F4.6 Head Gasket(s)?

[THE JUDGE]

Last night, after some fun with the Savage, I took it apart for cleaning and inspection. I took the head off and there were 2 copper gaskets. In the HPI manual, they only show one gasket. I'm wondering if anyone else can confirm or deny this...if my motor has too many gaskets from HPI, that means my motor has been running a lower than optimal compression ratio. I'm tempted to pull one out, but not until someone else can say whether there should be 1 or 2.

TIA
Greg

 

[RangerRock]

My k4.6 has 3 inside of it........

I left it alone and kept the 3 in since thats how many it had all along and ran awesome.

 

[THE JUDGE]

^^Go figure...HPI shows 2 gaskets on the K4.6. LOL!

 

[Larsenracing]

You are able to take one gasket out which will gain compression which inturn will give more power but the motor will not last quite as long.

 

[THE JUDGE]

Hmmm...I may just take one out anyway. I live above 5000ft., so the slight bump in compression should be OK.

 

[Pineapple]

I wouldn't- I think that each particular motor is built with the required shims-I would hate to see you mess up a perfectly good motor by either A-raising compression too much or B-having piston slam into head! Just my 2 cents though.
Dave

 

[Larsenracing]

Ya I'm not sure i would do it either I have just heard of people doing it. I have no experience with it. If there is a thin one you could try removing that one and rolling the motor over by hand using the flywheel making sure the piston misses the head and you should be of doing this. Actually I may try this at some point on my racer.

 

[THE JUDGE]

Oh I understand the clearance issue, guys-I've built/modded quite a few 1:1 motors, so checking clearances is the norm for me. It is also because of this that I know that motors inherently have a lower dynamic comp. ratio at higher altitude. On the big motors you can increase timing, run hotter plugs, reduce octane, or raise the compression as you go up in altitude. A small 2-stroke follows the same basic principles.

Sounds like a little experimentation is in order...

 

[HopIt]

This sounds very interesting, as I have a K4.6 sat on my bench doing nothing........hmmmm !

 

[Larsenracing]

Let us know how it turns out. I'm thinking about doing it on my Axials to.

 

[Bankrupter]

My 4.6 ss came with 2 shims. I was told if I wanted to run 30% to add a 3rd. Id melt it trying to get any more out of this mill with out port work...:nono:

 

[Blazer X]

I had one without the shims and it ran like a scalded dog, just take one and try it. You will like it.

 

[Larsenracing]

I had one without the shims and it ran like a scalded dog, just take one and try it. You will like it.

I agree.

Also, Blazer what altitude are you at?

 

[Blazer X]

Indiana altitude....?

 

[Larsenracing]

Indiana altitude....?

So somewhare between 1,257' and 320'.

 

[Double-O-Zilch]

I removed 1 shim on my F4.6 running 30% got some preignition. The evidence was the pitting on the head and piston. I may have been running her a little lean though. On the other hand it did run pretty good till it was overheating.