Pistons....

[JayRome]

heres an odd one... might just be me though...

for as long as i have been assembling engines and so forth i have never come across this style of piston before...

its brand new ACL (off ebay) Piston & ring set for the N/A 4g63 .050 bigger then stock.. sounds normal atm...

at further inspection the pistons didnt have any oil holes in them... sounds odd doesnt it?

its either they were built like that or they made a mistake during manufacturing and didnt drill them out.. but from every memory i have, of piston i have changed rings on... every single one has had oil holes..

normal pistons....

my pistons...

i'm probably still going to use them, but drill holes in the correct spots to make them work.... i just find this odd though....

thoughts??

 

[to4garret]

looks to me like the oil flows around to where the gudgeon pin is then flows off there.

personally, i wouldnt go drilling holes in the piston, ACL's are fragile enough without added holes.

they're not hyperlites by any chance?

 

[JayRome]

looks to me like the oil flows around to where the gudgeon pin is then flows off there.

personally, i wouldnt go drilling holes in the piston, ACL's are fragile enough without added holes.

they're not hyperlites by any chance?

nah Duralites..... even the box shows oiling holes on the picture.... its just really odd....

yer i thought about the oiling around the pin.... but then the entire piston would have to be filled with oil for that to happen and i dont think the oil squirters dont have enough flow for that...

it doesn't make sense....

 

[mannynz]

nah Duralites..... even the box shows oiling holes on the picture.... its just really odd..

If is't not the same as the picture in the box then take it back.

If you do not get enough oil in there then your engine will fail in a short time.

 

[EVO-00X]

ACL know a hell of a lot about engines so you can trust in their design. At first glance it might seem that they dont have piston oil ring drain holes at all but look on both sides of the piston on each end of the gudgeon pin... theres 3 rather large slots cast into the piston for oil drainage. These will be way less prone to clog up than the smaller holes found in most other piston designs and they will still allow sufficient oil drainage. I suppose it adds to the strength of the piston as well as theres no extra holes in the side of it, but on the other hand there's argument for heat build up too. I put it down to just the way ACL have designed this particular piston so dont worry. Theres plenty of space there for oil to be drained back into the crankcase rather than burn off or make its way into the combustion chamber.

I'm not a fan of seeing the casting marks on the side of the piston though with the embossed ACL lettering but that's just me. I'd rather see a piston have smooth surfaces all round to aid oil dranage and provide less hot spots.

When I rebuilt my 4G64 Nimbus's engine in December last year I found all the stock piston rings clogged with crud and nearly all the oil drain holes in the pistons fully clogged with rock hard shit!! I put that down to the previous owner probably driving around with shitty cheap shit oil for many km even after the rings were way past their used by date and the engine smoking like a MF. The only way to clean the holes was to drill them out. Its now rebuilt as my daily driver and doesnt miss a beat. Oil? Castrol Magnatec! I'll always pay that little bit extra for a mid to high quality oil and do regular changes. Look after your engine and it'll look after you

 

[JayRome]

ACL know a hell of a lot about engines so you can trust in their design. At first glance it might seem that they dont have piston oil ring drain holes at all but look on both sides of the piston on each end of the gudgeon pin... theres 3 rather large slots cast into the piston for oil drainage. These will be way less prone to clog up than the smaller holes found in most other piston designs and they will still allow sufficient oil drainage. I suppose it adds to the strength of the piston as well as theres no extra holes in the side of it, but on the other hand there's argument for heat build up too. I put it down to just the way ACL have designed this particular piston so dont worry. Theres plenty of space there for oil to be drained back into the crankcase rather than burn off or make its way into the combustion chamber.

I'm not a fan of seeing the casting marks on the side of the piston though with the embossed ACL lettering but that's just me. I'd rather see a piston have smooth surfaces all round to aid oil dranage and provide less hot spots.

When I rebuilt my 4G64 Nimbus's engine in December last year I found all the stock piston rings clogged with crud and nearly all the oil drain holes in the pistons fully clogged with rock hard shit!! I put that down to the previous owner probably driving around with shitty cheap shit oil for many km even after the rings were way past their used by date and the engine smoking like a MF. The only way to clean the holes was to drill them out. Its now rebuilt as my daily driver and doesnt miss a beat. Oil? Castrol Magnatec! I'll always pay that little bit extra for a mid to high quality oil and do regular changes. Look after your engine and it'll look after you

i know what you mean cuz...... the oil drainage is perfect etc... i like the design of it too.... but yer how in the world does the oil get to the 3rd set of rings first..... its a toss up between trusting ACL and using them with my new engine.. or using the old pistons and putting the new rings on...

if ACL screws up.... its going to be an expensive rebuild... so just asking for opinions...

thanks though...

 

[bazeng]

They are N/A pistons correct?

N/A blocks do not have squirters also correct?

I'd say ACL thought, no squirters, no need for the holes.

They are only the oil rings so I'm not sure if the holes are designed to feed oil into the rings or JUST to scrape the oil down.....

 

[Liberoz]

i know what you mean cuz...... the oil drainage is perfect etc... i like the design of it too.... but yer how in the world does the oil get to the 3rd set of rings first..... its a toss up between trusting ACL and using them with my new engine.. or using the old pistons and putting the new rings on...

if ACL screws up.... its going to be an expensive rebuild... so just asking for opinions...

thanks though...

Just contact them directly and ask!

 

[JayRome]

Just contact them directly and ask!

lol i will in the morning!

 

[Purple Monster]

so how did you end up going??

were they right or did they bugger up in manufacture?