I just bought a set of bare Brodix IK 200's. I'm in the midst of gathering all the pieces and parts that i need. Can anyone answer what is the advantage of longer valves?
Valve length
- Thread starter aint_no_half_stephen
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What about rocker ratio? I'm thinking about going with 1.6 rockers and +.100 long valves. Dont want too much lift, the heads are 67cc and they're going on a 383. The cam is a xe274h with 480/490 lift.
1.6:1 will give you .522in lift which should still clear the pistons, but it may depend on which pistons and deck height you have.
you can use 1.6 or 1.5:1 ratio rockers, the problem will be figuring out the proper pushrod length. i'd buy an adjustable length pushrod checker from summit and use that to figure things out.
you can use 1.6 or 1.5:1 ratio rockers, the problem will be figuring out the proper pushrod length. i'd buy an adjustable length pushrod checker from summit and use that to figure things out.
the engine is at standard deck height, with flat top speed pro pistons. With flat top pistons, what is the extreme someone can go as far as lift?- With a 64 cc head? Thanks Megaladon.
do you know what the part number is for the pistons? i may be able to figure things out with that (they have different piston heights).
i know what most people do is guess and than use clay on the piston and rotate the engine over to compress the clay. then they measure the depth of the clay for the clearence.
off the top of my head, 64cc heads with flat tops and 5.7in rods you should be fine with .550in lift.
i know what most people do is guess and than use clay on the piston and rotate the engine over to compress the clay. then they measure the depth of the clay for the clearence.
off the top of my head, 64cc heads with flat tops and 5.7in rods you should be fine with .550in lift.
the pistons are speed pro H860CP skirt coated. I'll probably do the clay thing as well just to make sure, cause when i turn the crank the face of the pistons are almost flush with the deck. almost meaning about .015 from being completely flush. And i'm not exactly sure how close they're supposed to be.
i'll keep looking, but i can't find the piston height right now.
i did see that they have valve reliefs so that's good. .015 in the hole isn't too bad, that's what mine is with the same cam and 1.5:1 rockers. of course i have dished pistons so it's not a direct comparison.
:edit: i found the piston height at 1.4250. the recommended height for your engine is 1.450 (according to a generic calculator) so the extra room and the reliefs together should allow plenty of room.
another thing to do is measure the depth of the reliefs and the heads combustion chambers, then add the .015in of below deck and the thickness of the head gaskets you plan on using (i'd use about .017 for tight quench) and you have the minumum distance (not counting timing).
i did see that they have valve reliefs so that's good. .015 in the hole isn't too bad, that's what mine is with the same cam and 1.5:1 rockers. of course i have dished pistons so it's not a direct comparison.
:edit: i found the piston height at 1.4250. the recommended height for your engine is 1.450 (according to a generic calculator) so the extra room and the reliefs together should allow plenty of room.
another thing to do is measure the depth of the reliefs and the heads combustion chambers, then add the .015in of below deck and the thickness of the head gaskets you plan on using (i'd use about .017 for tight quench) and you have the minumum distance (not counting timing).
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