Just engines Knukle manifold

[Vintage]

Hello sorry my english limited

Have any of you experience of overheatings problem with 90° exhaust deflector?

https://www.justengines.co.uk/shop/exhaust-systems/four-stroke-exhausts/four-stroke-headers-and-manifolds/40-61-knuckle-manifold/?v=cd32106bcb6d

Edited November 3, 2022 by Vintage

[Denis Watkins]

4 stroke headers get very very hot anyway Vintage, on any motor.

Is your set up just hot or does the motor stop?

Edited November 3, 2022 by Denis Watkins

[Paul De Tourtoulon]

I hope not I have just ordered one for my Saito FA-100

[J D 8]

      I have used/worked on many engines both model and full size and have never seen anything like the knuckle manifold on anything. It is just a bad idea expecting high speed exhaust gas to change direction as suddenly as that.  A steady curve is best as seen in many systems. Can't help but think a bend like the knuckle has will result in greater friction/heat. May well work but do nothing for the performance.

[Nigel R]

I wouldn't expect to find the engine overheat because of the 90deg knuckle although they cannot help performance. Is the engine inside a cowl? I would try a baffle to make sure cold air is forced over the engine cylinder fins.

 

 

OS make a couple of exhaust extensions that are a nice smooth curve. Would one of those fit? Might free up a few rpm.

 

 

[David Ovenden]

I don't have the Just Engines knuckle, but I have several Saito engines using 90 degree "elbow" manifolds. Some with the standard muffler and some with flex extensions plus muffler. Most are enclosed in cowlings. None of them have overheating problems. 

Is your engine really overheating? 4 stroke exhausts always do get pretty hot . Can you try your engine without the knuckle  to see if there is actualy a temp difference compared to when it's fitted?

[Solly]

I’ve used these for years in various scale models. Never seen overheating or noticed reduced power.

[Eric Robson]

I have used the knuckle and not had a problem, as the gas is forced out it has to bypass a valve which must be a similar restriction but being under pressure it has no choice but find a way out. However good gas flow will always be better but for the normal everyday use it won't make that much difference.

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[Paul De Tourtoulon]

My seller mucking me about that's 2 weeks now, luckily for me David has both the 12mm x 1 tap and die, I have had a busy day,

a bit of a heath Robison affair,,,,

still some work to be done.

[alan p]

Not sure whether the man himself would be able to sort that setup out😧

[Paul De Tourtoulon]

After a bit of thought I will start a new aluminium one today,,,,