very random question...
- Thread starter mjdub312
- Start date
The Rev
Dedicated LVC Member
Because people are idiots, lol. When people are selling (or bragging) about the mark its like mentioning the cobra thing means its a faster or meaner car. The cobras had a modified intake though. I wish they'd say "my cobra has a lincoln engine" but cobras are more popular so yeah
As far as im aware the engines are very different.
I won't vouch for its accuracy, but i found this 'snippet' of info on a reputable forum: (click the relevant title)
http://www.tccoa.com/articles/overall/index.html#
Probably plenty of other differences too.
I won't vouch for its accuracy, but i found this 'snippet' of info on a reputable forum: (click the relevant title)
http://www.tccoa.com/articles/overall/index.html#
Probably plenty of other differences too.
Tiltedhalo
Well-Known LVC Member
Corbra vs Mark VIII
I have had about 12 Mark VIII engines apart, and about 4 Cobras. All years aluminum blocks techsid and alike are identical, and interchangeable. The heads are identical right to the part numbers, intake cams have more duration on the intake side, exhaust are the same. Rods are fracture spilt on late 96-98's. The stock Mark VIII has a nodular cast crank, but I have seen two Gen 2 engines with forged units? with proper Mark VIII part numbers. I have also seen full floating pins on Gen 2 engines and pressed. Intake on the Cobra is designed for higher RPM power band, a result of the intake cam duration change. That is also the resulting 10+ HP.
I believe just like the early days of ford they use what they have for parts. Most Gen 2 engines closer resemble the Cobras, and next time somebody says Cobra motor for you Mark tell them don't you mean you Cobra has a Mark motor it was the original Lincoln design.
I have had about 12 Mark VIII engines apart, and about 4 Cobras. All years aluminum blocks techsid and alike are identical, and interchangeable. The heads are identical right to the part numbers, intake cams have more duration on the intake side, exhaust are the same. Rods are fracture spilt on late 96-98's. The stock Mark VIII has a nodular cast crank, but I have seen two Gen 2 engines with forged units? with proper Mark VIII part numbers. I have also seen full floating pins on Gen 2 engines and pressed. Intake on the Cobra is designed for higher RPM power band, a result of the intake cam duration change. That is also the resulting 10+ HP.
I believe just like the early days of ford they use what they have for parts. Most Gen 2 engines closer resemble the Cobras, and next time somebody says Cobra motor for you Mark tell them don't you mean you Cobra has a Mark motor it was the original Lincoln design.
Interesting stuff. So not all Mark VIIIs had 'cracked cap' rods?
Cobra had an 8 bolt fly wheel vs 6 bolt on Mark VIII too right?
I guess another difference would be that the SVT engines were hand assembled by 2 man teams as opposed to the Mark engine which was assembled on a normal line. Correct?
What about the IMRC controllers? I read somewhere that they work opposite way too.
Cobra had an 8 bolt fly wheel vs 6 bolt on Mark VIII too right?
I guess another difference would be that the SVT engines were hand assembled by 2 man teams as opposed to the Mark engine which was assembled on a normal line. Correct?
What about the IMRC controllers? I read somewhere that they work opposite way too.
Tiltedhalo
Well-Known LVC Member
Cobra vs Mark VIII
Yes the Mark is 6 bolt and the Cobra is 8, but one Cobra I saw backed with a special ordered auto had a 6? go figure. Ford would like all you buyers to believe all Cobras are hand assembled, think about the sale figures for Cobras, SVT's and the like over the past few years more of them made then 97 and 98 Marks.
The Gen 1 IMRC's are vacuum actuated and the default position is closed, as throttle increases vacuum decreases and the IMRC's open. Gen 2 and Cobras are all computer controlled and there default is closed.
Oh yeah and Gen 1 connecting rods are forged and caps cut to the best of my knowledge.
Yes the Mark is 6 bolt and the Cobra is 8, but one Cobra I saw backed with a special ordered auto had a 6? go figure. Ford would like all you buyers to believe all Cobras are hand assembled, think about the sale figures for Cobras, SVT's and the like over the past few years more of them made then 97 and 98 Marks.
The Gen 1 IMRC's are vacuum actuated and the default position is closed, as throttle increases vacuum decreases and the IMRC's open. Gen 2 and Cobras are all computer controlled and there default is closed.
Oh yeah and Gen 1 connecting rods are forged and caps cut to the best of my knowledge.
Good info!
Just another IMRC question if you don't mind.
On a gen 1 Mark (like mine) vacuum pushes against spring pressure and holds the butterflies closed, so when my car is off, they should be open, right?
Where as on a 96-98 cobra spring pressure holds the butterflies closed and a computer controlled solenoid pushes them open.
Thats what i meant by opposites. (springs holding closed vs springs holding open)
Am i right? or should i stop the Kool Aid? Lol.
Just another IMRC question if you don't mind.
On a gen 1 Mark (like mine) vacuum pushes against spring pressure and holds the butterflies closed, so when my car is off, they should be open, right?
Where as on a 96-98 cobra spring pressure holds the butterflies closed and a computer controlled solenoid pushes them open.
Thats what i meant by opposites. (springs holding closed vs springs holding open)
Am i right? or should i stop the Kool Aid? Lol.
Tiltedhalo
Well-Known LVC Member
IMRC's
YES, so go ahead and have some more KOOL AID.
YES, so go ahead and have some more KOOL AID.
unity
Dedicated LVC Member
Good info!
Just another IMRC question if you don't mind.
On a gen 1 Mark (like mine) vacuum pushes against spring pressure and holds the butterflies closed, so when my car is off, they should be open, right?
Where as on a 96-98 cobra spring pressure holds the butterflies closed and a computer controlled solenoid pushes them open.
Thats what i meant by opposites. (springs holding closed vs springs holding open)
Am i right? or should i stop the Kool Aid? Lol.
Nothing puts pressure on the IMRC plates. The actuators by default are open. When the engine starts a vacuum pull on the actuators pulls them closed since the IMRC solenoid is in the open position. Above 3k RPM the solenoid closes and the accumulators loose vacuum to outside air.
Since the cable driven system is not dependent on vacuum, they can indeed stay closed with engine off.
Tiltedhalo
Well-Known LVC Member
Hydro lock
Unity, what caused enough hydro lock to damage your engine???
PS thats a pretty big gulp of water.
Unity, what caused enough hydro lock to damage your engine???
PS thats a pretty big gulp of water.
Im confused! Lol. Are you saying that on a gen 1 there are no springs holding them open? I thought that vacuum holds them closed and if an actuator fails, the butterfly opens up due to spring pressure?
Edit: ah.. are you just refering to the cobra ones? That makes sense. So they are solenoid (or motor?) controlled in both directions as opposed to mine which are vacuum and spring?
unity
Dedicated LVC Member
On a Gen 1 the actuators themselves have springs in them with a vacuum diaphragm. At low RPM vacuum compresses the diaphragms and closes the plates. Above 3k RPM a solenoid controlled by the ECU (or something) closes the vacuum while opening to outside air. The diaphragms "inflate" and the open. While its true cars have less vacuum pull at higher RPM its not directly related to the action of the IMRCs.
On Cobra and Gen II marks they are controlled via an electronic box mounted in the valley with cables.
unity
Dedicated LVC Member
Yup, a VERY big "puddle" right on the other side of the block I lived on. Big storm had passed and the water was perfectly placid so I did not see it.
Insurance covered it and this is also why I have an 04 engine now
Upgrade!Thanks for the explanation! Will probably have the whole intake assembly out once i have a garage for 'freshening up' - those IMRC plates get filthy! Heck, might just look for the later style plastic runners with the larger ports!
Glad i removed my air intake silencer when i did, as its raised level probably saved me when we had floods in NJ last April!
Glad i removed my air intake silencer when i did, as its raised level probably saved me when we had floods in NJ last April!
Psychostang
Dedicated LVC Member
Just a note, you cannot use the cobra or Gen II IMRC plates on a Gen I, unless you change the upper intake plenum. They are physically different
unity
Dedicated LVC Member
Um... not really
Mine was out too! Now I have a Cobra conical setup, think I am pretty safe now.Dang it! I guess i won't be doing that then! Lol.