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Thoughts on high mileage Mustang Cobras - READ ONLY

54 messages,  Last post on Oct 31, 2002 at 6:18 AM

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Messages Page 4 of 7

#22 of 54 You are so wrong, bud. by zueslewis

Oct 28, 2002 (4:41 pm)

I don't sell cars. I haven't sold cars since 1994. I consult for a lawfirm on dealer fraud, lemon law and breach of warranty cases. I tesitify as an automotive expert in automotive repair and maintenance, vehicle appraisal and delaership sales and service policy.
 
I really don't care if you don't believe me. The hosts here on Edmunds have my curriculum vitae - it's also a matter of court record in PA, NJ and DE.
 
I am a hardcore Mustang owner - I'm on my 5th one now and will get an '03 Cobra next Spring, after the flurry is over and I can get one at a normal price. I understand the 4.6 Cobra motor. I also know the block casting techniques are no different than that of Ford's other engines.
 
You were talking about longevity of various makes of vehicles. How do you figure a person with thousands of vehicle appraisals under his belt wouldn't know what lasts and what doesn't? I say he'd better know when he's spending a dealer's money, or he won't have a job for long.

#23 of 54 no need to argue guys---just clarify things a bit.... by Mr_Shiftright HOST

Oct 28, 2002 (5:05 pm)

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.

#24 of 54 zues by newcar31

Oct 28, 2002 (5:23 pm)

"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?

#25 of 54 You here to fight or talk about Cobras? by zueslewis

Oct 28, 2002 (5:45 pm)

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.

#26 of 54 We're here to talk about by newcar31

Oct 28, 2002 (6:24 pm)

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.

#27 of 54 In my limited, non-credentialed, real world experience by americanflag

Oct 28, 2002 (6:55 pm)

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.)

#28 of 54 There are literally gillions by zueslewis

Oct 28, 2002 (7:16 pm)

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.

#29 of 54 by speedshift

Oct 28, 2002 (11:45 pm)

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?

#30 of 54 by Mr_Shiftright HOST

Oct 29, 2002 (10:36 am)

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.
 

#31 of 54 by q45man

Oct 29, 2002 (2:02 pm)

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.

Messages Page 4 of 7

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