early this year i bout a 96 cobra.... got a good deal on it and it needed a motor, the #1 rod bearing was gone. i had a buddy that had an extra engine out of a markVIII. as many of you may well know the cobra shares the same engine as the mark VIII lincolns. well there is one diffence and thats the cranks. the cobra has a steel crank and the lincoln a very good cast crank. but if you go to put one i a cobra BE AWARE that the cobra has a windsor engine and the lincoln a romeo. you will need a romeo flywheel the do not interchange. and this engine swap is only good for 96 to 98 cobras. but im kinda hit a rough patch with the car.. the engine only has 10 lbs of vacuum when it needs 20... so im in the proccess of hunting them down... if you have any questions let me know.
cobra knowledge...
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not really looking for advice unless you have any idea what would cause a loss of 10 lb of vacuum cause ive cheched all but 2 things..... and i have narrowed it to one of 2 things.... one is an intake gasket leak and the other is the imrc thats on the bottom of the intake. but it was more about putting some info out there to help others and make there swap easier... or if you have any questions on the cobras 96 to 99 i have done a good bit of work on them so i might be able to help
02nightmaregt
To hell with your Mustang, I want to see your HOG!
The Cobra and the Mark VIII engines are only the same from '96-'98. Before that, the '93-'95 Marks used a slightly different block. It is true though that the Cobra uses a forged steel crank and the Mark VIII uses a Cast crank. The heads and cams are the same, but the intakes are obviously different as well.
You're wrong about one of them being a Romeo and the other a Windsor though. ALL 4V engines are Romeo built. Automatics (Mark VIII, Mach 1, Mercury Marauder) use a 6-bolt flywheel, which is probably what threw you, but they're still Romeo engines none the less. The only cars that got Windsor’s were the ’99 to early-01 Mustangs. Windsor’s were otherwise dedicated to Trucks, Vans and Expeditions.
Do a leak down test to figure out exactly where the leak is. Put compressed air to the cylinder through the spark plug hole and listen for leaks. If you see/hear bubbles coming out your coolant it's your head gasket. Things can get tricky when you have the air coming out your crankcase, because it could be rings or head gasket.
Most "shops" voice their opinions based on an overall interchange on the mod motors. They get into one problem and they make it seem like any issue they get they can blame it on being on motor vs. the other.
well i did some old school vacuum gauge and the results point to an intake leak, because i have check and double checked everything else. i have low vac and its steady. when you stomp it it drops to 0 and rebounds like it should except for the fact it only goes back to 10.... and theres no real loss of power cause the car hauls ass. the motor i put in it was out of a grandma car that only had 30k and there is no bubbling in the resivoir, or overheating so the possiblity of a blown hg, bad rings or burnt/leaking vavle is unlikely. when i change the intake gasket when the come in i am also replacing the imrc because now its throwing codes which might also be a reason for the loss of vac if its functioning improperly. but the leak down test will be the next step seeing how its not anything else so far
What year Lincoln is the Mark VIII engine from? The early 4V's used aluminum IMRC plates, that over time would carbon up and cause the butterfly valves to stick. If this truly is a "grandma car" then there's a good chance it didn't see a lot of high RPM action and the plates are gummed up. The later Cobra and Mark VIII engines used ceramic plates that were more resistant to the carbon build up and didn't suffer from the same issues.
My advice to you would be to visually inspect them to ensure there isn't an excess of carbon. Then, once you get all the bugs worked out of it, you should run a can of Sea Foam through the engine to get rid of all of the junk that's built up in it over the years.
My advice to you would be to visually inspect them to ensure there isn't an excess of carbon. Then, once you get all the bugs worked out of it, you should run a can of Sea Foam through the engine to get rid of all of the junk that's built up in it over the years.
i finially found the source of the vacuum leaks on my cobra.... the bearing on the imrc rods were gone and leaking.... i am now in the process of trying to find replacement bearing because ford only sells the plates at 600 bucks a piece... when i get the new bearings i will post the part number for the people like me that like to have a car that is as close to100% correct as can be...
the replacement bearings i found are 688-2rs and ran me 8 bucks a piece
the replacement bearings i found are 688-2rs and ran me 8 bucks a piece
on the 96 to 98 cobras they have plates that go between the intake and the heads that have butterflys like you find in a throttle body that are used to block off every other intake valve... the imrc rods as i call them is what the butterflys are mounted to and when the rod is turns either opens or closes them. there are two of them one for each side and it seems that the sealed bearings that allow them to pivot when worn bad enough that it was my vacuum leak.
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