Rear Main Rope Seal – Alternatives For Many Older Engines

Rear Main Rope Seal - Alternatives For Many Older Engines
Rear Main Rope Seal - Alternatives For Many Older Engines

Firstly, using a rear main rope seal, is almost a thing of the past and has greatly diminished in use.

So, the rear main rope seal worked well in its time, as long as you completely understood the installation process.

As a result, the installation technique has slowly been lost, as they diminished in use. Furthermore, many younger installers, did not learn the technique. Because, the procedure was just far less common.

Subsequently, the rear main rope seal installition was passed back, to the seasoned mechanic.

Rear Main Rope Seal
Rear Main Rope Seal

Because, they usually had the experience doing them once before.

Therefore, as time went by, mechanics and engine rebuilders, slowly came up with alternative seals to make the job easier.

As a result, the list of alternative seals, has been growing with good success, solving problems, saving time and money.

But, don’t get me wrong, there is still a need, for a variety reasons:

  • Because, there is no alternative seal available.
  • For instance, your doing a repair or rebuild and you just want to keep it original.
  • For example, the rope seal may be used in a timing cover.
  • Finally, many water pumps, have used rope type seals.

So, whatever the reason, they will never completely go away. And, because they are getting less common, todays mechanics, my not even know what they are.

So, it has taken many years to collect this information. Consequently, this information is feedback, from people like you. People tell us these seals have worked fine for them, but will they work for you? Furthermore, there is no guarantee that they will work 100% of the time. However, the seals listed below, have proven to be the most successful.

Normal Split Seal Installation Instructions

Split Seal Type
Split Seal Type

During installation, offset or rotate each seal half ¼ to 3/8″ from the main cap parting line. Then, place a dab of anaerobic gel, on the ends of the seals that will butt together. In addition, lubricate the seal lip with, straight 50W oil or a bearing assembly lube. Above all, use a lube that will stay in place, until the engine is started.

Also, most seal manufacturers, do not recommend using white grease. Because, there have been way too many failures. As a result, of dry startups.

This is especially true in rebuilt engines, that sit on the shelf for long periods of time. So, have you ever seen a Ford 390 or 460 tear the whole lip off the seal. As a result, of being dry, it stuck to the crankshaft.

The Following Is A Suggested List, Of Rear Main Rope Seal Alternatives

Split Seal Type
Split Seal Type

In short, this list will show all the information you need:

  • Firstly, the application of the engine you are working on.
  • Then, the application of the engine the alternative seal came from.
  • Finally, the part numbers from major gasket and seal providers.


Working On Came From Detroit Enginetech Felpro Rol Victor
Buick 231 Jeep 225 17200 S-1389 BS40613 RS29470 JV742V
Buick 350 Ford 460 17043 N/A BS40032 RS29130 JV618
Buick 400 430 455 Ford 200 17042 N/A BS30135 RS29050 JV730
*GM 265 283 GM250 17053 S-0629 BS13241 RS29005 *JV728
* Install a .090″ (2.290 mm) diameter wire in the groove, behind the seal.
Caddy 265 Dodge 318 17032 S1196 BS40245 RS29040 JV606
Ford 312 Dodge 318 17032 S-1196 BS40245 RS29040 JV606
Olds 260 307 330 350 403 Ford 292 17175 N/A BS6141 RS29310 N/A
Olds 350D 400 425 455 Ford 460 17043 N/A BS40032 RS29130 JV618
Pont 301 Ford 460 17043 N/A BS40032 RS29130 JV618
Pont 350 GMC 637 17091 N/A BS40048 N/A JV616
Pont 455 Caddy 500 17008 N/A BS40012 RS29115 JV600

NOTE: It has also been reported that, replacing the timing cover rope seal, has proven effective on 455 Buick engines.

Use National Seal Part #450446
Use National Seal Part #450446

Use National seal Part #450446

However, there are engines that use, rope anti-rotation holes in the block and cap. Consequently, they need to be filled with (RTV) and let dry overnight.


So, today’s rear main rope seals, are not as effective at controlling oil as they once were.

Unfortunately, many things have impacted the use of rope seals:

  • Consequently, new environmental laws, limit the use of asbestos and other materials.
  • Also, the efforts of manufacturers, to limit part numbers.
  • Furthermore, by manipulating the dimensions of the seal to fit as many applications as possible.

As a result, the market for rope seals, has greatly diminished. Finally, compromises are often made, in order to offer a cost-effective product.

Thank You !