Upgrade thermostat

[tolsen]

Making a new disc is more work than one would think so initially I tried improving on the existing disc by turning it true on a lathe, removing check valve and sealing its hole:

Above was quite an improvement compared to how it was but it still leaked more than the original Wahler, mainly because seat is not perfectly true and round. Max gap between seat and disc (without O-ring) is 0.25 mm. I therefore manufactured a special lapping tool to sort this out.

I then made a new disc out of marine bronze:


The o-ring used is a 2 mm diameter profile of unknown type and material. Ideally I should use Viton.


O-ring groove is cut perpendicular to the 35 degree angle seat of thermostat housing chapeau. Dressed o-ring groove with a 1.7 mm diameter Lidl Dremel equivalent ball head bit.


I removed casting flash from the housing and ground the ends of the spring:


Assembled thermostat with L shaped locking pin out of 1.6 mm stainless steel TIG rod in original pin hole:


Initially I was worried the o-ring would either overcook or drop out of its groove in disc but has performed remarkably well after two years of service.

[mottofreee]

I will fit the bypass.
Seat deformation can be corrected by inserting a stainless steel bushings (similar to the cylinder head valve seats).

[tolsen]

Seat is slightly distorted on these Gates thermostats so I made a special lapping tool to correct that.

Your PTFE disc should work provided it can make a positive seal against seat.

Fit a 9 mm restrictor in bypass.

[mottofreee]

We found that two polka dots ( 60C ), is warm the hose what go to radiator=> thermostat unit compromise and anyway not working parameters.
The car remained as so and I bought another thermostat.
From what recounted TK, Gates thermostat is removable. I ordered component of the net and arrived in 24 hours (GATES TH40390G1). https://plus.google.com/photos/11282...18205146693954
In the 25th hour it was opened. https://plus.google.com/112827018205...ts/5bEwWuBm6Jb , https://plus.google.com/photos/11282...18205146693954
Flange which is pressed on wax unit is steel (not stainless steel). I want to replace it with one of PTFE. https://plus.google.com/photos/11282...18205146693954
The bypass valve remove it , depending on the functioning cooling systems at high temperatures (in summer) will reverse the decision.
I'm open to any suggestions.