ZHQ Engine Options

C-GZHQ Engine

Currently the engine is at 1125 hours SMOH. TBO 875 hours.

1975 – Started life an o-360-a4k.

1975 – 1987 – Converted to an a4m. No records are available on the history prior to 1987.

November 1987 – Overhauled and cam replaced.

June 1997 – Overhauled and cam replaced.

December 2002 – Repaired and cam replaced.

June 2005 – Overhauled.

April 2008 – Repaired due to cracked case.


Current condition

August 2012 – Filings evident in the engine oil and filter found during routine maintenance.

September 14, 2012 – 10 hour filter change. Filings still evident, oil sample sent for analysis. Oil sampling is of limited use however, as we have not been conducting routine analysis.

Oil leak from the crank case gasket has been ongoing and Bakerview are aware. This was to be corrected during the last routine maintenance service, due to the metal being found, it has been postponed until a decision on the engine is made.

The aircraft is now on a 10 hour maintenance inspection cycle. It must not be flown beyond the 10 hours from last filter inspection. Bakerview estimate we may not get more than another 20 hours of flight time before we have to address the engine issue and the aircraft will be unserviceable. This decision is still subject to the filter inspection results.

At present the aircraft is being flown very little.

Vendor Comments

From Bakerview Aviation:

‘As we had discussed the engine of C-GZHQ   Lycoming O-360-A4M  is making metal, steel, most likely from the camshaft and or lifters. This is an old  style engine of flat lifter type. I am prepared to sign it out with a notice to inspect the engine oil filter within  10 hours.  The options I have come up with are to remove the engine and have Progressive Air in Kamloops replace the cam and lifters. The options are new  or reground camshaft and lifters.

The price to repair is $6100.00 for new and $5300.00 for reground cam and lifters and that is the fee for the engine shop.

There would be freight on top of that, I would guess $250.00 each way. The cost to re&re the engine would be $2500.00 labor.

The oil cooler would have to be flushed, due to metal contamination, $400.00. The engine time continues as is after the repair. The time now is 1125.5 hours. The recommended overhaul time is 2000 hours.’


From Chad Van Vliet Vantech Aviation Inc.

‘Engine repair, camshaft and lifters would subject to engine evaluation upon tear down. As a base line for repair, I would budget $8000 Cdn. Labour portion would be the same as replacement. While it would not be foolish to repair the engine, taking into account the long term objectives of the Abbotsford Flying Club, I would advise replacement rather then repair due to the open ended nature of the repair and lack of guaranteed longevity.’


Further to the GM on Wednesday, September 12, 2012. We investigated the option of having our engine rebuilt by Okanagan Aero. The result of this was: 

From Chad Van Vliet, Vantech Aviation Inc

‘As follow on to our telephone conversation I conferred with Okanogan Aero Engines and confirmed that conversion of your engine to roller tappets is not possible during a field overhaul. That is the conversion can only be done at Lycoming.

His pricing for a field overhaul at his facility was approximately $4000 less then the factory remanufactured engine with roller tappets.’.


Options  (All prices are plus HST, which the club can recover)

Option 1: Repair the defects. Cost $8-Timeline 3 – 4 weeks.


– Lower initial cash outlay.
– Shorter downtime than option 2 & 3.


– If further damage is found or problems occur prior to TBO, costs increase significantly.
–  Has had 3 new cams, several overhauls and major damage repaired.
– After repair will still be the flat tappet design which has contributed to the problem.
– 37 year old engine
– Limited warranty, extending only to the parts replaced.
– Must use genuine Lycoming parts to be able to exchange the core in the future.
If after taking the crank apart, further damage is found and it is decided to go for the factory rebuild after all, Lycoming charge a $3-6k penalty depending on the damage found.


Option 2: Overhaul existing engine. Budgeted cost max. $25k. Timeline 3-5 Weeks.

– Lower initial cash outlay than factory rebuild.

– Overhauled and major repairs on at least 5 previous occasions.
– 37 year old engine.
– History 10 years prior to 1987 unknown.
– This engine is old technology with flat tappets, which have reliability and wear issues.
– Warranty limited.

Option 3: Replace current engine with a Factory Rebuilt. The same engine as we recently installed inCost approx. $30k Timeline 5-7 Weeks.

– Zero time engine, 2000 Hours TBO.
– New roller tappets.  This model was released in 2005.
– Two year warranty.
– Rebuilt to new engine tolerances. 



– Higher initial cash outlay
– Core exchange penalty as the exchange is not like for like. (We have since  managed to get Lycoming to waive the core penalty, so we can have the like for like price).


Cost Comparisons

Part of the club aeroplane rental rate includes a replacement recovery element (engine replacement reserve account), at $12 an hour. This is set aside to be used for future overhaul or replacement of the engine, but not repairs. Repairs do not come out of this account. With 1125 hours on the engine at $12 an hour cost recovery, we already have $13500 in the account to replace or overhaul the engine. 

  1. 1.Repair the defects at $8-10k this is our minimumComes from maintenance account.
  2. 2.–  $25k minus the $13500 in the engine reserve  account . Net cost $11500.
  3. 3.Factory rebuilt $30k minus $13500 in the engine reserveNet cost $16500

Our minimum cost, which we would have to spend is $10k to repair the fault.  In the engine reserve account we have $13500. Therefore we can allocate $23500 to an overhaul or replacement engine.

The real difference to consider when making this decision, which represents the lost 875 hours TBO:-

  1. 1.Repair existing problem $10k (estimate). This would buy us another 875 hours. The engine reserve account would continue to accumulate until we replace the engine in 875 hours (or sooner if other major faults occur).
  2. 2.current engine – $1150 This will take us to 2000 hours TBO
  3. 3.Factory Rebuild – $3000 This will take us to 2000 hours TBO



Repairing the existing engine is a lower cash outlay, but higher cost to the club. It has inherent risk of finding further problems and other issues occurring in the future. The engine has a sketchy history in its early life. It is 37 years old and has already had several overhauls and major repairs.  This is very much an unknown and carries significant risk.

Overhauling, whilst the lower cost to the club, also carries risk due to the sketchy early history pre 1987, the age of the engine and having several major repairs and overhauls and being the old flat tappet technology.

Should we find more extensive or expensive damage during overhaul or repair, we run the risk of a $3-6k penalty should we later change our minds and want to go for the rebuild after dismantling the existing engine. We also are at risk of not being able to return the core at all once the crank case is opened.

A factory rebuilt engine has a slightly higher cost to the club, however taking into account the $13500 already recovered toward engine replacement and the $10k minimum cost (repair),  this significantly lowers the real cost. The benefits of a factory rebuilt engine are significant to the club.

After investigation of the various options, the lowest risk and most cost effective option, taking into account the engine reserve account and for the long term, is to replace the existing engine with a factory rebuilt engine and return the core for credit to Lycoming. In addition while this is being done, we should also consider upgrades to the instrument panel as has been suggested by a number of members and the aircraft refurbishment committee.  No budget has been set yet for the panel upgrade.

The current average usage of ZHQ SMOH is 160 hours a year. A factory rebuild replacement engine would potentially offer 12.5 years TBO.  Although there is always a risk an engine could fail at any time, based on the history of our current engine, a factory rebuilt engine is significantly lower risk than a repair or overhauling our existing engine.


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21 thoughts on “ZHQ Engine Options

  1. member

    Do the repair for $8000 to $10,000 and get it back on line for another 5 to 6 years. This will stagger the TOB’s from the two other aircraft as HXT requires a new engine and is “on condition”. Therefore, IUK and HXT will have roughly the same TBO in the future. We’ll still have the $13,500 ZHQ reserve and this will build by another $10,000 to $11,000 before TBO 2018. Focus on HXT and spend the money there and get the engine and panel done. Regardless of how the numbers are fudged, it will still cost the AFC $30,000+ for a new engine for ZHQ.

  2. member

    If you recall there was a huge discussion just recently within the club about replacing HXT with “an exciting 2 place airplane”.

    When all the smoke and bafflegab cleared, the decision was to keep HXT supposedly as the exciting 2 place airplane.

    And now you are suggesting we re-engine HXT with a 180 HP engine and have to jump through all the hoops and expense required for such things as STC’s etc.

    For what purpose?

    To keep it as “an exciting 2 place airplane?”

    How soon we forget.

    Marty — you might want to dust off and polish up the Pipistrel pitch……

    Bob Robertson

  3. member

    I prefer Option 3 and suggest the following steps in order:

    1. Replace ZHQ’s engine with a factory rebuilt engine.
    2. Replace HXT’s engine, preferrably with the 180hp and gross weight increase to 2550lbs STC’s, just like ZHQ.
    3. Consider further upgrades (i.e. avionics, paint, etc.) as the budget will bear.

  4. member

    Go with the factory rebuilt and fix up the panel. It doesn’t owe the club anything and we need good reliable, effiecient aircraft (to fly to Oshkosh).

  5. member

    It went in for a filter change today. Bakerview would not sign it out for another 10 hours due to the amount of filings found in the filter. A decision will be made shortly (By the end of the board meeting next week at the latest) how best to proceed and what represents the best value for the club as a whole.

    Safety is the only consideration in the decision to ground the aircraft immediatley.

    Better to be on the ground wishing you were in the air, than in the air wishing you were on the ground!

    Stephen Head
    A/C Maintenance Director

  6. member

    I like your idea Mark T. It is nice to have the weight capasity and hsp for the mountain and long range trips.


  7. member

    Go with the factory rebuilt (like for like price) ASAP.
    I have always felt that 2005 & 2008 were bad decisions.

  8. member

    It seems that reality is a choice of one, a factory zero time engine. My two bits would be to defer other upgrades, we are working on IUK and XHT this year. Though we should run XHT on condition in the interim to spread the cash. I support Stephen’s decisions and thank him for the clarity. Ed

  9. member

    Comment #1.

    Stephen, regarding your comment (#14) about the board making a decision on both HXT and ZHQ. I hope part of the plan is to bring these decisions to the membership for approval, prior to committing the AFC to the costs associated with the decisions of the board.

    See the next post for my thoughts on what choice to make

  10. member

    A decision will be made at the next board meeting on both the ZHQ engine and the HXT engine. We can then place the orders and get things moving ASAP.

  11. member

    Put in the new factory engine as soon as possible. Order the same for HXT while your at it.

  12. member

    Thanks for all your hard work once again Steve H.
    I think the factory rebuilt is the way to go. Get a good safe engine with a warranty in ZHQ. Leave the panel til we get HXT sorted.

  13. member

    If I read the cost charts correctly, the total net difference between the least costly choice (repair the damage) and most expensive one (new engine) is only (only?) $8,000. With the first choice, there is no warranty, no assurance, of an engine that will give the AFC any amount of trouble-free service. With the other, the new engine will come with a two year warranty. Keep in mind that the engine case in ZHQ is almost as old as some of us longer time members. And we know that none of us would be candidates for any sort of rebuild program. The decision about this airplane should perhaps be made without the thought of what we want to (not need to) do to HXT. Thanks for listening,


  14. member

    Boy, I sure wouldn’t walk into a fancy restaurant and order steak and lobster without checking to see how much cash I had in my jeans! A couple of new engines for HXT and ZHQ would be great–so would a new Cessna off the showroom floor, but the big question is, “Can we afford it”? Just a few short years ago our treasurer told us we were insolvent. Reports of our current net worth have been scarce and we just dusted off a hundred and ten grand on IUK. Maybe we should wait for a complete and full treasurer’s report at the AGM before major decisions are made.

  15. member

    To address Rick’s first comment: This forum is to collect the opinion of the membership. As was made clear at last week’s GM, and as was done for IUK, the Board will take full account of this input and of any delegations at it meeting on wednesday, as well as the recommendations of the aircraft committee and maintenance director. This weeks Board meeting will decide on what to do with ZHQ’s engine as well as the HXT decisions that were already slated for this meeting. One aspect of these decisions will be prioritisation, the timetable, and cashflow.

  16. member

    ZHQ was given the status of “Our Number One Aircraft” through our fleet renewal process last year. It should get factory rebuild with the warranty. After the problem is solved, the options for the future of HXT in the club should then be re-examined as a seperate conversation.

  17. member

    We were technically insolvent in 2008 because the Bell Canada bond could not be traded, while at the same time we had hangar investors waiting to be paid back. Since then the bond was sold and the debts paid, and we have had a positive net income each year since. Our financial position has been reported regularly at Board meetings, and copies of those statements are available to all Members.
    Having said that, it has to be recognised that the ZHQ situation was not foreseen, and it definitely has an impact on the prioritisation and timetable we pursue with respect to aircraft revitalisation.

  18. member

    A factory rebuilt engine has been ordered. Completion is expected for mid to late November.


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