Ford Modular motors...question...

Discussion in '1996 - 2004 SN95 Mustang -General/Talk-' started by QuickCapri83, Apr 19, 2006.


  1. QuickCapri83

    QuickCapri83 New Member

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    Aight, I dunno if it's just me, and, I know this may seem to belong in the tech section, but I figure it's more just something to chat about, more like, opinions.

    So, this is my question/issue i'm wondering about. Pretty much every 4.6 or 5.4 I've come across(friends/family etc etc) has a knock to it, only noticable at idle. This i've noticed mostly in the 5.4 ford trucks. Everytime i'm next to one, like, today at teh bank, I was next to a brand new F150, it was the V8, nice ass truck, anyways I turn my car off in teh drive through so I can hear well. So i'm listening and I hear that his truck has the exact same sounding knock that my 35thAnny has, my car has 107k on it tho. His knock sound I would say is about 4 times louder than mine. Now, the knock that I get at idle on my car seems to be top end, I know these engines bottem ends are pretty much bullet proof, so, can someone give me an explanation as to why they all have this knocking sound. Like, not the kinda knock that sounds like a bearing is bad, no way, just, a slight knock. I have two friends, who at some point had F250's. Both had 5.4 triton, both had the same sound as my car. No matter what kind of oil I use it's there ,but, I have no trouble the car runs great and plenty of oil pressure.

    I pay alot of attention to things, and, every since I noticed the slight knock that my car does, I'm always listening to other vehicles to see if they do the same thing, and lotsa ford trucks seem to do it.

    Is this just some common, not serious...thing?

    Appreciate any insight. Also keep in mind i'm used to ovh engines, I just bought my '99 2 months ago, so i'm just now learning the ohc technology, never had any reason to before, my '97 explorer is ohv and '95 cougar is also, and my car was the '83 capri with a motor out of a '88 lincoln mk7. Pretty much same engine as stang, H.O. motor, I just converted to keep it carbuerated.....bad spelling prob. So anyways I dunno, I was thinking lifter, low pressure, ya know, but, are there lifters in a ohc engine? Heh, forgive the noobness, when it comes to a 5.0 I know it in and out, the 4.6 i'm just now bothering to discover. damn this post is long for such a simple point, sry for the long read if you made it this far :rolleyes:


    Thanks for input, and probably alot of patience, otherwise i'd expect negative feedback heh. I just cant get why I've heard the same lil knock sound in like 15 fords, all modular 4.6 or 5.4. Peace out, Stangs> forever

    -Dave

    :SNSign:
     
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  2. BurningRubber

    BurningRubber Active Member

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    Ever heard a high mileage Jeep 4.0 engine? Thats a knocker for ya...


    I dont know though, ive noticed it before also. Ive heard it in both pushrod and OHC 4.0's in Explorers... the pushrod 4.0 much more so. My 4.0 Jeep knocks like a mother after its warmed up, but has been sitting and then you drive it again, but only for the first minute or so. Oil pressure is fine... I dont know what it is.

    I hear like a rotational sound in the Mustang though... kind of like a knock, but not like a knock... its hard to explain.
     
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  3. QuickCapri83

    QuickCapri83 New Member

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    Hmm, I dunno. My stang, well, when I rev it it sounds perfect, but, I mean there's not alot of compression in that situation. So, when I'm driving, whenever I go over a bridge, or anything where I have something right next me I floor it, to see if there's any kind of knock from the engine. Call me paranoid, but, it's the first time I bought a car with 100k+ on it, other than the VR6 GTI I had. That thing from new made taps/knocks everything but is normal they all do it especially at idle.

    Anyways, my car, is really, just a very quiet knock, at idle, I can only hear it if i'm sitting, and I open my driver door, and just listen. Otherwise I can only barely hear it when i'm sitting in my driveway, windows down, but I "have" to be right next to something, simply, I park like 2.5 feet from the side of my house, so im really close any sound is reflected good.

    One other thing my car does....that my 5.0 did too, is, under 1200 rpm, if i'm in gear, say first or 2nd, dont matter, if I give gas to accelerate it makes the dieseling sound. My 5.0 did it only at very low rpm, like, 3rd gear at 15mph on a hill lol, i should be in a lower gear, but i do it sometimes and it dieseles. Anyways my '99 does it, no matter what, all the time, if i'm in gear giving gas below 1200 or so, maybe 1000 i guess. This i guess is normal maybe? The engine is under stress, im giving it throttle to accelerate, and the engine is simply not moving fast enough, i guess that's why it makes the diesel sound, i dunno. I've noticed other stangs do it too, if the rpm are really really low and u give lotsa gas to accel and the sound go's away instantly when the rpm gets to like 1200.

    Anyone at all, lemme know what you think of this stuff. Moreso the knock thing, it's werd to me i've heard it in so many stangs/f150's but none have ever had an engine failure. And yes, the sound is more noticable at startup, for a minute or so, i'm using Royal Purple oil, which is freaking awesome, and a K&n oil filter. When I bought it two months ago it had the ford motorcraft filter, and conventional oil, fresh tho, well, the car sat at the dealer for a year. uhg, yeah...peace for now, hope to hear some techy stuff, or personal experiences with this anomoly of modulars.

    p.s. My '97 explorer and my '95 cougar xr7 do a similar sound, but they're both ohv, the stang is ohc. Both have right about 100k. But the cougar had the head gasket redone/heads rebuilt completly.


    :SNSign:


    -Dave
     
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  4. BurningRubber

    BurningRubber Active Member

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    I think the deisel noise you are talking about is from stress at a low RPM like that. I accidently put it in 3rd the other day when I meant to be in first... Started to let the clutch out and I thought I was riding in a Mac truck, haha. It sounded horrible... just pinging, but thats cause there was way too much load on the engine.
     
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  5. jlhall_10

    jlhall_10 New Member

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  6. jstreet0204

    jstreet0204 Active Member

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    Modular engines suffer from a problem called piston slap. The problem is that part of the piston that is greatest in diameter is comes out of the bottom of the cylinder at the bottom of the stroke. This allows the piston to wobble in the cylinder until everything is warmed up and expanded. The 5.4's are more noticable.
     
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  7. BurningRubber

    BurningRubber Active Member

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    Same with the 4.0 Jeep engines.
     
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  8. SigmaPride

    SigmaPride New Member

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    I'm pretty sure mine does the same thing and I have done these same crazy things to listen. I found that if I get down under the car while running i hear it coming from the oil pan/engine area. It has done that for as long as I remember and no problems. I have 103k.
     
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  9. QuickCapri83

    QuickCapri83 New Member

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    Thanks for the replies! I feel alot better now, although I didnt really think it was too too serious, I still get paranoid and dwell on it when I notice it. Heh. thanks.


    -Dave


    :SNSign:
     
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