4/6 information and parts needed!

[78invader2]

Im rebuilding my 4/6 motor and need some information. First, are the rings the same as a regular 440 invader? Also, I found a gasket set but it just has normal 440 head gaskets with it. I heard there were 4/6 specific head gaskets for it. Any idea where I can buy these? Lastly, it has the wrong pistons in it (ring pins are in the wrong spot). Does anyone have a set for sale or know where I can buy the right ones?  Oh, also, what years were the 4/6 made? Thanks guys!!

[Lloyd (ljm)]

 Hi

 4/6's are a one year only 1980. They were a transition engine between the original Invader t7 engine and the mono block LTD engine. Original 4/6 pistons are very hard to find. Some but not all the SPI aftermarket Invader pistons have the locating pin in a spot that works with the 4/6. It is hit and miss. I have checked several pistons. Some will work , some won't.
 I believe the regular Invader rings will work. I think the 4/6 actually used the same rings as a John Deere Liquifire.   4/6 head gaskets are different. I have never tried using a regular Invader gasket in a 4/6. The 4/6 gaskets turn up on Ebay. I think some of the jet ski gaskets are the same.

 4/6's are fun engines, But parts are harder to find.


.

[gixxer6]

The regular Invader head gaskets should work, however I have never been able to sustain a seal using anything but the 4/6 gaskets on any of my Invader or 4/6 motors.  IMO they are worth the time in locating them and the extra $$$ spent on them.  Plus they are reusable.  Do as Llyod suggested and check ebay, or try calling Image. 

[Interceptor398]

Rings are the same and use the head gasket the uses the copper ring.  Just my 2 cents.

[78invader2]

Okay thanks a ton!! I have a set of pistons and rings lined up, so I just need the correct head gasket. Who sells the copper one? And is that the 4/6 gasket people had mentioned? Sorry for all the questions!

[Teherr]

I too am putting together a 4/6 motor and placing it into a liquifire chassis for oval racing.  The piston are unique but the rings appear to be the same as LTD, but not invader.  I happen to have one of each engine apart in my garage right now - invader, 4/6, and LTD Mono head.

Steve @ smkdoo@yahoo.com has serveral original copper gasket set (I just bought one) for $65. 

While we are on 4/6 motors, I would like to hear opinions as which motor has more potential (power) for oval racing - the 4/6 or monohead?  Steve, they guy with the gasket kits is putting a 4/6 motor into a ski doo RV chassis, and he claims to know someone who had a stock 4/6 motor with 38mm Mikuni's bored to 40, running pipes from a cat 440Z that put out 100hp.  Claims the ignition is a key component.  If this is true, could you run a 4/6 ignition on a monohead engine and do the same?  The monoheads are more available then the 4/6. 

Does anyone know or have any porting specs for any of the the 3 motors listed?  I have heard of a liquifire with invader motor running stock liquifire exhaust, although ported,  making 85hp. 

Terry

[Lloyd (ljm)]

 The 4/6 gaskets are two pieces. A rubber seal and a copper fire ring. The NOS Deere Liquifire gaskets use an outer fibre seal and the same copper fire ring that the 4/6 uses

[gixxer6]

I think it was Sprocket on here that has the 100hp 4/6?  There is a thread on this forum that discusses using the mono head ignition on an Invader or 4/6, it says that it is a direct swap although I haven't tried it yet. 

It doesn't seem very popular to modify a mono head 440 for more performance.  I think most guys swap the top end to 550 parts if they are looking for more from their mono head.  I would think the newer design mono head motor would have more potential. 

78Invader2,  I may have an extra NOS set of 4/6 head gaskets, I will look tonight and PM you. 

[78invader2]

okay thanks!!

[78invader2]

Find anything Gixxer?

[gixxer6]

Sorry, I did not get a chance to look.  We just finished moving and most of my stuff is in boxes.  I have been extremely busy with the move, work, and trying to get the new house ready for winter.  I will make myself a note to look tonight. 

[78invader2]

Not a problem!! I wont be back on here till Monday, so if you wanted to call or text me at 507-491-0948 you can do that too. Hopefully your move went well!