cooling on a 1641

[slammedkustom]

the bugpack kit flows the oil out from the oil pump via a new pump cover and back in via the oil pressure valve. its the big flat headed screw thing under the engine near the flywheel end. you get a new fitting for it
you might have to fiddle with the rear brace bar a bit for clearance on the pump cover :wink:

1641s always run hotter due to the thinner barrels much like the old 1835s. every 1641 ive ever had ive converted back to 1600, no more problems!

 

[speedwell68]

Why do thinner barrel walls make it run hotter?

 

[slammedkustom]

physics!
i dont make the rules but thats what happens, less metal to distribute the heat i guess. dont you think vw would have made them 1641 if it was viable in the long run.
bottom line is that 99% of 1641s are gonna run hot.

as a side note remember new engines will run hotter for quite a while till the wera in a bit and loosen up

 

[Fraggle]

I had a 1641, engle 110, twin 40's, extractor exhaust etc in my split with no extra cooling. It did run according to VDO guage at 120 - 125 degrees on long runs but never missed a beat and had no extra cooling.

Who knows eh!!

 

[slammedkustom]

splits are a far bit lighter than a bay, maybe thats part of it?

 

[Fraggle]

Yeah that's true as my current engine was out of a split and what with my enthusiastic driving style and heavily loaded bus it didn't last long sadly!!

Splits do however have poorer cooling but hey who knows.

 

[Araon]

Exactly SK the barrels have a lot less metal to dissipate heat away so are naturally prone to run hotter without a great deal of detriment as long as you are aware and drive accordingly.

By fitting a cooler in a drafty location as clear from the hot zone as you can not only do you increase the oil volume you increase the surface area to be cooled, again for the deep sump, a huge increase in oil and finned surface area to dissipate the heat.

Good tin ware and seals will help greatly. As will choice of black painted components in the engine bay and less shiney chrome bits... (matt black tinware)

My reason for cooler and deep sump is a belt and braces affair, peace of mind and the fact we intend doing long drives round the med area....

 

[Guest]

As will choice of black painted components in the engine bay and less shiney chrome bits... (matt black tinware)

So what your saying is... my shiny bits make me HOT! :lol:

 

[Araon]

And dont you know it :wink:

 

[strongy]

thanxs for all ya input,it is new and alot of the tin is shinney, so hopefully it will improve with time,think il strap a cooler on, the way its runing hot at the mo i have to choice,i took it for a tune a week ago and like i say it pulls and runns fantastic just gets hot when on a long run(very hot)

i had bought some exhaust wrap to try and keep the rear valance cooler in turn making the engine bay cooler but ive heard that can cause its own problems by not leting the heat out the engine,who knows

ive also thought about puting some lengths of flexi pipe up to the side vents and directing it straight in to the rear of the fan,in my mind this is an obvious solution but the im sure at 50 mph you get plenty of air in to the engine bay anyway :?

 

[lemonyellow]

didnt know changing to different oil would make adifference running quaturm 10/40 at present as remtec recommended as still running in?

 

[strongy]

i dont no much about oil im just using morris stuff that gsf sell what grade will that be? is the 10 40 you use semi synthetic?

 

[lemonyellow]

no,mineral . use to use any oil in old 1600cc never overheating prob then,tend to drive by temp gauge now

 

[speedwell68]

physics!
i dont make the rules but thats what happens, less metal to distribute the heat i guess. dont you think vw would have made them 1641 if it was viable in the long run.
bottom line is that 99% of 1641s are gonna run hot.

as a side note remember new engines will run hotter for quite a while till the wera in a bit and loosen up

The larger mass of metal will retain more heat. If you heated a piece of sheet steel 100mm x 100mm x 1mm to 100c and heated a block of steel with the same surface area but it was 10mm thick to 100c, the thinner piece would cool faster than the thick piece. To say all 1641 engines are going to over heat is a very sweeping statement. There are so many variables, tinware, engine seal, ignition timing, oil viscosity, fuel mixture, octane of the fuel the list goes on.

 

[speedwell68]

i dont no much about oil im just using morris stuff that gsf sell what grade will that be? is the 10 40 you use semi synthetic?

That'll be 30 grade, a bit old fashioned really, a good quality multigrade will handle the heat much better than an old fashioned mono grade oil. I use Quantum 15/40.

 

[Araon]

The larger mass of metal will retain more heat. If you heated a piece of sheet steel 100mm x 100mm x 1mm to 100c and heated a block of steel with the same surface area but it was 10mm thick to 100c, the thinner piece would cool faster than the thick piece. To say all 1641 engines are going to over heat is a very sweeping statement. There are so many variables, tinware, engine seal, ignition timing, oil viscosity, fuel mixture, octane of the fuel the list goes on.

Yes but it takes more energy to get it to that temp! In general your engine produces the energy that is transfered into heat for a larger mass of metal thereby it is on the whole cooler than the thiner material, your barrels are covered in fins to provide a greater surface area to cool (think elepants ears here), the thinner metal gets hot quicker, but your engine is continuosly pumping out all that heat at a reasonably constant rate (not accounting for hills etc..) the fins un aided can only dissipate so much.

If you try your heat experiment you will see how much hotter a thin sheet will get with a given source over a thick lump with the same source

 

[speedwell68]

The larger mass of metal will retain more heat. If you heated a piece of sheet steel 100mm x 100mm x 1mm to 100c and heated a block of steel with the same surface area but it was 10mm thick to 100c, the thinner piece would cool faster than the thick piece. To say all 1641 engines are going to over heat is a very sweeping statement. There are so many variables, tinware, engine seal, ignition timing, oil viscosity, fuel mixture, octane of the fuel the list goes on.

Yes but it takes more energy to get it to that temp! In general your engine produces the energy that is transfered into heat for a larger mass of metal thereby it is on the whole cooler than the thiner material, your barrels are covered in fins to provide a greater surface area to cool (think elepants ears here), the thinner metal gets hot quicker, but your engine is continuosly pumping out all that heat at a reasonably constant rate (not accounting for hills etc..) the fins un aided can only dissipate so much.

If you try your heat experiment you will see how much hotter a thin sheet will get with a given source over a thick lump with the same source

A very good point. My opinion is this, VW designed the engine to operate in a range of ambient temperatures often much higher than what we experience in the UK. As long as the engine is set up correctly, i.e genuine tin ware, correct ignition timing, good oil, good carburation and so on, It'll be fine. This summer I have completed over 2000 miles of trouble free motoring on a home built 1641.

 

[slammedkustom]

i can see your point but ive dealt with hundreds of engines, never would i recomend a 1641. at the same time as the thinner barrel problem i find half the time someone will buy a new engine and fit all the old ancilleries and poorly fitting tinware and then when there is a problem its the engines fault, not i cant get the timing right or tune a carb etc etc.
your engine may go for a 100-000miles but in my experiance 1641=poop :wink:
also a lot of these barrels n pistons are not made by someone like mahle, its some unheard of make, no thanks

on my own engines i take time to make sure the tinware fits properly, all the seals are in place and its tuned properly. :wink:

 

[strongy]

im starting to agree with slammed on this one ive poped this 1641 in mine,the engine has had

new crank case
new bairings(all of them)
new barells (mahle)
new pistons (mahle)
new heads
new rockers
new dizzy
new coil
new ht leads
new pluggs
new carbs
all new tin and all the seals(everylast piece)
new exhaust
new cooler
new alternater and belt
new stand
new fuel pump and pin thing :wink:
new oil :lol:
oh and a new batery
then i took it to a chap that i know is good to have it timed and tuned

but i still cant run at over 50 mph for 15 mins without it geting very very hot

 

[slammedkustom]

Ive not had one as bad as that tho strongy, id say there is something very wrong internally