packing plate?
I'm building a series two engine on which I intend to fit an Imola kit. I have a GP type quality crank which has a 110mm rod. If I use this crank? Would fitting a 3mm packer be the best option in order to give the 107mm stroke, that I believe the Imola requires.
you could put the barrel on without a packer then measure how far the piston sticks out at tdc and thus work out what size packer you need to obtain the correct spuish. If it the later imola with the head that drops in the barrel you would obviously need to take in to account the depth of the step on head.
- garry inglis
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Basic answer is yes plus normal gasket but you still need to check the piston at bdc is level with the transfer ports italion and Spanish casings can vary up to 1mm differens when you place the barrel on and then check your squish is correct
Yes, I'm referring to the latest Imola 186 kit. (haven't bought it yet) and it is a Spanish casing.
2.5 packer then gasket either side to get your 3 mm
Like that idea, ta.
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Or a combination of base & head gaskets still keeping the 1-1.5mm squish
to give a different quality ride ?? Ooooo matron
to give a different quality ride ?? Ooooo matron
- drunkmunkey6969
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Dry fit the kit first and using digital callipers and/or feeler gauge measure the 'deck height' (the gap between the top of the cylinder and piston crown when at TDC). Whatever that figure is, add your desired squish clearance and that's the thickness of packer you need.
So, for example, if piston crown is 1.75 above cylinder and desired squish is 1.25mm then you need a 3mm packer.
Or, if piston crown is 1.25 below top of cylinder and desired squish is 1.25mm then you don't need a packer at all.
This all assumes head has no recess and is zero deck (flat).
Next, when choosing where to place packer, if for example you need a 3mm packer....you can place ANY quantity of that above and/or below the cylinder in order to get the desired port timings. So you could put 3mm packer at the bottom to jack the timings up, or instead fit a 3mm head gasket to push the timings down, or fit any combination of above/below within that....e.g. 2mm base packer and 1mm head gasket...
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So, for example, if piston crown is 1.75 above cylinder and desired squish is 1.25mm then you need a 3mm packer.
Or, if piston crown is 1.25 below top of cylinder and desired squish is 1.25mm then you don't need a packer at all.
This all assumes head has no recess and is zero deck (flat).
Next, when choosing where to place packer, if for example you need a 3mm packer....you can place ANY quantity of that above and/or below the cylinder in order to get the desired port timings. So you could put 3mm packer at the bottom to jack the timings up, or instead fit a 3mm head gasket to push the timings down, or fit any combination of above/below within that....e.g. 2mm base packer and 1mm head gasket...
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Cheers Drunky. That may be a tad beyond my normal knowledge, but I'll give it a go. What would be the effect of raising the timings and conversely lowering them?