AJP engine noise - I found the cause - warning XXXX content!
Discussion
yes they were AE,this is the 4 th ajp8 that i have had with this problem 1x 4.5, 3 x4.2 . Dont know if it is a manufacturing fault as each car has done varied mileage and not close to each other. May just be the fact that it is the taper walls and the pin being brittle who knows, but i am in the process of trying to source none tapered pins, to see if this gives longer life.
itiejim said:
Blimey, Were they AE? I'm wondering whether I'm better off adapting something a little heavier duty?
I'd be keen to hear if you can source some non-tapered pins, otherwise I'll have to get my local engineering shop to search around or knock something up.
Have you ever approached AE about these failures?
Have you ever approached AE about these failures?
nemasis said:
yes they were AE,this is the 4 th ajp8 that i have had with this problem 1x 4.5, 3 x4.2 . Dont know if it is a manufacturing fault as each car has done varied mileage and not close to each other. May just be the fact that it is the taper walls and the pin being brittle who knows, but i am in the process of trying to source none tapered pins, to see if this gives longer life.
itiejim said:
Blimey, Were they AE? I'm wondering whether I'm better off adapting something a little heavier duty?
not approached AE YET but may be worth ago and see what they say, will keep everyone upto date on progress and see what comes through.
itiejim said:
I'd be keen to hear if you can source some non-tapered pins, otherwise I'll have to get my local engineering shop to search around or knock something up.
Have you ever approached AE about these failures?
Have you ever approached AE about these failures?
nemasis said:
yes they were AE,this is the 4 th ajp8 that i have had with this problem 1x 4.5, 3 x4.2 . Dont know if it is a manufacturing fault as each car has done varied mileage and not close to each other. May just be the fact that it is the taper walls and the pin being brittle who knows, but i am in the process of trying to source none tapered pins, to see if this gives longer life.
itiejim said:
Blimey, Were they AE? I'm wondering whether I'm better off adapting something a little heavier duty?
i dont think it will make much if any difference really, looking at the taper on the pin i would estimate that it will be like having an extra pin, or 2 at the most, in the engine therefore i would say the EXTRA would be neither here nor there.
Boosted LS1 said:
Don't forget that non tapered pins will be a fair bit heavier. What are the specs, I may have some pins?
please do i would be interested to know what they say about it!! i hope you get a better responce than i got when i approached ap about the failing fingers on the pressure plates??? "What do you mean there snapping,not our clutches obviously, no-one else has complained about them, we have never had anyone complain about our clutches, who are you again? A*******n Sports cars, Who? TVR service Centre, Ohh its only TVRs, Can i buy the finger plates as they are only bolted in?? Absolutely not we dont sell them as a repair item you will just have to get the customers to buy the full clutch from our dealer network, just think of the labour and mark up you can charge!!!!! to that the phone went dead. so as i said hope you have more luck.
itiejim said:
I'm on to AE now, I'll let you know how I get on.
nemasis said:
i dont think it will make much if any difference really, looking at the taper on the pin i would estimate that it will be like having an extra pin, or 2 at the most, in the engine therefore i would say the EXTRA would be neither here nor there.
It will be enough to change the balance especially if an alternative pin has a thicker wall then the original. Boosted LS1 said:
Don't forget that non tapered pins will be a fair bit heavier. What are the specs, I may have some pins?
Brummie, the original pins are 5cm long, with a diameter of .827" (2.10058 cm according to my online converter). They weigh 70g each.
I'm going to try to see what AE can do, but I'd certainly be keen to hear if you've got anything that would do the job.
I'm going to try to see what AE can do, but I'd certainly be keen to hear if you've got anything that would do the job.
nemasis said:
not approached AE YET but may be worth ago and see what they say, will keep everyone upto date on progress and see what comes through.
itiejim said:
I'd be keen to hear if you can source some non-tapered pins, otherwise I'll have to get my local engineering shop to search around or knock something up.
Have you ever approached AE about these failures?
Have you ever approached AE about these failures?
nemasis said:
yes they were AE,this is the 4 th ajp8 that i have had with this problem 1x 4.5, 3 x4.2 . Dont know if it is a manufacturing fault as each car has done varied mileage and not close to each other. May just be the fact that it is the taper walls and the pin being brittle who knows, but i am in the process of trying to source none tapered pins, to see if this gives longer life.
itiejim said:
Blimey, Were they AE? I'm wondering whether I'm better off adapting something a little heavier duty?
Maybe have a word with Paul from Austec, when they rebuilt my engine different pistons and pins were used, I got the impression the wrist angle could have been better on the originals.
Also, while I have no doubt in your engine builders skills, on your picture the piston has scratching on both sides, more so on the left.
Since you stripped the engine, you would have mentioned if a retaining clip wasn't present, looks like something rubbed the piston, there seems to be a small x mark on the right hand side, did you mark it as a point of damage?
Also, while I have no doubt in your engine builders skills, on your picture the piston has scratching on both sides, more so on the left.
Since you stripped the engine, you would have mentioned if a retaining clip wasn't present, looks like something rubbed the piston, there seems to be a small x mark on the right hand side, did you mark it as a point of damage?
Edited by Nickccc on Wednesday 9th September 13:05
Just to add my two pennies the internal taper of the pin is actually to relieve stress in the piston as the piston tends to flex and splay out under load and if you have a very stiff pin then this over loads the gudgeon pin bore. If the pin bends a little with the piston this reduces the piston stress.
I'd stick with tapered pins but concentrate on getting one properly hardness tested ( cut one up from a batch perhaps?
I'd stick with tapered pins but concentrate on getting one properly hardness tested ( cut one up from a batch perhaps?
Nick,
thanks for the steer re: Austec, I'll have a chat with them.
As for the marking on the pistons; all of the retaining clips were present and the contact faces of the pistons are in very good order. The only damage I can find on them is where the cracked pin has partially reamed the hole in the piston, therefore two pistons will be required. Each piston had been marked with an X to designate which way round they were fitted (all the X's pointed forwards if I recall correctly). The other mark you refer to is a superficial mark which looks like it's bee caused by whatever dremmel etc was used to mark the 'X'. Either way, nothing of any concern.
thanks for the steer re: Austec, I'll have a chat with them.
As for the marking on the pistons; all of the retaining clips were present and the contact faces of the pistons are in very good order. The only damage I can find on them is where the cracked pin has partially reamed the hole in the piston, therefore two pistons will be required. Each piston had been marked with an X to designate which way round they were fitted (all the X's pointed forwards if I recall correctly). The other mark you refer to is a superficial mark which looks like it's bee caused by whatever dremmel etc was used to mark the 'X'. Either way, nothing of any concern.
Nickccc said:
Maybe have a word with Paul from Austec, when they rebuilt my engine different pistons and pins were used, I got the impression the wrist angle could have been better on the originals.
Also, while I have no doubt in your engine builders skills, on your picture the piston has scratching on both sides, more so on the left.
Since you stripped the engine, you would have mentioned if a retaining clip wasn't present, looks like something rubbed the piston, there seems to be a small x mark on the right hand side, did you mark it as a point of damage?
Also, while I have no doubt in your engine builders skills, on your picture the piston has scratching on both sides, more so on the left.
Since you stripped the engine, you would have mentioned if a retaining clip wasn't present, looks like something rubbed the piston, there seems to be a small x mark on the right hand side, did you mark it as a point of damage?
Edited by Nickccc on Wednesday 9th September 13:05
350Matt said:
Just to add my two pennies the internal taper of the pin is actually to relieve stress in the piston as the piston tends to flex and splay out under load and if you have a very stiff pin then this over loads the gudgeon pin bore. If the pin bends a little with the piston this reduces the piston stress.
I've never heard this - don't think you'd want the piston pin being able to flex at all.With Formula Ford engines - stock with non-tapered piston pins - one of the performance tips is to taper the pins slightly, as this way they will allow any oil that gets inside them to drain easier. Also, as they are steel - you can remove more weight there for the amount of material that gets removed.
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