1958 35 Lark Questions

[ah09]

Hi all, I just had my lower end apart, I put all new seals in, and a new shift dog. While taking it apart I noticed that there are places for two copper tubes that come up from the water pump housing to the motor. Mine only has one tube and the other one is totally missing. My question is, Should I get another tube or was it supposed to be just one copper tube?

[kfa4303]

Some models did have 2 water tubes. If the waterpump housing is set up for two tubes, and it is original, then I would think you would need the second tube. You don't really want to take chances with cooling issues on the motor. One way to be sure is to take a flashlight and and look up into the lower unit to see if you can find where the second water tube may join to the underside of the powerhead. Look at the intact tube as a reference, then check to see if you have a second, similar site on the motor. I'm sure others will have more info that can help you out. Good luck. Keep us posted.

[F_R]

Is the lower unit the original one for the motor? There were two kinds used in 1958 and they are not interchangeable. In fact, they should not even bolt up to the wrong type. The 1958 Lark has two tubes, and the 1958 Big Twins have one water tube.

Does your motor have a double "shell" at the midsection that you had to remove to get the lower unit off? That would be the Lark. That kind must use a two-tube cooling system and will not work properly otherwise.

[ah09]

Yes it has a double shell, and yes it is the correct lower end. I bought the motor from a friend who took the lower end off because it leaked oil. I already asked him about it and he swears there was only one tube when he took it apart. When i look up inside the mid section to where the second tube fits into, I found it to be completely packed full of mud and sand. I unplugged it and I will just make a new tube that goes from the water pump housing to there. Why are there two tubes anyways?

[Joe Reeves]

When cold and the thermostat is closed, the wter pumps up to the powerhead then back down to the pump, circulating until the thermostat opens. If you're capable of making that second water tube, fine, but if not, contact me by clicking on my name to the left. Although they are no longer available, I have a couple left.

[ah09]

Thanks for all the input! I got it all back together and ready to go. I took the thermostat housing cover off and someone has taken it out. Would you suggest to run it with or without a thermostat? And another quick question: Does my motor have needle bearings in the motor? Just wondering what oil ratio to be running it at.

[Joe Reeves]

It's safe to use the 50/1 mixture on that engine (all bearings on moving parts).

Yes, install a thermostat assembly along with the poppet valve that goes under it if it's also missing.