This post just made me realize that with the Metro engine transplant we acquired in the Traveller, I may need to address this.

I just replaced the thermostat, but I am pretty sure the old one had no holes and I did not add holes to the new one.

I eventually plan to add a take off at the heater port, but currently have no place for a return. I plane to add one to the radiator.

I am assuming the lack of circulation leads to hot spots unitl coolant starts moving?

Terry

The general consensus when doing the Metro engine conversion with no by pass is to drill three 3/16" holes in the thermostat. You are doing the right thing by getting rid of the way overpriced SPI lower hose.

Thank you all

It is sounding like I have three options.

1.  To always have the in car heater allowed to ciculate, thus allowing the engine block to have coolent circulate with it before the thermostat opens.   (fine if I am the only driver and I don't forget.)

2. Put a T fitting on the lower rad hose where it returns to the in car heater and add a hose from the tee back to the conection on the sandwich plate.  This would allow circulation in the block before the thermostate opens and whether the in car heater is allowed or not.

3.  Drill another whole in the termostate.  The thermostat is made with one whole, two might be better.

Note,  It seams that the newer A Plus engines (not sure of the date started but certainly those in the 90s) which did not have the older small bypass hose connecting the head to the water pump, do require part of the complicated hose configuration even if one does not use the expantion tank is not used.  Unless sufficent holes are drilled into the termostat to allow circulation threw the block before the thermostat opens.

Comments

Wally

If you're removing the sandwich plate and going to the earlier type of heater setup with no bypass hose, you ought to drill a few holes round the outside of the thermostat.

No Bypass on water pump - no problem.

 With the late SPI head you will have to remove the blanking plug from the back of the head to install your early heater control valve (no issue).

 Also you will be simply removing the sandwich plate from the thermostat assembly (no issue).

I wouldnt foresee any issues all the way around.

For your whole aseembly-  are you adding Carb and Manifold ?- and A+ distrubutor to the works to make this all happen? Sounds like a solid conversion all way round!

the bypass is there to circulate the water between the head and the block until the thermostat opens and the engine is warmed up.

Hi A

I am setting up a 1994 SPI 1275 engine from Japan into my 1977 mini and will be using the old (1777 998) in car heater contol, instead of the in-line control.  I will also not be using the tap off the sandwich plate but will use the same connection off the water pump hose as on my 998 setup.  This in car heater setup will be exactly like that of a 1977 mini with all its hoses.  Question: is their a problem with doing this as their is no bypass hose between the water pump and head.  Is this bypass hose function done by the hose complication used on the 1992 to 1996 SPI engines?  Has anyone had success doing what I intend on doing?

Another question: what is this bypass hose's pupose?  Why would one want to recirculate warm coolent back threw the engine block?  Does this bypass hose play any part in circulating coolent threw the engine block before the thermostate opens, or is the hole in the thermostate enough to do the job?

Many thanks, sorry for so many questions