smallport 4age compression

[AE85coupe]

i'm wanting to up the compression on my smallport a bit

just wondering if about 11:1 sounds about right (for a car run on 98 mainly)

and if so, how much will i need to plane off the head?

[Jebus]

I would get the head planed square, and just use a 0.8mm TRD head gasket. Gasket is roughly $100, head planing may be about $30.

Would be the way id do it, dont have any tools or calculations to figure out what compression that will give, however someone will for sure.

[AE85coupe]

yeah my mate can do the planing for free, so i'm interested if someone can calculate exactly how many thou to take off

[AE85coupe]

o.k so can someone please tell me how much to plane off my head with a standard 4age head gasket to get some good, but not too crazy compression?

[Ae92typeX]

sorry, I aint got anything on file, but can your mate who will do free not work this out? (assuming its what they do for a job anyway)

[AE85coupe]

good point, i'd say he could

[jener8r]

correct me if i'm wrong but i thought they were about 10.3 standard?

www.geocities.com/MotorCity/Garage/8422/4age.htm

theres quite a bit of info on there if that helps

[Mr Revhead]

yep.

id just be going with a TRD gasket.
steel aswell

but what are your plans for the engine?

[AE85coupe]

i'm a student, i'm totally broke

i already have an acl gasket sitting here, so i won't be using a trd item

i don't have any plans for the engine in the near future (except keep it NA) haha, but i blew my head gasket so i figured i may as well setup the head nicely while its off, and any head work is free for me

so thats why i want to know roughly how much i should plane off

[craigt]

Im not going to work it out cause Ive just got home from work and my brain is fried.... but if you know the swept volume (bore times stroke or engine cc divided by 4) and the compression ratio then you should be able to work out the volume above the piston at tdc. Then work out number of ccs you need to remove you can use the calculation for the area of a circle (using bore size) to work out the thickness of headgasket required. If you only want to skim the head this gets harder because the combustion chamber in the head isnt the same size as the bore, but if you have a head off then it shouldnt be too difficult to get a rough idea

[AE85coupe]

o.k, i'm not so good with maths, you may have to explain a little more simply