AnswerID: 484081 Submitted: Tuesday, Apr 24, 2012 at 22:22
Eyspy - Get your engine reconditioned. Exchange engines quite often means you end up with someone elses pile of crap. Your engine may only need modest repairs, if it actually is low kms, as you say. If the vehicle was purchased used, the kms may not be correct. A low km engine shouldn't need a rebore, unless it's been run cold a lot.
The knock may have been caused by oil starvation, caused by sludgy oil. Many engines don't get adequate oil changes.
Oil changes need to be done on a time basis, not a kms basis, when vehicles aren't being used much.
I've come across large numbers of engines that suffer from massive sludge deposits inside them.
This is caused by cold running, short trips, inadequate oil change intervals, coolant contamination, and wrong oil type.
An exchange engine may come bored out to its maximum oversize, meaning you won't be able to exchange it next time.
It may have been in a major fire, and the metal in the block has gone soft. An exchange engine may have had a catastrophic failure and been repaired on a major scale - or still be suffering from the effects of that major damage, that wasn't picked up.
I've seen a bloke have enormous amounts of trouble with an exchange engine - then it was discovered that the crankshaft was twisted, and a check for crankshaft twist had never been carried out when it was rebuilt.
Engine blocks and heads suffer from corrosion in the water jacket areas. You may end up with an engine where the corrosion has been so bad, it develops a hole in the head or block within a short space of time after installation.
Lastly, engine designs change, even within a couple of years in the same model. The components can be re-engineered, upgraded, or strengthened. With an exchange engine, you may get an engine that is 5 or 8 yrs older than yours, and not have the engineering changes, upgrades, or strengthening, that your engine has.
Cheers - Ron.
Reply 2 of 3
FollowupID: 759330 Submitted:
Tuesday, Apr 24, 2012 at 22:37
Thank you for the detailed reply Ron, it was spot
on to the way my mind was thinking, but not voicing (I did not want to put words in others mouths).
The Km's seem to be genuine as I knew the owner that had it and he rarely had it out of the shed. It has log books and it all ties in with the servicing from reputable garages.
I have only just bought it and have been in contact with the owner and he swears that it has had the same knock for 4 years with no problems apart from a head gasket about 3 years ago.
My dilemma is do I let it go and see if it does last ? Or do I get i fixed ? (money is tight)
If I let it go I risk doing more serious damage and not have a trade if it blows, if I let it go I may get long life, noisy life but long ?
FollowUp 1 of 5
FollowupID: 759333 Submitted:
Tuesday, Apr 24, 2012 at 23:03
Ron N posted:
Eyspy - Get it fixed. A stitch in time saves nine. The knock may have been there for a while, but that's not to say it's a benign knock. It could be a loose component that will eventually destroy itself, then possibly the rest of the engine.
A knock is generally excessive clearance in some moving component - although it can also be caused by some other odd events
that are fairly uncommon.
A chunk of carbon stuck to the combustion chamber can get red hot and pre-ignite the fuel. However, this would only happen when the engine was hot.
If the knock is there all the time, hot or cold, it'll most likely be a moving component with excessive clearance.
It could be something simple, or it could be a bearing that is ready to "run", and thereby possibly damage the crankshaft beyond repair. The major thing is to have someone with extensive experience and a good track record to find the precise problem, and do the repairs on it.
A good repairer is very thorough and checks all components to ensure they meet specifications - and checks even things such as flywheel runout, which many repairers never check.
All engine components have specifications for wear, runout, clearance, etc ,and these must all be checked.
It's the thoroughly-repaired engine that keeps going. The slapdash repairers get all the "comebacks", because they weren't thorough enough.
Cheers - Ron.
FollowUp 2 of 5
FollowupID: 759336 Submitted:
Tuesday, Apr 24, 2012 at 23:09
Thanks Ron, I hear you and understand, I guess I am just wishful thinking at the moment. Save a few $$ today but cost more $$ tomorrow.
Next trip to Adelaide
I will see that bloke in Salisbury and get some better handle of the situation.
FollowUp 3 of 5
FollowupID: 759339 Submitted:
Tuesday, Apr 24, 2012 at 23:36
Ron N posted:
If it's a low km engine, it shouldn't require a major rebuild. The two things that modern engines die from, is cooling system corrosion, and electronics failure. In fact, most modern engines die an electronic death.
When a vehicle gets around 15 yrs old with high kms, the value has dropped to a low figure, and a major electronics component failure is usually the reason they're scrapped.
The second biggest source of problems is cooling system corrosion problems. A lack of cooling system maintenance (not flushing and changing coolant with factory recommended coolant every 3 years) will soon see corrosion holes appear in major components. It's worse now that so much alloy is used in todays engines.
If you keep your coolant in top condition, a modern engine will generally give little trouble - unless you overheat it through overloading, run at constant high speed in high ambient temperatures, never change the oil, etc.
After about 10 yrs, the third biggest source of problems is with hoses and wiring. Many hoses, plastic components, and attachments start to degrade, develop cracks and splits, or corroded connections, and thereby create engine problems.
Your problem may be a relatively simple one, or it may involve substantial engine dis-assembly. Get the repairer to examine your engine at length, and give you his opinion on the problem. A good mechanic with extensive experience will usually be able to pinpoint the problem and give you a written quote.
Never let anyone commence repairs until you have agreement on the problem, and the cost of the repair in writing.
Casual, verbal O.K.'s for repair work to be done, nearly always lead to sizeable cost over-runs and disputes. If the repairer pulls an engine down and finds something that needs to be repaired, that wasn't discussed or even imagined to be the problem - then he should cease repair and contact you to discuss what extra is required to be done, and then get your approval to proceed.
Cheers - Ron.
FollowUp 4 of 5
FollowupID: 759356 Submitted:
Wednesday, Apr 25, 2012 at 08:35
Thanks for the time you have taken, very helpful.
FollowUp 5 of 5