AJP Reliability
Discussion
Hi all,
I am starting this post to pool some information, for myself, I am aware that there are a few previous threads on the subject, but I wanted to clarify a few key points to myself.
There seems to be a great difference of opinion with regard to the reliability of the AJP units, with a lot of people claiming bulletproof reliability, and others reporting weak cranks, head gasket failures and various other failures.
For the purposes of this thread, I would prefer to stick to the V8 variants, both 4.2 and 4.5.
I am fully aware that there is no set criteria for engine failure, and that maintainence and machanical sympathy play a large part.
A lot of information I have read regarding the 4.2 engines seems to indicate that the early cars were the only ones to suffer from crankshaft failure, 96-97, is this correct? If so, what changed after 97, and how can the changeover point be determined.
I have read a lot of information which claims the 4.5 to be considerably stronger, why is this, and can the 4.2 be modified to this spec without an engine swap? Are the head gaskets stronger on 4.5's also?
Any other differences or points of discussion are welcome.
Thanks, Mark
I am starting this post to pool some information, for myself, I am aware that there are a few previous threads on the subject, but I wanted to clarify a few key points to myself.
There seems to be a great difference of opinion with regard to the reliability of the AJP units, with a lot of people claiming bulletproof reliability, and others reporting weak cranks, head gasket failures and various other failures.
For the purposes of this thread, I would prefer to stick to the V8 variants, both 4.2 and 4.5.
I am fully aware that there is no set criteria for engine failure, and that maintainence and machanical sympathy play a large part.
A lot of information I have read regarding the 4.2 engines seems to indicate that the early cars were the only ones to suffer from crankshaft failure, 96-97, is this correct? If so, what changed after 97, and how can the changeover point be determined.
I have read a lot of information which claims the 4.5 to be considerably stronger, why is this, and can the 4.2 be modified to this spec without an engine swap? Are the head gaskets stronger on 4.5's also?
Any other differences or points of discussion are welcome.
Thanks, Mark
In the 50k miles I have covered in mine I have not had a single mechanical failure with the engine. The head gaskets did start to weep coolant up the head bolts but that was an age related issue with the gaskets rotting after 18 years of service.
I have had a couple of issues with the gearbox but to be honest I do spank the old girl regularly, the engine seems to love it but the gearbox has complained about it twice.
A few electrical niggles like earthing issues and one set of clutch seals but only the gearbox has actually left me stranded.
Are they bullet proof, in my opinion yes they are with the provision that they are properly maintained.
If you can make it to Brands Hatch on Monday you can hop in for some pax rides, that should sell you on the engine:-)
I have had a couple of issues with the gearbox but to be honest I do spank the old girl regularly, the engine seems to love it but the gearbox has complained about it twice.
A few electrical niggles like earthing issues and one set of clutch seals but only the gearbox has actually left me stranded.
Are they bullet proof, in my opinion yes they are with the provision that they are properly maintained.
If you can make it to Brands Hatch on Monday you can hop in for some pax rides, that should sell you on the engine:-)
Edited by gruffalo on Friday 15th July 14:00
SimonKD said:
mjf93 said:
Are the head gaskets stronger on 4.5's also?
Hi MarkThis could end up being quite a long thread
Copper head gaskets IMO are an expensive but worthwhile upgrade as both 4.5 and 4.2 suffer from failures fairly often using standard gaskets.
Regards
Simon
A common cause of premature head gasket failure is engines being rebuilt by people who are inexperienced with the AJP who set the liners flush with the block face instead of proud of the block face.
The other main failure now is rotting due to age and that will happen in any car.
Some of the 4.2's had the larger crank but the early ones didn't and some snapped, most will have been sorted by now with either a 2.5 inch crank or a stronger billet steel crank so as to overcome this problem.
The AJP8 is a robust engine.
My knowledge extends to the following: Early cranks were cast, later ones were steel and the switch happened some time in 1997. Look for two train plugs on the sump (One either side) as that indicates a car that's most likely to have an early type of crankshaft. After this point, stronger crankshafts from the 4.5 engines are the norm.
Although it's a fatigue related failure, it's perhaps reasonable to expect that most of the cars which were likely to fail would have already failed by this point in time as they tended to fail quite early on, although a couple have failed many years later.
Apparently 614 Cerberas were made in 1996/7 and reported failure rates I've heard of range between 30 to 50 cars, with the latter still only representing 8.14% of the total Cerbera population. You therefore had a ~92% chance or greater of the car being completely fine with regards to the crankshaft 19/20 years ago.
It stands to reason therefore that, with those cars assumed fixed since they couldn't be driven after the failure, your chance of encountering a car with a crankshaft waiting to snap is further significantly reduced as those 30-50 cars are now fine again. Driving style and mechanical sympathy are obviously factors, but they are 20 years old now, so I doubt the future failure rate would exceed that of a reasonable margin for error for any car of this age.
If the engine has been rebuilt, you'll find many people (TVR Power in particular) now offering almost Kia like warranties on their engine work, so if someone decent has done it, that's something else to consider.
The AJP8 is one of the highest power output normally aspirated engines ever produced; it's a racing engine; in relation to its conception 4/5ths of a Honda F1 V10, so obviously it won't be as reliable as a General Motors inline 4. I do however have a feeling that if you seriously compared notes with owners of other 20 year old supercars (Which incidentally are slower... and not as cool...), the AJP8s around now in either 4.2 or 4.5L guise would appear quite remarkable.
I've talked to a few ex Aston DB7 owners for instance. Ex....
Although it's a fatigue related failure, it's perhaps reasonable to expect that most of the cars which were likely to fail would have already failed by this point in time as they tended to fail quite early on, although a couple have failed many years later.
Apparently 614 Cerberas were made in 1996/7 and reported failure rates I've heard of range between 30 to 50 cars, with the latter still only representing 8.14% of the total Cerbera population. You therefore had a ~92% chance or greater of the car being completely fine with regards to the crankshaft 19/20 years ago.
It stands to reason therefore that, with those cars assumed fixed since they couldn't be driven after the failure, your chance of encountering a car with a crankshaft waiting to snap is further significantly reduced as those 30-50 cars are now fine again. Driving style and mechanical sympathy are obviously factors, but they are 20 years old now, so I doubt the future failure rate would exceed that of a reasonable margin for error for any car of this age.
If the engine has been rebuilt, you'll find many people (TVR Power in particular) now offering almost Kia like warranties on their engine work, so if someone decent has done it, that's something else to consider.
The AJP8 is one of the highest power output normally aspirated engines ever produced; it's a racing engine; in relation to its conception 4/5ths of a Honda F1 V10, so obviously it won't be as reliable as a General Motors inline 4. I do however have a feeling that if you seriously compared notes with owners of other 20 year old supercars (Which incidentally are slower... and not as cool...), the AJP8s around now in either 4.2 or 4.5L guise would appear quite remarkable.
I've talked to a few ex Aston DB7 owners for instance. Ex....
Edited by NuddyRap on Friday 15th July 15:01
Thank you all for the replies. Very helpful information.
So to clarify, do the later 4.2 AJP cars have the larger crank journal size, as the 4.5, or are they simply made of a stronger material.
Head gaskets sound like something which may need attention on all variants then. As I understand, this problem is exacerbated by infrequent coolant changes. Is this correct?
I have also read, in various places, that the top end can be damaged by not having the valve clearances checked, a 12k service item I believe, is this you guys experience also? Is this also a time related service item, or just mileage?
So to clarify, do the later 4.2 AJP cars have the larger crank journal size, as the 4.5, or are they simply made of a stronger material.
Head gaskets sound like something which may need attention on all variants then. As I understand, this problem is exacerbated by infrequent coolant changes. Is this correct?
I have also read, in various places, that the top end can be damaged by not having the valve clearances checked, a 12k service item I believe, is this you guys experience also? Is this also a time related service item, or just mileage?
Steve_T said:
What changed from 4.2 to 4.5 (aside from bore and stroke) was crank journal size from 2.3 inches to 2.5.
Steve, from your profile, I believe it was yourself that I met at the Classic Le Mans, and took me for a spin. Thank you once again for the ride in your beautiful cerb, and helpful information. Since the OP is asking of differences... Here is a odd one that may enlighten further. I once ad that some Cerb 4.2 owners had an engine that was stamped as the 4.5? If so what did that imply? Was the capacity actually a 4.5 with the intake of a 4.2 or were ther actually other mechanical differences in the engine
Sorry to confuse or deviate
Sorry to confuse or deviate
Incognegro said:
Since the OP is asking of differences... Here is a odd one that may enlighten further. I once ad that some Cerb 4.2 owners had an engine that was stamped as the 4.5? If so what did that imply? Was the capacity actually a 4.5 with the intake of a 4.2 or were ther actually other mechanical differences in the engine
Sorry to confuse or deviate
Yep, post 2000 cars many 4.2 were in fact 4.5 but with 4.2 induction.Sorry to confuse or deviate
Later the car was standardised on 2.5 cranks. Many of the 2.3 cranks were replaced with billet steel cranks just a different way 2 crack the same nut.
I
Edited by gruffalo on Friday 15th July 22:24
gruffalo said:
In the 50k miles I have covered in mine I have not had a single mechanical failure with the engine. The head gaskets did start to weep coolant up the head bolts but that was an age related issue with the gaskets rotting after 18 years of service.
I have had a couple of issues with the gearbox but to be honest I do spank the old girl regularly, the engine seems to love it but the gearbox has complained about it twice.
A few electrical niggles like earthing issues and one set of clutch seals but only the gearbox has actually left me stranded.
Are they bullet proof, in my opinion yes they are with the provision that they are properly maintained.
If you can make it to Brands Hatch on Monday you can hop in for some pax rides, that should sell you on the engine:-)
Thank you very much for the insight and your offer. Sadly, I won't be at Brands on Monday to take up your offer, but if you get any videos from the day I would love to have a watch! I have had a couple of issues with the gearbox but to be honest I do spank the old girl regularly, the engine seems to love it but the gearbox has complained about it twice.
A few electrical niggles like earthing issues and one set of clutch seals but only the gearbox has actually left me stranded.
Are they bullet proof, in my opinion yes they are with the provision that they are properly maintained.
If you can make it to Brands Hatch on Monday you can hop in for some pax rides, that should sell you on the engine:-)
Edited by gruffalo on Friday 15th July 14:00
I guess my biggest reservation is I am coming from a GM production car, a Monaro, into a much more bespoke machine. Whilst that is a large part of the attraction, I need to know I could trust it to head down to Le Mans, or other road trips, on a yearly basis without catastrophe.
Put it into context:
Anything can go wrong with any car at any time; even brand new cars break down!
A car is only as reliable as (the things checked at) its last service.
Many components on mainstream cars are built to fail in a given time-span (anything from 5 to 10 years) whereas modern engines reliably reach 250,000 miles without bother.
This will be a 13 to 20 year old car, built with some off-the-shelf parts that were not even designed for automotive use (eg switches) and some made by outside contractors (eg ECUs), some in-house by TVR, none of which have enjoyed the extensive testing/R&D that Messrs Ford, GM, Mercedes etc carry out.
It is therefore unreasonable to expect 100% reliability, although it does seem that the engine itself is the least of our worries, provided (as with any car) that regular servicing and frequent oil changes are carried out.
Anything can go wrong with any car at any time; even brand new cars break down!
A car is only as reliable as (the things checked at) its last service.
Many components on mainstream cars are built to fail in a given time-span (anything from 5 to 10 years) whereas modern engines reliably reach 250,000 miles without bother.
This will be a 13 to 20 year old car, built with some off-the-shelf parts that were not even designed for automotive use (eg switches) and some made by outside contractors (eg ECUs), some in-house by TVR, none of which have enjoyed the extensive testing/R&D that Messrs Ford, GM, Mercedes etc carry out.
It is therefore unreasonable to expect 100% reliability, although it does seem that the engine itself is the least of our worries, provided (as with any car) that regular servicing and frequent oil changes are carried out.
mjf93 said:
I guess my biggest reservation is I am coming from a GM production car, a Monaro, into a much more bespoke machine. Whilst that is a large part of the attraction, I need to know I could trust it to head down to Le Mans, or other road trips, on a yearly basis without catastrophe.
After 3 pain free and VERY enjoyably trips to Le Mans from Yorkshire I can confirm these cars are excellent GT cars with huge boots. They can offer a relatively civilised cruise down the auto routes or a full on blast down the back roads. I debated for a long time to make the swap from an old Ford toy 4years ago and I have zero regrets. Hopefully people will agree that the key thing is buy on condition not which engine. For me it ended up being a 4.2 but a friend bought his 2 years ago and it was a latter 4.2 with the 4.5 block. He also has had 2 successful trips to Le Mans from Nottingham.
Happy hunting.
Twinkam said:
Put it into context:
Anything can go wrong with any car at any time; even brand new cars break down!
A car is only as reliable as (the things checked at) its last service.
Many components on mainstream cars are built to fail in a given time-span (anything from 5 to 10 years) whereas modern engines reliably reach 250,000 miles without bother.
This will be a 13 to 20 year old car, built with some off-the-shelf parts that were not even designed for automotive use (eg switches) and some made by outside contractors (eg ECUs), some in-house by TVR, none of which have enjoyed the extensive testing/R&D that Messrs Ford, GM, Mercedes etc carry out.
It is therefore unreasonable to expect 100% reliability, although it does seem that the engine itself is the least of our worries, provided (as with any car) that regular servicing and frequent oil changes are carried out.
From my point of view - and I think this is what the OP is also getting at is - are there any KNOWN weaknesses that might be more likely to give you a large unexpected bill that could be avoided by not purchasing a certain model / age of car.Anything can go wrong with any car at any time; even brand new cars break down!
A car is only as reliable as (the things checked at) its last service.
Many components on mainstream cars are built to fail in a given time-span (anything from 5 to 10 years) whereas modern engines reliably reach 250,000 miles without bother.
This will be a 13 to 20 year old car, built with some off-the-shelf parts that were not even designed for automotive use (eg switches) and some made by outside contractors (eg ECUs), some in-house by TVR, none of which have enjoyed the extensive testing/R&D that Messrs Ford, GM, Mercedes etc carry out.
It is therefore unreasonable to expect 100% reliability, although it does seem that the engine itself is the least of our worries, provided (as with any car) that regular servicing and frequent oil changes are carried out.
I'm not expecting 100% reliability and will expect to have an ongoing "to do" list of things that need attention - but if I can avoid an engine that's likely to grenade itself then so much the better!
From what's been suggested about cranks it would appear that those that have failed have been replaced with better parts and that those that haven't failed probably won't - as long as they've done a few miles.
That's quite encouraging that the expensive bespoke part of the car appears to be fairly robust.
Indeed. And some things are incalculable and can be argued both ways.
For example, consider the (ab)use these cars have been subjected to, let's face it, not many have had 'one careful lady owner'... if it's been spanked relentlessly does that mean it's all about to fall apart?.. or rather that it has been thoroughly tested in the real world and found to be more than capable?
Or does the book full of service stamps ensure that it's been better maintained (possibly by the spotty apprentice under time constraints) than by the owner, a skilled engineer with 30 years' experience, building his own race cars in his home workshop, who has all week to complete the job (and his own neck at risk)?
At the end of the day, it's a gamble. It was when they were new! But the personal testimonies to the reliability of these oft- maligned engines is most encouraging.
For example, consider the (ab)use these cars have been subjected to, let's face it, not many have had 'one careful lady owner'... if it's been spanked relentlessly does that mean it's all about to fall apart?.. or rather that it has been thoroughly tested in the real world and found to be more than capable?
Or does the book full of service stamps ensure that it's been better maintained (possibly by the spotty apprentice under time constraints) than by the owner, a skilled engineer with 30 years' experience, building his own race cars in his home workshop, who has all week to complete the job (and his own neck at risk)?
At the end of the day, it's a gamble. It was when they were new! But the personal testimonies to the reliability of these oft- maligned engines is most encouraging.
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