16 replies to this topic

[Paolo]

A recent thread about dodgy used cars and bikes in the Nostalgia Forum got me thinking about reconditioned machines.

I often see old engines that are rebuilt and labeled as "zero hours"; this seems very popular with Cosworth DFVs, especially.

It is of course also possible to overhaul an old chassis and improve its condition.

Yet some of the damage is likely to be permanent: the best rebuild will not take away metal fatigue from a sheet chassis unless it is actually built again from fresh aluminium... and probably it is the same for engine blocks, although I have heard that a block with some mileage in it could actually be better than a brand new one: BMW turbos for Formula One had, IIRC, used blocks to this purpose.

So, will a "zero hours" engine actually deliver the same power and reliability as a brand new one?
And how much worse is likely to be the condition of a chassis running in Historics than it was in its glory days from, say, a torsional stiffness point of view?

[cheapracer]

Many top race and drag car teams go to wreckers/dismantlers and go through old blocks that have been sitting out back since Noah was a kid - I'm sure someone like McGuire can give you the technical reasons why.

Thats cast iron, don't know if the same applies to aluminium.

Chassis on the other hand do get worse but on the other hand roll bar tech in both design and alloy has improved to balance or actually improve the situation.

[Paolo]

Well, I'm aware that a "new" historic car is usually a lot faster than the original spec, due to better setup, new tricks etc.

But I was referring to the basic chassis qualities such as stiffness, that I think go through a degradation process.

About the search for old blocks, I suspect thisis due to some easing of the casting internal stresses that might happen with time, but I'm no engine expert.

The problem is: can I realistically think to make an old engine "new" or it is impossible?

[McGuire]

In a classified ad for a racing or performance car, "zero hours" on an engine or component simply means it hasn't been run since it was last freshened -- which could mean anything, maybe just a valve job and a new set of rod bearing inserts.

It's not like a certified aircraft engine rebuild at an FAA-approved facility where every single component is tested and passed, and every component checked against a defined life cycle, so now the engine can time forward like a new one. Or even an industry-recognized standard like "remanufactured" for replacement engines for production cars and trucks which describes a certain number of new parts. "Zero hours" could mean anything here.

A sort of separate question: Can you build a "new" racing engine from a used block and heads? That is, will it be as powerful and reliable as an all-new engine? In most cases, yes -- there is no significant difference, especially with roughly production-based stuff in the sportsman racing categories.

Yet another separate issue someone asked about... yes, back in the old days we would search the wrecking yards for old blocks and heads, which were actually preferable to new components. Couple of reasons for that... often there were discontinued castings in circulation that were actually better than anything available over the counter as new that day. Extra webbing, additional tin or nickel content, etc. Also, with Detroit V8s especially, there is a lot to be said for a block that is "settled." That is, it has already been through some near-infinite number of stress and thermal cycles so when you get the block, it is what it is. The bores and saddles are done moving around and the cylinder case can be accurately machined and assembled. However, now we have all kinds of racing and high-performance blocks from the factory and the aftermarket. There is no longer any need to go searching through junkyards. Today the new stuff really is better.

[Paolo]

Illuminating, thanks.

But then, a question:

if rebuilding an engine as new is possible, why do F1 teams need 50 engines per season?

[saudoso]

Originally posted by Paolo
Illuminating, thanks.

But then, a question:

if rebuilding an engine as new is possible, why do F1 teams need 50 engines per season?

Most of those are just 'new rebuilds'

[cheapracer]

Originally posted by Paolo
Illuminating, thanks.

But then, a question:

if rebuilding an engine as new is possible, why do F1 teams need 50 engines per season?

Because all the components are at the borderline of weight and thickness etc. - they are on their last legs or maximum tolerances when new so to speak and a few hours later they are worn out.

[McGuire]

Originally posted by Paolo

The problem is: can I realistically think to make an old engine "new" or it is impossible?

Sure you can. If you start with an engine that has never been permanently damaged, is not worn beyond repair tolerances, and whose block and other basic components are not yet to the end of their fatigue life, it can be rebuilt to better than new. The average engine pulled out of a junkyard usually meets this description, subject to simple inspection.

Doing it right is time and labor-intensive and can exceed the cost of a factory-new or remanufactured engine. But when an engine is built right, it's right. And one of my favorite things.

[JtP1]

Originally posted by McGuire
In a classified ad for a racing or performance car, "zero hours" on an engine or component simply means it hasn't been run since it was last freshened -- which could mean anything, maybe just a valve job and a new set of rod bearing inserts.

It's not like a certified aircraft engine rebuild at an FAA-approved facility where every single component is tested and passed, and every component checked against a defined life cycle, so now the engine can time forward like a new one. Or even an industry-recognized standard like "remanufactured" for replacement engines for production cars and trucks which describes a certain number of new parts. "Zero hours" could mean anything here.

A sort of separate question: Can you build a "new" racing engine from a used block and heads? That is, will it be as powerful and reliable as an all-new engine? In most cases, yes -- there is no significant difference, especially with roughly production-based stuff in the sportsman racing categories.

Yet another separate issue someone asked about... yes, back in the old days we would search the wrecking yards for old blocks and heads, which were actually preferable to new components. Couple of reasons for that... often there were discontinued castings in circulation that were actually better than anything available over the counter as new that day. Extra webbing, additional tin or nickel content, etc. Also, with Detroit V8s especially, there is a lot to be said for a block that is "settled." That is, it has already been through some near-infinite number of stress and thermal cycles so when you get the block, it is what it is. The bores and saddles are done moving around and the cylinder case can be accurately machined and assembled. However, now we have all kinds of racing and high-performance blocks from the factory and the aftermarket. There is no longer any need to go searching through junkyards. Today the new stuff really is better.

I am quite sure the zero hours term comes from aircraft where engine life is measured in hours and has been adopted by other engine rebuilders. Afterall, DFVs seemed to be measured in miles. The description of the 70s was "running a DFV over 500 miles was like playing with a hand grenade with the pin pulled".

The advantage in using used cast iron blocks is they improve with age and use. BMW F1 turbo blocks were supposed to be sourced from returned engines from the factory reconditioning scheme. The most famous aged cast iron block was probably Patch, a much sought after Minister Formula Ford 1600 engine.

[Engineguy]

Originally posted by JtP1
... The most famous aged cast iron block was probably Patch, a much sought after Minister Formula Ford 1600 engine.

Nah... that would have to be the school bus engine Roger Rager qualified for the 1980 Indy 500...

... and he even led a couple laps.



.

[275 GTB-4]

Originally posted by McGuire
It's not like a certified aircraft engine rebuild at an FAA-approved facility where every single component is tested and passed, and every component checked against a defined life cycle, so now the engine can time forward like a new one. Or even an industry-recognized standard like "remanufactured" for replacement engines for production cars and trucks which describes a certain number of new parts. "Zero hours" could mean anything here.

But if you are going to claim or use the "aircraft quality" term..then...everything that can be overhauled and brought back to "like new" should be!! (end of story???)

[275 GTB-4]

Originally posted by McGuire
Doing it right is time and labor-intensive and can exceed the cost of a factory-new or remanufactured engine. But when an engine is built right, it's right. And one of my favorite things.

and indeed a thing of beauty...especially when first started

[J. Edlund]

Originally posted by Paolo
Illuminating, thanks.

But then, a question:

if rebuilding an engine as new is possible, why do F1 teams need 50 engines per season?

When a F1 engine needs replacing most parts are likely near the end of their fatigue life, so most parts needs to be replaced anyway. Going through all old engines and select parts that can be used again is probably not cost effective, it's must easier to just scrap the old engines and build a new engine with virgin parts.

Originally posted by JtP1
The advantage in using used cast iron blocks is they improve with age and use. BMW F1 turbo blocks were supposed to be sourced from returned engines from the factory reconditioning scheme. The most famous aged cast iron block was probably Patch, a much sought after Minister Formula Ford 1600 engine.

Note that this does not apply to aluminium heads and blocks. BMW also only used used blocks early on, I think that it later was replaced by some heat treatment process.

[Engineguy]

Originally posted by J. Edlund
When a F1 engine needs replacing most parts are likely near the end of their fatigue life, so most parts needs to be replaced anyway. Going through all old engines and select parts that can be used again is probably not cost effective, it's must easier to just scrap the old engines and build a new engine with virgin parts.

As I recall, Toyota had a no reuse policy their last year or two in Champ Car when manufacturer participation was at its height (Honda, Toyota, Mercedes, Ford). No engine ran two races and no parts were ever reused, not even blocks, heads, or cranks. Probably not as expensive as you might think if you fairly factor in the skilled personnel costs, logistics, and the reliability risks that come from parts refurbishment. If pace of development is rapid, some parts would be eliminated from the pool anyway because the specs have changed during the season. Remachining (and/or designing in the allowance for it) means at some point, either originally or afterwards, the component was not optimal. Disassembly is an opportunity to inflict unnoticed damage.

Rebuilding is an art, subject to human error and human decisions. Manufacturers are adept at the cold hard science of process control for churning out new, perfect, identical parts.
.

[marchof73]

Originally posted by JtP1


I The most famous aged cast iron block was probably Patch, a much sought after Minister Formula Ford 1600 engine.

From what I remember,Patch was a block that had a rod go through the side,and was subsequently welded,or brazed up with a Patch of metal over the hole.
I remember every top driver wanted Patch for the F/F festival and that the engine was in the winning car a number of year,s running.
Any reason why other than psychological and good driving?
Ian

[McGuire]

Originally posted by marchof73


Any reason why other than psychological and good driving?
Ian

I wouldn't think so. In a tightly regulated, low hp regime like FF1600 a well-prepared, thoroughly seasoned block is very important... straight main saddles for low friction, etc and so forth...and if you have a good block that you know is right you will be more prone to repair it when damaged rather than throw it away... but one with a hole punched through the side is of no particular advantage.

[johnny yuma]

I'm not a "new age" person but a druid in a pub told me if an iron engine was buried in soil for at least a few years it became more durable and good for reconditioning.His story was based on someone finding a stash of Morris Cowley motors buried on a farm,which seemed to posess great wear characteristics when reconditioned.