6 replies to this topic

[danny1]

right just been offered a +40 turbo block with 10cc turbo pistons

now im probbly being stupid, but as i always told in the navy no question is stupid, just might get a stupid reply.

so here i go, this is still fine to run with otu a trubo isnt it, on a std 5 port head and normal carb setup


thank you
danny

[Tommyboy12]

You will have to replace the pistons or compensate for the lower compression ratio with the cylinder head but there is no reason you cant run it naturally aspirated.

[danny1]

thank you :) its ok my last 1293 ran 10cc pistons, and that flew like a rocket

:)

[JustSteve]

thank you :) its ok my last 1293 ran 10cc pistons, and that flew like a rocket

:)

it must have had the head skimmed then, to lower the CR.


As Tommyboy12 said, you either need to get the head skimmed, or fit different pistons.

[Turbo Phil]

You need to measure how far they sit down the bore at TDC. If they are the cast Omega 10cc Turbo pistons then unless the block's been decked you should find they sit around 0.040" down the bore. This will give another 4.08cc on a +0.040" bore.

So you'll have 10cc piston dish, 4.08cc piston to block face, 4cc head gasket & whatever you have in the head.
With the head skimmed to give 18cc this will put you pretty much bang on 10.0-1 compression ratio. Ideal for a hot road motor.

Phil.

[danny1]

thanks thats ideal info guys, ill go check cc of my head

[danny1]

Hmm 28cc in the head I've got, and it's got 37.7 inlets and 29 exh and it's been ported and polished, I'm guessing this is way to low for std running on just a carb