Engine durability???

[Doubleclutch]

During the week I read an interesting line (not here) regarding early 70s muscle cars. Author believes that the engineering of engine components for the late 60s engines with 10 plus compression ratios carried over when the compression was dropped to 9 in the early 70s. He stated that 200k miles was a possibility without failure in the low compression engines?

Any MOPAR engineers or engine builders out there? Maybe some clues in the parts book as to the years that crankshafts, rods ect covered?

I have a 73 RR GTX with 440 engine documented 53k miles. Car was a demo in 73 and probably suffered a few stoplight dashes in the 10k in that years usage. Then bought by the MOPAR manager that had driven it as a demo and used lightly for 30 years with good maintenance. I've had the pan down to do the rear engine seal and its very clean inside. Engine showed normal oil pressure when I bought it ==assuming 30 weight oil --now running 20-50 so shows higher. I've been a little hesitant to push the RPMs? Its not a firebreather, but runs good for what it is. Is it possible the engine is only 30-50 % of its useful life?

 

[Photon440]

It's really hard to tell what condition the engine is in without a compression and leak down test performed to it. An accurate oil pressure reading at different rpms would be useful too.

 

[BIGSHCLUNK]

This is such an open ended question its unreal. I could easily come up with 10 "what ifs". But I will say we see 20X more cars than we used to with over 100K and stuff in the 150-200K area is very common. And this stuff is running just fine. That being said I can remeber my dad looking at a 61 Plymouth back in the day with 60K on it. He wouldnt buy it.....to many miles. IMHO I believ EFI has lots to do with it along with other engineering advances.

 

[dieseldazzle]

Moly coatings, metric ring packs, roller technology along with oil and fuel technology advances in ignition timing control, bearing technology, fuel delivery......lol overdrives....there are TONS of factors.

I guess if you are asking then take a 440-3 ( I think some of them had moly rings in them up in the late 70s) not sure but the one I took apart did, not sure if it was factory. Put a small roller cam in it and a direct port efi system and a cam and crank sensor and stick an overdrive behind of it and I bet it would go just as many miles as say a newer 5.7 or a chebby ls motor....

Is THIS what you are asking??????

 

[WileE]

Years ago, cars lasted alot longer than what their odometer showed.. a lot of funny stuff went on routinely. But don't ask me, "I know nothing " {Schultz}

 

[BIGSHCLUNK]

hehehehe.... I have know Idea what your talking about

 

[Dennis H]

I run Amsoil 10-40, don't know that a 50 weight is needed. Chassis dyno says it stops pulling at 4850 so no need to rev higher than that.

 

[khryslerkid]

The synthetic oils of today will make an engine last a lot longer then before. I remember dirt track cars running years ago, when they lost oil pressure the race was over. When synthetics came into the picture they would finish the race without any oil in the crankcase! Hell the engines of today are running steel against aluminum and they hold up for 200,000+ miles.

I had a '64 383, 100,000+ miles on it. Built the top end with hc heads, 500 cam, headers, 456 rear. Daily driver, raced on the weekends, ran the crap out of it for four years. It was still running strong when i sold it. There wasn't any synthetic oils back then. I wouldn't be afraid of running your 440 just like it is. You can do a compression test, a leak down test. Valve seal replacement might be in-store if they are hardened. Also frost plugs become thin with rust on these engines too. These engines are tough!