Ford 400m Deck Height Question Tim Meyer Pistons
#16
01-29-2017, 02:51 PM
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#17
01-29-2017, 03:50 PM
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Thanks for the help... Yes the block is at the machine shop. They were doing the machine work, and said that they found the difference of height of .025-.027 between cylinder banks. I am assuming they measured from the center of the crank somehow, and they seemed to indicate they would get both deck heights the same and then put the crank, rods and piston in and measure how far they down in the cylinder the top of the piston is from the deck.
In terms of zero decking I believe that would give me about 9.91 to 1 compression. I calculated this the CC volume of my heads (Trick Flow Aluminum) with 72CC chambers, and Tim's Pistons have a Dish of -13.33CC. I am assuming that is static compression ratio, not exactly sure on how to caculate dynamic compression ratio. I plan on using a Comp Cams 260HR retro roller cam, and I will have the machine shop measure for Push Rods after all machining is done.
In terms of quench, I am not sure exactly how to plan for/account for that.
Thaks, yes this is a learning experience, as this is the first time I have rebuilt one.
In terms of zero decking I believe that would give me about 9.91 to 1 compression. I calculated this the CC volume of my heads (Trick Flow Aluminum) with 72CC chambers, and Tim's Pistons have a Dish of -13.33CC. I am assuming that is static compression ratio, not exactly sure on how to caculate dynamic compression ratio. I plan on using a Comp Cams 260HR retro roller cam, and I will have the machine shop measure for Push Rods after all machining is done.
In terms of quench, I am not sure exactly how to plan for/account for that.
Thaks, yes this is a learning experience, as this is the first time I have rebuilt one.
Hi Joel,
You're not overthinking this, but the thoughts are all over the place !
In the first post you mentioned a measurement of 25 and 27 was given.
In your last post you feel that they will machine the deck and then measure.
Do you understand what this means ?
There's two measurements :
One to ensure both deck heights are equal.
One to measure the deck clearances with the new pistons.
Does the machine shop have just the block, or is it complete with existing crank and pistons still fitted ?
If it's the latter, measurements will be 100%.
If it's the former, how exactly did they arrive at 25 and 27 ?
Why did you decide on a zero deck ?
Machining the block face changes the geometry. No problem if you're within limits.
Have you checked/calculated that your pushrods, cam and valvetrain will work with the new geometry ?
Trust no one, and visit the machine shop to see for yourself !!
Gary mentioned "quench". What is "quench". Will yours be correct, or will it invite pinging ?
Either you've done homework, and not typed it here, or you need to do homework.
Either way, enjoy learning from your new build.
You're not overthinking this, but the thoughts are all over the place !
In the first post you mentioned a measurement of 25 and 27 was given.
In your last post you feel that they will machine the deck and then measure.
Do you understand what this means ?
There's two measurements :
One to ensure both deck heights are equal.
One to measure the deck clearances with the new pistons.
Does the machine shop have just the block, or is it complete with existing crank and pistons still fitted ?
If it's the latter, measurements will be 100%.
If it's the former, how exactly did they arrive at 25 and 27 ?
Why did you decide on a zero deck ?
Machining the block face changes the geometry. No problem if you're within limits.
Have you checked/calculated that your pushrods, cam and valvetrain will work with the new geometry ?
Trust no one, and visit the machine shop to see for yourself !!
Gary mentioned "quench". What is "quench". Will yours be correct, or will it invite pinging ?
Either you've done homework, and not typed it here, or you need to do homework.
Either way, enjoy learning from your new build.
#18
01-29-2017, 05:48 PM
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#19
01-29-2017, 05:54 PM
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Thank you. How do you like the Trick Flow Heads? The 260HR Cam from Comp Cams is the smallest roller cam they have that you can retrofit these engines with, so I am hoping for good torque at low RPMs.
#20
01-29-2017, 06:11 PM
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#21
01-29-2017, 07:46 PM
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I love the TFS heads. I'm running a comp cams 252H (straight up) and its very smooth and has tons of torque. Has no problem hitting 5.5K rpm and I averaged 11.5 MPG pulling a loaded uhaul trailer from Oregon to Arizona. That's with a 750 edelbrock and just the primaries, and idle tuned (roughly). Right now I'm in the process of a Fitech fuel injection install. Since right after break in I moved to Arizona, I still have a lot of fine tuning to do. You can read my unfinished build thread https://www.ford-trucks.com/forums/1...-big-blue.html. if you want more detail on my build.
#22
01-30-2017, 08:13 AM
Hi Joel,
I've attached my calculation of your estimated SCR for info.
My result is close to yours.
BUT, assuming the base figures are correct, you will have negative deck height.
Not a train smash, as it can be manipulated with head gasket thickness as already mentioned by kopfenjager.
With regard to squish, you might find the attached interesting.
Post up the exact part number of the cam, and I'll see if I can work out the DCR.
I've attached my calculation of your estimated SCR for info.
My result is close to yours.
BUT, assuming the base figures are correct, you will have negative deck height.
Not a train smash, as it can be manipulated with head gasket thickness as already mentioned by kopfenjager.
With regard to squish, you might find the attached interesting.
Post up the exact part number of the cam, and I'll see if I can work out the DCR.
#23
01-30-2017, 10:11 AM
Join Date: Feb 2007
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Hi Joel,
I've attached my calculation of your estimated SCR for info.
My result is close to yours.
BUT, assuming the base figures are correct, you will have negative deck height.
Not a train smash, as it can be manipulated with head gasket thickness as already mentioned by kopfenjager.
With regard to squish, you might find the attached interesting.
Post up the exact part number of the cam, and I'll see if I can work out the DCR.
I've attached my calculation of your estimated SCR for info.
My result is close to yours.
BUT, assuming the base figures are correct, you will have negative deck height.
Not a train smash, as it can be manipulated with head gasket thickness as already mentioned by kopfenjager.
With regard to squish, you might find the attached interesting.
Post up the exact part number of the cam, and I'll see if I can work out the DCR.
Thank you very much for the time and data. The Part number on the CAM is CL32-411-8 . It is a 260HR grind for Ford 351C,M/400
#24
01-30-2017, 10:59 AM
@ kopfenjager :
Nice build !
No comment about the pulleys.
@ Joel :
You're welcome.
What made you consider that cam ?
Did you consider K32-411-8 ? You'll need the springs etc anyway.
Pay real attention to the cam notes. !
The cam is the absolute backbone of your build, and you need to get the specs spot on to avoid problems.
Did you look at kopfenjager's build thread ? Very informative.
I used Wallace Racing online calculator in the past for the DCR, but, add 20 to the cranking pressure !!
Wallace Racing: Dynamic Compression Ratio Calculator
Punch in your numbers and you'll see the DCR is at +/-8.3 with a cranking pressure of +/-168. (Add 20 = 188)
Hmmm. A tad high.
You used the word ''assume'' somewhere. Don't assume !!
Ok, the suspense is killing me. How did the machine shop acquire the 25 and 27 figures ?
Catchyalater
Nice build !
No comment about the pulleys.
@ Joel :
You're welcome.
What made you consider that cam ?
Did you consider K32-411-8 ? You'll need the springs etc anyway.
Pay real attention to the cam notes. !
The cam is the absolute backbone of your build, and you need to get the specs spot on to avoid problems.
Did you look at kopfenjager's build thread ? Very informative.
I used Wallace Racing online calculator in the past for the DCR, but, add 20 to the cranking pressure !!
Wallace Racing: Dynamic Compression Ratio Calculator
Punch in your numbers and you'll see the DCR is at +/-8.3 with a cranking pressure of +/-168. (Add 20 = 188)
Hmmm. A tad high.
You used the word ''assume'' somewhere. Don't assume !!
Ok, the suspense is killing me. How did the machine shop acquire the 25 and 27 figures ?
Catchyalater
#26
02-01-2017, 08:10 PM
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I love the TFS heads. I'm running a comp cams 252H (straight up) and its very smooth and has tons of torque. Has no problem hitting 5.5K rpm and I averaged 11.5 MPG pulling a loaded uhaul trailer from Oregon to Arizona. That's with a 750 edelbrock and just the primaries, and idle tuned (roughly). Right now I'm in the process of a Fitech fuel injection install. Since right after break in I moved to Arizona, I still have a lot of fine tuning to do. You can read my unfinished build thread https://www.ford-trucks.com/forums/1...-big-blue.html. if you want more detail on my build.
#27
02-02-2017, 02:18 PM
Posting Guru
No, if I keep it under 210 deg I can run 91 octane just fine. But its on the edge, per se (as temps climb you can notice the octane tolerance lowers). No pinging except under part throttle load, where my vacuum adv pulls in too much timing(I cruise with 20-24 hg's of vacuum) and then its just a flutter (doesn't ping with the vacuum adv disconnected). But that's a timing issue, not a compression issue. I was also pulling a loaded uhaul (moved 1200 miles from Oregon to Arizona) and my temps where a good 220-230 thru the Arizona desert (no fan shroud, I know I know), havn't driven it unloaded yet. once I get the Fitech installed I can get out there and get a good tune and I will get it all ironed out.
If you want to run 87 octane vs 91-93 oct, I would shoot for a DCR of 8-1 with aluminum heads and good quench. I wanted to make the most out of premium fuel, and with the small cam, better mileage. Its my baby and I only run premium anyway, mite as well make the most of it.
If you want to run 87 octane vs 91-93 oct, I would shoot for a DCR of 8-1 with aluminum heads and good quench. I wanted to make the most out of premium fuel, and with the small cam, better mileage. Its my baby and I only run premium anyway, mite as well make the most of it.
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