Jump to content

Looking for a spitfire


Recommended Posts

I've ordered a big syringe to oil the trunnions this weekend. GL4 oil is correct for this?

However, getting the water pump done so I can put antifreeze in is my first priority. I'm going to give that a go on Friday, but before I do, does anyone have any final suggestions to unblock the block drain hole or get the heater working? I've probed about in the drain hole with wire etc. Whatever I poke in goes about 1 1/2 inches and stops. Can't seem to find any passage sideways/upwards. I guess that'll have to wait till I need to take the head off for some reason (hopefully not too soon...) but the heater is rather frustrating. I think the car is running at the correct temperature as I can touch the top of the radiator for a couple of seconds. I wouldn't call any of the pipes hot, but all are fairly similar including the heater pipes. I'm rather at a loss...

Link to comment
Share on other sites

1 hour ago, Pete Lewis said:

Did you check the small bypass metal  tube is actually clear ?? 

Pretty sure I checked all pipes but I'll check again before filling with antifreeze. Would that explain the heater never working if it was blocked?

33 minutes ago, daverclasper said:

Is your heater return hose at least warm when the valve is open (apparently even when there is some flow through the matrix, it can still be partially blocked and not generating enough heat though).

The hoses all feel quite a similar temperature. When the system was drained I attached a hose to the heater valve (open) and water came out of the other heater hose (along with a load of nastiness...)

since water is presumably circulating through the heater, I don't really understand why it's not working :/

Link to comment
Share on other sites

You need a good volume to get the output  a small flow will over cool the incoming , and give no output 

If the pipe or its adaptor into the back of the pump is blocked you get poor flow to the heater and theres no  bypass when the stats shut

So the pump cant circulate till the stat starts to open then you get fast local heating up but still no heater 

Pete

 

Link to comment
Share on other sites

  • 2 weeks later...

I took the spitfire to see a mechanic friend today. We got it up on his lift to have a really good look underneath, which looks pretty good (better than I was expecting actually). There is surface rust over most of the chassis under flaking underseal,  but nothing rotten. He checked the timing with his strobe and it was rather more advanced than it ought to be so set it to 10 degrees BTDC.

He also said the reason the heater wasn't working was that the water was passing through the return under the manifolds much more easily than the heater matrix which seems logical. So, he clamped that hose shut and that made the heater work. Now I have a clearer picture in my mind of how the water circulates I don't really see how the heater was supposed to work when new. Why would the water ever flow through the heater matrix instead of the bypass return?

Anyway, for now, as long as the heater valve is open I assume I can leave that hose closed?

Link to comment
Share on other sites

39 minutes ago, chris.eg said:

Now I have a clearer picture in my mind of how the water circulates I don't really see how the heater was supposed to work when new. Why would the water ever flow through the heater matrix instead of the bypass return?

The bypass part has a restriction in it. If the heater matrix is clear and the valve is open (and also clear) then it's an easier path for the coolant than the bypass. There are three common reasons why the bypass would pass more than the heater:

1) the heater matrix and/or valve are (partially) blocked by silt and corrosion

2) the restriction in the bypass has rusted away or been drilled out by an ignorant PO

3) the ignorant PO has swapped the hoses so that the restricted pipe is now the heater

Link to comment
Share on other sites

7 minutes ago, NonMember said:

1) the heater matrix and/or valve are (partially) blocked by silt and corrosion

2) the restriction in the bypass has rusted away or been drilled out by an ignorant PO

3) the ignorant PO has swapped the hoses so that the restricted pipe is now the heater 

Ok. So is the restriction in the steel pipe under the manifold? On mine there is a steel T-shaped connection for the hoses near the back of the manifold. As far as I can remember the top connection is to the heater return, the side connection to the inlet manifold heating pipe and the bottom is connected by a rubber hose to the steel return under the manifold. Is that much correct?

Link to comment
Share on other sites

There were a few different designs over the years. If you have a tee off the side of the return pipe under the manifold, which I think is what you're describing, then that side-branch should have a restricted hole into the main pipe, and should connect to the manifold. If you've got a separate T-piece connected by rubber hoses then it's possible the PO who fitted that was not aware of the need for a restriction.

Photos would help!

Link to comment
Share on other sites

  • 2 weeks later...

Went through all this earlier in the year. After hosing out the muck from the system it turned out that the tee piece spliting the water flow between the heater and the return was in the wrong position. Make sure that the flow goes straight through the tee piece to the heater valve and that the side branch of the tee piece goes to the return. I always believed for years that water entering a tee piece splits equally... it doesn't. It does, of couse, take the path of least resistance, ie, straight through. When you have done that, check for an air lock in the highest point of the plumbing. Dealing with both of these fixed my heater. Thanks to Uncle Pete for the advice. You can find the full tale via this link

https://forum.tssc.org.uk/topic/2623-back-to-collecting-repaint-stuff-nose-to-tail-1972-spitfire-mkiv-restoration-upgrades/?page=17

Link to comment
Share on other sites

On 23/12/2018 at 09:17, NonMember said:

There were a few different designs over the years. If you have a tee off the side of the return pipe under the manifold, which I think is what you're describing, then that side-branch should have a restricted hole into the main pipe, and should connect to the manifold. If you've got a separate T-piece connected by rubber hoses then it's possible the PO who fitted that was not aware of the need for a restriction.

Photos would help!

 

On 31/12/2018 at 18:58, Badwolf said:

Went through all this earlier in the year. After hosing out the muck from the system it turned out that the tee piece spliting the water flow between the heater and the return was in the wrong position. Make sure that the flow goes straight through the tee piece to the heater valve and that the side branch of the tee piece goes to the return. I always believed for years that water entering a tee piece splits equally... it doesn't. It does, of couse, take the path of least resistance, ie, straight through. When you have done that, check for an air lock in the highest point of the plumbing. Dealing with both of these fixed my heater. Thanks to Uncle Pete for the advice. You can find the full tale via this link

Thanks for the ideas. I'm away from the car for a couple of weeks, but then I'll take some pictures to post so someone can hopefully tell me if it's connected up properly :)

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...