Anyone ever had intermittent rod knock? My engine has been making the "tick of death" pretty bad from the lifters for quite a while. I know that my oil pump needs replaced, as well as a few really, actually, bad HLAs. You can hear 3 different HLAs tickin. But lately it seems as though the sound, or another sound, is deeper and heavier. Much more like rod knock. BUT... it goes away after warmin up and driving a bit, just like the HLA tick. comes in and out sometimes at idle. Just like the HLA tick. I would think that a rod bearing with slop would have slop always, and not really change with driving.

Also I just put 5000 miles on in a month.(cross country road trip:headbang: ) it was making this sound for awhile before the trip and the mileage didn't seem to change it. I would think running 70mph+ for days on end non-stop would kill an engine with a rod loose. Or at least make it worse or change.

 

What do you guys think?

First off...have you tried the Seafoam/MMO trick yet? to help clean the gunk out...works wonders ( IMHO) My Bucky has has TOD since I have owned him ...4 years..Even after rebuilding the oil pump it was still there on cold days...one day I will get around to replacing the HLAs...they can sound horrible horrible at times. I havent heard of anyone having troubles with rod knock..but that doesnt mean it doesnt happen..the only other noise I get from mine ...when cold..is from the throw out bearing or something else in the tranny( I believe) and it goes away also after warmed up

I have often had rod knock that goes away after the oil pressure builds, maybe after 10 or 15 seconds, and the engines have ran for many many miles. Of course these are big V8's, maybe not applicable to the Subaru world, but advice none-the-less. So it's possible. I wouldn't be hitting 6K rpm any time soon.

that TOD is so annoying...

 

reseal the oil pump, mickey mouse gasket and shaft seal. hows the oil pressure? check the PCV system too for buildup. i had to replace the PCV hoses and the valve.

 

use some rislone or MMO with 20/50 dino oil and drive it around, maybe rev it up high for a little bit "italian tuneup"

 

i bought my car for $125 with a "blown engine"... this fixed my problem

Blu, my OBW, had a rod knock that came and went. It took me by surprise on a cross country trip. About 3000 miles later it threw the rod.

The rod knock was hard to hear at times, but in retrospect it was there. Oddly the very last fill up i thought the car was running exceptionally well, then 20 miles later all sorts of excitement.

 

Best way to see if its a rod knock, pull the plug wire for that cylinder and see if it changes pitch.

 

 

nipper

I have often had rod knock that goes away after the oil pressure builds, maybe after 10 or 15 seconds, and the engines have ran for many many miles. Of course these are big V8's, maybe not applicable to the Subaru world, but advice none-the-less. So it's possible. I wouldn't be hitting 6K rpm any time soon.

 

No this goes on for more like 10-15 minutes. 2 or 3 if it's warmed up already. The pressure has ussually dropped to warm levels by the time it goes away, so I think it is perhaps a flow issue through the crank and rod bearings when the fluid is thick(pressure high, slow flow). Once enough volume of oil starts flowing they quiet down?

I'm building up a fresh motor already, so I guess this one will continue to be an experiment. I threw this motor toghether to get it home after buying it on ebay. It had an engine fire and all the wiring and plumbing and most of the sensors were toast, Literally:Flame:

 

The heads AND Turbo charger were cracked. Failed Wastegate on the Turbo. car must have been severely overheated till the up-pipe and turbo got so hot they lit the cv boot up and it burned from there. I scraped everything but the Block.

 

I knew it was burned up so I brought everything rubber under the hood with and all the sensors and seals as well as T-belts. I bought an old XT motor from a J-yard for 150 bucks and scavenged the heads. That was about all I could use from it cause it had sat for X# of years outside in Oregon:(

The heads needed a thorough clean up on the valves and new seals, I skipped the guides. They have big "crack of death"between the valves. O yeah the Turbo sucks and has "too much" rattle.

 

So you see, I don't really plan on doin anything but drivin this motor til it dies.

 

New motor will be bottom end on up rebuild with new turbo.

bump

have your headgaskets or intake manifold gaskets ever failed or has the engine ever been run with very low oil? these issues in the past can prematurely wear road bearings and cause them to fail later.

 

it's hard to say without hearing it, might want to find a local that's familiar with subaru sounds and have them take a look? nippers idea of pulling the plug sounds interesting to try and at least it's easy.

 

lots of TOD info on the board here, might want to start there if you can't figure it out. i do not know a way to tell someone to differentiate between ticking and rod knock.

I'm having similar issues with my 85. The A/T gave out on the highway, and I revved the motor up pretty high while trying to get it to the side of the road. It was making some strange noises before I dropped the tranny for replacement, but the consensus was that I should see if it clears out after replacing the tranny (this weekend hopefully).

I came accross some old skool troubleshooting info that describes using a vacuum guage to assess engine noises. I've never really had much faith in those since the results are easily misinterpreted, but if read correctly, it should give some insight. A lot of the old-time hot rodders swear by those vacuum guages!!.

I'm going to try this on mine, and maybe the plug suggestion above, before messing with Marvels or Sea Foam. I'll let you guys know if the vacuum test turns out to be useful.

 

good luck, John

Actually a vaccum gauge is one of the best tools to find engine problems that a compression test wont pick up, and its really easy to read.

I dont see how its easy to misread.

 

http://www.fordf150.net/howto/diagnoseengine.php

 

nipper

As an old fart that runs a vac gauge in most of my rides or in my turbos

a vac/boost gauge.

 

I see no way it will help diagnose a rod knock??

 

which, aside from tangents, was the original question.

 

Maybe a ticking HLA woulds show up?? but a rod knock??

 

My lame suggestion is a mechanics stethoscope

have your headgaskets or intake manifold gaskets ever failed or has the engine ever been run with very low oil?

 

Uh, well it got hot as hell, the right side CV boot caught fire and roasted everything rubber inside engine bay. The only thing still in the car from before the fire is the block. So there is a possibility that it suffered damage from the overheating/fire. There was only water in the Radiator, rusty water. And Both the turbo and the right side head where cracked, so my guess is it was overheated pretty bad. I think the wastegate on the turbo failed, cause it was cracked around there and the edges of the crack were melted!

I'm really not sure excactly how hot it got though. The fire happened before I bought it on ebay. I knew I was going to have to put a new engine in it, or rebuild this one. But I really could not get any good info on the history or how the fire started.

wow, well i can't say i have much experience with engines engulfed in flames. i did have one soob catch on fire, but didn't try to reuse any engine stuff off of it.

 

fire and having likely set for awhile in a questionable condition could have something to do with it. i'm not one to cry wolf though, it could be really loud HLA's, they can tap and they can also TAP! i've never had much of a problem diagnosing a tap from a rod knock, but i haven't seen that many rod knocks either. i think i'd address the oil pump and if that doesn't solve it, you'll still have the oil pump for the next motor anyway. oil pump work is easy enough to do, it'd be worth the effort to find out.

my sube sat for like 2 years, when i started it, BOY were those lifters LOUD for the first 15 minutes, like it sounded like rod nock, i got sorta scard, but it went away after like 15-20 minutes and now u cant even hear them.

when i got a rodnock in the death wedge it was very quiet, like thats sounds bad but not serouse quiet, it was much quieter and deeper than a lifter tick for like three weeks then it gave its ten seconds of notice before putting a 6inch hole in the top of the block on it way out. by notice i mean the stereo was all the way up and i was going seventey on the freeway and i heard it and had time to turn the stereo down before i heard it blow and richoet off the bottom of my car as it flew off down the freeway behind me

Well, I am now very sure it is rod knock. After a fresh oil change, I have no trace of TOD, but there is still a slight rattatatat. Not tickityticktick. And I can hear induce it by slight on/off throttle movements. In fact it really only knocks right around the point where the crankshaft goes from "driving" as opposed to being "driven" by flywheel momentum(this is an Auto so TC). this adds up to classic rod knock, and I will need to kick start my rebuild progress on the new motor.

when i got a rodnock in the death wedge it was very quiet, like thats sounds bad but not serouse quiet, it was much quieter and deeper than a lifter tick for like three weeks then it gave its ten seconds of notice before putting a 6inch hole in the top of the block on it way out. by notice i mean the stereo was all the way up and i was going seventey on the freeway and i heard it and had time to turn the stereo down before i heard it blow and richoet off the bottom of my car as it flew off down the freeway behind me

 

Mine was the same way, except i was climbing donner pass. Mine went through the top of the block

 

http://www.ultimatesubaru.org/photos/showgallery.php?cat=935

The pic is fuzzy as it is from a cell phone, but you can see the damage.

It seems rod knock on a sooby is a sign of impending doom, not something that you can just baby for a while.

 

nipper

Back a few years when I first got my 85 wagon, which had sat for five years, I spent many oil changes, MMO, Seafoam,new oil pump, much fiddling and time trying determine if what I was hearing was TOD, piston slap, or rod knock. I'm kindda half deaf in one ear, no stereo, this throws things off. Tried the pulling plug wires one at a time. No change.

 

I'm still not 100% sure, and I do not have access to listen to a new and quiet EA-82, never have, so don't even know what a normaly quiet one sounds like, but----------

 

Back then, when I was still fretting about it, I discovered a few 100s of "crank walk". Ran this by the board, and a couple of guys said, "well, yea, maybe thats what your hearing". Apparently it's uncommon in these engines, though not unheard of.

 

This engine only had about 12000 on a longblock, I've driven it about 6000 since I resurected it, and it still has some tapping or clacking or whatever at times, mostly in cold weather. Heck I can't find it.

 

Now I try not to worry about it. Runs good, great compression.

 

Pyro

 

Back then, when I was still fretting about it, I discovered a few 100s of "crank walk". Ran this by the board, and a couple of guys said, "well, yea, maybe thats what your hearing". Apparently it's uncommon in these engines, though not unheard of.

 

Pyro

 

I had a 69 vw bus with "crank walk". Ussually that kind of thing will trash front and rear main seals. I don't have any signs of leaking from them. I am 99.9 % sure I've got a rod going.