Kombi Pistons

[Golfie.NC]

Good Day Ladies and Gents,i need some specs on the following kombi pistons please if anyone can help me, the reason why om asking i want to fit kombi pistons in a 4 cylinder 1.8/2.0 engine but according to my understanding there is a difference between 2.3 ; 2.5 & 2.6 Kombi pistons so what i need to know the difference between them like wrist pin size and height? i know they're all 82.5mm standard bore size. Any help and advice will be appreciated, thank you!

[missioner]

Good Day Ladies and Gents,i need some specs on the following kombi pistons please if anyone can help me, the reason why om asking i want to fit kombi pistons in a 4 cylinder 1.8/2.0 engine but according to my understanding there is a difference between 2.3 ; 2.5 & 2.6 Kombi pistons so what i need to know the difference between them like wrist pin size and height? i know they're all 82.5mm standard bore size. Any help and advice will be appreciated, thank you!

All the 5 cylinder motors use the same size pins as the 1.3/4/6/8 motors. It's why they are used for swaps as it means that you don't need other conrods.

The 2.5/6 pistons are the same height as 2E/ADY (etc) pistons and joined to a 2.0l crank will stroke a short block to 2.0l. Lots of clearancing needs to be done inside the crankcase to get it to spin freely. This has been discussed many times and some search function will bring up the details of what's needed.

2.3 pistons have the same height as 1.8l pistons and with minor machining will produce close to 1.9l capacity using the 1.8l crank.

Those are all applicable to short block engines, long block (aka 2.0l) all use larger pins and therefore none of the 5 cylinder pistons will work. Nissan CA18, BMW M50/2 pistons are common choices here, but they do require changes to the small end bush to fit. Neither of these are worth using if the 8V head is still in service as 84mm is the preferred diameter.

If you are contemplating a turbo build then all of the above is useless, none are strong enough for meaningful amounts of boost.

[Golfie.NC]

Thanks alot for all that info, i have 2x blocks and thats the reason why i asked. The 1.8 block was bored 020 previously and engineering guys said its needs to be rebored again or either re-sleeve and thus i thought of using 82.5mm kombi pistons. I know the wrist pin is 20mm on the 1.6/1.8 engines but just wanted to confirm on the Kombi piston side. On the 2.0 long block im struggling to get rods as the ones i have can't be used again according to engineering place and was wondering if i used 1.8 rods with the 2.0 crank in the long block then maybe i could use some other pistons with a higher deck. Once again, thanks for all the info. I really appreciate it

[missioner]

The 1.8 rods are shorter than the 2.0, they won't work out. Taller pistons will increase the inertia and reduce acceleration speeds with a long stroke engine. To overcome this use a shorter stroke crank.

If you have a long block, you will have to stick to long conrods regardless of what crank you use.

I don't know the conrods lengths in mm, but the rod length is related to the bore length.

For decent power and rev characteristics you want to get the bore and stroke to what known as square, that means the two numbers are the same. For example the Opel C20 engine uses 86 x 86mm and Toyota 2ZZ has 82 x 82mm dimensions. Our VW motors are not designed for this from the start (unlike those other two I mentioned) so we have to get creative. We are mostly limited by cylinder spacing and that limits cylinder diameter, maximum is 83.5mm on a short block and 84mm on a long block. This is for 2 reasons, 1st is cylinder wall thickness and the other is head gasket availability, the head gasket problem is very overlooked. When I built my 1.9 motor I had to specially order my gasket because I could only find one supplier that had a gasket that cleared my 83.5mm pistons. If I had used the others it would have caused my engine to fail.

First let's see what you have to work with and then we can work out a recipe for a fun little engine that will make decent numbers without killing the budget. Give us a list of all the parts you have available already so we can prevent unnecessary spending and come up with something sweet.

[missioner]

Thanks alot for all that info, i have 2x blocks and thats the reason why i asked. The 1.8 block was bored 020 previously and engineering guys said its needs to be rebored again or either re-sleeve and thus i thought of using 82.5mm kombi pistons. I know the wrist pin is 20mm on the 1.6/1.8 engines but just wanted to confirm on the Kombi piston side. On the 2.0 long block im struggling to get rods as the ones i have can't be used again according to engineering place and was wondering if i used 1.8 rods with the 2.0 crank in the long block then maybe i could use some other pistons with a higher deck. Once again, thanks for all the info. I really appreciate it

Sorry just reread this.

Quick recipes
1. 1.8 short block and rods, 2.0l 90.5mm crank, 82.5mm pistons from 2.5 motor (Caravelle) = 2.0l motor

2. 1.8 block and rods, 1.8l 86.4mm crank, 83mm or 83.5mm pistons (microbus 2.3 and Audi 500 C4) = 1875cc (83mm) and 1897cc (83.5)

3. 2.0 long block and rods, 2.0l crank, 84mm BMW piston = 2.1l (+/-)

4. 2.0l block, 1.9 TDi crank 95.5mm, 84mm BMW pistons = 2.3l (+/-). @Torker has a 16v setup like this, I believe it doest behave well with regular 95RON and needs to use an Ethanol blend.

[Golfie.NC]

Thank you @missioner, i'm just struggling to get 2.0 long block rods in and around my town, do you perhaps know the conrod length on 2.0 short block or would they be the same as 1.6/1.8?

[missioner]

Thank you @missioner, i'm just struggling to get 2.0 long block rods in and around my town, do you perhaps know the conrod length on 2.0 short block or would they be the same as 1.6/1.8?

2.0 short block uses 1.6/8 conrods

[Golfie.NC]

[PapaJo]

2L crank stroke is 92.8mm

[missioner]

2L crank stroke is 92.8mm

Thanks. My memory is slipping.

[PapaJo]

2L crank stroke is 92.8mm

Thanks. My memory is slipping.

[wian_SMIT]

Thanks alot for all that info, i have 2x blocks and thats the reason why i asked. The 1.8 block was bored 020 previously and engineering guys said its needs to be rebored again or either re-sleeve and thus i thought of using 82.5mm kombi pistons. I know the wrist pin is 20mm on the 1.6/1.8 engines but just wanted to confirm on the Kombi piston side. On the 2.0 long block im struggling to get rods as the ones i have can't be used again according to engineering place and was wondering if i used 1.8 rods with the 2.0 crank in the long block then maybe i could use some other pistons with a higher deck. Once again, thanks for all the info. I really appreciate it

Sorry just reread this.

Quick recipes
1. 1.8 short block and rods, 2.0l 90.5mm crank, 82.5mm pistons from 2.5 motor (Caravelle) = 2.0l motor

2. 1.8 block and rods, 1.8l 86.4mm crank, 83mm or 83.5mm pistons (microbus 2.3 and Audi 500 C4) = 1875cc (83mm) and 1897cc (83.5)

3. 2.0 long block and rods, 2.0l crank, 84mm BMW piston = 2.1l (+/-)

4. 2.0l block, 1.9 TDi crank 95.5mm, 84mm BMW pistons = 2.3l (+/-). @Torker has a 16v setup like this, I believe it doest behave well with regular 95RON and needs to use an Ethanol blend.

i have an standard 1.8 fuel injection mk1 caddy bakkie

i need to rebore because i did have slight piston play, to what size do i need to bore for decent power or to fit 2.3 or 2.5 caravelle pistons or do have you a nice recipe to do with standard 1.8?

and also is it going to have any affect with that if i bore bigger that i also need to change computer box?