Crankshaft Failure Chances

[Exp98]

Hello,

I recently replaced my primary guides and tensioners on my SOHC. However, I just found out from some more reading, that there have been issues with crankshafts breaking? As far as I have read, there is no consensus as to wether it is caused by improper balancer installation or a manufacturing defect, or just luck. Also, was this the proper way to reinstall by balancer? 1. Line up keyway 2. Tap in with mallet 3. Start by turning by hand to engage threads fully 4. tighten with impact 5. back off slightly. 6. torque to 80 lb ft and 1/2 turn. Assuming the procedure was correct, what are the chances of crank failure? Also, is there any preventative maintenance that should be done as I crossed 300k not too long ago. (I do oil every 3.5 Mobil Full Syn HM, Fram Xtra filter, fuel filter every 80, plugs every 70, front/rear diffs every 30-35, trans fluid every 25, trans filter every 100, hydraulic tensioners every 100, coolant every 40, decarbonization every oil change) I probably forgot something lol Thank you very much!

Regards,
Exp98

 

[donalds]

Video on the let me guess

Ok ....tic tickity tic tickity tick tock
disappears at about a thousand rpm

almost sounds like the valves closing

 

[Exp98]

Video on the let me guess

Ok ....tic tickity tic tickity tick tock
disappears at about a thousand rpm

almost sounds like the valves closing

no not really, I've taken it to 2k and it still does. I suspect its from the bottom end (eg torque converter, flywheel)

 

[RickOTR]

Lash Adjusters are a weak part of the SOHC engine. I bet that's your problem.

 

[Exp98]

Lash Adjusters are a weak part of the SOHC engine. I bet that's your problem.

hmm... seems probable... they're stock for 300k.. ill look into it...

 

[RickOTR]

hmm... seems probable... they're stock for 300k.. ill look into it...

Those lash adjusters are DOA, replace them before you throw a cam follower and destroy the engine. They're only good for around 150K miles then the sping inside becomes weak. Pre-oil them before installing though.

 

[donalds]

Front jackshaft tensioner is my best guess
Does it kinda sound like keys jiggling

 

[Exp98]

Front jackshaft tensioner is my best guess
Does it kinda sound like keys jiggling

hmm... I replaced it about 10k ago... ill post vid soon.

 

[Exp98]

hmm... I replaced it about 10k ago... ill post vid soon.

until I get my butt off the couch... it sounds like the exhuast cooling after u shut it off, but moderate speed. maybe like 3 clicks per second... I'm thinking torque converter, possible exhaust or as RICKOTR had mentioned, lash adjuster... I gotta stop watching Miami vice and get off the couch

 

[Exp98]

until I get my butt off the couch... it sounds like the exhuast cooling after u shut it off, but moderate speed. maybe like 3 clicks per second... I'm thinking torque converter, possible exhaust or as RICKOTR had mentioned, lash adjuster... I gotta stop watching Miami vice and get off the couch

EDIT: here it is

could it be a clogged lash adjuster? it occurred during the time i had my timing rattle. the rattle was repaired 10k ago. if it is clogged, is there harm leaving it without flushing? thanks.

 

[RickOTR]

That is not a bad lash adjuster. Sounds like the substrate in the Catalytic Converter is coming apart. Not uncommon for the SOHC engine. Ford had problems with it but they never recalled the cats. I ended up replacing mine and the sound went away.

 

[Exp98]

That is not a bad lash adjuster. Sounds like the substrate in the Catalytic Converter is coming apart. Not uncommon for the SOHC engine. Ford had problems with it but they never recalled the cats. I ended up replacing mine and the sound went away.

So... its just a nuisance right? Is the cat losing efficiency by not catching the fumes? thanks.

 

[RickOTR]

Take a look at this video...



You'll see what I mean

 

[Exp98]

Take a look at this video...



You'll see what I mean

I see now... i stuck a mallet in between and yup, it went away... so... i may just replace the cat... woyld addibg a magnaflow hi flo increase HP or do i need some backpressure considering i have no resonator abd a straight thru muffler (borla pro xs)

 

[KeenKilo]

If the drone of the exhaust uphill is an annoying frequency I say giver er gas until it shifts up a gear. Prolly have to pick up the pace a little but may save the headache

 

[RickOTR]

You need the backpressure or else you'll have problems with power. I have the Magnaflows on my with no problems

 

[DP96XLT]

In regards to your drone, I have the OHV version of the engine, but I ended up going three different routes to get rid of drone and annoyances...

1) Gibson full stainless exhaust - Sounded like a UPS truck... Drone, hollow, just all around suckage to my ears
2) Gibson stainless pipes, Borla 40665 Turbo XL Center/Offset Universal Performance Muffler... Pretty close to the Borla Pro XS as they are both straight through... No UPS truck sound, but I couldn't handle the drone... crisper, tighter, all around "Borla" sound, but still too much drone, especially on the highway
3) Gibson stainless pipes, Vibrant 1141 2.5" Ultra Quiet Resonator + Vibrant 1106 Oval Stainless Steel Muffler... Resonator connected close to the cat, then into the muffler with a stainless band clamp... Best sound overall, no drone at all, exhaust noise in the truck is so minimal you can talk comfortably. After about 4-6k miles it is totally broken in and you can barely notice at highway speeds and you can talk in whispers. Basically I can hear the K&N intake and the tires more than I hear the exhaust after it is broken in. Nice part is when you are getting on it, there is a nice authoritative rumble from it. Both the resonator and muffler are straight-through designs, so no backpressure

If you want I can grab some pics of the setup in the next couple of days (we have rain forecast for tomorrow) and I can probably grab a couple of video clips so you can hear what it sounds like inside the truck at highway speeds as well as what it sounds like accelerating.

Personally, if I could do it over again, I would have tried to find a Borla resonator to match the shorter version of the Borla muffler I bought. That would have fit the way the Vibrant setup did, but would have had all Borla components. I am something of a Borla *****, as I have those systems on both my F-Bodies as well as having had their setup on a number of other cars I no longer own. My favorite for a "loud" car was a SLP Loudmouth exhaust with a round Borla Pro in place of the SLP resonator... Nothing else in the 3" piping... That was in a 1994 Trans-Am with a 355 engine, big cam that spun to the moon, 4200 stall converter and it sounded like a car with a CVT transmission at part throttle as it revved up and hung there with a 400-500 rpm difference between shifts. When you mashed the gas that damn thing screamed to 7000rpm before shifting and sent blue flames out the tailpipes for over 3 feet (no cats, straight through and it was as rich as was needed to produce excellent power). It was also SOOOO loud when you got on it, think full-on NASCAR... Kicker was there was no drone, it idled great, at part throttle it sounded fantastic. Too bad I had to sell that car, as I would probably still have it today if I didn't "have" to sell it at the time.

 

[donalds]

Yea I had to

I say why not

 

[DP96XLT]

You need the backpressure or else you'll have problems with power. I have the Magnaflows on my with no problems

Actually, backpressure is NEVER a good thing. In certain instances a "tuned" system that makes use of exhaust gas pulses to evacuate and scavenge (ie, create vacuum in the exhaust runner) the cylinder beyond the end of the exhaust stroke (ie, just as the intake opens and pulls fresh air into the cylinder before the piston gets a chance to create vacuum) is beneficial, but to make full use of that you need a finely tuned system (ie, all primaries need to be a calculated length, the collectors need to be calculated and you cannot have ANY backpressure in the rest of the exhaust and that all has to be matched to a properly designed intake system (runner length, plenum and throttlebody/air piping/filter) to provide air charge to afford for any such gains.

That all goes back to designed engine systems. Long-runners for mid-range torque, short runners for high-rpm is the simplest "summation" of those designs with everything else in-between. There are even sliding intake runner plenums in some systems (or systems that open up and collapse chambers in the intakes) to afford for such tuning.

In all cases, backpressure is a misnomer. It is discussed and comes about when people end up messing up a "tuned system" by hacking into place aftermarket headers, exhuast, intakes, etc... So the "idea" that backpressure is needed to increase torque is floated around as a "band-aide" to fix things when people screw things up.

If you end up doing the math and validate things, you will find in ALL cases a properly tuned system can get the gains you want. When you start messing with "tuned systems" (such as changing intake systems and exhausts) the end-result is basically that you are ALWAYS better off going as big as possible to make sure you don't have any "backpressure" in the exhaust or "vacuum" in the intake.

Now, that being said, if the system you are messing with is so finely tuned (ie, cam design, intake design, exhaust design, even torque converter stall speed, gear ratios, etc, etc) are all set to maximize a given combination, then in those cases ANY sort of modification to those systems ends up in changing and damaging the finely tuned balance that was so hard-fought to achieve with such systems. In those cases you are ALWAYS better off leaving it all alone and using it as designed. And, as a side-note, there are quite a few examples of a lot of vehicles that are built with a ton of engineering for just those types of systems. From trucks and heavy-duty vehicles to (more commonly) high-performance sports cars and even hybrids and "ultra-efficient" vehicles. Very little in the modern age is just "thrown together" with an idea of "lets reuse and make it work".

That kind of "reuse and make it work" type of thinking went out in the early 90s, as just about everything from then on is setup with purposeful design. Sure you get the "cookie cutter" uber-cheap vehicles that are still thrown together, but they don't produce much power anyways.

 

[Exp98]

In regards to your drone, I have the OHV version of the engine, but I ended up going three different routes to get rid of drone and annoyances...

1) Gibson full stainless exhaust - Sounded like a UPS truck... Drone, hollow, just all around suckage to my ears
2) Gibson stainless pipes, Borla 40665 Turbo XL Center/Offset Universal Performance Muffler... Pretty close to the Borla Pro XS as they are both straight through... No UPS truck sound, but I couldn't handle the drone... crisper, tighter, all around "Borla" sound, but still too much drone, especially on the highway
3) Gibson stainless pipes, Vibrant 1141 2.5" Ultra Quiet Resonator + Vibrant 1106 Oval Stainless Steel Muffler... Resonator connected close to the cat, then into the muffler with a stainless band clamp... Best sound overall, no drone at all, exhaust noise in the truck is so minimal you can talk comfortably. After about 4-6k miles it is totally broken in and you can barely notice at highway speeds and you can talk in whispers. Basically I can hear the K&N intake and the tires more than I hear the exhaust after it is broken in. Nice part is when you are getting on it, there is a nice authoritative rumble from it. Both the resonator and muffler are straight-through designs, so no backpressure

If you want I can grab some pics of the setup in the next couple of days (we have rain forecast for tomorrow) and I can probably grab a couple of video clips so you can hear what it sounds like inside the truck at highway speeds as well as what it sounds like accelerating.

Personally, if I could do it over again, I would have tried to find a Borla resonator to match the shorter version of the Borla muffler I bought. That would have fit the way the Vibrant setup did, but would have had all Borla components. I am something of a Borla *****, as I have those systems on both my F-Bodies as well as having had their setup on a number of other cars I no longer own. My favorite for a "loud" car was a SLP Loudmouth exhaust with a round Borla Pro in place of the SLP resonator... Nothing else in the 3" piping... That was in a 1994 Trans-Am with a 355 engine, big cam that spun to the moon, 4200 stall converter and it sounded like a car with a CVT transmission at part throttle as it revved up and hung there with a 400-500 rpm difference between shifts. When you mashed the gas that damn thing screamed to 7000rpm before shifting and sent blue flames out the tailpipes for over 3 feet (no cats, straight through and it was as rich as was needed to produce excellent power). It was also SOOOO loud when you got on it, think full-on NASCAR... Kicker was there was no drone, it idled great, at part throttle it sounded fantastic. Too bad I had to sell that car, as I would probably still have it today if I didn't "have" to sell it at the time.

If you could getsome exhaust clips that would be amazing!! Also @donalds ive been eyeing the boom tubes for a while, do they do anything in terms of sound? thanks.