Barrel shim advice

[Isoraidatorcap]

I'm getting ready to rebuild my 1600dp using the 1700cc bolt on kit from toplineparts.com I wanna raise the compression up a bit but don't wanna kill all the new parts by slapping the piston and heads ... The heads are 53cc and I'm using the factory cam and crank /rods the kit came with .020 shims . I don't know what the motor has in it now as far as shims but yea this will be my first time getting this deep into a vw motor and I want it to last me seeing as its my daily. Thanks much in advanced

[modok]

You will have to flycutt he heads, bore them for bigger cylidners, or stroke it, to raise the compression any significant amount.

If the pistons are too close the head, shims are used to fix that, and that's all they really should be used for. Compression is controlled by the heads.


I don't know what a 1700 kit is....
but stay away from thinwall cylinders, if it NEEDS to last.

[Isoraidatorcap]

[clonebug]

If those are the 88mm thickwall P/C's then with an untouched case you will probably be at about .050 in. deck if it is anything like mine. If you are running a longer stroke crank then you will have less deck.

I am running 88mm pistons on a stock crank and have .062 in. deck with a .010 barrel shim and 52cc chamber heads for a compression of 7.8:1.

If you want higher compression you can go .040 deck with the 53cc chamber heads to bump it up a bit. That will get you to 8.1:1. You might have to deck the case to get that.

I run a W-100 cam with my engine and it runs nice.
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[Isoraidatorcap]

Yes they are the thick walled 88s the motor in my big was rebuilt before I got er I'm assuming its going to be stock 69mm stroke crank and cam. I would love to be at the 8:1:1 ratio so I can have that little extra performance for the budget lol. I've had a couple people in a fb group tell me that at a .040 id hit the heads I've had others tell me naw you are fine u can go to a .030 and get 8:5:1 and it will run forever kinda thing. but I keep getting the same answer I do like that's consistent go to the samba you can get a true answer to the questions u ask . I've run the calculator on cb performance to
Get the right numbers but if it will work is the biggest question

[clonebug]

[Isoraidatorcap]

I would love to boost my bug I've always been a boost baby myself and would really like to go this route myself when the budget permits what all have you done to boost prep ur motor and what kinda boost are u running

[Danwvw]

I just did what your doing and I had my case cleaned up ie decked .005" and with the rods I had, my deck came up at .050" I would have it rather been .030 but with stock or even a W-100 cam (which is what I have) it's better if the compression does not get too high.

Here is the post I made at the time:

[clonebug]