Redesigned Head?

[cannedmushroom]

I got this head when I bought a box of parts from a guy. Does anyone know anything about it?
I want to use it on my blaster, but don’t know if it will work. Blaster is ported and polished w/ standard stroke. Looks to be about 2.5mm bored in. I found a few post on here but I am not sure if this can be used w/ a standard stroke or if it is designed for a stroker.
Any information will be greatly appreciated.

 

[blasterBruce]

Trade you a Stock head for it !

 

[cannedmushroom]

Running one now, I would love to use it but I need to find out if I can before I change it out.

 

[blasterBruce]

Well there is a way to check it , Put it on and Do a Squish test with a piece of Solder , There are vids on you tube !

 

[sicivicdude]

That head looks like it's been cut for a stroker crank without spacer plate. From the general looks of it, I'd say a +4 hotrods.

It's also not going to perform very well at high rpms as the combustion chamber area is relatively small in diameter compared to the rest of the relief.

 

[blasterfreek30]

defently cut for a longer stroke crank wthout a spacer plate

 

[cannedmushroom]

The squish clearance is large, I am running it right now and it has added better response and raise my compression from 125psi to 145psi.
What is the issues running it?

 

[sicivicdude]

Simply inefficiency. You're not going to hurt a thing running it as long as it's not too tight. Check the squish clearance and report back.

 

[best]

That head looks like it's been cut for a stroker crank without spacer plate. From the general looks of it, I'd say a +4 hotrods.

It's also not going to perform very well at high rpms as the combustion chamber area is relatively small in diameter compared to the rest of the relief.

I think you may be mistaken here.
Notice the deep undercut is OUTSIDE of the head bolts?
And that it still seems to have the stock .5mm step into the squish?
All this head will do is lower the plug and chamber and still has the poor stock Blaster chamber shape.

I don't know what someone was thinking when they made this head except for getting the plug closer to the piston by about 5mm.

You should really have checked out your squish gap before running it, or you could have problems.

Not a great gain over a stock head, but may show some improvement with the plug placement and increased compression at low rpm.

I'd love to lower my plug by 5mm so nice to see you doing it!

 

[cannedmushroom]

The squish is 0.114. What else can be done with it at this point?

 

[Triplecrown421]

The squish is 0.114. What else can be done with it at this point?

thats good the "safe squish" is anything above 0.040..... in our case. im running a head at around 0.055 with no worrys.

if the head works better then stock then RUNN IT. remember supreme gas

 

[sicivicdude]

I think you may be mistaken here.
Notice the deep undercut is OUTSIDE of the head bolts?
And that it still seems to have the stock .5mm step into the squish?
All this head will do is lower the plug and chamber and still has the poor stock Blaster chamber shape.

I don't know what someone was thinking when they made this head except for getting the plug closer to the piston by about 5mm.

You should really have checked out your squish gap before running it, or you could have problems.

Not a great gain over a stock head, but may show some improvement with the plug placement and increased compression at low rpm.

I'd love to lower my plug by 5mm so nice to see you doing it!

Stock stroke engines have a deck height of about -.5mm (.020")

A stock copper gasket is .8mm (.032")

If you are running a +3 mm stroker crank without the spacer plate, your piston, instead of being .5mm under the deck height will stick up above the deck height by 1.0mm (.040"). which means that the piston crown will protrude out of the head gasket by about .008" or .04mm.

If he has a stock stroke engine right now that means his piston crown is located .052" under the head gasket mating area. A current squish of .114" minus the .052" (if it was a stroker crank) would give a semi respectable squish area of .062".

A +4mm stroker crank would have the piston move .020" or .5mm farther out of the head gasket mating area. Do the math for that and the squish is a REALLY respectable .042".

Cannedmushrooms, you have a race gas head cut for a +4 stroker crank. You can run it the way it is but it's not optimal for a stock stroke engine. The only negative aspect is that it's leaving some efficiency on the table for your particular engine build. If you want to, you could sell that head to someone with a +4 stroker crank and have one cut specific to your engine.

 

[scotj77]

that squish band is freaking humongoid wide

 

[best]

The squish is 0.114. What else can be done with it at this point?

You could remove the basegasket and seal the cylinder to case with Three Bond 1104 or 1194 sealant or Yamabond (same stuff).
This will lower your cylinder and head and squish by 0.020"-0.040" depending on what gasket you have in.
This will decrease your squish to a minimum of 0.074" which works well for squish, but may be too tight for compression with that shape chamber.
You don't know unless you try, but listen carefully and know what detonation sounds like.

A 4mm stroker would extend the piston about 0.080" higher, so your squish would be 0.034", which is a racing value.
Dang you SiCivicDude, why do you always have to be so.... right???!!!

 

[sicivicdude]

A 4mm stroker would extend the piston about 0.080" higher, so your squish would be 0.034", which is a racing value.
Dang you SiCivicDude, why do you always have to be so.... right???!!!

I tried to do it in my head instead of writing it all down and doing my sums like my 2nd grade math teacher told me to! :-[ When I'm in the garage I measure, write it down, do the math, write that down, and then go over and cut. When I'm all done I measure, twice!

The difference in my math was the .008" that a +3 stroker crank pushed the piston above the gasket. Got myself all confused!

Simple addition and subtraction aside, I believe that's a race head for a +4 stroker crank. The squish area seems to be quite wide and the combustion chamber QUITE small even for race gasoline. I'd be interested to see what sort of compression that head has on a stroker crank.... might not be usable!