Engine building- learned something new ( Tinbasherdan?)

[Greeves246]

Mention on an American Norton forum about silk thread between surfaces, so I googled and came across this.

Silk Thread: Incorrect use can lead to disaster

Incorrect use can lead to disaster By Joe Escobar In the assembly procedure of a piston engine, it is standard practice to use silk thread and a thin film of sealant to seal ...

www.aviationpros.com

 

[Seadog]

A friend of mine used to use cotton thread. He claims that it made his racing Bantams oil tight.

 

[beeRS]

Reminds me of older Rover V8 engines using rope seals for the crank.

 

[Burdekin]

Reminds me of older Rover V8 engines using rope seals for the crank.

Still use them on old Volvos as well. You have to get a wide decent neoprene seal to be as good, thin cheapo ones just score the shaft and leak worse.

 

[colnerov]

Reminds me of older Rover V8 engines using rope seals for the crank.

Use to be common on all sorts of older engines. Along with labyrinth seals.

 

[bricol]

Still use them on old Volvos as well. You have to get a wide decent neoprene seal to be as good, thin cheapo ones just score the shaft and leak worse.

Need to fit a speedy sleeve or similar - a lip seals needs to run on a hardened surface or it will wear a groove just as you say.

 

[Tinbasherdan]

Never done it but have watched one of the local engine builders assemble a Lycoming which had it on the case halves!

 

[Morrisman]

Reminds me of older Rover V8 engines using rope seals for the crank.

The RV8 I put in my old hot rod dribbled slightly from the front crank seal, so I hooked up a 3/8 hose from one rocker cover to the brake vacuum stub on the intake manifold, then put a small filter on the other rocker cover. The engine was then running on a sort of partial vacuum internally.

I put a restrictor in the vacuum pipe, drilled 1.5mm, so it didn’t suck too much and upset the tickover.
Sorted out the oil drip, with no adverse affects to anything else.
I think it’s a primitive version of PCV on more modern engine, but it worked.

 

[indy4x]

Didn't know this was a thing until a few days ago, someone doing the gasket sealer and cotton/silk thread jobbie popped up on Instagram

 

[Erie Fred]

Never done it but have watched one of the local engine builders assemble a Lycoming which had it on the case halves!

Yes, IIRC it's in the book.

 

[Bornfree]

That's a new one for me. You certainly don't need it with loctite 515

 

[Erie Fred]

That's a new one for me. You certainly don't need it with loctite 515

I was told it set's the crank bearing gap.

 

[Morrisman]

That's a new one for me. You certainly don't need it with loctite 515

With properly cleaned engine case surfaces and modern sealants there’s no reason for any engine to leak from casing joints.

 

[Keithmac]

The RV8 I put in my old hot rod dribbled slightly from the front crank seal, so I hooked up a 3/8 hose from one rocker cover to the brake vacuum stub on the intake manifold, then put a small filter on the other rocker cover. The engine was then running on a sort of partial vacuum internally.

I put a restrictor in the vacuum pipe, drilled 1.5mm, so it didn’t suck too much and upset the tickover.
Sorted out the oil drip, with no adverse affects to anything else.
I think it’s a primitive version of PCV on more modern engine, but it worked.

You can buy dedicated vacuum crankcase pumps, they help the stem seals and turbo oil returns.

As you say modern engines run PCV but that is more for emissions compliance.