head gasket question

DBMonster85

DBMonster85

New Member
#1
#1
i have a 69730 predator that has a mild build. so far it has
ARC billet flywheel
ARC billet +20 rod
black mamba cam
header+air cleaner
22mm mikuni
26# springs
and im adding a 14cc head ported and milled 65thousands 27mm intake 25mm out. stainless valves locks and retainers and chromoly pushrods. the piston is the stock dish. i would like to upgrade to a flattop but for now it will remain. i have not measured how far i'm in the hole as of now but i'm wondering what would be a safe but thin head gasket to use with my setup? and if it all depends on how far i'm in the hole then how far do i need to be to run like a 10 thousand gasket. and so you guys know ive been out of work for months now with a broke foot and iv'e read like everything on this forum. lol for real like every post.
 
DBMonster85

DBMonster85

New Member
#3
#3
thanks thats what I was looking for. this was my first build and i know every motor is going to very with these clones but i knew there had to be some what of a safe point. and since that piston is a dish would i measure it from the highest point of the piston? i guess thats the only way it would make sense.lol
 
OND

OND

#4
#4
Yes If its a dish piston you would measure it from the outside..the highest point. I try to measure all four sides of the piston area..because the blocks are mass produced one side could be higher than the other..
 
minibikin'

minibikin'

Sho-nuff
#5
#5
^ what he said. :) seems like the deck height is all over the place on the predator...


Sent from my Texas Instruments Speak and Spell...[emoji2]
 
DBMonster85

DBMonster85

New Member
#6
#6
cool!!! you guys are great. i just picked up a bully 2 disk clutch today also i can't wait till all this comes together. i wanted too run a bigger cam but didn't know anyone to machine the spring pockets on my head for dual springs.oh well from what i have read here the black mamba is a pretty decent cam.
 
Y

youngengines

New Member
#7
#7
DBMonster85 said:
cool!!! you guys are great. i just picked up a bully 2 disk clutch today also i can't wait till all this comes together. i wanted too run a bigger cam but didn't know anyone to machine the spring pockets on my head for dual springs.oh well from what i have read here the black mamba is a pretty decent cam.
Click to expand...
The Black Mamba is very good. I turn one of my hemi predators 8200 to 8400 every lap with one. (stock piston, and rocker arms)
 
DBMonster85

DBMonster85

New Member
#8
#8
so its safe to run like a .010 head gasket if I'm .015 in the hole or more? and I'm also wondering about my push rods if I buy 1.3 rockers. I know this is off the topic of the thread but I don't want to keep starting threads. basically I milled my head and if I added 1.3's can I use stock length pushrods or will it change? I've bought chromoly ones but at the time I only needed stock anyway. not a big deal either way I will build another motor soon just wondering if you may have ran similar setup.:shrug:
 
OND

OND

#9
#9
I would say you are safe with a.010 gasket if you are .015 or more in the hole, How much did you mill off the head .010 or .020 and you should be ok with what you've got.
 
minibikin'

minibikin'

Sho-nuff
#10
#10
Check the rocker geometry at 1/2 lift. The rocker tip should be centered on the valve stem.


Sent from my Texas Instruments Speak and Spell...[emoji2]
 
DBMonster85

DBMonster85

New Member
#11
#11
yea I guess there's really no answer but to measure. thanks again. and again that piece of advice was basically what I needed. thanks minibikin. and the rest of you as well.
 
D

davidlamb78

Member
#12
#12
OND said:
I try to measure all four sides of the piston area..because the blocks are mass produced one side could be higher than the other..
Click to expand...
Do you run those new square pistons? Hehehehehehe...I'm just messing with you OND. That's sound advice. These motors are all over the place. I've not run the Mamba, but I've only read good things. I'm assuming you're going to run the Mamba and not the Mamba Jr.? Is this going on a daily rider? It looked like you're running a knobby on the back, so I'm assuming you're not drag racing this thing? Are you running alky? I don't know what your compression will be, but I've always been told that high compression likes high octane fuel. I've got a lot of the same mods you do, and I run pump gas in mine, but I didn't shave my head, and I am using a fairly thick gasket. I can't remember what it is off of the top of my head. This thing will be fun to ride. Be careful, you may brake more bones. This front wheel won't stay on the ground.
 
Norcalputput

Norcalputput

Member
#13
#13
DBMonster85 said:
so its safe to run like a .010 head gasket if I'm .015 in the hole or more? and I'm also wondering about my push rods if I buy 1.3 rockers. I know this is off the topic of the thread but I don't want to keep starting threads. basically I milled my head and if I added 1.3's can I use stock length pushrods or will it change? I've bought chromoly ones but at the time I only needed stock anyway. not a big deal either way I will build another motor soon just wondering if you may have ran similar setup.:shrug:
Click to expand...
That's only .025 piston to head clearance you still need to equate for piston to valve clearance .060-.080"in. .100"Ex. +.030 for aluminum rod


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DBMonster85

DBMonster85

New Member
#14
#14
my compression will be like 12:1 or 12.5:1 around there. i'll be running 110 (we call it turbo blue here) the head is milled .065. and I guess its a race bike. after I put the head on and the 300 dollar bully clutch I just got it's not much of a daily rider. I don't want my clutch going to crap and I'm sure putting around wont be good on my valvetrain. the bike tire has changed that was a old pic when I started the bike it now has a live axle setup and a 4 ply tire with better bearings. hydro brake and blah blah blah. same as everyone else I guess. you can call it a doodle bug with the works
 
SnakePliscan

SnakePliscan

New Member
#16
#16
Push rod dope

DBMonster85 said:
so its safe to run like a .010 head gasket if I'm .015 in the hole or more? and I'm also wondering about my push rods if I buy 1.3 rockers. I know this is off the topic of the thread but I don't want to keep starting threads. basically I milled my head and if I added 1.3's can I use stock length pushrods or will it change? I've bought chromoly ones but at the time I only needed stock anyway. not a big deal either way I will build another motor soon just wondering if you may have ran similar setup.:shrug:
Click to expand...
If you were not milling the head you would have to run longer push rods, the mumba cam has a dropped base circle to obtain a big lift number, when a cam is reground that way longer push rods are requiered to resquare the valve train. But because your milling the crap out of the head your inadvertantly correcting the rocker arm geometry that way. (your moving the rockers closer to the reduced base circle) understand?
Heavy duty (higher carbon content) push rods are a good idea when running a hi ratio rocker up against stiffer valve springs.
 
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