21 dj engine with big bore kit 2,2liters

[rickard95]

hi
i have helped my grandpa with a installation of a big bore kit with 2,2 liter on a 2,1 liters dj engine.
but it will not run good. have anybody done this before and know if i have to change anything on the fuelinjection or anything else?

need help 
//Rickard

[Aidan]

you shouldn't need to change anything I wouldn't have thought - time the engine as per the fuel being used
Have you timed the engine by the book ?
What is the compression like ?

[rickard95]

the compression is about 10 i think  it should have about that and what do you mean by timing the fuel?

[Aidan]

DJ was originally designed to run on 4 Star petrol and was timed at 10' BTDC.

If running on E10 unleaded 95 RON you'd time it at 5' BTDC, if you use SuperPlus or Premium 98/99RON you can run at 10' BTDC - some of us find the extra power and fuel economy of running Premium is worth it, YMMV.

If the timing mark is 15mm in front of the TDC mark on the pully that is the 10' mark, if it's 7.5mm between the marks that's the 5' mark, replacement engines from VW supplied after the full advent of unleaded fuel in the early 90s came with a 5' pulley, and many engines are not in their original factory state now, so worth checking how yours is marked.

Timing adjustment procedure is slightly fiddly and specific; it's in the Haynes or you can download the appropriate VW engine manual(s) in English from Syncrosport or Sir Adventure's websites

Andrew at Campershack may have more information on the 2.2 kit and optimum set up, I don't actually have any experience of any engine built using it, there were issues with the piston rings supplied with the Chinese made kits and it lowered the compression ratio as I understood it, so may not be happy at the original timing as the DJ was the high compression ratio version of the 2.1.

[Stesaw]

the compression is about 10 i think  it should have about that and what do you mean by timing the fuel?

Compression is 10?? What bar or psi?

[Robsey]

10.5:1 is the compression ratio.
Not a pressure value.
The other 2.1 engines are 9:1

I suspect that the pressure reading on a compression tester would be in the area of approx. 154 to 196 psi, for a good set-up. (11 to 14 bar)
And each cylinder should be within approx 3 bar (42psi) of the others.

Tested whilst cranking until no increase in pressure is observed.
At a temperature of 30°C,
And with the throttle valve fully open

[tobydog]

the compression is about 10 i think  it should have about that and what do you mean by timing the fuel?

Compression is 10?? What bar or psi?

Fruit pastilles

[silverbullet]

"Bolt on, no machining necessary. 95.5mm pistons increase the size from 2054cc to 2120cc"
Well if they can't even get the basic dimensions right then it doesn't inspire confidence in the product.
A 2.1 is 2109cc iirc? These kits are low compression going by the photos. Its a lot of effort for very small gains, any performance increase probably more due to the rebuild itself.
https://www.heritagepartscentre.com/uk/ ... C5EALw_wcB

[Aidan]

half the price direct from AA performance in the states whose website just looks like a US based operation selling Chinese manufactured stuff, built out of GEX who state they are ' the nation's Largest Rebuilder of Premium Motors for Volkswagen Powered Vehicles' - note no testimonials - but search on the Samba and it seems the owners of GEX retired and sold out the brand , which had a pretty poor reputation from what I can gather, last year...

their description is

Brand new Set 95.5mm Big Bore water cooled piston and cylinders, for the 1986 to 91 Vanagon, 2.1L WaterBoxer engine. This Big Bore kit is the easiest way to turn your 2.1L into a 2.2L and give your a little more torque and HP with out any major changes.

Engine size: 2100cc

Stroke: 76mm stroke pistons

Cylinders: Cast Iron

Pistons: Hypereutectic aluminum alloy

Compression Height: 36.8mm

Dish CC: 46cc

Set includes: 4 pistons, 4 cylinders, 4 pins, and clips and a set of rings

Very nebulous description 'a little more torque and power' with no actual figures quoted or dyno graphs or real technical information about piston weight tolerances, balanced sets etc...no builder information

Swept volume I calculate as 2177cc against original 2109cc, that bit of maths I can do but is the compression ratio simply the 544.25cc per cylinder swept volume divided by 46cc dish in which case it is 11.83:1 or is it more complicated than that ? I suspect it is...

[tobydog]

Is 46cc the volume of the cylinder at tdc?

If it is, then would the compression ratio be (544.4 + 46) / 46, equals 12.83?

Last time I got involved with compression ratios was tuning A series Mini engines in the mid 80's

 

[silverbullet]

Swept volume plus combustion chamber and squish volume, all divided by chamber plus squish volume.
They look like MV style pistons to me.
I did a thread on chamber cc and scr some years ago.

[silverbullet]

Here it is

viewtopic.php?t=149884&hilit=Combustion+chamber+cc

[Aidan]

Anyone know what happened to 937Carrera, over a year since he's been on, did he sell up the T3s and drive off into the sunset in a Porsche ?

so using Ian's figures the 2.2 kit is 8 and a bit:1 compression ratio