OHV vs SOHC

[UrbanRedneckKid]

Id rather listen to a lifter tick until warms up rather than a timing chain slap until it blows up....

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Hit it on the head. There is no question, I'll take the reliability over a little more power any day.

Although on the other hand, my truck is quicker than a 4.0 Mustang through 2 stoplights. It's been mildly worked over, bit it's still got the stock cam in it.

OHV ftw

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[PlumCrazy]

I figure a boosted OHV will be the best of both both worlds.. bullet proof and perfect power output for a geared trail trail truck that still sees some asphalt.

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[ZMan]

My coworker has a sohc in his explorer, he put a new engine in at 160k because of timing chains. He also has an fx4 level 2 ranger that has 250k that has had no issues at all, doesn't even make any noise.

 

[Scrambler82]

I figure a boosted OHV will be the best of both both worlds.. bullet proof and perfect power output for a geared trail trail truck that still sees some asphalt.

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Which one, they are both overhead valves ?

Take a push rod 4.0 and add some 1.7 rocker arms and you will get a little more power, a good set of headers to open up the air flow to the rear, an air intake system and you will get a seat of the pants increase that you will feel.

 

[PlumCrazy]

Most people refer to the pushrod engine as an OHV......

I already have a mild cam, headers, and larger TB.

I am putting together a supercharged 98 OHV with ported 95TM heads, larger valves, shorty headers, 66mm TB, 100mm MAF, and the same cam/pushrod/rocker/spring setup I have now.


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[kryptonitecb]

My pushrod has 120k miles and the lifter tick but it has no issues. I'd rather stay away from a chain replacement every decade and deal with a little extra noise. Plus when wheeling I rarely go over 3k rpm's, any more than that and I get wheel hop.

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[bigmark303]

In all reality comparing the two engines as far as reliability is mute. They are both just as reliable. The timing chain issue people run into with the SOHC 4.0 is from not having knowledge that the guides need to be replaced between 80k-100k as preventative maintenance on almost any OHC engine design. You get some cam chain guides that last forever but most dont. Every OHC design suffers from the same issue and its because people are unaware of the fact that just like a timing belt these guides need to be inspected/replaced at certain mileage to prevent failure.

Other than that if you have the money to replace the entire setup every 100k the SOHC 4.0 will last you just as long as the OHV (pushrod) 4.0. Both engines are built Ford tough. One just has more Horsepower than the other.

As far as screaming over 4k rpm in a given gear, if you are doing that to a Ranger you just need a different truck or you use it for racing. Gear the truck correctly and you wont see over 2k rpm with either engine. Both have the same low end power to be able too move or not move the same loads.

I will say though, I have 5 OHV pushrod 4.0s right now and have not had any lifter issues needing remedy. Engine #1 199k, Engine #2 194k, Engine #3 195k, Engine #4 192k, and Engine #5 91k. Engine 1 and 2 are doner engines if I may ever need one for either of my three trucks. All 1997 year also.

 

[exbass94]

Yeah. Look really closely at the numbers on the bottom of that chart.

I drove like an idiot the first 8 years I had my license. I still drive like an idiot sometimes. Almost every vehicle I have owned had a tach in it. I can count on one hand the number of times in 11 years that I have had an engine spinning at 4000 RPM or higher in gear. I rarely get it above 2500, even my 2.9.

Explain to me again how having more power in a part of the RPM band that isn't used after first gear is helpful in anything but a dedicated tow rig.

Again, you're just looking at peak numbers. The chart says the OHV is PEAKING at 225 lb ft at 2750 RPM. How much is the SOHC making at 2750 RPM (the SAME RPM)? Oh yeah, MORE than 225 lb ft. How's that for low end torque? Like I said before, the OHV makes a lousy 7 ft lbs or so more below 1700 RPM. Big friggin deal. At all other RPMs, the SOHC is making as much or more torque and HP than the OHV.

And Ford revised the timing chain tensioners so they don't fail prematurely any more. I'll check back here when I reached 200k on my original chains and tensioners.

EDIT: I marked the graph to better illustrate my point.

 

[Snoranger]

Which one, they are both overhead valves ?

Seriously??? You know what he means... No one here is stupid enough to think the SOHC isnt also over head valve, its just a simple way to differentiate the two engines.

In all reality comparing the two engines as far as reliability is mute. They are both just as reliable. The timing chain issue people run into with the SOHC 4.0 is from not having knowledge that the guides need to be replaced between 80k-100k as preventative maintenance on almost any OHC engine design. You get some cam chain guides that last forever but most dont. Every OHC design suffers from the same issue and its because people are unaware of the fact that just like a timing belt these guides need to be inspected/replaced at certain mileage to prevent failure.



As far as screaming over 4k rpm in a given gear, if you are doing that to a Ranger you just need a different truck or you use it for racing. Gear the truck correctly and you wont see over 2k rpm with either engine. Both have the same low end power to be able too move or not move the same loads.

Tell that to dozen or so sub 100K mile SOHCs I've seen with the timing chain sticking through the valve cover!!

Never need to go over 2k RPMs??? I'm over 2K just to cruise down the freeway at the posted speed limit. (because I would NEVER exceed that.)

 

[bigmark303]

Tell that to dozen or so sub 100K mile SOHCs I've seen with the timing chain sticking through the valve cover!!

Never need to go over 2k RPMs??? I'm over 2K just to cruise down the freeway at the posted speed limit. (because I would NEVER exceed that.)

And I bet not a single one of them knew what kind of engine they had. Preventative maintenance is key to engine life. Changing the timing guides is part of that. Ford and many other makes have had plenty of timing guide issues on OHC engine designs. Its nothing new and hasnt been for some time. Wether the owner chooses to change them or not is up to them. Plus they rattle and tick like hell for a good while before they let go. Anyone who is paying attention knows something is wrong.

We all drive different but there is no need to be over 2k with either version of 4.0. Two of my 4.0 trucks had 3.27 gears and I still never found the need to be over 2k wether on the road driving or hauling something up a hill. If your truck is loaded where you need to be screaming to get that extra power then you are easily over the limit of what the 4.0 can handle and just need a more powerfull motor. For the record all my trucks are used to haul 1000-1500lb loads of 6ft log lenght. With my 3.27s and 33s I never needed more than 2k rpm to make it anywhere. With the 3.73 and 4.56s I now have I barely break 1700 rpm most days and never get over 2k rpm in any gear.

 

[PlumCrazy]

Im on 35s with 4.10s and 65 mph is over 2k....

So a stock truck with 4.10s would be well over 2k...

Typically you want to run you engine just past peak torque, so when it sees load(a hill) it can bog down slightly and still maintain speed. If you run a right at peak output, you will end up downshifting...

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[Jraymer360]

i constantly shift at 3 to 3500 rpm. 33's with 3.27s? that must have sucked.

 

[bigmark303]

55mph is the highway speed around here. Just a difference in area then. If it were 65mph I could see maybe 2100 rpm at max but I do have the 5R55E transmissions in all my trucks. With the 4 speed auto I could see rpms getting higher in the 2500 range

 

[bigmark303]

i constantly shift at 3 to 3500 rpm. 33's with 3.27s? that must have sucked.

Besides not being able to use 4 wheel high it wasnt that bad at all compared to the number of people who claim its dreadful. Truck still had plenty of power for my driving style.

 

[adsm08]

Again, you're just looking at peak numbers. The chart says the OHV is PEAKING at 225 lb ft at 2750 RPM. How much is the SOHC making at 2750 RPM (the SAME RPM)? Oh yeah, MORE than 225 lb ft. How's that for low end torque? Like I said before, the OHV makes a lousy 7 ft lbs or so more below 1700 RPM. Big friggin deal. At all other RPMs, the SOHC is making as much or more torque and HP than the OHV.

And Ford revised the timing chain tensioners so they don't fail prematurely any more. I'll check back here when I reached 200k on my original chains and tensioners.

EDIT: I marked the graph to better illustrate my point.

I'm not saying it doesn't make more power. We all know it does.

I am saying that the extra power it makes is pointless. The number differences are too small and the RPMs are too high. The only times my engines hit those RPMs are when I am trying to burn fuel or tires. My 4.0 has yet to get over 2500 RPM since I put it in..