since 1940

Aircraft Exhaust Gasket Frequently Asked Question

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77611 Lycoming style no-blow exhaust gasket

When using the thin metal style no-blow gaskets, which way do the beads go together?

The Continental 630365 (Continental 360 series engines) and the Lycoming 632837 gasket are used two per port and installed with the raised beads interlocking and facing the exhaust stack flange.

What is a "No Blow" exhaust gasket?

Don't be fooled by the name - all exhaust gaskets will leak (blow) if the contact surfaces are eroded.

There are two generally two different styles of "no blow" gaskets - spiral wound and sandwich. The most popular is the spiral wound gasket such as the 77611 for Lycoming 320's or the 628260 for the Continental 470 and 520 series engines.

Spiral wound gaskets work excellent IF the mating surfaces are in good condition. If they are not, they willl leak.

Don't allow the exhaust gasket to leak. Leakage will erode the cylinder exhaust port face. Once eroded you have to mill the port face down to get a good gasket seal. This generally requires cylinder removal

Another reason not to allow the exhaust port to leak is that if the exhaust leakage is directed to the spark plug you can raise the spark plug temperature to the point of preignition and cylinder destruction.

The most common signs of exhaust gas leakage past the exhaust gasket is a whitish deposit extending outward from the gasket face.

One gasket that I personally favor for the Lycoming 2-hole exhaust port is the LW-19296. This is a copper crush gasket that has more tolorance for eroded exhaust ports than the No-Blow 77611 style.

What Exhaust Gasket goes on my engine?

Style		Rapco PN	OEM PN	Airborne PN	Superior PN	Application
Solid		RA630365	63065	N/A	SA630365	IO-360-A, C, D, G, H, J, K
Spriral Wound		RA970	N/A	N/A	N/A	IO-360-A, C, D, G, H, J, K, TSIO-360-A, B
Solid		RA632837	632837 21493	157	SA632837	A65, A-75, C-85-8F, 12F, 14F, 16F, E-165, E-185, E-225, O-200-A, -B, 0-300-A, -C, -D, O-470-A, -E, -J
Spriral Wound		RA627429	627429	999	SA627429	A65, A-75, C-85-8F, 12F, 14F, 16F, E-165, E-185, E-225, O-200-A, -B, 0-300-A, -C, -D, O-470-A, -E, -J
Solid		RA631544	631544 537379	158	SA631544	O-470-B, -G, -K, -L, -M, -P, -R, -S, -U
Spriral Wound		RA628260	628260	972	SA628260	O-470-B, -G, -K, -L, -M, -P, -R, -S, -U, IO-470-D, -U, -V, TSIO-470-B, TSIO-520-B, -C, -D, GTSIO-520-C, -D
Turbo Charger Gasket		RA636465	636465	N/A	SA636465	For use with Garrett Airesearch Turbo Systems
Solid		RA75118	75118 73720 67196 65321	160	N/A	All Engines using two (2) hole exhaust flanges
Spriral Wound		RA77611	77611	1000	SL77611	All Engines using two (2) hole exhaust flanges
Solid		RALW15619	LW15619 74756	161	SL15619	All Engines using three (3) hole exhaust flanges
Spriral Wound		RALW15486	LW15486	971	SL15619	All Engines using three (3) hole exhaust flanges
Solid		RA985	3503	N/A	N/A	R985 Pratt & Whitney

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