP connecting rod bolts/nuts.
- new gaskets + seals.
- plugs, wires, air+oil filters.
- JBA 2.9L Headers with "H" pipe.
- Stage8 locking header bolts.
- bored stock T/B to 64mm.
-custom 2¼" dual Borla Turbo (ProXs) exhaust.
- new stock Ford lifters.
- 01 SOHC 2 piece oil pan with built in girdle.
- Hypertech Stage 1 PCM.

BETTER THAN NEW! I was able to accomplish all this for under $2,400.

UPDATED build components

 

[410Fortune]

That’s a nice list! $2400 not bad actually!! How does she run?
What is the compression with those sohc pistons? And can you run pump gas?

That is like a good solid performance n/a recipe right there… but it’s also like playing with fire! Ohv cologne takes serious dedication

 

[Project91Jp]

+1

Gazios, could you tell me more about the 2.9 rockers with spacers and the benefits of the jba headers? I scoured this site for any info about the 4.0s but this is a first for me.