3.6 Reliability Issues Resolved ?

[ShadowsPapa]

I could be wrong, I often am,
but I think the low end torque
comes from the longer stroke
that most push rod engines had.
Not from placement of camshafts.

The newer OHC engines
are typically short stroked
and high revving.

An old hot rodder trick
was to build a stroker motor
with longer crank arms
longer connecting rods
and shorter pistons.
This increased displacement
without boring out the cylinders
and improved grunt off the line.

Cam profile and timing also matters. Change cam timing and you can shift the torque either up or down the RPM range.
To get HP out of a small displacement requires RPM. And for that, OHC is better. But you also run into profile issues with the engine. The top end becomes large and doesn't fit well into some cars.

I put a different cam in my 4.0 and increased torque even more, but you lose some top end.

Cam profile, duration, lift, timing - doesn't matter WHERE the cam is.
But a cam-in-block engine has a lot more mass to deal with. More parts to get moving and then to stop their movement or control it. You shove up a heavy lifter, pushrod, and shove a valve open, there's some mass moving and you can get the valves to "float". Doesn't happen so much with an OHC system - extremely low mass. The cam operates on a follower or fulcrum and pushes the valve open directly. There's very little mass to deal with. You can run a lot lighter valve springs with OHC vs. cam in block/push rod types. To get the higher RPM for higher HP in a cam in block engine, you have to run some heavier valve springs. That's increased wear and friction right there.

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[JTGuy]

I remember back in the 70's when there was a selection of aftermarket cams and you could change them with no issues. Those days are gone.

 

[Geoarch]

I am looking into getting my 6th JT - been reading alot about roller/lifter/lash adjuster failure - now i am hearing about cam phaser issues. Has this stuff been mended ? Or is stellantis still using sub quality component suppliers ?

Geez, only two for me. I'm waiting on the PHEV.

 

[Geoarch]

I remember back in the 70's when there was a selection of aftermarket cams and you could change them with no issues. Those days are gone.

Yeah, I put a Crower in my 70 Chevy Nova SS's 327. What a screamer and at idle and low speed the cam lope rattled windows, and people called the cops. I miss those days sometimes.

 

[Hoss]

Why are we worried about reliability if you’re only going to own it for 8 months?

 

[Geoarch]

If you started in the 70s then you likely saw that by then they were talking 7,500 mile oil changes.
I've some owners manuals and TSMs (Technical Service Manuals) for AMC/Jeep, as well as some other vehicles.
That's with the oil chemistry of the 1970s and the carbureted engines often running either too rich or too lean or with something else "off" leading to crappy combustion.

Yeah, that pretty well describes my 73 CJ-5 with the 258 (I want it back!). I changed oil about every 7500. That was in the 70s. By the way, the 73 CJ cost $3400 new in 73.

 

[Geoarch]

Another WOW!
OUTF(oops)Standing!

I think most of us here are in need of an intervention - my M1097R1 (HMMWV) - getting a new top - repainting it - maintenance and will see how it does on the trails.

Some of the ex sailors & others I train with have these equipped with big & small block gm engines.
They can keep up with fast moving traffic & even pass some.
Much better than the NA 6.2 oil burner.
Love the riveted aluminum construction!
I bucked rivets in the Navy on Viet-nam era A7 Bravo's & later Echo's..

69-70 Vietnam, Marines, Tracked vehicle repairman, with an emphasis on constant repair. Cam Ranh Bay. What fun, and remember we were there to same democracy.

 

[jwolfejt]

Why are we worried about reliability if you’re only going to own it for 8 months?

Well it would be nice to have it 100% in those 8 months - vs 6 of those months sitting at the dealership.

 

[Hoss]

Well it would be nice to have it 100% in those 8 months - vs 6 of those months sitting at the dealership.

Buddy if that’s been your experience and you’ve done it 6 times going on a seventh, then I think you’re doing something wrong lmao.

 

[jwolfejt]

Buddy if that’s been your experience and you’ve done it 6 times going on a seventh, then I think you’re doing something wrong lmao.

If you read my prior posts in this thread - it was far from my experience. I was just raising the thread to see if Stellantis has gone with more cost cutting since then and made something worse (never heard of cam phasers failing on a 3.6 for example until I've seen posts pop up in the forums here).

 

[ShadowsPapa]

(never heard of cam phasers failing on a 3.6 for example until I've seen posts pop up in the forums here).

With that- want to ask a question - do you mean you never heard of it happening in a Gladiator? Or a 3.6 in general?

Wondering - how else would you hear if not in a forum?

Wranglers didn't have these until the JL.
The phaser range was totally changed in the upgrade engine and the JK never had this engine.

It's also going to take time - so you might not hear about it in the first couple of years, until dirt and grime gets into them. (there are cleaning cycles you can run via JSCAN)

Doubt that the phasers were made "cheaper" in the last year or two.

 

[Mr Miami]

Yeah, that pretty well describes my 73 CJ-5 with the 258 (I want it back!). I changed oil about every 7500. That was in the 70s. By the way, the 73 CJ cost $3400 new in 73.

Not to change the topic but you did mention what you paid in '73 for your CJ. In my case, just after high school my best friend and I each bought new Jeeps. He was driving an old International Scout and I had a '66 Jeepster. We both bought '75's. Him, a new CJ7, soft top, V8 (304) with Quadrac for $4,900. I bought a J10 for about $4,700 with the 3 speed manual, 360 V8 2 barrel. I kept telling him he paid too much. How times have changed.

Ok, back to the topic.

 

[Geoarch]

Not to change the topic but you did mention what you paid in '73 for your CJ. In my case, just after high school my best friend and I each bought new Jeeps. He was driving an old International Scout and I had a '66 Jeepster. We both bought '75's. Him, a new CJ7, soft top, V8 (304) with Quadrac for $4,900. I bought a J10 for about $4,700 with the 3 speed manual, 360 V8 2 barrel. I kept telling him he paid too much. How times have changed.

Ok, back to the topic.

I paid $3400 for that new '73 CJ-5. Those were the days.

 

[7BJT]

I've owned multiple 4.0 TJs, 3.6 JKs, etc, with no serious issues. I just had a new engine put in my Mojave at 25k. Unreal. My warranty is already almost up. I've always owned Jeeps and Toyotas. If there was a solid axle FJ or Landcruiser with removable doors and roof, I'd be first in line. That's where I'm at. Sad for M'urica.

 

[SwolebaFett]

I am looking into getting my 6th JT - been reading alot about roller/lifter/lash adjuster failure - now i am hearing about cam phaser issues. Has this stuff been mended ? Or is stellantis still using sub quality component suppliers ?

I believe I’m having this same issue. Crazy clicking/ticking sound when I’m driving around. Any luck with anything? I’m taking mine in next week to have them look at it.

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