455 longevity

Post your technical questions and information here.
Posts: 3
Joined: Wed Jul 25, 2018 12:45 pm
TOA Membership Number: 0
Years Owned: 1969 Toronado owned 4 years

455 longevity

Postby Val » Wed Aug 01, 2018 5:35 pm

What is the expected life span for a 455? I'm seeing many early Toronados for sale with mileage under 100k but with rebuilt or non original motors? Recently found my car also has had a motor change, at around 70k miles, which is when it was restored to this present condition.
Val. T

Otto Skorzeny
Posts: 1048
Joined: Fri Feb 28, 2014 12:41 pm
TOA Membership Number: 0
Years Owned: 1966 Toronado

Re: 455 longevity

Postby Otto Skorzeny » Thu Aug 02, 2018 4:58 am

I think the biggest problem with the engine is that GM used nylon coated timing gears. The nylon disintegrates over time regardless of mileage. The pieces flake off and clog the oil pump, etc.

Hopefully yours was replaced with a regular, nylon free gear set.

Posts: 118
Joined: Tue Aug 11, 2009 7:26 am
TOA Membership Number: 100
Location: New Haven, CT

Re: 455 longevity

Postby Mikel » Sat Aug 18, 2018 6:03 pm

A well maintained and tuned 455 will last a very long time.

These old engines didn't have the benefit of a self-adjusting EFI system, positive crankcase ventilation or modern oils.

Posts: 205
Joined: Thu Nov 15, 2012 12:25 pm
TOA Membership Number: 378
Years Owned: 79 Toronado or Eldorado

Re: 455 longevity

Postby bcroe » Tue Aug 21, 2018 6:03 am

My own experience is that the emissions engines starting about 1976 need
a whole lot less attention than the high performance 60s engines. I credit
this to the hardened valve seats, valve rotators, HEI ignition, and likely better
rings. My 60s engines seemed to soon need valve jobs and other levels of
overhaul, but the emissions engine properly maintained (new timing chain)
just keep running. Peak power is down some, but the 87 unleaded fuel is
a lot cheaper.

Olds 403 is the choice here, 350s run well also. Bruce Roe

Posts: 13
Joined: Tue Dec 11, 2018 11:52 am
TOA Membership Number: 0
Years Owned: 1966/67
Location: Escondido, Ca

Re: 455 longevity

Postby gearhead141 » Thu Dec 13, 2018 2:40 pm

I just wanted to say that if you look back at the time that these cars were made, they weren't expected to make 100k miles without a rebuild. I can remember that my Dad wouldn't keep a car more than 60k miles because things were starting to need repair. Ring technology was not what it is today. Valve stem seals and valve guides would wear out sooner than today's engines. And as Otto mentioned, GM tried to quiet down the timing chain with the nylon cam gear, which again will most likely not last 100k miles. Folks lived closer to their jobs and didn't commute as far. The average yearly miles put on a car was on the average of 10k miles or less. For the time that the 425 was made, it was a great engine, but at the very least, seals need to be replaced. If properly taken care of, the engine will last a very long time; longer than the body will depending on where you live.

Return to “Technical Talk”

Who is online

Users browsing this forum: No registered users and 4 guests