Charlie,
I suspect there are several things going on here ,but let me give you my
Best guess ,since I can't diagnose it in email .....
First off , there are a few more tests that need to be checked before
you dismiss these aspects .I would make sure your head gasket and head
are not related to this ,since you didn't give any history of what they
are supposed to be .I would do a leaky head gasket test first before I
condemned Anything at this point .It seems to be the Weakest aspect of
these
owner repaired cars I have ever seen over the years .Also ,you mention
that this problem has been since day 1. Is that 1964 ,or since the used
engine was gotten running again , or rebuilt ?? Usually the head gasket
repairs was Never done correctly,i.e., Head bolts not properly torqued
,by lubing the Clean threads of them ,making sure block threads are
clean by chasing them before installation .....Have you ever warmed up
the car with the radiator cap off to see if any bubbles appear in the
system ?? Are you running a no higher than a New 180 thermostat ?
Depending on your answers ,I would visit the radiator again. Assuming
this was a low mileage unit than the following may not apply .Just
because a Radiator can flow coolant ,doesn't always make it a good
rejecter of heat .I have had many over the years ,particularly on Z cars
that were clean ,had good flow ,and still didn't cool well .The problem
was the Fins to tubes connections .After all the heat cycles ,and time,
the fins loose their mechanical bond to the tubes,therefore the tubes
are just flowing coolant and not dissipating heat out of the radiator
with the fins cooling the tubes .
The radiator size is marginal on these cars to begin with so these
things are were I would start not knowing the original answers to my
preface statements . Another thing about timing is that if there is Too
much Total advance at high RPMS ,this can be trouble too especially with
high compression . Worn out and or a distributor that has an issue with
the advance weighs can give too much advance for a set RPM . You need a
timing light or use a distributor machine that will show total advance
.I probably would not have over a total of 38 degrees . Back down
initial if it is ,or get it fixed .
The cap leakage issues may be a result and not the cause of the problem
,however not sure I would condemn them yet.
Let me know if you have any questions .
Steve Ehlers
Rising Sun Performance Inc
Fort Worth ,Texas
My 1964 SPL310 (1500) has run hot since day one. It has a fairly pristine
3-row radiator core. I live in the Dallas Texas, area, and it gets pretty hot
around here. The stock idiot gauge steadily pegs on the highway at about 65
mph. I put an after market gauge in which showed the temperature close to 290
deg. Slowing down to 55 MPH brings the temperature down but it still runs at
275deg. After running around town and turning the motor off, it often blows
most of the coolant from the upper tank through the overflow tube. It often
vapor locks after it gets turned off. I took my radiator to the local old
school radiator guru today. He did a flow test and it was fine. However, he
noticed that my cap was pretty week. He thinks my stock cap may only be a
3-4lb cap and suggested that I purchase a 12 lb cap. . He's thinking that
that my roadster may be continuously be losing coolant when it gets pressurised
and allows air into the system, which makes the car run even hotter.
A tighter cap would hold coolant better and help the cooling. The
temperature would stay lower, even under more pressure. The stock radiator caps
are not exactly growing on trees, so getting a 12 lb cap to give it a try may
not be obtainable. The radiator shop says they can put a new cap assembly o
the unit, but I hate doing that before I even know if it will solve my issue.
Does anyone know a source for a 12lb cap that will fit a 1500 radiator?
Feedback from those in the know would be appreciated.
> .Charlie Hubbard
> Flower Mound, TX
> cehubbard@verizon.net
---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com
________________________________________
datsun-roadsters@autox.team.net
Archive: http://www.team.net/archive
Unsubscribe:
http://autox.team.net/mailman/options/datsun-roadsters/mharc@autox.team.net
|