Engine Life

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Original submission by T Jan 16th 2007:

Back to the Engine Section

The Oil Filler Cap on an HT 186 Kingswood. White emulsion is water vapour which can be caused by an excessive number of short runs without the correct driving intervals in between. Note the heavy buildup of carbon caused by the lag in the engine oil temperature. The engine has not been getting hot enough for long enough. Click to Enlargen. Photo by Mynew69ht.

The Factors That Determine Long Engine Life:

Routine Maintenance:

It's no secret that Engines thrive on routine maintenance. The efficiency
of the Engine effects both its Performance and Economy so routine Tuneups
and Oil and Filter Changes are a must if an owner is to see the best Performance
and Fuel Economy from any investment in a car.
Short runs cause the sump and tinwear areas to be filled with the thick black sludge you can see in the image. The same sludge finds its way into the piston ring grooves, fills them up and blocks them off. The result is that the ring pack loses gas pressurisation as in the animation. Without gas pressurisation, compression is lost. With reduced compression the combustion temperatures fall and heavy combustion chamber deposits result, causing pinging. Power loss and oil burning also result. Click to Enlargen. Photo by Mynew69ht.

Gunk buildup in an Holden red Six as a result of improper use and/or maintenance. Photo by HR Ambo. Click to Enlargen.
White Sludge formed under the Oil Filler Cap of a Grey 138 cu in Holden Six Cylinder Engine. Lots of Short Runs that don't allow the Oil to fully heat up are a major cause of this problem. Click to Enlargen. Photo by Scott4571.
 
No 3 Big End and Main Bearing Caps after 16 years of proper Oil Changes. Photo by HJDave. Click to Enlargen.
Photo by Mynew69ht. Engine Oil on the top of the Rocker Cover around the Oil Filler hole shows that the piston rings are gummed up and allowing excessive blowby past the rings. Another legacy of short runs, warming up or improper running in general.

Other Factors:

After that some other factors come into play which have been covered in other
pages at the site.
Engine Oil
PCV
Economy
202 with around 750,000kms. No warming up or short runs. Note the inner cleanliness. Oil used is GTX-2. Allowing the Engine Oil to reach operating temperature makes any Water vapour in the Oil evaporate out and be burned through the PCV system. Photo by T. Click to Enlargen.
 

Engine Loading:

In addition to those factors, how the Engine is loaded is a critical factor.
Contrary to popular belief the little old person who only drove their car to the
supermarket on Sunday did more to ruin the Engine than almost any other driver.
Not only did the short runs contribute to all the negative effects covered
in those other pages it left the Engine underloaded.
Engines need to work to load up the Compression Rings. This not only makes
the Rings seal properly but it keeps the Bore Faces (the surfaces of the Cylinders) work hardened. Since the bores are made of soft Cast Iron something has to be working for them to give them long life. That something is the effect of a Natural Bearing.

PistonRings.gif

Blue 3.3 6 Cyl CF Bedford Engine. This Engine was steamed through just before the head was removed. Photo by reppilF. Click to Enlargen.

Gas Pressurisation of the Piston Rings:

The animation shows how the Compression Rings are forced against the Bore Faces
when the Engine is driving the ideal load. There is enough resistance to the downward
force applied to the Piston to force the Compression Rings against the Bore Faces.
The animation also shows what happens when the Engine is not working hard enough. The Compression Rings are not forced against the Bore Faces and the Piston Ring Grooves
clog up with Carbon. 
Blow-By covered Pistons from an HR Red Six.  Note the Carbon buildup in the Top Piston Grooves.  Click to Enlargen. Photo by TomKelly.
Photo by TomKelly. The Piston is Cam Ground meaning that it is oval shaped when cold but becomes round as it expands.  Blow-By has been getting past the Rings on the Piston's oval Side because the Piston has not become hot enough to expand sufficiently. Click to Enlargen.
Photo by TomKelly. Note the heavy black deposits on top of each Piston meaning that the Engine has not had proper running.  Click to Enlargen.
 
    
  

The Natural Bearing:

Throughout an Old Holden Engine there are many Natural Bearings. These are formed
when a soft metal runs in contact with a hard metal. Examples are ...


 
 Material One
  Material Two
  Hard Valve Stems
 Soft Cast Iron.
 Hard Piston Rings
  Softer Cast Iron
  Soft Alloy Pistons
  Harder Cast Iron
  Hard Big End Journals (Bearings)
 Soft White Metal Big End Bearings.
 Hard Crankshaft Journals (Bearings)
 Soft White Metal Main Bearings
 Hard Rocker Arms Soft White Metal Saddle Bearings
 Hard Camshaft Bearings   Soft White Metal Cam Bearings
 Hard Rockers (non-adjustable) Soft Alloy Bridges (non-adjustable)

These bearings run in hot Oil and with friction. As a consequence a bearing surface
is made where the two different metals make contact.

Work Hardening:

When it comes to the Bores, these are dependent on hard Piston Rings to wear a work hardened face onto them. They are also affected by the Oil Scraper Ring which has the job of pulling Oil back into the sump so that only a tiny amount
makes it into the Combustion Chamber.
The fact that the bores have Compression Rings whose natural action is to work harden the bores and the opposing action of the Oil Rings to scrape them clean means that under certain circumstances either the Compression Rings or the Oil Rings can gain the upper hand.

The Oil Rings As the Bore Wear Culprit:

The Oil Rings can gain the upper hand and start tearing down the work hardening on the bore faces if the Compression Rings get too easy a time. That situation would occur if the Engine were running too light a load. Too light a load will occur if the Differential Ratio permits an excessive number of Engine turns for any speed of the car.

The Compression Rings as the Bore Life Extender:

The Compression Rings can gain the upper hand and keep the work hardening on the bore faces if put to work properly. That situation would occur if the Engine were running the correct load. The correct load will occur if the Differential Ratio permits an appropriate number of Engine turns for any speed of the car.
 
Poor Oil management has resulted in this thick accumulation of goo in the bottom of the Sump in a 179. Click to Enlargen. Photo by HRAmbo.

=

Driving Style:=

The way a car is driven can also determine the Engine life. In a Manual Car, changing up to the next gear early and flooring the Accelerator loads the Engine correctly, makes the mixture burn more completely and gives the best gas mileage.
Revving the car out in each gear burns up the bores as well as a lot of fuel.
In short, keeping the revs down and making the Engine work gets the best results.

Diff Ratios in Old Holdens:

Looking across the model range of Holdens from 48/215 to HQ some interesting info appears.

Model/6 Cyl Engine/Diff Ratio Comparison:

 
Model
Engine Size
 Standard Diff Ratio
Wheel Size  15" Wheel Size GMH equiv Diff
  VB 173/202 Cubic Inches (2850/3300cc)3.08 A (appropriately-geared)
 
 14 inch
 3.36 A
HZ  173/202 Cubic Inches (2850/3300cc)
 3.55 M 3.36 A (under-geared)
 14 inch
  3.89 M 3.55 A
  HX
 173/202 Cubic Inches (2850/3300cc)  3.55 M 3.36 A (under-geared)
 14 inch
 3.89 M 3.55 A
  HJ

 173/202 Cubic Inches (2850/3300cc)
 3.55 M 3.36 A (under-geared)
 14 inch
 3.89 M 3.55 A
  LJ

 138/173/202 Cubic Inches (2250/2850/3300cc)
 3.08 M 3.08 A (appropriately-geared)
 13 inch
  3.55 M 3.55 A
  HQ
 173/202 Cubic Inches (2850/3300cc) 3.55 M 3.36 A (under-geared)
 14 inch
 3.89 M 3.55 A
LC
  161/186 Cubic Inches (2600/3050cc)   3.08 M 3.08 A (appropriately-geared) 13 inch 3.55 M 3.55 A
 HG
 161/186 Cubic Inches (2600/3050cc)
  3.55 M 3.36 A (under-geared)
 14 inch
 3.89 M 3.55 A
  HT
  161/186 Cubic Inches (2600/3050cc)
 3.55 M 3.36 A (under-geared)
 14 inch
 3.89 M 3.55 A
 HK
 161/186 Cubic Inches (2600/3050cc)
 3.55 M 3.36 A (under-geared)
 14 inch
  3.89 M 3.55 A
  HR
 161/186 Cubic Inches (2600/3050cc)
 3.55 M 3.36 A (under-geared)
 13 inch 4.41 M 3.89 A
HD
 
 149/179 Cubic Inches (2440/2935cc)
3.55 M 3.36 A (under-geared)
 
13 inch
 
4.41 M 3.89 A
 
 EH
 149/179 Cubic Inches (2440/2935cc)
 3.55 M 3.36 A (under-geared)
 13 inch
 
4.41 M 3.89 A
 
 EJ
 138 Cubic Inches 2250 cc
 3.89 (under-geared)
 13 inch Nothing High Enough Available
 EK
 138 Cubic Inches 2250 cc
 3.89 (under-geared)
 13 inch Nothing High Enough Available
 FB
 138 Cubic Inches 2250 cc
 3.89 (under-geared)
 13 inch Nothing High Enough Available
 FE 132 Cubic Inches 2150 cc
 3.89 (under-geared)
 13 inch Nothing High Enough Available
 FJ
 132 Cubic Inches 2150 cc
 3.89 (critically-geared)
 15 inch 3.89
  48/215/FX
 132 Cubic Inches 2150 cc
 3.89 (critically-geared) 15 inch
 3.89
     48/215 Holdens and FJ's had 132 CID Engines driving 3.89 diffs into 15" wheels. They handled
this adequately.
The subsequent drop to 13" wheels (FE - HR) saw 3.89 diffs for
the remaining grey motor sedans and 3.55 for the red motor manuals.
If the 48/215 and FJ diffs are extended from their wheels sizes
they would have been running 3.36 diffs into 13" wheels and
still handled the gearing fine.
When red motor Holdens appeared with 3.55 diffs for the manuals it
was surprising how fast these cars started pumping blow-by gas
from their "umbrella handle" Engine breathers. The issue was far
more noticeable than on grey motor Holdens and became less prevalent
when the HK and later appeared with 14" wheels because the larger wheel
size placed better loading on the Engines.
My point here is that 6 cylinder Torana's came standard with
3.08 diffs and 13" wheels meaning that EH - HR was chronically
under geared.
VB Commodores appeared with red 202's (3300cc) Engines, Trimatic gearboxes,
14" wheels and 3.08 diffs. In FX/FJ terms this would be the equivalent of replacing the
3.89 diff with a 3.36 diff making good sense considering the Engine is 1 litre larger in capacity.
Undergearing sold well in an era that was keen to get extra
performance on largely goat-track roads. Overtaking was made
much easier by just flooring the throttle and letting the low
diff ratio take care of things.
With the advent of expressways these original red motor ratios
burn up engines. 

Is My Engine Really Worn Out?:

Blocked Piston Ring Grooves cause Compression loss and Oil Burning as demonstrated in the animations.  
Clear Piston Ring Grooves. Click to Enlargen. Image by T
An Engine whose bore and Piston clearance is still within spec can be caused to show wear symptoms even under a Compression test.  
Blocked Piston Ring Grooves. Click to Enlargen. Image by T
  
Broken Adjustable Rocker Saddle. A Steel Rocker running friction against a Steel Ball is not a natural bearing. The Image shows a failed Rocker Arm. Image by  HGKingswood186. Click to Enlargen
Broken Adjustable Rocker Saddle. A Steel Rocker running friction against a Steel Ball is not a natural bearing. The Image shows a failed Rocker Arm. Image by  HGKingswood186. Click to Enlargen

Undergearing in 6 Cylinder Toranas:


Undergearing is a direct cause of Oil Leaks in main stream 6 Cylinder Toranas (excludes
XU1's). A 3.08 diff and 13" wheels is not enough load for a red six
that might equally have been fitted to a Kingswood with 14" wheels.
Steaming out the cylinders periodically is a cure if a diff ratio change cannot be effected.
Rescheduling the driving style can help. Changing up early and flooring it in a manual
will make the compression rings bite in harder. Fitting a Power/Economy Switch
can increase the Engine's workload in a Trimatic.

Late Model Cars:

These run quite tall diffs with gearboxes that have more ratios than Old Holdens.
Since Late Model Cars also have changes to the Engines to allow them to produce power more
efficiently they are able to drive tall gearing and still give good performance.
These are covered under the Economy page.

The Cold Start Wear Myth:

It's generally considered that Cold Starts cause a high degree of Engine wear because the Oil needs time to flow through. The Image shows a Rocker Arm that is furthest from the Sump and that it's laced with Oil.  You can see that Cold Starts pose little problem for a Red Six.
Pre-Cold Start. Note the Rocker Arm is laced with Oil. Photo by T. Click to Enlargen.
 
Piston from a mis-used Grey Motor. Dirty Oil and not reaching operating Temperature are only 2 of the problems. Photo by 1962_EJ. Click to Enlargen.
The Piston is Cam Ground meaning that it is oval shaped cold and becomes round as reaches operating Temperature. Photo by 1962_EJ. Click to Enlargen.
Note that the Ring Lands show minimal wear yet the outside of the Piston Rings are  burned. The Piston Ring Grooves are filled with watery/Oil sludge preventing the Ring Pack from Gas Pressurising properly. Photo by 1962_EJ. Click to Enlargen.
 
Incorrect running coupled with incorrect Oil Change Intervals results in moulded Sludge inside the Engine. Photo by Juzzy. Click to Enlargen.
 
Con Rod failure. Can be caused by Oil Starvation. Photo by Ben Simpson. Click to Enlargen.

Links:

Dusty's Catastrophic Failure Collection

Bearing Caps Thread

Terms:

Terms

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