Rear Main Rope Seal – There Are Alternatives For Many Older Engines

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

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

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

Also, The installation technique of a rear main rope seal, was slowly being lost as they diminished in use. Many younger installers did learn the technique, but it was far less common.

So, In many cases this operation was passed back to the seasoned mechanic.

Rear Main Rope Seal
Rear Main Rope Seal

As, They usually had the experience doing them once before.

So, As time went by mechanics and engine rebuilders slowly come 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. Consequently, It was common for rear main rope seals to leak.

But, Don’t get me wrong, There is still a need for a variety reasons:

  • There is no alternative seal available
  • Doing a repair or rebuild and you just want to keep it original
  • The rope seal may be used in a timing cover
  • Many water pumps have used rope type seals

So, Whatever the reason, They will never completely go away. But, 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? Also, There is no guarantee that they will work 100% of the time. But, The seals listed below have proven to be the most successful.

Use 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. Also, Lubricate the seal lip with straight 50W oil or a bearing assembly lube. Consequently, Use a lube that will stay in place until the engine is started.

Seal manufacturers do not recommend white grease alone, because they have seen too many failures from dry startups.

This is especially true in rebuilt engines that, sit on the shelf for long periods of time. Consequently, I have seen chunks torn out of the contact face of the seals that have leaked. So, Have you ever seen a Ford 390 or 460 tear the whole lip off the seal. Well, It happened because it was dry started and stuck to the crankshaft.

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

Split Seal Type
Split Seal Type

Consequently, This list will show all the information you need:

  • Application of the engine you are working on
  • Application of the engine the alternative seal came from
  • Part numbers from major gasket and seal providers

REAR MAIN ROPE SEAL ALTERNATIVES
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 case rope seal has proven effective on 455 Buick engines.

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

National seal Part #450446

Also, Engines which use rope anti-rotation holes in the block and cap, fill them with RTV and let dry overnight.

Conclusion

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

Because, Things are impacting rope seal performance:

  • So, The environmental laws that limit the use of asbestos and other materials used in the original seals.
  • Also, The efforts of manufacturers to limit part numbers. Consequently, By manipulating the dimensions of the seal to fit as many applications as possible.
  • Finally, The market for rope seals has greatly diminished. As a result, Compromises are often made in order to offer a cost-effective product.

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