Pancake filters
Discussion
Just going over my new purchase and decided to have a look at the air filters, They are the chrome plated disc bolted onto each SU carb. Took each off and thought the foam looked like it could do with a clean. The car has seen little use over the past decade or so, just enough to keep things going at 100 miles year.
Dropped the filters into paraffin bath and after ten minutes gave them a sloshing around. At this point the foam disintegrated. Off to the motoring accessory shops for some air filter foam.
Tried two shops and both offered the same product, a can of carb cleaner!! Seems that younger generations have no clue about old cars.
Ordered two replacement pancakes from fleabay outlet, almost as cheap as the foam replacement and as my filter bodies were corroding it was a no brainer.
Dropped the filters into paraffin bath and after ten minutes gave them a sloshing around. At this point the foam disintegrated. Off to the motoring accessory shops for some air filter foam.
Tried two shops and both offered the same product, a can of carb cleaner!! Seems that younger generations have no clue about old cars.
Ordered two replacement pancakes from fleabay outlet, almost as cheap as the foam replacement and as my filter bodies were corroding it was a no brainer.
Foam melted? Bin the hardware as well. Pancakes aspirate their air from the hot stuff in the engine compartment, hot so expanded and less oxygen per litre, so less bang for your buck. About 1% per degree C, which can be a lot!
Filter in front of the radiator, wide ducting, as large an airbox as you can on the intakes. That's the way to do it!
JOhn
Filter in front of the radiator, wide ducting, as large an airbox as you can on the intakes. That's the way to do it!
JOhn
Thanks for inputs, the old foam literally crumbled apart as it was so old. I take the point regarding new air intakes but want to keep the car fairly original and prepared to sa rift e a little performance. I do have the original chamber and pan air filter so maybe at the end of season I might put these back in.
Just to add, the pancakes were fitted to the car when I purchased. My understanding is that the old pancakes were a popular ‘sporty accessory’ back in the 1960’s.
Looks good but diminishes performance
Just to add, the pancakes were fitted to the car when I purchased. My understanding is that the old pancakes were a popular ‘sporty accessory’ back in the 1960’s.
Looks good but diminishes performance

Edited by crankedup on Wednesday 2nd May 19:14
jsf55 said:
You can buy filter foam quite cheaply
https://www.ebay.co.uk/itm/New-Universal-Air-Filte...
Spotted that earlier but thanks anyway. https://www.ebay.co.uk/itm/New-Universal-Air-Filte...
Purchased two new pancakes complete with foam for 16 quid in the end. They will do for now.
crankedup said:
My new pancake filters have arrived today, of course I need to oil the foam elements, will it be OK to use silicone 3 in 1 oil??
I do have some sae 30 but think this may be to heavy grade and the specialist oils are not available locally. Thanks for advise / comments.
Why do you say that you need to oil the foam?I do have some sae 30 but think this may be to heavy grade and the specialist oils are not available locally. Thanks for advise / comments.
Never did that back in the day when using cheap chrome pancake filters. The foam was washable and that's all you'd do.
You'll ruin the foam if you put oil on them.
This oiling of filters lark didn't arrive until K&N became the 'in thing' to fit in the early 80's.
That’s interesting to hear of a ‘no oiling’ on foam filter required. I can very vaguely recall oiling filters in the 1960s, idea to trap fine dust. Coming from pre 1930s stuff now is like re-education
for me, Once I am reminded it floods back. I’ve used sae 30 oil now on my filter foam, just a light smearing on the outer surface.
For the sake of conversation I also recall using some old stockings cut up and secured over the open bellmouths of my dear old Honda 250 SS. Provided. perfect taut fine mesh over the open end and seemed to work well. Things seem more complicated on modern stuff now.
for me, Once I am reminded it floods back. I’ve used sae 30 oil now on my filter foam, just a light smearing on the outer surface.
For the sake of conversation I also recall using some old stockings cut up and secured over the open bellmouths of my dear old Honda 250 SS. Provided. perfect taut fine mesh over the open end and seemed to work well. Things seem more complicated on modern stuff now.
Edited by crankedup on Friday 4th May 16:00
Christ! I thought 'foam' filters went out with the ark? I remember them in the 60s and 70s but 'paper' types since.
K&N etc 'can' be daft money.
For SUs and similar I'd stick these on twins before I'd remotely even consider 'ye olde'
foam pancake filters. Cheap too.
https://www.ebay.co.uk/p/Triumph-Spitfire-MK-1-to-...
K&N etc 'can' be daft money.
For SUs and similar I'd stick these on twins before I'd remotely even consider 'ye olde'
foam pancake filters. Cheap too.https://www.ebay.co.uk/p/Triumph-Spitfire-MK-1-to-...
I had some chrome 'accessory' filters on a 1725 sunbeam engine. When I worked out the induction area was far too small I set about inproving it.
So made them deeper, went from 1" to around 2" deep, (around 5" dia) because each end piece had a 1/4" lip original induction depth was only 1/2". All it needed was some filter foam and longer securing bolts. After the mod the car felt like pulled harder at high revs.
So made them deeper, went from 1" to around 2" deep, (around 5" dia) because each end piece had a 1/4" lip original induction depth was only 1/2". All it needed was some filter foam and longer securing bolts. After the mod the car felt like pulled harder at high revs.
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