How much compression should i run?
06-22-2008, 11:31 AM
#16
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Join Date: Jul 2002
Location: Phoenix, AZ
Posts: 1,277
. Am i going to have to run shorter pushrods taking that much off? If thats the case, i wont mill as much. Also now that i have the cylinder head off, it doesnt look like there is much room to mill at all before you would be hitting the valves... not quite what i had recalled from the last set of heads i worked on.
Further, unless you know how to tune well, you should not be pushing high CR's.
Don't skimp and good luck!
06-22-2008, 12:00 PM
#17
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Join Date: Aug 2003
Location: Detroit
Posts: 2,926
You take the valves out to mill. So they arent there, so long as you dont mill past the top cut on the valve job you should be fine. Alot of lt1 heads end up with valves proud of the deck surface when you get done milling them....
Pushrod length should always be verified with new rockers and camshafts as either can change the geometry, it should also be verified when milling heads or running thinner gaskets as well.
After you get done milling you may even have to do a little work so the intake will bolt back on properly.
While they're off at least have the clearances checked, and have them cleaned and a valve job done.
I already said if it were me I would leave well enough alone until I was ready to really go through the heads and have them ported. I think its a whole lot of brain damage for nothing much. But what do I know I only did engine r&d for 6 months last year for a major auto maker.
Good luck to you.
Pushrod length should always be verified with new rockers and camshafts as either can change the geometry, it should also be verified when milling heads or running thinner gaskets as well.
After you get done milling you may even have to do a little work so the intake will bolt back on properly.
While they're off at least have the clearances checked, and have them cleaned and a valve job done.
I already said if it were me I would leave well enough alone until I was ready to really go through the heads and have them ported. I think its a whole lot of brain damage for nothing much. But what do I know I only did engine r&d for 6 months last year for a major auto maker.
Good luck to you.
I might be doing mild porting as well depending on what kind of price he gives me on that. The thing is, I have a LOT more time to work with than money. I dont mind tinkering around under the hood to get a decent combo and I really enjoy working on the car anyway. This is a budget build, if it wasnt I would have pulled the engine at this stage of its life and started fresh with a stroker. I just want something a little more fun than a stock motor for the next few years while i finish college and find a real job. If i can get close to 375rwhp for now that would be fan-tastic, but i dont really wanna push a stock bottom more than that. It is what it is, if i dont hit my goals oh well.
I think i might only do .015 or .020 thousandths now but Im not really worried about the tuning part of it. Again I have time for that as well as friends that have pretty good tuning experience. I just dont want to do anything that is going to throw the geometry off too much that i need to get different pushrods or make the intake not line up. I figure ill have to drill the holes out at least a little. I know i should have thought of this before I ordered the kit, live and learn. I'll get my hands on a checker and see what it looks like.
Last edited by JoeliusZ28; 06-22-2008 at 12:07 PM.
06-22-2008, 01:00 PM
#18
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Join Date: Oct 2001
Location: Engineerland
Posts: 1,517
I am really not trying to slam you here, but if you're in college and dont have alot of money you should not have even considered this.
You have already spent money that maybe you dont realize. A set of head gaskets is going to run you about $60-80. A set of head bolts from arp is going to be $50 (stock bolts are 1 time use). Milling your heads is going to be from $75-125 depending. A valve job is probably in order which will run you somewhere between $100-200 Then you have disassembly cleaning and reassembly to pay for at shop rates unless you're capable and have the tools (barrel mic, spring compressor etc).
All of that and you're worried about a set of 80 dollar pushrods?! Which by the way depending on what rockers you're running, if you need guideplates you need new pushrods anyway
.
Just hypothetically what are you going to do when it spins a bearing after the new cam and reworked heads have been on it for 10 miles. I know thats not the case every time, but I would have to take my shoes off to count the local stories of just that thing happening in the last year or two.
Don't worry about the tuning it is freaking cake until you get to wot. See my post in the tuning section about what to change before firing up a 383 for the first time. Maf mode will put up with damn near anything with minor changes. Just have to get the wot a/f in line and not overdo the timing.
Your mileage is also going to take a hit so consider that, that cost never goes away it just keeps gettin bigger.
You have already spent money that maybe you dont realize. A set of head gaskets is going to run you about $60-80. A set of head bolts from arp is going to be $50 (stock bolts are 1 time use). Milling your heads is going to be from $75-125 depending. A valve job is probably in order which will run you somewhere between $100-200 Then you have disassembly cleaning and reassembly to pay for at shop rates unless you're capable and have the tools (barrel mic, spring compressor etc).
All of that and you're worried about a set of 80 dollar pushrods?! Which by the way depending on what rockers you're running, if you need guideplates you need new pushrods anyway
.Just hypothetically what are you going to do when it spins a bearing after the new cam and reworked heads have been on it for 10 miles. I know thats not the case every time, but I would have to take my shoes off to count the local stories of just that thing happening in the last year or two.
Don't worry about the tuning it is freaking cake until you get to wot. See my post in the tuning section about what to change before firing up a 383 for the first time. Maf mode will put up with damn near anything with minor changes. Just have to get the wot a/f in line and not overdo the timing.
Your mileage is also going to take a hit so consider that, that cost never goes away it just keeps gettin bigger.
06-22-2008, 02:01 PM
#19
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Thread Starter
Join Date: Aug 2003
Location: Detroit
Posts: 2,926
I am really not trying to slam you here, but if you're in college and dont have alot of money you should not have even considered this.
You have already spent money that maybe you dont realize. A set of head gaskets is going to run you about $60-80. A set of head bolts from arp is going to be $50 (stock bolts are 1 time use). Milling your heads is going to be from $75-125 depending. A valve job is probably in order which will run you somewhere between $100-200 Then you have disassembly cleaning and reassembly to pay for at shop rates unless you're capable and have the tools (barrel mic, spring compressor etc).
All of that and you're worried about a set of 80 dollar pushrods?! Which by the way depending on what rockers you're running, if you need guideplates you need new pushrods anyway.
Just hypothetically what are you going to do when it spins a bearing after the new cam and reworked heads have been on it for 10 miles. I know thats not the case every time, but I would have to take my shoes off to count the local stories of just that thing happening in the last year or two.
Don't worry about the tuning it is freaking cake until you get to wot. See my post in the tuning section about what to change before firing up a 383 for the first time. Maf mode will put up with damn near anything with minor changes. Just have to get the wot a/f in line and not overdo the timing.
Your mileage is also going to take a hit so consider that, that cost never goes away it just keeps gettin bigger.
You have already spent money that maybe you dont realize. A set of head gaskets is going to run you about $60-80. A set of head bolts from arp is going to be $50 (stock bolts are 1 time use). Milling your heads is going to be from $75-125 depending. A valve job is probably in order which will run you somewhere between $100-200 Then you have disassembly cleaning and reassembly to pay for at shop rates unless you're capable and have the tools (barrel mic, spring compressor etc).
All of that and you're worried about a set of 80 dollar pushrods?! Which by the way depending on what rockers you're running, if you need guideplates you need new pushrods anyway
.Just hypothetically what are you going to do when it spins a bearing after the new cam and reworked heads have been on it for 10 miles. I know thats not the case every time, but I would have to take my shoes off to count the local stories of just that thing happening in the last year or two.
Don't worry about the tuning it is freaking cake until you get to wot. See my post in the tuning section about what to change before firing up a 383 for the first time. Maf mode will put up with damn near anything with minor changes. Just have to get the wot a/f in line and not overdo the timing.
Your mileage is also going to take a hit so consider that, that cost never goes away it just keeps gettin bigger.
I am also getting the impala gaskets for $35 and the headwork done (milling, cleaning, assembly) for $100. The bolts are the only thing i havent bought yet, and i was aware they are one time use.Some bolts and/or pushrods arent out of my budget. $1000 in porting is, although i may have some mild work done yet anyway, we will see
I also plan on flushing a LOT of dino oil through this thing after i put it back together. I am not taking any chances with **** floating around in there.
Last edited by JoeliusZ28; 06-22-2008 at 02:04 PM.
06-22-2008, 03:17 PM
#20
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Join Date: Oct 2001
Location: Engineerland
Posts: 1,517
AI will trade you pushrods with little fuss I imagine they sell plenty of em. That is quite a bargain on the machine work. Spinning bearings isnt from **** floating in the oil its from added stress (rpm) and you beating it more to feel the power. Sounds like you got it all figured out, carry on.
06-22-2008, 03:34 PM
#21
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Join Date: Aug 2003
Location: Detroit
Posts: 2,926
AI will trade you pushrods with little fuss I imagine they sell plenty of em. That is quite a bargain on the machine work. Spinning bearings isnt from **** floating in the oil its from added stress (rpm) and you beating it more to feel the power. Sounds like you got it all figured out, carry on.
and by the way your input is appreciated, I am not one to toss advice from the experienced aside
I am probably not going to mill as much.Hopefully I will be posting some feedback in the next couple of weeks
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