Hi everyone,

Following various checks I've now arrived at the conclusion that I have piston slap on just one piston of my 3.5 X350. It's a low mileage car so I'm hoping that I may be able to strip the engine and have the cylinder liner replaced (it looks quite scored using a borescope) and fit a new piston. Obviously that will entail engine removal etc. Reading the Jaguar manual they refer to "Special Tools" ?? to lock the flywheel prior to removal of the crankshaft pulley. I've discovered that there is a tool produced by Laser (No 7059) that is for the 5.0 V8 engine but I don't know whether it would be usable on a 3.5 or 4.2 - does anyone have knowledge of this tool and can it be used ?? Reading various posts on this forum mention has been made of using a 24" chain wrench to hold the pulley. Has anyone tried that or any other method to remove the crankshaft pulley, which I understand can be VERY tight ? I presume the "Special Tools" Jaguar refer to is simply a screwdriver or suchlike to jam the flywheel (which I wouldn't be happy doing as there is a risk of damaging the teeth). Any comments welcome.

 

Have you checked that the parts you propose to replace are available ?

 

Good Morning Fraser,

David Manners website shows the piston (AJ89921) as being out of stock but available to order at £230 plus VAT. I believe the cylinder liner is the same as for the 4.2 ? Have you had some experience of getting such parts yourself - I think it's disgusting that JLR no longer stock these parts (they show NLA). I think I'll double check with David Manners (& other sources) before committing. Thank you for your response. Regards Keith

 

Further update. Piston is not available from David Manners either - don't know yet about other sources BUT thinking about it it's possible that the piston will not need replacing - the compression is good (150psi) so I'm puzzled what has caused what looks like 'Piston Slap', could be that one of the piston rings has snapped or perhaps the gudgeon pin has become loose in the piston ???? The 3.5 engine wasn't sold in any great numbers and apart from the pistons, connecting rods and crank, the rest of the components are as the 4.2 (including piston rings), the 4.2 has increased capacity due to a larger crankshaft throw.

 

Damage to the cylinder liner is rather uncommon on the AJ8, the cause could be i.e. a broken piston ring or a piston damaged by thermal overload. Depending on the degree of damage there is still compression to be measured.

I would first remove the cylinder head from the affected bank. Depending on the repair method this has be done anyway so there is no additional effort. If the cylinder head is dismantled you will be able to assess the damage much better and decide whether a repair makes sense or not.

For the disassembly of the crank pulley there is a holding tool 303-191, the flywheel has not to be blocked. And it is not necessary to disassemble the pulley in order to get the engine out.

Fritz

 

@CaptainQ, there are several points to pay attention to whilst working on the AJV8:

• DO NOT rotate the engine in an anti-clock direction when viewed from the front of the vehicle as damage to the main and rod bearings is the result.
• To remove the crankshaft front pulley, use a cut piece of serpentine belt with a chain spanner to hold the pulley so the 24mm centre bolt can be loosened. DO NOT use the crankshaft holding tool as the flex plate can become distorted.
• Inspect the secondary timing chain tensioners for broken slider blocks.
• Use the information in the Engine Course to correctly set the camshaft timing to 45 degrees ATDC. Here is a link to the course: https://www.dropbox.com/s/vqpy3bbjzd...e_168.pdf?dl=0

 

I don't have experience with the 3.5 liter x350 but assuming the crank pulley setup is the same as the 4.2, you can get the crank hold tool off ebay for around 100 USD. This tool is used to both hold the crankshaft pulley in place as you remove the bolt, but can also be used to pull off the crank pulley itself once you have the bolt off.

I don't have the torque specs handy, but in my case the pulley crank bolt required crazy amounts of torque to take off. I used a 6 foot bar on my breaker bar to take it off.

Note, you can buy the timing gear hold-down kits on ebay too which include the flywheel alignment plug. Do not use the timing kits to hold the crank while removing the crank pulley bolt, the forces are too high.

 

Good Morning All. Thank you everyone for your suggestions & advice - it really is appreciated. I'm still contemplating my next move regarding this car - taking and dismantling the V8 is not a five-minute job and, as one gets older, the thought of lying underneath a car becomes less attractive - lol. I've advertised it for sale whilst explaining the knock when cold so hopefully someone else will take the job on. If it is indeed 'Piston Slap' then it would appear that it isn't an urgent rectification. If nobody buys as is then I will have to bite the bullet and take the job on myself (once I've invested in the tool - 303-191 that Fritz refers to, to lock the crank pulley). I contacted several UK piston suppliers yesterday and it appears that there are no aftermarket 3.5 pistons available and Jaguar ones are NLA ! That puts me in a bit of a dilemna - if I strip the engine and find that the piston is damaged then, unless I can find a secondhand piston I'll end up with a pile of scrap aluminium. However, one option would be to get the problematic scored sleeve replaced and change the crank, pistons & connecting rods to 4.2 (I believe the block was the same for both capacities ??). I'm not 100% happy with that solution, however, as it may entail further problems (ECU etc).
Before doing any stripping of the engine I'll do as Fritz has suggested and remove the cylinder head from that bank to make an assesment. I'm puzzled (if it is Piston Slap) as to why it has occurred - the car only has 67,000 miles recorded and has been regularly serviced. Looking at old invoices it appears that the knocking when cold has been there for some time - one garage checked & adjusted all of the valves with a bill for almost £2,000 GBP but then, afterwards, reported that the knock was still present ! The next owners garage checked the car and found that one of the exhaust cams was slightly out and so re-timed it, entailing another substantial bill, all to no avail. I think that owner had then had enough expense and decided to sell. I'm in agreement with Fritz in that it may well be a broken piston ring (may have been broken during initial assembly at jaguar) or a worn connecting rod 'little end' or 'gudgeon pin'. I'll post an update in due course. Thanks once again everyone.

 

Thank you NBCat for the link to the course notes - look very comprehensive and informative. Cheers.