: 5.7 lt1 VS. FORD 4.6 which is more durable



Hammondsix
12-11-06, 01:33 PM
Ive had a 4.6 before in a grand marquis. It seems more reliable. But which one is more durable? it seems that an all Cast iron motor would last longer than an aluminium motor but if you look at ebay it seems that there are more fords with higher milage. I saw a lincoln with 650000+ miles on it!! (but it ran on propane)

what do you think?

90Brougham350
12-11-06, 01:46 PM
Either are great motors if they're well maintained. The LT1 is a tried and true small-block Chevy that will do hundreds of thousands of miles if you maintain it properly, so is the 4.6. The optispark on the LT1 maybe even makes it more reliable. Either are good motors, I don't know if I'd say there's a better engine between the two. As far as wear and tear, the 4.6 needs to spend more of its life in the higher RPM's, so the basic laws of engine wear say the 4.6 has more wear and tear on it than an LT1 if they have the same number of miles, but I wouldn't put one ahead of the other.

Hammondsix
12-11-06, 04:36 PM
i thought the 4.6 was a newer design...

I~LUV~Caddys8792
12-11-06, 06:07 PM
Both are great engines, very very durable motors, probably the most durable modern american V8's ever. The LT1 does have that optispark, which is very reliable, but it's costly to repair. The early SOHC 4.6's have an oil burning issue because the valves don't seal all the way. Between the two of them, I'd probably say that the 350 is more reliable, but only very slightly more.

CadiJeff
12-11-06, 06:21 PM
to close to call....I would say that it would depend on the owner (maint. driving style, habits ect.)

Hammondsix
12-11-06, 06:41 PM
yeah the valve seals were bad on the 92-95 engines, but the 96- were equipped with a plastink manifold that was prone to crack. Annoying repairs but not devastating sort of like the , exhaust bolts and waterpump/distributor on the LT.

Phantom&RedGoat2004
12-11-06, 07:07 PM
I think they are both great engines, but my purely biased opinion says that GM is superior. Now go ask a Ford forum, and see what they say. (*_~)

N0DIH
12-12-06, 03:33 AM
Newer doesn't mean better


i thought the 4.6 was a newer design...

drewsdeville
12-12-06, 08:28 AM
Since we are comparing to the LT1, we'd have to use the older 4.6's to compare. are we comparing engines or drivetrains?

I had 2 buddies, between them, 3 Grand Marquis. Yes, strange. 2 1992's and 1 1993.

1 1992 had 150,000 on it. Was a huge problem car. Plagued from the start. Many thousands of dollars into the transmission. It was done twice. I always found Ford's trannies to be their weakness....
The oil pan rusted through
Numeruous vacuum leaks
Coil packs
Lots of failed sensors

The other '92 had only 70,000 on it.
Same thing, numerous vacuum leaks
oil pan rusted through on this one as well
Overdrive never shifted correctly, but the rest of the tranny seemed fine
Coil packs

Wow, now that I am listing this stuff, these guys had identical problems, I never even realized it.

Both used oil

However, the 1993 was a trouble free car. That one never had a problem while he had it. Sold it at 103,000 or something like that. He gave it up for a 2000 Grand Marquis

I can only list problems I've seen with the 4.6 because I never knew anyone with an LT1... so yeah :)

N0DIH
12-12-06, 08:47 AM
I have 209K on my ride. Eng has no evidence of ever being opened, and for sure not since I have had it in the last 60K. Trans is stock, rear end is stock (but has a pair of badly worn axle shafts thanks to GM installing the wrong diff gasket). The only real issues that this car ever had before I got it was AC compressor. Factory one died in 2002 and replacement was bad and had to be replaced less than 1 year later.

Engine itself, almost untouched for 209K. Even factory water pump and distributor/cap/rotor.

Mine is a 94 Cadillac Fleetwood Brougham with the factory V4P 7000# towing package.

drewsdeville
12-12-06, 08:56 AM
Even factory water pump and distributor/cap/rotor.



Is that possible??? How do you know it's factory??? The contacts on the cap and rotor wouldn't even be touching each other by now...

But I guess, you know your car better than I. If tht's true, those contacts must be some sort of exotic metal...

The water pump doesn't suprise me. Most cast-iron water pumps can outlast the car they are in.

N0DIH
12-12-06, 09:07 AM
My distributor is under the water pump (Optispark). It has a huge cap and has a bad rap for failures. But most are at 150K+ before they do. Most cars can't even ponder going 100K on a factory cap/rotor and these cars commonly do it. I am sure it NEEDS it, but it is a major job to do it. I need to get a water pump, timing set (209K it needs it too), and distributor (common to replace with a new GM unit). Katshot said statistically they replaced them all at 142K miles for a reliability standpoint.

BCs71
12-12-06, 04:33 PM
Not familiar with the 4.6 so can't comment.

But the iron-headed LT1 engine is in livery Fleetwoods, taxi cab Caprices & 9C1 cop cars.
I have a pal who went 297,000 miles on his ex-cop car AND ex-taxi use vehicle. Engine failure occurred because he decided to do a 100mph jaunt on the highway when the oil pump failed (taking out the engine in the process). He could of went much longer on that stock 300K mile abused multiple fleet service engine had the oil pump been replaced at some point!

N0DIH
12-12-06, 05:01 PM
Hmmm, maybe I should drop the pan and put in a fresh oil pump. I have heard a BBC oil pump is a worthy upgrade (10 vane vs 6) and much improved oiling.

I really just want to save my $$ and drop in a 6.0L truck LS1....

JTraik
12-15-06, 06:56 PM
To Fords credit...ahem... my father has a transporation business with several town cars. One was retired a while ago but is still in use is a '98 town car with around 200k, other than tranny problems the car rides and runs like silk. Before that we had the 5.0 lincolns and they ran forever to with proper maintenance. The I prefer a ford 5.0 over their 4.6 for their cast iron construction, cheapness to fix and sheer simplicity. GM small blocks carry my same preference, they are so easy and usually cheap to fix especially gen I's Not to mention they outlast anything given proper care ;-)

RocketFast321
12-22-06, 02:45 AM
My cousin had a 95 Vic fgor about 2 years. He put about 45k on it and sold it at 120k. No problems. It did smoked a little.

caddycruiser
12-22-06, 03:56 PM
Is that possible??? How do you know it's factory??? The contacts on the cap and rotor wouldn't even be touching each other by now...

But I guess, you know your car better than I. If tht's true, those contacts must be some sort of exotic metal...

The water pump doesn't suprise me. Most cast-iron water pumps can outlast the car they are in.

Actually, with the LT1, the water pumps do tend to go by a certain time, but still generally last quite a long time.

The Optisparks, on the other hand, right on the front of the block below the water pump just as N0DIH said, last a LONG, LONG time both with proper maintenance and without. SSStealth was one member on this board who owned his '94 Fleetwood from new and passed over 300k miles without ever touching his.

Here's a terrific thread on that matter, posted by him quite a while ago:

http://www.cadillacforums.com/forums/rwd-19xx-1985-deville-fleetwood-1985/12021-just-300-000-miles.html

He's still active on the Impala SS board, still has the car--though it was for sale there for a while, as he just bought a new STS-V and also has a company car--and it still is largely untouched in many ways. Last check-in was 335,600.

Also, just to show more recent stuff, here's a link to his pics of the car:

http://s82.photobucket.com/albums/j248/ssstealth/Fleetwood%20SS/?start=all

--------------------------

I've seen both 4.6 OHC's and LT1's cross similar high mileage with, apparently, the same small number of repairs. But overall, I've seen a bit more LT1's that have been run through the gamit and taken a beating, yet still run almost bizarrely well--so I give that engine the edge.l

96Fleetwood
12-22-06, 05:26 PM
Bah, the 4.6!! I had a 1993 Town Car Cartier... it was the worst 7 months of vehicle ownership. Engine wise, the intake manifold drove me nuts and eventually caused several other $$$$ problems. The car was also plagued by electrical gremlins!! Guess that is what I get for buying a low mileage 1 owner South Florida car :cookoo:

I~LUV~Caddys8792
12-22-06, 07:09 PM
That's the only time I've heard of an intake manifold problem on a pre '95 SOHC 4.6. What happened?

96Fleetwood
12-22-06, 07:25 PM
Overheating and more overheating... I am pretty sure when I sold the car the engine was 90% gone from all the overheating. I was completing my masters when I had that car and I just kept driving it despite the overheating just because I was so pissed. I would drive it until it would cut off from being so hot. At least I sold it cheap and with a trunk load of parts to fix it. The body and interior were mint on that car... such a shame.

Hammondsix
12-26-06, 11:41 PM
i love my fleet, to death BUT, i have seen an airport taxi with over 650000 miles on it. It was propane powered and looked like shit inside. it was a lincoln 4.6, i have never seen an lt 1 with that milage. Is this due so the main bearings?

96Fleetwood
12-27-06, 06:47 AM
Our friend's 1994 Fleetwood stretch limo has 432,000 on the original LT1.. but that is the highest I haver personally seen.

N0DIH
01-01-07, 08:17 PM
Very cool. Any list of what sort of maint he had to do to keep it running that long? What are the "weak" points? I just cleaned up my Opti, new seals all around and replaced the water pump with a NAPA rebuilt.

RocketFast321
01-02-07, 11:18 AM
i love my fleet, to death BUT, i have seen an airport taxi with over 650000 miles on it. It was propane powered and looked like shit inside. it was a lincoln 4.6, i have never seen an lt 1 with that milage. Is this due so the main bearings?

I remember seeing this on another site. 94 9c1.

Adam
01-02-07, 12:23 PM
ive had both engines and i prefer my LT1. the 4.6 was an awesome motor that ran extremely well... i just like saying "yeah, i got a Vette engine." both have their strong points and are very well made.

N0DIH
01-02-07, 04:22 PM
And now, compare the COST of both engines, or better yet, a 4.6L/5.4L to a 4.8L/5.3L GM V8. The GM being several thousand cheaper....

bigbluebrougham
01-05-07, 05:22 PM
Very cool. Any list of what sort of maint he had to do to keep it running that long? What are the "weak" points? I just cleaned up my Opti, new seals all around and replaced the water pump with a NAPA rebuilt.

N0DIH,

Good luck with the NAPA rebuilt. I am on my second one since I bought the car and I have only owned it since 11-01-06. I am in process of filing a labor claim with them to get reimbursed. One pump is a fluke, two pumps is ridiculous. I don;t mind the work to put it in, but having to do it three time ins the middle of the winter is no fun. :(

BBB

N0DIH
01-05-07, 05:35 PM
How long did the pump last? The seal looked similar to the seal that I put in from GM for the water pump drive. I hope it is a good one...

bigbluebrougham
01-05-07, 05:44 PM
How long did the pump last? The seal looked similar to the seal that I put in from GM for the water pump drive. I hope it is a good one...

My first one lasted a month before the weep hole was leaking like a siv (sp?) and the second one is a manufacturers defect I think...the upper radiator hose mount that is pressed into the body of the pump is leaking. I had the second one for two days before that one was leaking and it is still in my car because I don't want to buy another one until I get everything cleared up with NAPA. I worked there for about three months this past summer. I knew the owner of the NAPA from 2000 when I worked there for a year, so I bought my stuff from him since I got his discount. I will still buy stuff from NAPA because I like going there and they are always friendly, however I doubt I will by another water pump, well at least a rebuilt one anyway. I would just watch your pump, that's all. Maybe I had bad luck.

I~LUV~Caddys8792
01-05-07, 09:28 PM
And now, compare the COST of both engines, or better yet, a 4.6L/5.4L to a 4.8L/5.3L GM V8. The GM being several thousand cheaper....


i just like saying "yeah, i got a Vette engine." both have their strong points and are very well made.

True, but the 4.6 is the Mustang motor, which is sorta the same. The LT1 was the detuned, slightly changed Corvette engine. If you get the dual exhaust SOHC 4.6, it's the exact same motor they used in the Mustangs. I believe even the hp rating is the same at 210.

N0DIH
01-06-07, 10:52 PM
The same pathetic 210 hp.... I still can't believe that is all it makes in the shadow of the N*...