Made a shocking discovery today!!!
22-10-2009, 12:57 PM
#1
Made a shocking discovery today!!!
Turns out i've been running Accralite, low comp, oversized pistons!!! 
I had no idea as I didnt build the bottom end, it's just as I bought it....
Was cleaning up the pistons, and noticed they were totally different to the other standard pistons I had on the bench, rods are different too, and little ends......
Does any one know if these are standard rods, or are they uprated too?
Cheers!
I had no idea as I didnt build the bottom end, it's just as I bought it....
Was cleaning up the pistons, and noticed they were totally different to the other standard pistons I had on the bench, rods are different too, and little ends......
Does any one know if these are standard rods, or are they uprated too?
Cheers!
Last edited by Karlos G; 22-10-2009 at 12:59 PM.
22-10-2009, 02:06 PM
#6
Wye Valley Hardcore
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22-10-2009, 02:31 PM
#8
But they are not going back in, I will be using standard Mahles as soon as I can get a bloody block, want to stay standard CR for maximum response off boost!
Were you still on standard rods at 300bhp Christian?
Oh and they are 1.5mm oversize!!
Fuck knows what cc that equates to?
Last edited by Karlos G; 22-10-2009 at 02:47 PM.
22-10-2009, 05:24 PM
#21
YES I KNOW I CANT SPELL
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im prity sure this is c and b's escort
http://www.youtube.com/watch?v=spDIREX6nOY
22-10-2009, 05:35 PM
#22
PassionFord Post Troll
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so does 300bhp +160 odd mph not enouth for you then
im prity sure this is c and b's escort
http://www.youtube.com/watch?v=spDIREX6nOY
im prity sure this is c and b's escort
http://www.youtube.com/watch?v=spDIREX6nOY
Last edited by rstdave; 22-10-2009 at 05:37 PM.
22-10-2009, 10:18 PM
#24
It Wasnt Me!
23-10-2009, 04:38 AM
#25
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23-10-2009, 07:59 AM
#26
Wye Valley Hardcore
Apparently they can be noisey when cold as Accralite use a central gudgeon pin, not an offset pin. They also have a shorter skirt. My old block with Accralites in rattled when cold, I hope my new one doesn't. Sounded like a deisel on cold mornings.
23-10-2009, 08:47 AM
#27
Yeah never really going to find out, but I have a set of Mahles here with new rings and hopefully picking up a standard EFI block over the weekend that just needs a hone, so thats what i'll be bolting back together!
Even if I wanted to use the Accralites it's more money to have the bores opened out by 1.5mm and right now I dont have it, in fact the Accralites will be going on ebay as they are worth reasonable money and will help fund my rebuild!
lol
23-10-2009, 11:43 AM
#28
somebody correct me if i'm wrong but what you had was probably mild piston slap as forged pistons need larger bore clearances then standard cast pistons so as a result they move about more in the bores. if the engine was getting on a bit then it's likely that it was worn and was allowing the pistons to move about more than they should do, hence the knocking noise making it sound like a diesel.
regards
Tom
23-10-2009, 12:27 PM
#30
Wye Valley Hardcore
It was piston slap yes. Quick Motorsport told me that when they set it up. But they also told me Accralite use a central gudgeon pin and a shorter skirt which does make them more noisey certainly then standard cast pistons but also other forged psitons on the market. Forgot to mention the bit about bore clearence!
23-10-2009, 01:21 PM
#31
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It was piston slap yes. Quick Motorsport told me that when they set it up. But they also told me Accralite use a central gudgeon pin and a shorter skirt which does make them more noisey certainly then standard cast pistons but also other forged psitons on the market. Forgot to mention the bit about bore clearence!
23-10-2009, 02:51 PM
#32
Wye Valley Hardcore
"Cosworth and Accralite pistons are made from an alloy forging that is classed as high expansion aluminium alloy. In addition these pistons also use a central gudgeon pin whereas the std mahle Rs turbo piston has a 2mm offset pin.
As such cosworth and accralite equiped engines that are built with the above parameters and built correctly with the correct clearances do result in a significant amount of piston slap at cold start.
In the early days of an engines life this slap will be reasonably quiet but as you close on towards 10,000 miles the noise will become very apparent at cold start
This is because the bore wear on a high power engine is horific and as such by 10,000 miles there will be anywhere up to an extra 2 thou thrust and top ring reversal wear.
Bores wear oval due to the thrust loadings and to be fair any high power (i.e. more than 150bhp per litre engine)engine will be VERY worn after 20,000 miles use."
As such cosworth and accralite equiped engines that are built with the above parameters and built correctly with the correct clearances do result in a significant amount of piston slap at cold start.
In the early days of an engines life this slap will be reasonably quiet but as you close on towards 10,000 miles the noise will become very apparent at cold start
This is because the bore wear on a high power engine is horific and as such by 10,000 miles there will be anywhere up to an extra 2 thou thrust and top ring reversal wear.
Bores wear oval due to the thrust loadings and to be fair any high power (i.e. more than 150bhp per litre engine)engine will be VERY worn after 20,000 miles use."
23-10-2009, 07:32 PM
#36
It Wasnt Me!
lol
Yeah never really going to find out, but I have a set of Mahles here with new rings and hopefully picking up a standard EFI block over the weekend that just needs a hone, so thats what i'll be bolting back together!
Even if I wanted to use the Accralites it's more money to have the bores opened out by 1.5mm and right now I dont have it, in fact the Accralites will be going on ebay as they are worth reasonable money and will help fund my rebuild!
lol
Yeah never really going to find out, but I have a set of Mahles here with new rings and hopefully picking up a standard EFI block over the weekend that just needs a hone, so thats what i'll be bolting back together!
Even if I wanted to use the Accralites it's more money to have the bores opened out by 1.5mm and right now I dont have it, in fact the Accralites will be going on ebay as they are worth reasonable money and will help fund my rebuild!
lolcheers
23-10-2009, 07:52 PM
#37
Yes mate 7.95:1 and 1.5mm oversize, although they will be a little lower again now i'm having them topped.
Second ones in the list on this page if your interested.... http://www.accralite.com/accralite/index1.htm
Second ones in the list on this page if your interested.... http://www.accralite.com/accralite/index1.htm
23-10-2009, 09:09 PM
#38
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"Cosworth and Accralite pistons are made from an alloy forging that is classed as high expansion aluminium alloy. In addition these pistons also use a central gudgeon pin whereas the std mahle Rs turbo piston has a 2mm offset pin.
As such cosworth and accralite equiped engines that are built with the above parameters and built correctly with the correct clearances do result in a significant amount of piston slap at cold start.
In the early days of an engines life this slap will be reasonably quiet but as you close on towards 10,000 miles the noise will become very apparent at cold start
This is because the bore wear on a high power engine is horific and as such by 10,000 miles there will be anywhere up to an extra 2 thou thrust and top ring reversal wear.
Bores wear oval due to the thrust loadings and to be fair any high power (i.e. more than 150bhp per litre engine)engine will be VERY worn after 20,000 miles use."
As such cosworth and accralite equiped engines that are built with the above parameters and built correctly with the correct clearances do result in a significant amount of piston slap at cold start.
In the early days of an engines life this slap will be reasonably quiet but as you close on towards 10,000 miles the noise will become very apparent at cold start
This is because the bore wear on a high power engine is horific and as such by 10,000 miles there will be anywhere up to an extra 2 thou thrust and top ring reversal wear.
Bores wear oval due to the thrust loadings and to be fair any high power (i.e. more than 150bhp per litre engine)engine will be VERY worn after 20,000 miles use."
Taken from the Accralite site, so not all have a central gudgeon pin
23-10-2009, 09:29 PM
#39
Wye Valley Hardcore
Either way let's hand karlos his thread back
Still thy quote holds some good info for people!
23-10-2009, 09:47 PM
#40
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