What does your V10 sound like when you load it a little. Mine only has 500mi on it but it sounds almost like a baby diesel when I get on it. It not detonating, it's more like valves need adjusting or even an exhaust leak. Whatever it is, it doesn't sound right. Is this normal? The dealer is trying to tell me yes. It runs great and makes good power. I just thought it would be more of a smooth sounding motor. Thanks in advance.
Ricky

[This message has been edited by Ricky Best (edited 12-14-1999).]

 

Are you sure it's not spark knock. I have heard cases that were so loud that you couldn't belive that it was just spark knock.
Could be something to do with ignition timing. most common reason is bad gas or gas with too many additives for the cold weather in it. Hope this helps.

 

Piston slap?

 

My 5.4L (y2k f250 SD), has the same symptom..

What is spark knock? Based on the term I can maybe guess what it means, but if you can explain more, I'll learn something..
I'm fairly knowledgable about engines etc, but far from knowing everything..

fast46: nope, its not piston slap.. Our symptom doesnt go away when warm, and the 'knock' only occurs when accelerating, not at cold engine start time..

 

V10 sounds lika sewing machine. I'm going backto a V8 cause I can't stand tha sound!!! I hava 99 Superduty supercab longbed 4X4 Lariat with alotta extras, but ya jus cant gettit to sound goood! Igot it with allthe options, but ya jus cant makit sound cool. (I put 4 different exhaust systems onit, so nomatta whatcha do, it aint gonna sound right)

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2000f150 Lariat Supercab Flareside 4X4 Black 5.4 engine Leather Captains 3.55 Limited-slip and all the goodies, just ordered,traded my 99 f250 superduty Lariat V-10. Wife drives a 98 Navigator 4X4. Had a 97 Lariat 4x4 supercab Just ordered a lightning front and rear bumper,power tube,K&N filter,makin a 4X4 Harley ......... Toy: 91 Heritage Softtail Classic/lowered and chromed..................[img]//www.f150online.com/fordnews/harley1.jpg[/img]

 

From the descriptions I would have to say it is spark knock. It is normal if it does it only once in a while. I bet that it knocks for only a few seconds when accelerating then clears up. I know on my truck I can gas on it get a few spark knocks then clears up. My mothers expedition, and dads 90 model 302 and my uncles 96 chevy 350 do also. Spark knock is the preignition of gas in the combustion chamber. It it does this continuously it will cause damage but on occasions is normal. If it is not spark knock I do not have any idea what it is.

 

Looks like I'll be taking a trip to the dealer. I hear the sound the entire time while accelerating, or whenever I demand power. Once I'm at speed on level, it goes away, but to gain speed, or pull a small grade, it will make the sound..

 

Ricky,

Like Cabraco says the V10 sounds like no other. It's hard to tell just what the sound is without hearing it. I know that when my truck was new it made all kinds of strange noises, especially from the exhaust. If there is nothing wrong with the engine then I'd guess that it's just the exhaust system trying to keep things quiet.

 

Ford-tough1 explained spark knock very well.
Ricky from your explination of when the sound occurs (under load) is why i say spark knock. It ussally happens when the timimg does not advance enough when the engine is under a load or accelerating.

 

Spark knock can occur when the timing does not RETARD enough upon acceleration. Assuming that Mr. Bess has NOT yet tried premium (for which he's probably smart-enough to have already tried that), if premium stops it, then he's probably got some bad gas. Most engines today have a knock-sensor -- which just might be deaf.

Spark knock can be described as sounding like small ball-peen hammers (many) hitting the side of the block in rapid succession -- kind of a "craaaaakakakakak" real fast (once per cylinder fire of the offending cylinders).

A cheap 'fix' as a test is to run a tank of gasohol (which burns slower and cooler than regular gas) and see if it subsides.

Question: does the suspected spark knock disappear when it's raining (moist air burns a little more predictably).

Does the noise have any throttle-position difference (ie: more noise at part-throttle acceleration, but subsides at full-throttle)?

Is the noise gasoline sensitive (knocks on Meijer, but doesn't on Shell, etc)?

Jim

 

Well....I'm pretty sure that it's not spark knock. Being a supercharger specialist, I've had plenty of experiance with that. It really sounds like its just a real loud rotating assy. I've only owned the truck for a week but I have tried various grades of fuel from different suppliers. I have a really good friend that is heading up a V10 project over at Ford advanced powertrain. When he gets back into town, I will try to find out if he knows what's going on. Thanks for the help guys.
Ricky

 

I'm starting to doubt that its spark knock..
I'm currently running 89 octane (vs the normal 87) to see if it subsided, but it hasn't. I heard other engines knock, but this seems 'softer' than that.
It occurs at part and full throttle,

Occurs in wet weather
Occurs when running both Texaco and Amaco (which I run in all of my vehicles).
I don't think its 'bad gas' as I've had the truck for a month now (2200 miles).

I'm thinking this just might be normal. I'll find out when I testdrive another truck to compare..

 

The reason that the V10 sounds different is because of its odd firing order.

 

I was wrong on the timing thing and Jim is exactly correct.