Sorry I did not read the entire thing. That's what I get for scanning stuff.
[ December 07, 2003, 02:34 AM: Message edited by: KW ]
GM ENGINES KNOCK
- Thread starter Terry
- Start date
- Status
[ December 07, 2003, 02:34 AM: Message edited by: KW ]
(Nothing serious about this comment):
Ahhh, just go back to a 383 Chrysler: Forged crank and 6.1" forged rods with -- although heavy -- well-made cast pistons in a 4.25 bore/3.38 stroke motor for a 1.88 ratio. Deep skirted, extra-strong blocks, etc, etc. Runs forever.
(An easy flywheel 325 HP/425 TQ engine what with todays gizmos. The big block that revv'd like a small block).
Too bad it was larger and heavier (in some respects) than a 454 Chevy (though to be fair, a good bit smaller than a 440 Chrysler).
Used to be that the foreigners had it over us for the elegance of design, et. al., but couldn't begin to match American cars for good old durability and reliability.
I miss it.
(And no surpise that I'm looking around for another 2WD 2001 Cherokee to complement the one we already have: plenty of off-idle torque and a wide power band in a 242 cid straight six (225 TQ @ 3000/195 HP @ 4600]; very good Aisin-Warner transmission [similar to a TH-700]. Front-engine, rear-wheel drive, high ground clearance, solid axles, excellent mileage, long-wearing, millions-made [and still in prodiction overseas]: The Model A all over again. Adaptable to many missions).
Hearing about production engine design that belongs on a race-only vehicle (those pistons/rings, ukgaaah), what a disappointment.
It's all dependent on the electronic control devices acting perfectly to never exceed preset parameters (yeah, right).
Ahhh, just go back to a 383 Chrysler: Forged crank and 6.1" forged rods with -- although heavy -- well-made cast pistons in a 4.25 bore/3.38 stroke motor for a 1.88 ratio. Deep skirted, extra-strong blocks, etc, etc. Runs forever.
(An easy flywheel 325 HP/425 TQ engine what with todays gizmos. The big block that revv'd like a small block).
Too bad it was larger and heavier (in some respects) than a 454 Chevy (though to be fair, a good bit smaller than a 440 Chrysler).
Used to be that the foreigners had it over us for the elegance of design, et. al., but couldn't begin to match American cars for good old durability and reliability.
I miss it.
(And no surpise that I'm looking around for another 2WD 2001 Cherokee to complement the one we already have: plenty of off-idle torque and a wide power band in a 242 cid straight six (225 TQ @ 3000/195 HP @ 4600]; very good Aisin-Warner transmission [similar to a TH-700]. Front-engine, rear-wheel drive, high ground clearance, solid axles, excellent mileage, long-wearing, millions-made [and still in prodiction overseas]: The Model A all over again. Adaptable to many missions).
Hearing about production engine design that belongs on a race-only vehicle (those pistons/rings, ukgaaah), what a disappointment.
It's all dependent on the electronic control devices acting perfectly to never exceed preset parameters (yeah, right).
All the talk of piston skirts, rings with low tension, etc appears to be true. Another contributor appears to be carbon buildup which may be related to the fast quench of aluminum heads. Sometimes the "knock" goes away at least temporarily when the GM carbon soad is used. The easy tipping of the pistons allows them to tilt and the skirt raps the wall when the rings or whatever hits the carbon buildup upon cold startup.
Terry,
I'm glad you are taking a stab at this problem. As you know, you should be receiving my report within a couple of days and you are more than welcome to post it here so we can all discuss this problem.
For those who don't know, my daily driver is a 02 Z28 with the LS1 engine. This engine seems to suffer from the piston slap and lifter noises. Upon starting the vehicle in the morning, there is no abnormal sound for the first 30 seconds or so as long as the engine is idling. If I drive away within 2-3 minutes after startup, the engine makes a slapping sound. This sound however lasts for only a few seconds or about half a block. Immediately after this sound goes away, the lifter sound shows up. This sound can be best described as lifter clatter while driving and an engine very low on oil while at idle. It is loud and obnoxious, especially at idle. I've been told by a couple of guys who don't know to check the oil because it's low. I always say "oh, ok!" instead of just saying "it's normal", just to avoid embarrasement. Oil brand does not seem to affect/diminish the sound at all.
Anyway, I'm hoping Terry with the help of others can figure what the noises are and what to do about them.
Rick
EDIT: One thing I forgot....I DO NOT have oil consumption issues. I just drove 4047 miles on my last OCI and there was a very small amout of oil cunsumed....maybe 5-6 ounces.
[ December 07, 2003, 08:04 PM: Message edited by: Last_Z ]
KW the pistons are not forged steel. I did not The material is aluminum but they are forged not cast. I wrongfuly assumed that ALuminum for the piston material was a given in a modern petrol engine. I do not know what alloy is used for them though as their are many different alloys of aluminum.
[ December 07, 2003, 08:50 PM: Message edited by: JohnBrowning ]
[ December 07, 2003, 08:50 PM: Message edited by: JohnBrowning ]
Ok. Like I said I scanned the post, posted then read it. Oops.
JohnBrowning you are thinking like I am that the unbalanced condition is causing alot of the problems, varying rates of heat dissipation is another issue also contributing.
I just finished a 'read' of a LS1 rebuild @12,000 miles ( under warranty for the knock) and the cu is stable and much less than half the original testing we saw. The customer is a member here and hopefully will share the raw data for all to see like Z is. He does use FP and LC and I think that is zeroing out the piston deposit build-up issue which should help keep things smooth and quiet.
Terry
I just finished a 'read' of a LS1 rebuild @12,000 miles ( under warranty for the knock) and the cu is stable and much less than half the original testing we saw. The customer is a member here and hopefully will share the raw data for all to see like Z is. He does use FP and LC and I think that is zeroing out the piston deposit build-up issue which should help keep things smooth and quiet.
Terry
Everyone,
I am not knocking either fp or lc, I use neutra myself, but it seems the basic design of the engines is deficient if the only way one can get it to run right is to load it up with additives. Add on top of that part of the price one pays for a corvette is the quailty of the engine. By default a corvette is a performance car and should be built to take a beating. If not its not worth the entry price.
Dan
Dan, agreed, it is a shame that the "US" makers can't execute any better on their designs.
To be fair the Toyotas and VWs are slowly taking over production and I think that will be a shame.
Once we sell our productive souls to the mainland Chinese we'll regret it and its happening as we write here.
The FEW, power brokers/greedy are killing the backbone of the US production machine for pennies on the dollar. You and I,the worker bees are helping fund the demise by self funding our IRA"S/401ks and not voting.
Ask a worker at the Toyota truck plant how he likes his medical plan compared to a GM worker in Lansing. Both make about the same but the retirement and medical are light years apart.
Sorry for the diatribe.....
[ December 08, 2003, 02:53 PM: Message edited by: Terry ]
To be fair the Toyotas and VWs are slowly taking over production and I think that will be a shame.
Once we sell our productive souls to the mainland Chinese we'll regret it and its happening as we write here.
The FEW, power brokers/greedy are killing the backbone of the US production machine for pennies on the dollar. You and I,the worker bees are helping fund the demise by self funding our IRA"S/401ks and not voting.
Ask a worker at the Toyota truck plant how he likes his medical plan compared to a GM worker in Lansing. Both make about the same but the retirement and medical are light years apart.
Sorry for the diatribe.....
[ December 08, 2003, 02:53 PM: Message edited by: Terry ]
Patman
Staff member
The 98 Formula I owned, which had the LS1 engine, needed no additives in the oil or the fuel in order to get it to run right. I had no consumption issues or piston slap with that engine. It ran very strongly in the quarter mile (12.68 at 110.6mph with just basic mods, nothing done to the engine internally either) so there was no evidence of any carbon buildup in it either.
I hope I have similar luck when I purchase a 97 Corvette in a few years.
So don't go thinking all of these engines are bad.
But the GM plans are probably unsustainable. GM has more retirees than active workers, as do many other older companies in the U.S., and the cost of their pay-as-you-go medical plans is nearly at the breaking point. (Pension plans are supposed to be funded in advance of retirement...not so for medical plans.) I certainly don't have an answer, and I'm also in the situation of being a retiree from an industry with more retirees than workers--and I'm paying more for my medical co-pay every year. I've seen the actual numbers in my case, I don't like paying more, but I know that it's necessary and the best option at the present.
Ken
[ December 08, 2003, 03:38 PM: Message edited by: Ken2 ]
That is my LS1 and I justed posted the UOA. I have not used LC in my LS1 in this 1st 12,000 miles befor the rebuild but I did use FP to keep injectors clean. It ran good burned a little oil and the combustion efffiency was great as the insolubes were 0.2 but knocked bad. Now that the rebuild break-in is done I'm using LC to see how it will help. Next UOA will tell!
He specifically referenced running light throttle in a lower than normal gear - being able to blip the throttle to zip along.
Cruising around town, light throttle, lower than top gear was the scenerio of the high oil consumption mode.
Other drivers had no abnormal consumption. It sounded like GM had done their homework on investigating the root cause of the oil consumption problem.
Don't apologize for just stating the facts Terry!
I find it a disturbing long term trend in many industries.
Interestingly, the Japanese are facing the same situation with Korean labor/outsourcing!
You are right to mention the Chinese. Such a massive population available to supply cheap labor depending on the political winds.
[ December 08, 2003, 08:29 PM: Message edited by: Mark in NY ]
I think dragboat and Thetansedan hit the nail on the head.
The GM engine design team likely wanted another 1/2 inch of deck height on the engine block, over-ruled by the low-hood-line designers.
Wasn't it Olds who laid down their V8 BBO 425 bank angle from 45* to 39* to fit under the 68 Toranado hood?
Its nice to see GM finally catching up to Mopar in the rod length department to lower the frictional losses, but someone forgot to tell them they needed a taller deck as well to accomodate a normal street service piston.
The GM engine design team likely wanted another 1/2 inch of deck height on the engine block, over-ruled by the low-hood-line designers.
Wasn't it Olds who laid down their V8 BBO 425 bank angle from 45* to 39* to fit under the 68 Toranado hood?
Its nice to see GM finally catching up to Mopar in the rod length department to lower the frictional losses, but someone forgot to tell them they needed a taller deck as well to accomodate a normal street service piston.
The R\S ratio of the LS-1 isn't that much better than a traditional 350 SBC. The reduced sideloading, may reduce frictional losses (slightly), but what about the additional weight added to the reciprocating assembly?
As much as I do not get along with most engineers I have always thought that they should be given the final say. The designers, accountants and marketing departments should play second fiddle! I think GM has been had big marketing at the wheel for too long!
I wounder if an external hamonic ballancer like the "Rattler" would work on this engine. I have seen harmonics at 12,000 RPM's tear a bearing to shreads through non-contact. The bearing materials resonante freg. was hit and the bearing started to come apart.
[ December 08, 2003, 09:05 PM: Message edited by: JohnBrowning ]
I wounder if an external hamonic ballancer like the "Rattler" would work on this engine. I have seen harmonics at 12,000 RPM's tear a bearing to shreads through non-contact. The bearing materials resonante freg. was hit and the bearing started to come apart.
[ December 08, 2003, 09:05 PM: Message edited by: JohnBrowning ]
Guys,
The LS1 engine DOES have a harmonic dampner, just like the old SBCs.....the dampner serves also as a pulley though. The problem might be that the dampner isn't heavy enough?
Rick
Terry,
Can't wait for you to read my report....my nails are all gone!
The LS1 engine DOES have a harmonic dampner, just like the old SBCs.....the dampner serves also as a pulley though. The problem might be that the dampner isn't heavy enough?
Rick
Terry,
Can't wait for you to read my report....my nails are all gone!
There's another thing that plagues almost all the US V8 engines. The companies like to use a similar or even identical engine in trucks. This means square or oversquare designs are not nearly as desirable since they tend to lack low end torque, all other things being equal.
There are many examples of this. You'll see many more Ford 460's or Chevy 427's in trucks than in cars. The best flowing small block Ford heads for years were the truck heads that didn't show up on the cars until '87. Even now the GT-40 SBF manifold from Ford Motorsport is pretty much what was put on 5.0L Explorers stock.
I still think if the engineers were left alone to make high performance car engine they could do it right. Hot rodders and aftermarket engine builders have been doing it for years...
As to oversquare motors lacking torque -- and while I understand the premise -- have a look at some of the postings on the RV boards where you'll come across owners of 454 Chevs/460 Fords/440 Chryslers fairly comparing drivetrains versus weight (for relatively similar use) in 14-16k pound motorhomes.
Ironically, a recent car mag build-up (featuring "name" engine builders) had the Chrysler in second or third place for torque, and first or second in horsepower; overall superior to the rest.
The proof is in the pudding: Which engine still has excellent compression past 100K? I think you'll see that the oversquare Chrysler more than holds its own, it generally is still a step ahead if detonation/overheating hasn't been an issue (to which IT IS very sensitive, by such a large piston surface area). What it has is a far superior bore/stroke ratio and rod ratio that keeps wear and tear to a minimum, so to speak (among other virtues numerous).
End of regular production in 1978 means most guys have no real memories of this superior engine (the majority of Americans today were born during or after 1967). The stock of industrial engines (440-3) would have ended, I'm guessing, by the middle 1980s. The comparisons I mention are often found from the earlier years of the Internet; and one has to recall that GM and Ford kept their big-blocks in production right into the 1990s (and incremental changes -- especially TBI -- made big differences). Look for numbers from the late 1970's/early 1980's.
The torque "problem" is overcome -- significantly, IMO -- by the excellent seal and reduced wear of a Chrysler V8, the most "oversquare" of the Big Three motors.
The alternative is by what example? Super long rod motors --like a straight six or straight eight that won't rev? Not to be argumentative, per se, it just seems to me that a decent compromise was struck for weight/size/packaging in the big 90-degree V8's versus a straight motor OR an undersquare engine of another design. What would be an alternative?
I'm a fan of straight sixes (am currently stuck with a Ford I-6 200 -- seven main bearings is nice, as is the 160 TQ @ 1600 rpm [witha rippin' 85 HP at 3600] -- but I'da much rather had Slant-6. Even the Bimmer guys admit to it's superiority). But they're long and heavy. A 302 Ford doesn't weigh all that much more. And the great Packard Straight 8's were mightily heavy.
(Sorry to beat the Mopar drum so often, even Dan4510 and other moparists must be tired of it).
[ December 09, 2003, 04:20 AM: Message edited by: TheTanSedan ]
Ironically, a recent car mag build-up (featuring "name" engine builders) had the Chrysler in second or third place for torque, and first or second in horsepower; overall superior to the rest.
The proof is in the pudding: Which engine still has excellent compression past 100K? I think you'll see that the oversquare Chrysler more than holds its own, it generally is still a step ahead if detonation/overheating hasn't been an issue (to which IT IS very sensitive, by such a large piston surface area). What it has is a far superior bore/stroke ratio and rod ratio that keeps wear and tear to a minimum, so to speak (among other virtues numerous).
End of regular production in 1978 means most guys have no real memories of this superior engine (the majority of Americans today were born during or after 1967). The stock of industrial engines (440-3) would have ended, I'm guessing, by the middle 1980s. The comparisons I mention are often found from the earlier years of the Internet; and one has to recall that GM and Ford kept their big-blocks in production right into the 1990s (and incremental changes -- especially TBI -- made big differences). Look for numbers from the late 1970's/early 1980's.
The torque "problem" is overcome -- significantly, IMO -- by the excellent seal and reduced wear of a Chrysler V8, the most "oversquare" of the Big Three motors.
The alternative is by what example? Super long rod motors --like a straight six or straight eight that won't rev? Not to be argumentative, per se, it just seems to me that a decent compromise was struck for weight/size/packaging in the big 90-degree V8's versus a straight motor OR an undersquare engine of another design. What would be an alternative?
I'm a fan of straight sixes (am currently stuck with a Ford I-6 200 -- seven main bearings is nice, as is the 160 TQ @ 1600 rpm [witha rippin' 85 HP at 3600] -- but I'da much rather had Slant-6. Even the Bimmer guys admit to it's superiority). But they're long and heavy. A 302 Ford doesn't weigh all that much more. And the great Packard Straight 8's were mightily heavy.
(Sorry to beat the Mopar drum so often, even Dan4510 and other moparists must be tired of it).
[ December 09, 2003, 04:20 AM: Message edited by: TheTanSedan ]
- Status
Similar threads
- Locked