2.0L piston/cylinder clearance question

[BoomerMuskoka]

how much clearance between the cylinder and piston is too much, and what will fail if i build one a little loose? :confused: :thumbsup: only reason i ask is i got to see inside of a 300 drag and the clearances in that motor we're huge compared to my little fishin motor. can someone explain.

[dompie99]

Hi Boomer, what do you mean by '' HUGE '' ???

[BoomerMuskoka]

i mean i thought the cylinders we're out of round in the 300 drag, but the owner said " nope its in spec" and moved the piston into the middle of the cylinder., ,, my 2.0l is tight not much clearance ,

[BoomerMuskoka]

im not sure what his clearances are , but the're way looser than a fishing motor :confused: what is a standard bore for a 2.0l. ? 3.125 ? what is going to break if i bore it to 3.130 " and put it back together. nothing or something

[dagodiver]

Clearance is based on piston material and diameter.
Manufacturer will give a number per inch of diameter.
Ive seen from .001 to .0022 per inch of piston diameter.

[Capt.Insane-o]

Cast piston .003. Preferably a Vertex piston.

[BoomerMuskoka]

how big is to big and what is going to break?, rods? or rings?

[BoomerMuskoka]

:D what kind of piston can i go .0066" :thumbsup:

[Capt.Insane-o]

Wiseco.

[BoomerMuskoka]

to allow for expansion ?

[dagodiver]

Knurl the skirts.

[BoomerMuskoka]

so what are the specs for a 300 drag bore/clearance, perhaps he was running wiseco and mine are cast, would that be the difference i noticed :confused: or do the drag motors have even more clearance

[BoomerMuskoka]

Knurl the skirts.

im sorry im lost on this answer ? im a newbie :confused: is that to hold oil?

[Capt.Insane-o]

to allow for expansion ?


Yeah, .006 is perfect for a Wiseco in a 2.0. NO synthetic oil for break in , not even a blend. I use Valvoline or BRP xd25/30 for break in @32:1 for 50 gallons with many many heat cycles.

[BoomerMuskoka]

im sorry im lost on this answer ? im a newbie :confused: is that to hold oil?

or reduce friction

[BoomerMuskoka]

Knurl the skirts.

or is that what happens when the clearance is too big? :confused: motors blow my mind

[wired247]

Knurl the skirts.

Ah yes, the good old days. Chokes, knurled pistons , O ring valve seals, gaskets cut out of tide boxes, knurled valve guides, oil bath air cleaners and those wonderful timing sprockets with plastic teeth.

[Mr. Demeanor]

Make sure were all talking about the same clearance. Piston to wall vs. overall piston dia. to bore size.

If your judging the clearance by moving a cold piston crown around in a bore your way off. A piston is smaller in dia. at the top then at the skirt to allow for expansion when its hot.

[BoomerMuskoka]

Make sure were all talking about the same clearance. Piston to wall vs. overall piston dia. to bore size.

If your judging the clearance by moving a cold piston crown around in a bore your way off. A piston is smaller in dia. at the top then at the skirt to allow for expansion when its hot.

im just wondering what the differences in any clearances anywhere in a fishing motor vs a drag motor.

[BoomerMuskoka]

heres one now that i have every ones attention..... i have a bradgeport with 6 mahle pistons, 5 steel sleeves and 1 nikasil, or chrome dunno.,,.., how do i tell what rings are for what bore. i have a pile the mahles came with rings the person i got them from said there for steel bore.. i haven't a clue so want as many opinions as possible, this block looks bad ass. i cant wait for spring

[BoomerMuskoka]

http://i1327.photobucket.com/albums/u670/boomermuskoka/Mobile%20Uploads/fresh20l001_zpscaf16500.jpg (http://s1327.photobucket.com/user/boomermuskoka/media/Mobile%20Uploads/fresh20l001_zpscaf16500.jpg.html)

http://i1327.photobucket.com/albums/u670/boomermuskoka/Mobile%20Uploads/20lmercassembled001_zps7fd3bd9f.jpg (http://s1327.photobucket.com/user/boomermuskoka/media/Mobile%20Uploads/20lmercassembled001_zps7fd3bd9f.jpg.html)

what are the chances of this thing piling up into a ball of shrapnel when i spark it up? :D my first rebuild 2.0L 150, horizontal 5 pedal front wh-31 carbs. donno what i have for a tuner or jets, any suggestions :eek: