Omega Owners Forum

Chat Area => General Car Chat => Topic started by: Ian_D on 07 September 2011, 22:57:59

Title: Whats the weakest part...
Post by: Ian_D on 07 September 2011, 22:57:59
I've always wondered this...

What’s the weakest part in the V6 engines? Mainly the X30XE lumps.

If it were pushed all day long, what would go 'bang' first (Standard Engine)

And the same again (Engine with Standard internals, but the power increased somehow, ie turboed / supercharged / nos or something like)

Any opinions? Or better still experiences?
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 07 September 2011, 23:41:38
I find the cooling system inadequate under those conditions

mountain roads (obviously uphill)
temperature above 30 celcius
revs above 5000 rpm in 2nd, 3rd gear

within 5,6 minutes temp gauge reaches the limit :(

ps:newly built engine with new thermostat and sensors..
Title: Re: Whats the weakest part...
Post by: Andy B on 07 September 2011, 23:46:34
Quote
....
temperature above 30 celcius....

That's not usually a problem in the UK  ;) ;) ;)
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 07 September 2011, 23:53:19
Quote
Quote
....
temperature above 30 celcius....

That's not usually a problem in the UK  ;) ;) ;)

Andy, although engine  is built in Ellismere port, this car is under use nearly on all continents  .. so UK market alone is not decisive..
Title: Re: Whats the weakest part...
Post by: Andy B on 07 September 2011, 23:58:14
Quote
Quote
Quote
....
temperature above 30 celcius....

That's not usually a problem in the UK  ;) ;) ;)

Andy, although engine  is built in Ellesmere port, this car is under use nearly on all continents  .. so UK market alone is not decisive..

 :y :y :y  ;)
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 08 September 2011, 00:03:58
Quote
Quote
Quote
Quote
....
temperature above 30 celcius....

That's not usually a problem in the UK  ;) ;) ;)

Andy, although engine  is built in Ellesmere port, this car is under use nearly on all continents  .. so UK market alone is not decisive..

 :y :y :y  ;)

 :y :y :y
Title: Re: Whats the weakest part...
Post by: Ian_D on 08 September 2011, 00:13:30
Quote
I find the cooling system inadequate under those conditions

mountain roads (obviously uphill)
temperature above 30 celcius
revs above 5000 rpm in 2nd, 3rd gear

within 5,6 minutes temp gauge reaches the limit :(

ps:newly built engine with new thermostat and sensors..

Yikes!  :o Thought they may last a bit longer than that!

Was any damage done with the temp going so high? Or did you catch it in time?
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 08 September 2011, 00:26:23
Quote
Quote
I find the cooling system inadequate under those conditions

mountain roads (obviously uphill)
temperature above 30 celcius
revs above 5000 rpm in 2nd, 3rd gear

within 5,6 minutes temp gauge reaches the limit :(

ps:newly built engine with new thermostat and sensors..

Yikes!  :o Thought they may last a bit longer than that!

Was any damage done with the temp going so high? Or did you catch it in time?

as I live this problem every summer I follow the temp gauge closely , and when it hits the limit I dropped the revs.. this was done as a test for the newly built engine.. not my everyday style.. but must admit the first time I was really panicked..

the other 4 pot go-cart dont have this problem.. tested at the same route fully loaded and hammered .. but no , doesnt do it and makes me angry when I see the temp gauge even dont move :o
but they say k4m is a race developed engine .. :-/
Title: Re: Whats the weakest part...
Post by: albitz on 08 September 2011, 06:22:19
V6 cooling system is known to be marginal.The weakest area mechanically ? not sure, what would break first under duress ?
Ive a feeling it might be the crank, but Im not sure why tbh. :-/
Title: Re: Whats the weakest part...
Post by: Marks DTM Calib on 08 September 2011, 08:10:37
Cant see the bottom nend going what witha the use of a girdle to striffen the mains etc.

The 3.2 even has a forger crank so even stronger.

I suspect the rods may suffer first on tuning.

I also suspect the engine cooling is fine in normal tune under all conditions, I do have concerns about airflow over the rad particularly with a dirty great bit clogged up aircon condenser in front of it (which if the aircon is on will pre heat the cooling air). The presence of the small plastic under tray also helps cool things down a bit to.

Up the go and the head cooling can be an issue (but can also be addressed)
Title: Re: Whats the weakest part...
Post by: 2woody on 08 September 2011, 09:26:12
just about every engine I've got has some signs of early big-end trouble, so crankshaft problems I'd say.

there are two main causes - Omega has a relatively high mass coolant temperature ( emissions performance ) and most have at least a couple of broken "O"-rings stuck in the oil pick-up/strainer.

I'd say the basic design is very good, and should the coolant mass temp be lowered, then will perform well at significantly higher power levels.
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 08 September 2011, 11:13:40
Quote
Cant see the bottom nend going what witha the use of a girdle to striffen the mains etc.

The 3.2 even has a forger crank so even stronger.

I suspect the rods may suffer first on tuning.

I also suspect the engine cooling is fine in normal tune under all conditions, I do have concerns about airflow over the rad particularly with a dirty great bit clogged up aircon condenser in front of it (which if the aircon is on will pre heat the cooling air). The presence of the small plastic under tray also helps cool things down a bit to.

Up the go and the head cooling can be an issue (but can also be addressed)

yep.. as proven..

first time my engine overheated mechanics advice to pressure wash radiators.. now which I do every year in spring.. also cleaned the radiator (only) inside with chemicals to dissolve lime particles.. and it was unbelievable to watch the "pieces" the radiator spitted :o ;D
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 08 September 2011, 11:16:43
Quote
just about every engine I've got has some signs of early big-end trouble, so crankshaft problems I'd say.

there are two main causes - Omega has a relatively high mass coolant temperature ( emissions performance ) and most have at least a couple of broken "O"-rings stuck in the oil pick-up/strainer.

I'd say the basic design is very good, and should the coolant mass temp be lowered, then will perform well at significantly higher power levels.

agreed.. definitely coolant temp must be lowered.. but I doubt changing thermostat alone will be sufficient.. a faster turning water pump may well be effective.. also if there were enough space , I would install extra coolers for the engine block like a cpu ;D
Title: Re: Whats the weakest part...
Post by: TheBoy on 08 September 2011, 11:28:23
As a test, coming home from Lakes meet fully laden with roof box, we decided to do 'the struggle', a section of road traditionally known to stress cars.

No issues, despite it being a hot UK day. Gauge never went over about 97C (prefacelift). Probably about 176k on clock, original rad, and autobox cooler in main rad
Title: Re: Whats the weakest part...
Post by: TheBoy on 08 September 2011, 11:30:43
Both turbo'd ones I've seen had what sounded to me to be big end issues (deep knocking noise at idle)
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 08 September 2011, 11:44:06
Quote
As a test, coming home from Lakes meet fully laden with roof box, we decided to do 'the struggle', a section of road traditionally known to stress cars.

No issues, despite it being a hot UK day. Gauge never went over about 97C (prefacelift). Probably about 176k on clock, original rad, and autobox cooler in main rad

my estimation is that your route was not a mountain road uphill so the car can do higher speeds without cooling issues..
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 08 September 2011, 12:00:10
Quote
Quote
As a test, coming home from Lakes meet fully laden with roof box, we decided to do 'the struggle', a section of road traditionally known to stress cars.

No issues, despite it being a hot UK day. Gauge never went over about 97C (prefacelift). Probably about 176k on clock, original rad, and autobox cooler in main rad

my estimation is that your route was not a mountain road uphill so the car can do higher speeds without cooling issues..

now called some friends which also used the same route on those mountains.. his car is 2001 bmw 530i.. had the same heating problems when he hammered.. (he is a 35 years old bmw mechanic)

seems like those cold countries produce the cars for themselves only ;D :y
Title: Re: Whats the weakest part...
Post by: TheBoy on 08 September 2011, 12:17:45
Quote
Quote
As a test, coming home from Lakes meet fully laden with roof box, we decided to do 'the struggle', a section of road traditionally known to stress cars.

No issues, despite it being a hot UK day. Gauge never went over about 97C (prefacelift). Probably about 176k on clock, original rad, and autobox cooler in main rad

my estimation is that your route was not a mountain road uphill so the car can do higher speeds without cooling issues..
It's a UK mountain pass, only about 3 miles though. Max speed is probably 30mph, due to traffic
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 08 September 2011, 13:49:17
Quote
Quote
Quote
As a test, coming home from Lakes meet fully laden with roof box, we decided to do 'the struggle', a section of road traditionally known to stress cars.

No issues, despite it being a hot UK day. Gauge never went over about 97C (prefacelift). Probably about 176k on clock, original rad, and autobox cooler in main rad

my estimation is that your route was not a mountain road uphill so the car can do higher speeds without cooling issues..
It's a UK mountain pass, only about 3 miles though. Max speed is probably 30mph, due to traffic


hmmm.. 3 miles , approx. 4 and a half kilometers..  30 mph  approx 45 km/hr..  and traffic.. I dont think you have  chance for spirited driving for long enough :-/
Title: Re: Whats the weakest part...
Post by: feeutfo on 08 September 2011, 16:09:18
Have read on here forced induction is likely to kill the bottom end. Good for 260bhp ish? Tops?

Mv6 v8 was born of a supercharged v6 that failed. Blew the bottom end.

V6 does run hot. 70 degrees considered optimum generally afaik.
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 08 September 2011, 16:50:38
interestingly Bmw 540 v8 engines also have cooling issues .. and they try interesting ways to solve the problem.. and I'm sure someone can find similiar solutions..

http://forums.bimmerforums.com/forum/showthread.php?t=1636432
Title: Re: Whats the weakest part...
Post by: Kevin Wood on 08 September 2011, 17:23:23
Quote
interestingly Bmw 540 v8 engines also have cooling issues .. and they try interesting ways to solve the problem.. and I'm sure someone can find similiar solutions..

http://forums.bimmerforums.com/forum/showthread.php?t=1636432

Ahh, the old "drill some holes in the thermostat" "fix". (http://dl.dropbox.com/u/26795734/Smilies/smack.gif)
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 08 September 2011, 17:46:25
Quote
Quote
interestingly Bmw 540 v8 engines also have cooling issues .. and they try interesting ways to solve the problem.. and I'm sure someone can find similiar solutions..

http://forums.bimmerforums.com/forum/showthread.php?t=1636432

Ahh, the old "drill some holes in the thermostat" "fix". (http://dl.dropbox.com/u/26795734/Smilies/smack.gif)

dont know about it.. but obviously there must be ways to solve this cooling problem.. and seriously I dont think GM leave the omega v8 just for cooling issues.. imo if thats the case its really weird for such an old company to give up easily.. :-/
Title: Re: Whats the weakest part...
Post by: TheBoy on 08 September 2011, 19:23:39
Quote
Quote
Quote
Quote
As a test, coming home from Lakes meet fully laden with roof box, we decided to do 'the struggle', a section of road traditionally known to stress cars.

No issues, despite it being a hot UK day. Gauge never went over about 97C (prefacelift). Probably about 176k on clock, original rad, and autobox cooler in main rad

my estimation is that your route was not a mountain road uphill so the car can do higher speeds without cooling issues..
It's a UK mountain pass, only about 3 miles though. Max speed is probably 30mph, due to traffic


hmmm.. 3 miles , approx. 4 and a half kilometers..  30 mph  approx 45 km/hr..  and traffic.. I dont think you have  chance for spirited driving for long enough :-/
true, we don't have 'proper' mountains in UK ;D

I did keep leaving gaps, so I could play with rear end traction, much to Mrs TB's annoyance ;D
Title: Re: Whats the weakest part...
Post by: Ian_D on 09 September 2011, 00:35:42
Yes thought cooling would be an issue on the V6.

Remember last year when I towed the caravan to Billing the temp crept up on the hills, so I ended up slowing down to 50mph ish and putting the heater on full (windows wide open! ;D) AC off. Managed to keep the temp around 3/4 on the gauge (preface dash).

Thought this was a bit high, so tried flushing the radiator (made no difference). So put a new radiator on in the end. I also got the airline out and blasted all the crap out of the AC radiator (airlined it from behind).

This year, the same trip to Billing was better, 65mph up the hills. Caravan loaded, + 2 passengers this time + the car boot was full of the PA system + genny + 5 or 6 car batts! Temp was between 1/2 and 3/4 on the gauge. (Without heater on full blast, and most likely the AC on too).

What is a safe hot running temp for these engines? Are they fine towing uphill with the temp sat at 3/4?
Title: Re: Whats the weakest part...
Post by: TheBoy on 09 September 2011, 13:19:54
I wouldn't like to see it above 100C on the gauge (pre or FL)
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 09 September 2011, 13:55:24
Quote
I wouldn't like to see it above 100C on the gauge (pre or FL)

neither do I , in the middle of nowhere  ;D :-/
Title: Re: Whats the weakest part...
Post by: cem_devecioglu on 09 September 2011, 14:03:08
some question comes to mind.. why they immerse this oil cooler in an already boiling water.. and why not use some place near/behind radiator etc.. :(
Title: Re: Whats the weakest part...
Post by: TheBoy on 09 September 2011, 14:11:46
Quote
some question comes to mind.. why they immerse this oil cooler in an already boiling water.. and why not use some place near/behind radiator etc.. :(
kepps eveything at the 'correct' temp ;)

The oil helps heat the coolant during warm up, and coolant cools (without over cooling) the oil in normal use
Title: Re: Whats the weakest part...
Post by: Kevin Wood on 09 September 2011, 14:29:17
Quote
Quote
some question comes to mind.. why they immerse this oil cooler in an already boiling water.. and why not use some place near/behind radiator etc.. :(
kepps eveything at the 'correct' temp ;)

The oil helps heat the coolant during warm up, and coolant cools (without over cooling) the oil in normal use

Indeed. (Actually, coolant normally heats up quicker than the oil, but it's beneficial to help the oil get to normal temperature ASAP).

If an external oil cooler were used, there would need to be a thermostat to ensure the oil could not be over-cooled. There would also need to be rubber hoses carrying oil forward to the cooler, which would be vulnerable to damage, causing loss of oil pressure and a dead engine.

So, bar the occasional leak due to poor coolant maintenance, the internal oil cooler has far less potential to go wrong. :y