Liquifire Parts and Questions

tieszo6 · Post by **tieszo6** » Tue Dec 02, 2008 1:07 am

I'm curious as to how much higher the compression was on the Invaders compared to the LFs. I have some 4/6 heads that have a volume of 16.5cc's. Does anyone have a value for a LF head? Also has anyone ever put bearings and seals in the water pump? If so, where did you get the parts and do you have any part numbers?

Thanks

Mark

Trucker · Post by **Trucker** » Tue Dec 02, 2008 8:24 pm

Here is an Invader VS Liquifire comparison that should help you

tieszo6 · Post by **tieszo6** » Wed Dec 03, 2008 12:04 am

Thanks! That was exactly what I was looking for.

jdsledfarm · Post by **jdsledfarm** » Wed Dec 03, 2008 2:22 am

I rebuilt a liquifire water pump that was almost froze up, last season. I got the bearings from my local Deere dealer. I want to say the bearing number was 6600, you will find the number on the bearing. You will need two bearings. Be careful not to damage the nylon button under the impeller, its glued to the housing. clen the button contact surface, as well as the nylon on the backside of the impeller. My pump turned much much easier with the new bearings. I hope this helps.

Post by **ICCSF 108** » Wed Dec 03, 2008 7:21 am

I don't know the volume of the Kawi heads but we have used them in the past, Make sure to use the Invader heads & not the 4/6 heads UNLESS your converting the whole engine electrical over to use the duel plug heads...
Also when using the Invader Heads I would advise bumping the timing up to Invader specs I believe it's 18 deg. BTDC ( unless you have a 82 or newer liquifire )
You will defiantly notice the difference in power
Kenny

That Girl Racing · Post by **That Girl Racing** » Wed Dec 03, 2008 10:16 am

As always I have an opinion on this. The head on the left has a very wide squish band that would produce good bottom end power but would be very prone to detonation under high speed loads. The right head is typical of the modern two stroke head. It would have good top end and also good bottom end because it would tolerate more ignition timing. The 5cc volume difference would be about 1 point of compression. My personal choice would be the right head with some volume taken out of it to slightly bump up the compression. I would never even consider using a head like the left one. Peter

Mr. Deere · Post by **Mr. Deere** » Wed Dec 03, 2008 11:46 am

Really?? I also need to rebuild my pump. It freezes up when there is no coolant in it. I have to keep spinning it now that its off the sled to keep it loose.

tieszo6 · Post by **tieszo6** » Wed Dec 03, 2008 7:33 pm

Sledfarm, The bearings were 6200ZZ and I found some, but still working on the seal,

Kenny, yes the intent is a complete 4/6 transplant.

Peter,
As always, your opinions are appreciated. Your comments on the squish band are completely opposite of my understanding, and you can tell me why I'm wrong

Here are some of the things I thought it did:
I thought the squish band centralized the charge in order to prevent detonation? By pushing everything to the center, no combustion would "initially" take place at the edges, therefore preventing any preignition waves from propagating across the combustion chamber.
The charge gets pushed away from the edges of the piston then the combustion only reaches the edges well after TDC. This keeps the exhaust side cooler and prevents burn down.
The charge rushing in from the edges promotes thorough mixing.

Thanks in advance, I respect and enjoy your comments because I know you have the timeslips to back them up .

That Girl Racing · Post by **That Girl Racing** » Thu Dec 04, 2008 11:08 am

You are absolutely right that the squish pushes the mixture toward the center of the cylinder to avoid hot spots and detonation. Like everthing else to much is not always a good thing. Most engine builders look for a 50% squish band area, meaning that the band covers 50% of the piston sweep area. On a 68mm bore that would be about 8mm. When we go more than that the flame front is confined to a much smaller area on the top of the dome. The more piston exposed to the flame front the easier it is to transfer the heat away from the face of the dome and the cooler the piston face will be. The cooler the piston face , the more timing advance can be run without detonation. Detonation is the enemy of two stoke power and occurs on most high performance motors . It is not always detectable but always kills power. I see it clearly on the dyno. The wide squish works well in a motor that is lugged hard at RPM's lower that peak HP. An example would be a pump that is loaded hard during startup but spins fairly freely once it is going. It appears that the JD engineers were acutely aware of the issue with detonation and its effect on power and engine life. This two stroke theory stuff is very complex and racers and engine builders often take different routes to achieve the same end result. There will always be different opinions on this so take what I say with an open mind. This is what works for me and the a lot of the teams I race with but is not gospel. Peter

That Girl Racing · Post by **That Girl Racing** » Sat Dec 06, 2008 10:33 am

I discussed the 440 Kawi porting the other day with Paul McLeod from Union Bay Engines. He is recognized as one of the best two stroke engine builders around and builds race motors for a lot of top snowmobile race teams. We are going to work on a modern porting program for the 440 and I will do my Liquifire engine to that program. If I get time I will put it on the dyno and see what it produces. Peter

tieszo6 · Post by **tieszo6** » Mon Dec 08, 2008 1:26 am

Can't wait to hear the results.

Mark

Post by **ICCSF 108** » Mon Dec 08, 2008 2:01 am

That Girl Racing wrote: The right head is typical of the modern two stroke head. It would have good top end and also good bottom end because it would tolerate more ignition timing. The 5cc volume difference would be about 1 point of compression. My personal choice would be the right head with some volume taken out of it to slightly bump up the compression. I would never even consider using a head like the left one. Peter

Peter, Being you wouldn't use the Kawi Invader head on the left with Std Kawi timing I think 18-20 deg BTDC, "You said the (Deere/Kawi) right head with some volume taken out, what would you do plain the head?? (how Much?)
How much Engine timing would you advance too? I believe the std 80-81 Liquifire 440 is @ 16 Deg BTDC.. Using mod Deere head could you go to 20-22 Deg or higher or what would be a good timing for Bottom end & WOT operations??

Kenny

That Girl Racing · Post by **That Girl Racing** » Mon Dec 08, 2008 9:41 am

Kenny. Do you know what the squish clearance on the Kawi head is? As far as taking a cut off the head, you also have to recut the squish band . Not sure on how much it would be and not sure on the timing deal. I really do not like to guess. There is a formula. I would assume that if Kawi ran more initial timing than Deere that the squish clearance is pretty loose on the Kawi head. I am going to play around with some of this stuff this winter and I will keep you informed. Peter

Post by **ICCSF 108** » Tue Dec 09, 2008 4:19 am

Peter: I guess I'm not sure if I know what your asking me?? if asking the exact squish clearance in 0.0??? no I don't..
If asking if I know what squish clearance is?? isn't that the amount clearance between the piston & head when the gasket or head drops toward the top of the cyl. when a head is torqued down??

Kenny

That Girl Racing · Post by **That Girl Racing** » Tue Dec 09, 2008 10:15 am

Kenny, that is what it is. To measure it, take a piece of very soft solder, ( 50/50 is good) bend it to a "L" shape, shove it through the sprarkplug hole perpendicular to the wrist pin. Make sure it goes all the way to the cylinder wall. Turn the clutch to bring the the piston to TDC and crush the solder. Measure the crush at the thinest point. It should be tapered out toward the spark plug but the thin spot is generally used as the squish measurment. Peter