4g64 head questions

[minimotos95]

i have a 8v SOHC 4g64, i know that a 4g63 head swap is doable but requires custom pistons. so would a 16v SOHC head from a 2g spyder gs bolt up w/o new pistons or do i need 4 valves per cylinder pistons?

i dont know much about cars(or 4 strokes).

 

[MidShipCivic]

You do not need ''custom pistons'' to use a 4g63 head you need 4g63 pistons to use a 4g63 head.

You will also have to plug 5 needless holes in the cylinder deck that the head will not use.

Since you say you don't know much about these engines.

The 4g63 and the 4g64 use the same length connecting rod and piston height so they are interchangeable.

One thing I think you should know is that using 8 valve head with 4 valve pistons
creates a higher compression ratio 12-13 to 1 range so it shouldn't be done.


Just to add this picture is a fwd 4g64 engine with oil drain back holes plugged you must do the same thing to your rwd block.

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[minimotos95]

the 64 has a larger bore. how are you supposed to use pistons 1.5mm smaller?

 

[MidShipCivic]

the 64 has a larger bore. how are you supposed to use pistons 1.5mm smaller?

Oversized pistons.

 

[minimotos95]

i just looked up pistons, magnus is $700+(only place i could find with pistons) that's twice what i payed for the truck. so has anyone done a 16v sohc swap to a 8v motor? Google didn't find any.

i would be on one of the MM d50 forums but there dead

 

[MidShipCivic]

i just looked up pistons, magnus is $700+(only place i could find with pistons) that's twice what i payed for the truck. so has anyone done a 16v sohc swap to a 8v motor? Google didn't find any.

i would be on one of the MM d50 forums but there dead

If you want me to be literal yes you can put a SOHC 16v head if you wanted, HOWEVER I previously explained that installing a 16v head = same volume as 4g63 head will cause a high compression ratio because the volume is smaller netting you high compression.

It was measured by member ''moby the van'' 8 valve head had a volume of 67cc's the 16v head DOESNT MATTER IF IT'S SOHC OR DOHC = 47cc's will have a high compression ratio well over 12.5 to 1.


What's wrong if using the stock pistons ? If you really want a dohc head ... you can have 4g64 pistons machined to 22mm pin's ( 1g ) and use them oem replacements that is your only way.

Understand now?

 

[minimotos95]

there was a typo (you mixed them up) in your first post. now i understand

One thing I think you should know is that using 8 valve head with 4 valve pistons
creates a higher compression ratio 12-13 to 1 range so it shouldn't be done.

 

[okm12346]

you dont need custom pistons for the dohc head swap

 

[minimotos95]

midship already said that. just need big bore 4g63 pistons.
i read it("je custom pistons") off this site Project 4G64 , i hate when people call aftermarket custom(usually rims).

 

[m_0ney_pit]

hey MidShipCivic what did you use to plug the oil drains that aren't used? I heard of people using silicone and thin metal before.

did you tap the holes and put them in? it looks really good

 

[MidShipCivic]

there was a typo (you mixed them up) in your first post. now i understand

Sorry about that.

hey MidShipCivic what did you use to plug the oil drains that aren't used? I heard of people using silicone and thin metal before.

did you tap the holes and put them in? it looks really good

These are hex plugs you can find in ace hardware and some freeze plugs the holes are slightly enlarged to fit the plugs.

 

[minimotos95]

according to poorboyj on automotiveforums there isn't the oil drain holes on pre 93' 4g64s. is this true?

why cant cars be simple 2 strokes....

 

[Kickerbeast]

according to poorboyj on automotiveforums there isn't the oil drain holes on pre 93' 4g64s. is this true?

why cant cars be simple 2 strokes....

since when did 2 stokes not have pistons and heads? Your talking about mixing and matching parts here, nothing is simple, even if it is a 2 stroke.

2 strokes are great!!....Just like rotaries!!!

Sorry, I couldn't resist.

 

[minimotos95]

2 strokes don't have valves(except power valves) or oil(besides premix, yum) in the top end.

 

[Kickerbeast]

Ya, unfortunately, I know about 2 strokes. Spent quite a few years wrenching at a Yamaha dealer

The real issue here is the piston/combustion chamber size, not the number of valves. Doesn't matter what number of strokes it has. You would have the same problem with a 2 stroke if you were trying to fit different parts to it. One you get over that fact that this has a valvetrain the rest of the problem will become very simple for you. If you understand the rotating mass of an engine, you should be fine figureing this out.

 

[mko]

IDK why you guys making it so complicated. Yes you can use 0.6'' over Eclipse pistons, but there are pistons specificly made for 4g64 and the pricing is the same and they are available in different CR