Edelbrock Performer erratic water temperature

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stu60
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Re: Edelbrock Performer erratic water temperature

Post by stu60 » Fri Nov 01, 2019 6:48 pm

Hi All
for those of you with too much time on your hands... have a look at this and let me know waht you think.

http://www.v8register.net/FilesV8WN/V8N ... 9.1.08.pdf

rgds
Stuart

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peterc
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Re: Edelbrock Performer erratic water temperature

Post by peterc » Sat Nov 02, 2019 10:55 am

Hi Stuart.
An interesting and thorough investigation making a good read albeit centered around a standard MGB V8 rather than a Cobra installation.
Certainly thought provoking.
I was surprised at the revelation of the position of the heater return pipe being close to the by-pass port on the pump having a significant effect on the cooling suggesting that the engineers made an error.
I would have to consider how that affects my set up in so much as my heater piping is different to start with. I do not have any isolation valve on that circuit plus the heater inlet coming from rear of the manifold goes into the top of the heater and the bottom returns under the manifold. I had worked on the same principle of the rad and the cooler water would naturally want to exit from the bottom from any heat exchanger.
I also run with a 5 mm hole in the top half of the stat to assist in permanent water flow having tested 2 and 3 hole versions.
You can't get away from the design of the Edelbrock manifold in having the water temperature sender position immediately next to the cylinder outlet and the stat being further along the flow path resulting in such swings of temperature readings. E.g the sender reads instantaneous temperature and the stat sees an average with a time gap.
I have also been concerned that cylinders 7 & 8 do not have a direct outlet like the others.
I would have thought that the pressure rating of the rad cap would only change the boiling point and not affect the running temp lower down. I would need to speak to a process engineer on that aspect.
I have also considered the under bonnet temperatures in a fiberglass car and the general air flow away from the rad. I am currently investigating a fan for the offside wing vent. I would hasten to add that has only come to the forefront after being stuck in stationary traffic for over 30 mins a on a rather hot summers day and not having the courage to switch off.
Just remember that its better to run the engine nearer to 90 C than 80 C.
Peter C

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Re: Edelbrock Performer erratic water temperature

Post by Homewood » Sat Nov 02, 2019 8:06 pm

I will let you know when I test drive with heater valve open. Last test drive, heater closed, when I think all air was bled out, it behaved itself whereas prior it would have shot up in temperature which I put down to air (steam at that point).

Basically the article said the heater return needs to be moved and bleed valves used. He clearly did a lot of tests.

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peterc
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Re: Edelbrock Performer erratic water temperature

Post by peterc » Sun Nov 03, 2019 9:02 am

Yes it always helps to have a bleed point at any potential high point. E.g the heater hose circuit.
Peter C

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Re: Edelbrock Performer erratic water temperature

Post by Homewood » Sun Nov 03, 2019 3:57 pm

Difficult with spitfire heater

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Re: Edelbrock Performer erratic water temperature

Post by Homewood » Mon Aug 03, 2020 8:50 pm

Decided to take thermostat out today. I still think an air lock but I did notice the jiggle pin wasn't at 12 o'clock more like 2 o'clock and the jiggle pin looks to me the wrong way round. Water flows through thermostat to top hose of radiater, this pin would not allow air or water through. Am I right ?
IMG_20200803_203611520.jpg
When I look at this one it's around the other way. Assuming the spring side is correct fitting into the manifold then the racerestorations one below would work like I think it should. Any ideas ?

http://www.racetorations.co.uk/triumph- ... stat-p1254

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peterc
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Re: Edelbrock Performer erratic water temperature

Post by peterc » Mon Aug 03, 2020 10:34 pm

Sorry Tony I don’t see the difference between the two of them. The bigger/ heavier end of the jiggle it still the thermo actuator side of the thermostat.The heavy end of the jiggle ensures it will be angled down to allow the air to pass. I don’t think the pin would prevent the flow of air whilst filling the system. Yes the jiggle should have been at 12 o’clock for the best result.
I have several thermostats in stock. One of them doesn’t even have a jiggle pin but has the smallest of indents in the circumference of the closure disc instead which would be lower than the equivalent jiggle.
When I experimented with several thermostat designs I ended up with a unit with a single 5mm hole to allow a small permanent flow of water and of course positioned at 12.oclock.
Suggest you cut the jiggle off and put the thermostat back in after you have tested it opens at the correct temperature.
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Re: Edelbrock Performer erratic water temperature

Post by stu60 » Tue Aug 04, 2020 11:31 am

I am not sure if this will help your particular installation but I had erratic temperatures for months. Final solution was

1. Radiator recored and 2 x Mishimoto fans installed to replace single large one) I don’t believe this made Any difference but eliminated any doubts).
2. Some basic ducting installed in nose to ensure air not spilling over top of new radiator.
3. Modded then edelbrock manifold with the 2 holes drilled (can be done in situ if you are very careful). I think this cured erratic temp readings
4. I don’t have heater and originally heater in/out blanked off on Edelbrock as flow pattern suggests you can do BUT I think lose some cooling of manifold capacity/circulation. So I installed stainless pipe down drivers rocker cover (to avoid problem of running under manifold). I then connected a flexible u-bend pipe where heater matrix would be BUT installed nylon insert with I think 8mm hole to replicate heater restriction flow.
5. I had the thermostat housing modded to ensure header tank connection not too high. Just in case I then installed a bleed valve between thermostat and header tank. The valve has never collected any air as think mod to thermostat housing solved highest point issue.
6. I do have a catch tank installed that sees a very little amount of flow in/out

Result of above is no erratic temps and sits around 90degrees whatever conditions. I realise I went belt,braces and some but believe the manifold Hole mod and thermostat Outlet angle and possibly the heater pipe replication to be the key changes. Some pics below (hopefully!)
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clive
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Re: Edelbrock Performer erratic water temperature

Post by clive » Tue Aug 04, 2020 12:03 pm

The only time I have had erratic water temp readings was if the electric temp sender in the manifold got wet.
Cheers, Clive.

(If I'm not here I'm in my workshop or on the golf course!)

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Re: Edelbrock Performer erratic water temperature

Post by Homewood » Sun Aug 16, 2020 2:46 pm

I've taken the thermostat out again and runs without overheating but runs between 70-75C going up to 90C in the heat of last week but not boiling over.

So it's an issue with the stat which has been tested. I now see jiggle pin just holds it open. I took it out and drilled a 5mm hole but still overheated. It runs for long periods 20mins or so behaving itself at 80-90C then all of a sudden it goes ballistic which to me sounds like steam or air pocket but I'm not sure. I will get the system pressure tested for any leaks with a new stat I've bought and get them to fill it with a vaccum coolant filler. Then try again.

I'm reluctant to drill holes in the stat area but might as a last resort.

Maybe I should try another inlet manifold ?

What a pain this is.

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