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| 66 coupe |
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we are currently building an au 4L with offset ground crank, pistons 5 thou out of the bore, 60 thou off the head and a custom solid cam. piston to valve clearence is going to be your biggest issue unless you flycut the pistons.
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| JayEdXr6 |
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66 coupe wrote: we are currently building an au 4L with offset ground crank, pistons 5 thou out of the bore, 60 thou off the head and a custom solid cam. piston to valve clearence is going to be your biggest issue unless you flycut the pistons. Yer fly cut the pistons is fine but to a safe limit? when the ACL au piston crown is 9mm thick Wow 5thou out so that leaves 20 thou overal quench with an mls?? Is that a speedway motor? What sort of power are you looking at? What is an "offset ground" crank?
_________________ Poly green Ed xr6-new n/a motor on the way. |
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| 66 coupe |
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for this build we are using the stock pistons, if it breaks it breaks no big investment lost.
We have flycut the pistons to provide inlet and exhaust valve reliefs, the main point of contact is on the edge of the piston, and we have removed 4mm. unfortunately have no pics to post up on what we did. 5 thou out - we have run them this tight before with no probs upto 6700rpm, broken plenty of valves but never had pistons hit the head. Its a street motor with solid cam and adjustable rockers. Sees the burnout pad occasionally. We are trying different things with different builds, like i said above if it breaks it breaks, few hundred dollars we buy another motor and go again. |
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| 66 coupe |
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re offset ground cranks, this is where the crank journals are ground to move the centreline, therefore altering the stroke.
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| JayEdXr6 |
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66 coupe wrote: re offset ground cranks, this is where the crank journals are ground to move the centreline, therefore altering the stroke. Okay kool I sorta thought that
_________________ Poly green Ed xr6-new n/a motor on the way. |
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| SWC |
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Just want to clarify somethings.
You want to build for 12.5:1 comp, 225RwKw NA and have it streetable and you want it to rev out to 7,000rpm. Sound good but not realistic. Not from a SOHC 4.0l. I know of one 200RwKw NA 4.0l SOHC and it is not really streetable. You can drive it but, I wouldn't want do it in City traffic every day. 200RwKw has been the magic figure for SOHC 4.0l NA for many years and not many have achieved it. All I can say is good luck  .
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| SWC |
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Just want to clarify somethings.
You want to build for 12.5:1 comp, 225RwKw NA and have it streetable and you want it to rev out to 7,000rpm. Sound good but not realistic. Not from a SOHC 4.0l. I know of one 200RwKw NA 4.0l SOHC and it is not really streetable. You can drive it but, I wouldn't want do it in City traffic every day. 200RwKw has been the magic figure for SOHC 4.0l NA for many years and not many have achieved it. All I can say is good luck .
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| JayEdXr6 |
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SWC wrote: Just want to clarify somethings. You want to build for 12.5:1 comp, 225RwKw NA and have it streetable and you want it to rev out to 7,000rpm. Sound good but not realistic. Not from a SOHC 4.0l. I know of one 200RwKw NA 4.0l SOHC and it is not really streetable. You can drive it but, I wouldn't want do it in City traffic every day. 200RwKw has been the magic figure for SOHC 4.0l NA for many years and not many have achieved it. All I can say is good luck .Yer my goals are pretty outrageous, lucky I don't live in the city ; ). But in all seriousness my Ed only gets used on weekends and some afternoons, so it's not like it's my daily streeter. I can't imagine it would be a very "streetable" car, start stoping would be pretty average but I know this is hard to understand no one does, but I sorta want a engine that's with the characteristics of a speedway car. Of course I will not have a cam with like 106 lobe separation and 290 @50 etc, I don't mind if it's a challenge to drive around.
_________________ Poly green Ed xr6-new n/a motor on the way. |
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| JayEdXr6 |
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66 coupe wrote: for this build we are using the stock pistons, if it breaks it breaks no big investment lost. We have flycut the pistons to provide inlet and exhaust valve reliefs, the main point of contact is on the edge of the piston, and we have removed 4mm. unfortunately have no pics to post up on what we did. 5 thou out - we have run them this tight before with no probs upto 6700rpm, broken plenty of valves but never had pistons hit the head. Its a street motor with solid cam and adjustable rockers. Sees the burnout pad occasionally. We are trying different things with different builds, like i said above if it breaks it breaks, few hundred dollars we buy another motor and go again. That's gotta be a seriously tuff street motor, will you share the output? Build me one!!
_________________ Poly green Ed xr6-new n/a motor on the way. |
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| 66 coupe |
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once its built, running and i get it on the dyno to do the tuning i'll let you know
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| JayEdXr6 |
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66 coupe wrote: once its built, running and i get it on the dyno to do the tuning i'll let you know s**t yer, mine blocks going to get bathed and checked Wednesday.
_________________ Poly green Ed xr6-new n/a motor on the way. |
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| skidder |
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66 coupe wrote: for this build we are using the stock pistons, if it breaks it breaks no big investment lost. We have flycut the pistons to provide inlet and exhaust valve reliefs, the main point of contact is on the edge of the piston, and we have removed 4mm. unfortunately have no pics to post up on what we did. 5 thou out - we have run them this tight before with no probs upto 6700rpm, broken plenty of valves but never had pistons hit the head. Its a street motor with solid cam and adjustable rockers. Sees the burnout pad occasionally. We are trying different things with different builds, like i said above if it breaks it breaks, few hundred dollars we buy another motor and go again. How many kays have you had engines go to? Aside from piston/valves would be interesting to see how long you could get/if pistons ever did hit the head. Hard out set up though, will be interesting to see numbers.
_________________ EVL098 wrote: Cramping in the hand from having it on your Wang for an excessive period of time is a definate con. Seriously do people google "f**k up modifications for Fords owned by Jews" and get linked straight to this site nowadays? AU,factory fitted tickford kit/IRS, t5,Sports ryder/KYB: gone. |
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| JayEdXr6 |
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So I've settled on a machinist in Brisbane named plr engine reconditioning they are basically engine machinist specialists.
-acid bathed -decked (minimal until final assembly) -bored and torque honed(suited to au acl pistons which they are ordering) -main caps ground -align hone crank tunnel -acid bath crank -check and regrind and linish if nessecery They are also ordering my rods from scat. I'm leaving them with my flywheel and brand new balancer, there going to do a full balance which includes individual unit weight matching, end to end for rods, de-bur and smooth counterweights on crank and a rotating assembly balance, the flywheel is also beeing lightened and balanced to 8.5 killos. I spoke to one of the guys in the shop and he said for a street performance motor zero deck height will be fine, infact he said it is ideal. I trust these guys knowledge coz they do many expensive hi horsepower builds. he said it's best to trial assembly the short motor and have the deck shaved to suit, he also recommended fly cutting the pistons slightly further, depending on piston to valve with trial assembly, only if I'm gonna run a big cam but said he will help and show me that once we sort out the deck heights.
_________________ Poly green Ed xr6-new n/a motor on the way. |
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| 66 coupe |
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what block are you using?
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| JayEdXr6 |
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Ef block why's that?
_________________ Poly green Ed xr6-new n/a motor on the way. |
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