Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Thoughts on high mileage Mustang Cobras



  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,413
    Well, look, we can't bust apart engines on line, so forget the argument. You'll just talk to each other until you are blue in the face.

    The best "proof" I can offer you isn't proof at all, but history. I've busted apart engines of various types and if I went by the past, a Japanese engine is machined and made to a higher standard than an American engine. There is certainly that "pattern" in my own experience. If you build lots of engines, I would certainly listen to a counterargument--then we'd be on the "same page" regarding experience, or you'd even be ahead of me and I'll respect that. But so far, the professionals I know would, I feel, back me up. Also, I've been appraising cars for almost 20 years, and this experience backs up my assumptions.

    Could a certain Ford engine go against this pattern? Sure.Of course. I'm just betting on the odds that it doesn't, but sure. I'm not saying the people at Ford don't know HOW to build a longer-lived (notice I didn't say "better") engine than Lexus, I'm just saying they choose not to, for cost reasons for one thing.

    So let's call it "an educated guess" and no more than that. Which is what I meant by a Lexus engine being more "likely" to get to 300K than a Mustang's.

    I'd also like to add that some of the world's greatest and most competitive engines would never get to 300K. Long mileage is not a sign of a 'great engine" in my book. I doubt a brand new Ferari engine would ever get near that mileage, and I know that famous engines like the Mercedes Gullwing, Jaguar XKE, etc etc., could barely do 1/3 that.

    Last of all, being "hand-built" is not a plus for longevity or a minus. A man only assembles what the machines have made.


  • newcar31newcar31 Posts: 3,711
    "How do you figure a person with thousands of vehicle appraisals under his belt wouldn't know what lasts and what doesn't?"

    You said it yourself. You've never seen a Cobra with that many miles. Cobras with a lot of miles are rare, so how would you know how long the motors last? Have you rebuilt a Lexus, Infiniti, or Ford DOHC V8? How can you compare tolerances between them?

    "I also know the block casting techniques are no different than that of Ford's other engines."

    The block is aluminum and cast by Teksid of Italy, the same folks that do the Ferrari Formula 1 blocks. The SOHC block isn't. The crank comes from Gertach in Germany. If they are the same, why the need for the experience of these folks?
  • zueslewiszueslewis Posts: 2,353
    For that matter, why the subject? To me it's like "would you buy a 140,000 mile Ferrari 355?" It just doesn't matter - I only came in because the word "Cobra" was mentioned.
  • newcar31newcar31 Posts: 3,711
    buying a high mileage Cobra. I thought it was an interesting topic since there aren't too many Cobra DOHC 4.6L engines with many miles on them yet. So far, the speculation of whether or not it is going to last that long is based on other Ford engines. It was relevant to point out that the Cobra 4.6L DOHC engine is not like other Ford engines. Of course reliability depends on how the engine was treated during those miles, but engine design is a major factor. So far, no one has been able to prove or disprove the idea that the Japanese V8s are better with regards to manufacturing tolerances or long term reliabilty. Generally, I know that Japanese designed engines are better than Domestic designed engines, but I think this comparison is unique.
  • I know I put 209k miles on my 88 Acura Integra. The engine was still running pretty well at 209k, but the a/c went, so rather than replace it I traded the car in on a Honda Civic HX. I traded the Civic in at 90k miles, and the engine was running about perfect. So I have some limited experience putting miles on cars.

    Back in the eighties, I remember American cars had a horrible reputation for reliability. That kept me away from them until this September, when I got a 03 GT. I am very interested to see how this car holds up when it gets mileage on it.

    But I notice you guys are drawing a distinction between the SOHC and the DOHC. Wouldn't the SOHC last longer, since it is a simpler design (all other things being equal)?

    Let's put aside 300k miles for a minute, is 200k miles unreasonable assuming proper maintenance for either of the 4.6 Ford engines? (Also, can we say some nice things about Ford engines because they are, well, Ford engines and not rice burner engines.)
  • zueslewiszueslewis Posts: 2,353
    of 150,000 and 200,000 mile SOHC 4.6s in service. Since the Caprice died in 1996, law enforcement has purchased Crown Vics for 95% of their fleets - a few Impalas, Intrepids and Camaros thrown in. Most retired PD cars become taxis - I saw a 325,000 Crown Vic here in Philly - looked like a reman motor, but two engines in 325K is still great.

    My only concern about the DOHC 4.6 is that it's high strung. Then again, Saleen supercharges them (not easy on the bottom end) - so does Steeda and Roush. Another choice (other than the '03) is to buy a used up '99-00 (if I can find one) and drop in a crate motor from Probe Industries with a Vortech or Paxton. Could be fun.
  • speedshiftspeedshift Posts: 1,598
    Shifty, were any of the engines you mentioned built by the factory at the loose side of tolerances so they'd perform better right out of the box?
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,413
    Well, very high performance engines are generally built loose, yes, for safety and reliability, but your average passenger car engine these days is built to a pretty tight tolerance. In the 60s, I think they were just sloppy, that's all, with no intention one way or the other. That's all the skill they had, most of them.

    As far as longevity goes, any car that is super or turbo charged is going to loose some engine life. That's just the laws of physics. It might only be 10-15%, and you the driver may never have to "pay the price" if you trade it in after a couple years, but if you stress and engine for more power you are going to lose something in the bargain.

    As for a Ford dohc going 200K miles, the answer is "it depends". Will all of them get that far---no, I don't think so, because most cars don't get that far---they are crashed, stolen, rusted or some other major component or combination of components fail and cause the car to be retired prior to engine failure.

    If you scan the average junkyard, you will not see very many 200K+ cars, because there are many factors that send a car to the grave.

    But certainly will good care and good luck, 200K is no big deal on any modern V8---but it's the exception, not the rule.

    All I want to stress is this: If you're buying a car with 150K on it, you are buying a car that is pretty much used up. If it has 100K, it's at least 1/2 used up, maybe 2/3. A car is a "total package", not just an engine. After 150K, you're going ot have to start re-making it, piece by piece, as you drive.


  • q45manq45man Posts: 416
    The 4.5 liter Q engine is built to a significantly higher tolerance.

    All specs from the 1992 Q45 shop manual!!!!!!!
    Each crankshaft bearing has 6 choices [grades from 0-6] increments of 0.0001". The crankshaft maximum taper is 0.0002".
    The main bearing clearance is specified to be 0.0005" to 0.0012" with a recommended 0.0008" and an upper limit of 0.002".
    The connecting rod bearing clearance is specified at 0.0013" and a max limit of 0.0026".
    There are 5 grades of pistons available in 0.0004" increments and the wrist pin fit is specifyied at zero to a max of 0.0002".

    I can assure you that an 8-13 MICRON fit is at least twice as tight as a Cobra engine is built too. The Yamaha SHO V8 closest was 20 microns!
    Each Q engine has a series of 16 codes stamped into the block showing the grade of bearings and pistons utilized in the build......remember this was Nissan first V8 and they tried to do it right from the forged crank to forged rods to special cast pistons to the expensive bearing girdle [main bearing beam] to attach the 6 bolts per cap.
    name any engine designed in 1988 that had 6 bolts per main].
    By the way the exhaust values are sodium filled stainless steel, the intakes are just stainless. Viton seals are used thoughout [each cost $8.00 for each of 32 valves].

    We have at least 7 clients with Q engines over 240,000 miles so 300,000 is easily obtain same with 4 90 LS400 over 250,000 miles.

    The ones maintained don't smoke, the bad ones do and I have seen 96Q destroyed at 136,000 miles by lack of oil changes.
  • newcar31newcar31 Posts: 3,711
    There we go! Now we have some numbers. The Cobra's engine wasn't designed in 88' but it also has a 6 bolt main. Who wants to dig up the Cobra's #s now?
  • Another factor would be city versus highway miles. If the guy with a 100k miles on his Cobra put them on in a daily highway commute without starting and stopping alot that is different than if the miles came from city driving. In fact, it occurs to me that if he put 100k on that fast, he probably was doing highway miles. Also, hopefully the owner of the Cobra was 50 years old plus, that would imply conservative driving habits. The best way I can think of to shorten a car engine's life would be to give the car to a teenager or young male driver and let them drive it for a while.

    Nothing will protect a car against cold starts, and this is going to occur with a car doing alot of city miles, even with a conservative driver.

    Shifty, what about synthetic oil? If the vehicle owners were using synthetic oil with changes at proper intervals, would this increase the vehicles life significantly? Also, wouldn't this help with cold starts involved in city driving?

    If I was looking at buying this car, I would want to see maintenance records.
  • jacuzzjacuzz Posts: 3
    Question one --why do you want to by a Cobra Vs a Z or say a Supra or even a Lexus

    Question two --if I buy the Cobra how will I use it.

    Question three-The Test drive should tell you what you need to initially know.

    other thoughts could be -do I care about re-sale.

    If the price is right and the engine fails Would I put another engine in the car.

    Putting the engine aside- is the car fatigued--suspension, interior,leaks -take it out in the rain.

    Most important is how you feel. To me arguing over a lexus engine Vs a Nissan engine is a mute point. Take a really hard look around on what is really on the road as far as sports cars,,Cobra's
    are rare because they are a limited production car, Camaros, supras and Z's are out there, but hey in my opinion there are a heck of lot more mustangs of the same years still around looking and running good.

    Fun, enjoyment and looks of what you are driving is in the eyes and hands of the beholder. If you like it get it, agonizing over the mileage is important based on how you want to use the car. I know one thing when I see a Cobra,
    that looks good I am always impressed.

    As my wife always puts it you get what you pay for,and if you are buying a high mileage car and that is what it is --a great car with high mileage, heck find out what a engine costs for that Cobra if available, especially if you want to keep it.

    Fun, function, investment what is it you are looking for, weigh them out, and the answer will be there for you.
  • newcar31newcar31 Posts: 3,711
    "heck find out what a engine costs for that Cobra if available"

    I'll bet it would cost too much. If you're going to get a new engine, why get a Cobra? At that price, you're better off with a built 351 or 302. Ford makes some really nice crate motors, some with lots of power right out of the box for less money than a new DOHC 4.6L (if it's even available new). Do you really have to have a Cobra? Are you concerned with image or performance because you can easily build a low mileage Cobra killer for the money you'd spend putting a new DOHC 4.6L in the high mileage Cobra. IMO, who cares what it says on your rear bumper if that GT next to you isn't going to see your rear bumper.
  • zueslewiszueslewis Posts: 2,353
    rear apron ($200), front air dam ($200-300) and put in a Cobra or Cobra R wing and have a Cobra clone.
  • newcar31newcar31 Posts: 3,711
    Don't do that! That's like slappin' a "5.0L" badge on a 4 cyl Mustang. If this person wants a performer, pick up a clean 91-93 LX 5.0L 5sp coupe and go to town. Those cars are relatively light, cheap to buy, and have an absolutely HUGE aftermarket. A little money spent on one of these rides gets you major performance. If the decision were up to me, I'd much rather have a clean, low mileage, LX 5.0L (they're out there) than a high mileage Cobra "image" machine. If you need a best bang for the buck Mustang thumper, the LX coupe is the way to go. Look out Camaros, Firechickens, and COBRAS!

    BTW, I may be a little biased. I used to own a deep jewel green 91' LX 5.0L 5sp coupe. That car was a BLAST.
  • zueslewiszueslewis Posts: 2,353
    I live my '86. It absolutely screams and beats the Corvettes at autocrosses.
  • newcar31newcar31 Posts: 3,711
    This forum makes me want my Mustang back. God I miss that raucous, [non-permissible content removed] kickin' beast. There is nothing like the sound of a lumpy 302 inhaling gobs of air and fuel.
  • zueslewiszueslewis Posts: 2,353
    (but street legal) 88 GT racing in E Modified this last weekend at our autocross in Nazareth. He ran open exhaust, gutted, but very nicely painted interior (he shows the car), suspension by Griggs Racing, Cervini's fiberglass, etc. He was running a 347 stroker and a FRPP F cam - it absolutely thumped.

    That is definitely the cam that is going in my motor when I rebuild.
  • newcar31newcar31 Posts: 3,711
    I used to work at a Ford dealer, so I'd get all of the motorsports parts at 10% over cost. It was a pretty good deal on most parts but the problem was me spending all of my money in that catalog. I was running a motorsports E series cam which is pretty mild but the car still shook a little at idle. It was a nice combination of drivability and power.
  • zueslewiszueslewis Posts: 2,353
    it's cheaper than nay dealer's retail pricing.

    We were talking about replacing Cobra motors. Sean Hyland Motorsports sells 575 rear wheel hp (guaranteed with a 10 psi blower) long blocks.
This discussion has been closed.