'97 5.4 engine knock

[Corey]

Hi all, I know there's a ton of knock threads already posted, but my knock may be different. Just bought a 97 4x4 with 144k on the 5.4. At start-up (when the engine first fires and briefly revs before settling to idle) there is a loud knock that seems to be coming from the driver's side top of the motor. As soon as it settles to idle, the knock all but disappears. At that point a stethascope seems to indicate it's near the back on the driver's side. As soon as the engine is under load, the knock gets loud like at start-up. I bought it with the intention of swapping the motor, but if it is fairly painless to repair, I'd rather do that. my first thought was damaged/broken timing chain guides, but the knock is too far back. I removed the driver's side valve/cam cover and saw very little sludge and no obvious damage. Otherwise it idles steady as a rock, has no leaks and does not smoke. I haven't driven it more than about 200 ft since I don't know what the cause is. The knock sound like something rapping against the inside of the valve/cam cover. it's definitely not an exhaust leak and I'd be very surprised if it was a spark plug. It sounds very much like tapping on a hollow cast aluminum boxes I guess.
Anyway, anybody got any ideas? I've rebuilt several engines in the past, but nothing this modern so any advice is appreciated.
(BTW, paid $800 for it. It's an Eddie Bauer with a very solid body and interior)

 

[Corey]

Update: I ran the engine with the drivers cam/valve cover removed and the realized the knock is ot coing from there. After putting it all together I decided to take it for a drive. THe **** came and went but wasn't really consistent with engine load. At one point, I noticed the oil pressure had dropped to 0. I shut it off and pulled over. After a few seconds I started it and the pressure went right back up to about 2/3 between Low and High, where it is on start up. There is plenty of oil in the engine and the the knock didnt change when the pressure went to 0. Anyone think the oil pump could be the culprit?

 

[Corey]

Removed the serpentine belt today and ran it to rule out a bad bearing on any of the accessories. Chnaged the oil (first time since I brought it home last week) and no debris, just dirty. Knock isn't as bad with the new oil and filter though. Almost sounds like the knock is coming from the hollow part under the intake. Driving wise, it has plenty of power. I hope to drop the oil pan this weekend to look at the bearings.

 

[Corey]

I guess this isn't really a request for assistance (since nobody has offered any), and is now a running diary that hopefully someone else can benefit from some day.
I've gone over the engine the best I can without further dismantling and after some very minor driving for troubleshooting purposes this is what I know now for sure: the knock is loudest at start upwhich subsides at idle and under load. It gets louder during unloaded engine decceleration, which should indicate it's a rod bearing. Otherwise the engine runs starts and runs as solid as I've seen. I plan to change all the rod bearings this weekend. Many uknowns for me though. If I'm lucky, I can replace the rodbearings without removing the pistons with the truck on a lift. I've purchased all new bolts as well since I understand they are one-time-use TTY bolts. I plan to remove the cross frame member and the center portion of the front drive to enable the oil pan to come off. If there's a better way of getting the pan clear of a 4x4, let's hear it!

to be continued...

 

[toms89]

What your describing sounds like rod knock. Excessive clearance in bearing will cause drop in oil pressure. Hopefully crank journal is ok if bearing is bad?!

Can try 20w-50 oil to help "fill in" the gap. May help with symptom temporarily..

Can you post a video? Helps a lot when others can hear it.

 

[Soldier777]

Corey sorry for the non response, I am too green to answers your questions but your thread might of fell through the cracks with this website being merged with the other expedition website that had about 10x the activity. Hopefully someone with experience will chime in soon.

 

[BakerEdition]

Corey we want to help....but we all have jobs and work and sometimes take a while to get a response... don't get upset...we are a family here and try to help each other...I had a F-150 with a 4.6 that did the same thing....I mean exactly....ended up needing main bearings because the pick up screen and tube was plugged solid...I got lucky and put a new set of rod and main bearings in along with an oil pump and new pick up tube...put 20-50 oil in it and was quite as a church mouse....I sold it after about 500 miles still quite..the other thing I have had happen....I had a 96 Chevy Caprice with the LT1 vette engine...it developed what sounded like a rod knock...deep from the back back on the bottom and ended up being a cracked flywheel...

 

[Corey]

Don't get me wrong folks, I'm not upset with the lack of responses. I just figured nobody had much to add. In any case, I appreciate you guys replying. I'm supposed to get it on the lift this Saturday morning. I feel like I've unwrapped my Christmas gift but've had to leave it under the trtee til well into February! I finally installed a stereo tonight, a whole other accomplishment for another thread...

Well, I am really hoping to post positive results Saturday afternoon. Aside from the bearings all I need to do is replace the drivers side mirro (just the lens), swap rear bumpers with my F150, eventually replace the windshield and tires and frankly, this Expy will be in pretty excellent condition. I can't wait to post pics of my $800 investment.

 

[Corey]

Well, a preliminary check by a very experienced local mechanic is leading me to just replace the engine. I'm actually relieved because I plan to have this Expy for awhile and if I just changed the bearings I'd always wonder on a road trip 'is it gonna make it?'.

That being said, I can get a remanufactured 5.4 for that year by Marshall Engines with a 3 yr/100000 mile warranty thru rock auto for $2165.00 shipped plus core. Anyone have any experience with either rockauto or Marshall engines? This is $600 less than any place else with the same warranty...

 

[BakerEdition]

Corey....are any of these places near your home? I always feel rebuilding your own is the best way....just my opinion...meaning the engine in your truck...

 

[Expeditionary]

im sorry but i know you got the truck for 800 bucks but... a rod knock and your replacing the engine. Sounds to me like your mechanic is trying to screw you. did you mention "i will be doing all the work myself and i just want a diagnosis" because that way they know they arent gonna make money off you lying through their teeth at you. I have a trusted mechanic that my family has been going to for over 15years and he still charged me $400 to fix a CV axle on a toyota pickup. Then again he did get me a new alternator for $190 installed lol so...

Just something to think about

 

[BakerEdition]

Expeditionary....I would hate to be your mechanic....next time dont sugar coat it.....lol

 

[Thermo]

Corey, I have something very similar to what you are talking about. The engine has been running like that for 60K miles. Through some playing around, what I have found mind to be is the lifter for the #3 cylinder is sticking, leading to excessive rocker clearance. That is causing the tapping sound that you are hearing.

With that being said, you can replace the lifters by getting a special tool (about $150) that will allow you to compress the valve spring and give you the clearance you need to slide the rocker out of the way. Then, you can use your fingers or a pair of needlenose pliers to pull the lifter up and out. You may find that the lifter in question will be a real pain to get out as it is semi frozen in place. I had to do a little bit of work to get mine out. From there, you can possibly use something like a brake cylinder hone to clean up the cylinder for the lifter and then install a new lifter.

 

[jacks3am]

I trust everyone here so if it is somthing bad, throw some High compression pistons, forged rods and a cam in there and go to town!

 

[Corey]

Thanks for the feedback everyone. I can say that the mechanic who is helping me swap motors is one of my best friends and is on the level. He was going to let me use his bay for free, but my time is limited so I approached him about just having he and his boys do the work. The mechanic who diagnosed it was a friend who gets nothing out of it, good or bad. It's a small town and everyone knows eneryone kinda thing. Anyway, the knock got considerably worse when I was driving it to the garage. It went from pretty damn mild all the way to 'crap! that doesn't sound good!' I guess once the oil got really warmed up things changed. As I said, I've been inside a motor plenty of times, but diagnosing this one from the outside was a challenge. It's definitely coming from the bottom end and as loud as it was yesterday, I would never feel comfortable throwing in new bearings and taking a roadtrip. Doing anything more substantial is easier if te engine is pulled. So if I'm pulling it, something new is going back in. Time is the biggest factor.
Again, The motor and install will be less than $3k. That gives me a dependable EB with a new motor, clean body and interior for under $4k. I'm cool with that. I was preparred to do this as a worse case scenario when I bought it. So far I have learned a lot about the oiling characteritics and that will help me get max miles from the new engine.
Aside from the CAI, I'm afraid there wont be any performance mods. This one will be hauling kids up and down the beach, so dependability wins that battle.
Thanks again for your feedback, everyone. I'll update when I get it back with a review of Marshall Engines. I'll poke around the core before I send it back and see if I can get some good picks of what I expect to be at least one spun bearing.

 

[Expeditionary]

Expeditionary....I would hate to be your mechanic....next time dont sugar coat it.....lol

I pay my guy for diagnosing it. Dont get me wrong. I would however and do take my truck to just brakes, tires plus and the like and ask them to "check it out" and see whats wrong. They give me a full estimate and parts list. Then im out the door and on my way to Advance or Napa hahah.

 

[Corey]

well, the old motor is out and one of the main bearings was spun. There was a notable groove in the crank as well. I guess I'm not surprised and kinda glad I bought a reman. The more I looked under the hood, the more I saw evidence that someone had been in there before. Looking at how many miles were on it when the previous owner bough it and what was on it when he sold it, coupled with the tell tale signs of someone being under the hood (wire looms nolonger fastened in their ziplocks, things like that...) I'm betting someone got a knock around 120K, slapped in some new bearings and sold it before it started knocking again. Sucks for the guy who owned it before me because he paid like $6k for it. AT least I bought it preparred to replace the motor if necessary.
Anyway, I should have it on the road by the end of the weekend.

Whatever happened to the good old days of being able to pull a motor that was still fully assembled?

 

[jacks3am]

Gotta say ford makes the smallest engine bays ever they really are tiny

 

[BakerEdition]

Those days are long gone my friend....no as long as it fits on the engineers paper drawing thats all that matters....it those jerks had to fixed what they designed....you bet your sweet A$% there would be some changes....

 

[Corey]

It...
is...
Alive!

First drives today. Runs beautifully! Getting one code for a Shift Solenoid B failure, but nothing was noticable while driving. time to research that one...