Engine swap for my '96 GT
03-02-2012, 11:05 AM
#11
My motors currently out and I decided to go through the top instead of risking damage to my aftermarket k frame, the hardest part is removing a long tube head in my case to drop the trans. I pulled my motor out through the top and didn't even have to take the hood off.
03-02-2012, 04:09 PM
#12
4th Gear Member
Join Date: May 2009
Location: DFW, TX
Posts: 1,925
Hey guys, you all seem to know what you are talking about, so don't take this the wrong way, because I am ignorant in the matter. Isn't a Lincoln Mark VIII cammed different, and de-tuned, compared to a Mustang motor? You know, less power? Or do you guys do something to remedy that? Like I said, I am a mental midget about this sort of thing, so please enlighten me, and be nice,lol!
Thanks for the replies. I found a '98 VIII engine not too far from here. It has less than 70k miles so I might go and pick it up tomorrow. A couple of more questions if I could. I do not have a shop to working on it will be restricted to nice days in the driveway. That said, which way would you recommend swapping the engine; out of the top or drop the k-member and out of the bottom? Also, when I go to pick the engine up, what additional Mark VIII parts are critical?
As for the IMRC, the way that I understand it is that the IMRC keeps the runner to one of the two intake valves closed during low-RPM operation. Above a certain RPM a butterfly valve opens letting intake air into the second valve. Is this correct? If so, does disabling the system permanently open the intake air to both valves? How does a blocking plate accomplish this? What are the alternatives? The way that I understand it, the '96 GT computer has no control for this valve so if I use the IMRC, then I will have to come up with a tach threshold circuit which would control a relay. Is there a published circuit for this. (I am an electrical engineer).
One last question; I see that afterward a 'tune' is recommended. Where does on go to get a tune?
Sorry for so many questions I'm sure that I will have more.
Hey it's the weekend (almost).
Monty
As for the IMRC, the way that I understand it is that the IMRC keeps the runner to one of the two intake valves closed during low-RPM operation. Above a certain RPM a butterfly valve opens letting intake air into the second valve. Is this correct? If so, does disabling the system permanently open the intake air to both valves? How does a blocking plate accomplish this? What are the alternatives? The way that I understand it, the '96 GT computer has no control for this valve so if I use the IMRC, then I will have to come up with a tach threshold circuit which would control a relay. Is there a published circuit for this. (I am an electrical engineer).
One last question; I see that afterward a 'tune' is recommended. Where does on go to get a tune?
Sorry for so many questions I'm sure that I will have more.
Hey it's the weekend (almost).
Monty
03-02-2012, 07:51 PM
#13
Banned
Join Date: Aug 2006
Location: sc
Posts: 457
Best way is to drop the engine out the bottom.You will have to do an IMRC delete.There's a rod that runs lengthways through the imrc's and has butterflies fastened to it.Take the butterflies off and pull the rod out.Then you either can weld the holes or epoxy them shut.You will lose some low end torque but will gain hp at higher rpm's.You will need a handheld tuner like an sct or diablo.Find a high performance shop around you to see if they can dyno tune it for you.I think the mark viii motors made 285 hp and the cobra engines made 305 hp.The major difference is the cams and the cobra has a forged crank.
03-03-2012, 12:33 AM
#14
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Join Date: Jul 2010
Location: Pennsylvania
Posts: 704
On the cobras(not sure about the mark viii)the butterflies would open up at around 3200 rpm.I pulled my butterflies and my rods out then my friends dad welded the holes shut.After that I sanded the welds smooth.BTW I bought a set of mark vii heads first then got a complete cobra motor,when I was doing my imrc delete I discovered that the mark viii heads and cobra imrc's wouldn't work together.Just fyi
03-03-2012, 01:31 AM
#15
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Join Date: May 2009
Location: DFW, TX
Posts: 1,925
On the cobras(not sure about the mark viii)the butterflies would open up at around 3200 rpm.I pulled my butterflies and my rods out then my friends dad welded the holes shut.After that I sanded the welds smooth.BTW I bought a set of mark vii heads first then got a complete cobra motor,when I was doing my imrc delete I discovered that the mark viii heads and cobra imrc's wouldn't work together.Just fyi
03-03-2012, 11:41 AM
#16
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Join Date: Jun 2011
Location: East middle of no where, WV
Posts: 585
If he is getting a 97 or 98 Mark VIII motor the IMRC's are composite plastic stuff and can't be welded. I used Quiksteel from the local AutoZone and close to 3K miles later it's still holding. I would say if you can afford it, definitely get a dyno tune the 24LB/h injectors that should come with the motor. It does run okay, but I feel that I could get much more out of this motor with better injectors and a tune. (I'm also on the stock tune at close to 3 thousand miles)
03-03-2012, 06:08 PM
#17
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Thread Starter
Join Date: Mar 2012
Location: MA
Posts: 78
03-03-2012, 07:08 PM
#18
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Join Date: Jul 2010
Location: Pennsylvania
Posts: 704
You need to buy a handheld tuner such as an SCT or diablosport.When you take it to have your car dyno tuned(highly recommended),the technician will use the handheld tuner to upload a custom tune for your car.The tuner is what you use to set the rev limiter at the rpm's you would like.The tuner uploads your custom tune and downloads then stores your stock tune.
JC316 the mark viii heads I got have one square intake port and one oval intake port for each cylander.My Cobra imrc's had two oval ports for each cylander if I remember correctly.
JC316 the mark viii heads I got have one square intake port and one oval intake port for each cylander.My Cobra imrc's had two oval ports for each cylander if I remember correctly.
03-07-2012, 08:50 AM
#20
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Thread Starter
Join Date: Mar 2012
Location: MA
Posts: 78
Hi all,
I've found a guy selling some FRPP shorty headers supposedly for a 96-98 DOHC cobra engine for $100. I can't find these from any current FRPP seller. Perhaps they were discontinued? Anyway they are ceramic coated stainless steel in fair shape. Will they work and bolt up to my '96 GT exhaust?
Thanks,
Monty
I've found a guy selling some FRPP shorty headers supposedly for a 96-98 DOHC cobra engine for $100. I can't find these from any current FRPP seller. Perhaps they were discontinued? Anyway they are ceramic coated stainless steel in fair shape. Will they work and bolt up to my '96 GT exhaust?
Thanks,
Monty
