Project: Xu12J4

[Tguedes98 0]

On 4/17/2013 at 10:12 AM, B1ack_Mi16 said:

Btw. it you decide to get new rods I can give you the prod. number on my Pauters.

With slight modifications to length and small end thickness on those I think you will get the right ones.

Hi mate! Can you still give me the prod. number on your Pauters please? 

Thankssss

[Tguedes98 0]

On 12/1/2023 at 11:28 PM, jonathan_steenbergen said:

Long time ago, 10 years ;-). Still working on it.. busy, house, shed, business but perfectionated it in the last years. Maybe some pics soon.

Hi Jonathan! Hopefully you can shed some light on your project, and thus, on my project as well! So, I'm trying to build a 2.2L with 92mm crank from a 2.1td and 87mm bore with forged rods and pistons!

However, I just found out that the rods for the 2.1 td crank are 26.xx mm, compared to the 24.xx mm rods from s16/gti6, they're 2mm wider! Meaning there's way to much play in the rods to just intall it like this!
Also, I'm not sure what to do! I think I'll be using 158mm custom forged rods with 26mm big end and custom pistons, 3mm shorter than normal gti6 pistons in order to compensate for the extra 3mm stroke!

 

What do you suggest? I'd love to hear from you guys that are more experiencied in the matter!

[welshpug 1,657]

Thats exactly it.

 

Be VERY careful to do a dry build and confirm valve clearance and compression ratio unless measured and drawn highly accurately and made to a custom order, every piston will need some machining.

[Tguedes98 0]

5 minutes ago, welshpug said:

Thats exactly it.

 

Be VERY careful to do a dry build and confirm valve clearance and compression ratio unless measured and drawn highly accurately and made to a custom order, every piston will need some machining.

Hi Welsh! Think you could most probably help me! I've sent you a PM on facebook! It'd be awesome if you could shed some light regarding the matter of the 2.2 build I think you have/had! I'm really wondering regarding the rods width on big end! As I said, think I'll use normal 158mm forged gti6 rods with a custom made 3mm short piston! Evene if the piston rings have to be installed after installing the pins! Cuz i guess that decreasing piston height 3mm, the oil control ring will start to enter the realm of the gudgeon pin!

What do you thinK I should do?

[welshpug 1,657]

Rings are not a problem, my engine uses an off the shelf omega  high conpression cast piston for the GM  2.0 engine, modified to suit.

 

Off the shelf gti6 rod will not work as the crank is wider like you found.

 

All this is in my thread btw.

Edited June 12 by welshpug

[Tguedes98 0]

50 minutes ago, welshpug said:

Rings are not a problem, my engine uses an off the shelf omega  high conpression cast piston for the GM  2.0 engine, modified to suit.

 

Off the shelf gti6 rod will not work as the crank is wider like you found.

 

All this is in my thread btw.

Where can I find your thread exactly? That'd be awesome to read I bet! Can you post the link please?

What rods are you using then? This is what's bugging me now, as I dont have any other solution rather than custom rods!
 

[welshpug 1,657]

You replied to it on the 306gti6 forum!

 

My rods are custom.

[Tguedes98 0]

12 hours ago, welshpug said:

You replied to it on the 306gti6 forum!

 

My rods are custom.

Oooooh! Got it! I'm still catching up on some threads! 205 4X4 T16 and your ZX! Haven't finished reading it! So what brand are your rods?

[Tguedes98 0]

21 hours ago, welshpug said:

You replied to it on the 306gti6 forum!

 

My rods are custom.

Hi mate! Just finished reading your Thread! What a fantastic piece of work!!!

Only question that remains is rods and pistons!

Compression cast piston for the GM 2.0 engine, modified to suit on the piston side right?

Rods wise, what brand did you use? You had them custom made to what spec? 26.xx mm wide but what height, center to center? 158mm? 155? or 152?, really wondering here!!! 

[welshpug 1,657]

custom rods, length to suit the pistons I used, big end width to suit the crank.

 

 

you need to find whatever piston suits your needs and have a conrod made to suit,  a few have used peugeot pistons, honda pistons and GM pistons, and of course custom pistons made to exact specification.

[SRDT 175]

If you you have a hard time finding 26mm wide rods the 96mm stroke crank from a 2.2 HDI has 24mm crankpins.

[welshpug 1,657]

Which in turn would require custom rods to suit the piston you choose to use.

 

Easy to find rods to the specific width, you have them made to spec,   the difference in price is not huge, though lead times can be a little long.

Edited June 14 by welshpug

[petert 586]

I'd just buy new, custom rods too. After you've considered essential resizing of the big ends and quality new rods bolts, for your 2nd hand rods, the cost of new rods is not that bad.

[SRDT 175]

You can also go with off the shelf forged rods and modified pistons :

 

 

[Tguedes98 0]

On 6/14/2024 at 10:14 AM, welshpug said:

custom rods, length to suit the pistons I used, big end width to suit the crank.

 

 

you need to find whatever piston suits your needs and have a conrod made to suit,  a few have used peugeot pistons, honda pistons and GM pistons, and of course custom pistons made to exact specification.

Hi welsh!

 

Not exactly sure what pistons to use! I wanna take it a little higher, but I still want to use pump gas (98 octane), not race fuel, so probably around 12.0 to 12.5 I'd say, so I can keep using pump gas.

 

Will have rods custom-made to fit the 26.xx mm journals, no doubt there! I'll have to go forward and see the best option regarding pistons!

Would like to use off-the-shelf forged pistons for Peugeot and use like a 0.76mm cometic gasket for maximum squish! So maybe get the rods custom-made to fit an off-the-shelf 20/22mm gudgeon pin piston! 

 

What do you say Welsh?

 

On 6/14/2024 at 3:17 PM, SRDT said:

If you you have a hard time finding 26mm wide rods the 96mm stroke crank from a 2.2 HDI has 24mm crankpins.

Hey mate! Yeah, I'm definitely not using a 96mm crank mate! I wanna try and keep the build as simple as possible! 92mm crank will be more than plenty for what I'm after! Also, I already would the 92mm crank and she's in mint condition! Thanks anyway mate!!!

 

On 6/14/2024 at 11:02 PM, welshpug said:

Which in turn would require custom rods to suit the piston you choose to use.

 

Easy to find rods to the specific width, you have them made to spec,   the difference in price is not huge, though lead times can be a little long.

Do you recommend any specific brand on con rods that will make them to spec? Many thanks!

 

On 6/15/2024 at 3:23 AM, petert said:

I'd just buy new, custom rods too. After you've considered essential resizing of the big ends and quality new rods bolts, for your 2nd hand rods, the cost of new rods is not that bad.

Hey Petert! Most definitely that's what I'll do! Custom con rods made to work with a thin cometic gasket, so I have a nice squish band, and made to work with off-the-shelf pistons! My only problem is that off-the-shelf pistons are not made to work with 92mm cranks, so the squish band will decrease, leading to lower engine efficiency - not cool - and thus, fewer horsies.

My solution would be machining some mm's off the top of the piston domes to take the compression down a bit, otherwise, to have a nice compression, squish band will not be in the correct range cuz I'll be forced to make shorter rods to compensate for the longer stroke! 

 

Do you guys agree with me? Or what do you say? Many thanks!

[Tguedes98 0]

On 6/15/2024 at 9:36 AM, SRDT said:

You can also go with off the shelf forged rods and modified pistons :

 

 

Yeah, I've seen that thread! I'm not to keen on taking a dremmel to my block for the crank to clear tho... Would like to make something simpler!!

[petert 586]

3 hours ago, Tguedes98 said:

My solution would be machining some mm's off the top of the piston domes to take the compression down a bit, otherwise, to have a nice compression, squish band will not be in the correct range cuz I'll be forced to make shorter rods to compensate for the longer stroke!

87 x 92 will need a dished piston, such Honda K20 turbo. Then you will have zero squish with a custom rod. A -7.7cc dish gives approx. 10.7:1. Part number CP SC70402

Edited June 17 by petert

[Tguedes98 0]

9 hours ago, petert said:

87 x 92 will need a dished piston, such Honda K20 turbo. Then you will have zero squish with a custom rod. A -7.7cc dish gives approx. 10.7:1. Part number CP SC70402

Meaning that with 87x92mm the piston has to be dished? it can't be domed? to have a 12.0 CR I would probably need a flat piston only with the valve cutouts right?

What do you mean by "zero squish"? The flat part of the piston coming up to the block?

Many thanks

[welshpug 1,657]

from memory the crown of my pistons are above the deck but the sides are about 1.5mm below,

[petert 586]

11 hours ago, Tguedes98 said:

Meaning that with 87x92mm the piston has to be dished? it can't be domed? to have a 12.0 CR I would probably need a flat piston only with the valve cutouts right?

What do you mean by "zero squish"? The flat part of the piston coming up to the block?

Many thanks

Zero squish means the top of the piston is level with the top of block. You want that, regardless of the CR. Here are the calcs for 12:1 in 87 x 92 with a K20 piston.

Bore 87mm

Stroke 92mm

Deck Height 234mm

Compression Height 30mm

Rod Length 158mm

Dish & Valve Pockets -1cc

 

Are you hung up on 12:1? Why not use the SC70457 flat top piston which has -3.3cc pockets and would give 11.5:1.

 

[Tguedes98 0]

11 hours ago, petert said:

Zero squish means the top of the piston is level with the top of block. You want that, regardless of the CR. Here are the calcs for 12:1 in 87 x 92 with a K20 piston.

Bore 87mm

Stroke 92mm

Deck Height 234mm

Compression Height 30mm

Rod Length 158mm

Dish & Valve Pockets -1cc

 

Are you hung up on 12:1? Why not use the SC70457 flat top piston which has -3.3cc pockets and would give 11.5:1.

 

Hi Peter!

Many thanks from your inputs! I take it that Hovis16 was already talking with you!!!
 

Deck Height 234mm

- means i have to take 1mm out of the block right?

 

Compression Height 30mm

- stock k20 piston compression height?

 

Rod Length 158mm

-stock length gti6 rod? I'll be using forged ones with 26.xx mm in the big end. Should I get them with 20 or 22mm gudgeon pin?

 

Dish & Valve Pockets -1cc

those are flat pistons then right? just with the valve reliefs? I'd imagine so! These are not forged right? stock k20 pistons?

 

I'm definitely no hung up on 12:1, 11.5:1 would already be very good I imagine, and most probably safer for knock as well right? those 2.3 cc less will give more 0.5 comrpession ratio then I imagine!

 

 

[petert 586]

Sorry, my bad. You’d need 159mm rods as deck height is 235.

 

There is no -1cc piston. I was trying to point out theoretical number required. 

Edited June 18 by petert

[petert 586]

These are the K20 pistons I'm using for SC and turbo builds. They have a 9cc dish and a Ø22 pin. These end up at approx. 10:1. Note that they still have a squish band.

[Tguedes98 0]

On 6/18/2024 at 3:15 AM, petert said:

Zero squish means the top of the piston is level with the top of block. You want that, regardless of the CR.

Hi Peter! 

I got intrigued so i started searching for more info regarding squish band. Zero squish is actually when the piston comes in touch with the squish band in the cylinder head (which obviously isn´t possible or it would explode). And it makes sense to be that way! Otherwise, if it was when piston is level with the block that would mean that having a 1.1mm head gasket or having a 3mm head gasket wouldn't make a diference. This is not the case! You can never achieve zero squish!

What you should aim for is a squish band height of around 1mm (given from the head gasket), that's where it starts to get efficient

 

15 hours ago, petert said:

Sorry, my bad. You’d need 159mm rods as deck height is 235.

Are you saying it that to run those k20 pistons I'd have to run 159mm rods then? no block machining then

15 hours ago, petert said:

 

There is no -1cc piston. I was trying to point out theoretical number required. 

Ah ok, that makes sense! I'm not very keen o using a piston designed for a K20 on a Xu10... I know it works, but for the price, I bet you can get one off pistons for a little more

 

What do you think? Many thanks

[Tguedes98 0]

1 hour ago, petert said:

These are the K20 pistons I'm using for SC and turbo builds. They have a 9cc dish and a Ø22 pin. These end up at approx. 10:1. Note that they still have a squish band.

How much are those beautiful lookin pistons?

Those are NOT the SC70457 flat top piston you talked about right?

 

10:1 for a SC/Turbo build isn't it a bit high? Those engines must be crazy mad!!!

 

Did you use those for 2.2 builds on 92mm crank?

 

Many thanks mate!