4ag build question

ae86cesar
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4ag build question

Postby ae86cesar » Fri Jan 22, 2016 12:12 pm

Hey guys, I'm currently trying to get a ae86 coupe on the road, I have a silvertop 20v that I didn't want to install because I want to smog it with no problems. I also have a 16v large port head but it's the bare head, no valvetrain or cams or covers etc etc.. would it be cheaper to find another large port head complete. Or should I build the one I have? I'm also on the fence if I should use the 20v block or get a 7af block. Either option will get megasquirt ecu.

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yoshimitsuspeed
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Re: 4ag build question

Postby yoshimitsuspeed » Fri Jan 22, 2016 2:28 pm

ae86cesar wrote:Hey guys, I'm currently trying to get a ae86 coupe on the road, I have a silvertop 20v that I didn't want to install because I want to smog it with no problems. I also have a 16v large port head but it's the bare head, no valvetrain or cams or covers etc etc.. would it be cheaper to find another large port head complete. Or should I build the one I have? I'm also on the fence if I should use the 20v block or get a 7af block. Either option will get megasquirt ecu.

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If you found a LP head and didn't do anything to it then it wold be cheaper to buy a complete head. If you built that head then it depends on what you are doing to it.
Whether you want to use the 20v block or 7A is a personal prefrence. Generally I vote 7A.

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oldeskewltoy
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Re: 4ag build question

Postby oldeskewltoy » Fri Jan 22, 2016 3:12 pm

A used head can be had for about $50-$200... some times you can use them directly... but a minimal rebuild then typically needs about $200(clean, pressure check, machine surface)in machine work, plus valve seals($40-$120), and as long as the seats are not too bad, a little lapping compound will get you a tight valve to seat seal

Because you mentioned smog... the block MAY be a problem, Cally might find the extra 7A block height and fail it... the 20V silvertop short block isn't the best option, but the piston should provide about a 10.5 to 1 static compression ratio, so it'll have some decent power... but do to piston shape, the engine would be interference based now

Guessing you are not Cally because you mention using aftermarket management....
OST Cyl head porting, - viewtopic.php?f=22&t=300

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ae86cesar
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Re: 4ag build question

Postby ae86cesar » Fri Jan 22, 2016 3:24 pm

oldeskewltoy wrote:A used head can be had for about $50-$200... some times you can use them directly... but a minimal rebuild then typically needs about $200(clean, pressure check, machine surface)in machine work, plus valve seals($40-$120), and as long as the seats are not too bad, a little lapping compound will get you a tight valve to seat seal

Because you mentioned smog... the block MAY be a problem, Cally might find the extra 7A block height and fail it... the 20V silvertop short block isn't the best option, but the piston should provide about a 10.5 to 1 static compression ratio, so it'll have some decent power... but do to piston shape, the engine would be interference based now

Guessing you are not Cally because you mention using aftermarket management....

I'm located in Las Vegas nv, I'll look around for a used one. Or mr2 donor at my local pic a part. There is ways locally to "pass" smog if you know what i mean. But when I had a 4ag on my ae86 hatch it passed legally no problem. I regret selling that swap.

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