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Which IMS bearing to use


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I know there are many opinions on this and I have read all the posts. Over and over again. Not trying to start anything, just looking for opinions in a more fact based forum. Hence the post here.

A little history.

99 Carrera 4 Cab. Bought with 37K miles. Had the IMS changed with the LN bearing. During the process discovered the bearing failed, metal in oil, but no engine damage. Decided at that time to just swap the bearing and monitor (against the mechanics advice). Well, 5K miles later metal showing up in oil again. Car is now on its way to CA for an engine rebuild. Discussed the IMS with the mechanic. He uses a standard German bearing as part of the rebuild and has not had any failures in 4 years of rebuilds. This is included in the price. But he will install any bearing I want (at the added cost of the bearing).

Should I go with the "eternal" with the roller bearings? Another LN? the Pelican Bearing?

His opinion is that the standard bearing is fine as long as the car is driven and oil changed at 5K and always in the normal range.

Just looking for opinions.

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I know there are many opinions on this and I have read all the posts. Over and over again. Not trying to start anything, just looking for opinions in a more fact based forum. Hence the post here.

A little history.

99 Carrera 4 Cab. Bought with 37K miles. Had the IMS changed with the LN bearing. During the process discovered the bearing failed, metal in oil, but no engine damage. Decided at that time to just swap the bearing and monitor (against the mechanics advice). Well, 5K miles later metal showing up in oil again. Car is now on its way to CA for an engine rebuild. Discussed the IMS with the mechanic. He uses a standard German bearing as part of the rebuild and has not had any failures in 4 years of rebuilds. This is included in the price. But he will install any bearing I want (at the added cost of the bearing).

Should I go with the "eternal" with the roller bearings? Another LN? the Pelican Bearing?

His opinion is that the standard bearing is fine as long as the car is driven and oil changed at 5K and always in the normal range.

Just looking for opinions.

From the very introduction of the ceramic bearing retrofits, LN Engineering has specifically said not to retrofit engines that already had metal shards in them from a failing IMS bearing (http://imsretrofit.com/bearing-already-failing/). And while a few have had success "flushing" the metal out with repeated oil and filter changes, they are in the minority; most engines retrofitted with metal already circulating in them typically fail after the retrofits.

As you have a dual row engine, your best bet would be to go with the LN triple row option during the rebuild; this is the most robust system LN developed, and can only be installed during an engine rebuild. You next best option would be a fresh LN dual row; there are literally tens of thousands of these on the road with no signs of failures.

As for the Pelican system, it is an OEM style single row steel single row bearing and a spacer, you would be replacing the most durable IMS design (dual row) with the most problem plagued design (single row). Somehow, that just does not make any sense, even if you are on a tight budget.

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I know there are many opinions on this and I have read all the posts. Over and over again. Not trying to start anything, just looking for opinions in a more fact based forum. Hence the post here.

A little history.

99 Carrera 4 Cab. Bought with 37K miles. Had the IMS changed with the LN bearing. During the process discovered the bearing failed, metal in oil, but no engine damage. Decided at that time to just swap the bearing and monitor (against the mechanics advice). Well, 5K miles later metal showing up in oil again. Car is now on its way to CA for an engine rebuild. Discussed the IMS with the mechanic. He uses a standard German bearing as part of the rebuild and has not had any failures in 4 years of rebuilds. This is included in the price. But he will install any bearing I want (at the added cost of the bearing).

Should I go with the "eternal" with the roller bearings? Another LN? the Pelican Bearing?

His opinion is that the standard bearing is fine as long as the car is driven and oil changed at 5K and always in the normal range.

Just looking for opinions.

From the very introduction of the ceramic bearing retrofits, LN Engineering has specifically said not to retrofit engines that already had metal shards in them from a failing IMS bearing (http://imsretrofit.com/bearing-already-failing/). And while a few have had success "flushing" the metal out with repeated oil and filter changes, they are in the minority; most engines retrofitted with metal already circulating in them typically fail after the retrofits.

As you have a dual row engine, your best bet would be to go with the LN triple row option during the rebuild; this is the most robust system LN developed, and can only be installed during an engine rebuild. You next best option would be a fresh LN dual row; there are literally tens of thousands of these on the road with no signs of failures.

As for the Pelican system, it is an OEM style single row steel single row bearing and a spacer, you would be replacing the most durable IMS design (dual row) with the most problem plagued design (single row). Somehow, that just does not make any sense, even if you are on a tight budget.

JFP, IS the LN bearing sealed or open to engine oil? If it is sealed would you take the seals out??

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I know there are many opinions on this and I have read all the posts. Over and over again. Not trying to start anything, just looking for opinions in a more fact based forum. Hence the post here.

A little history.

99 Carrera 4 Cab. Bought with 37K miles. Had the IMS changed with the LN bearing. During the process discovered the bearing failed, metal in oil, but no engine damage. Decided at that time to just swap the bearing and monitor (against the mechanics advice). Well, 5K miles later metal showing up in oil again. Car is now on its way to CA for an engine rebuild. Discussed the IMS with the mechanic. He uses a standard German bearing as part of the rebuild and has not had any failures in 4 years of rebuilds. This is included in the price. But he will install any bearing I want (at the added cost of the bearing).

Should I go with the "eternal" with the roller bearings? Another LN? the Pelican Bearing?

His opinion is that the standard bearing is fine as long as the car is driven and oil changed at 5K and always in the normal range.

Just looking for opinions.

From the very introduction of the ceramic bearing retrofits, LN Engineering has specifically said not to retrofit engines that already had metal shards in them from a failing IMS bearing (http://imsretrofit.com/bearing-already-failing/). And while a few have had success "flushing" the metal out with repeated oil and filter changes, they are in the minority; most engines retrofitted with metal already circulating in them typically fail after the retrofits.

As you have a dual row engine, your best bet would be to go with the LN triple row option during the rebuild; this is the most robust system LN developed, and can only be installed during an engine rebuild. You next best option would be a fresh LN dual row; there are literally tens of thousands of these on the road with no signs of failures.

As for the Pelican system, it is an OEM style single row steel single row bearing and a spacer, you would be replacing the most durable IMS design (dual row) with the most problem plagued design (single row). Somehow, that just does not make any sense, even if you are on a tight budget.

JFP, IS the LN bearing sealed or open to engine oil? If it is sealed would you take the seals out??

All of the LN bearings are open to oil and the engine side, sealed on the shaft side, so they can be splash lubricated by the engine.

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JFP,

what exactly will the center row of bearings do? They will never be in contact with the shaft. With the dual row, the opposing bearings on the second row will contact the shaft; increasing load capacity. But, the true solution is roller bearings with DOF. Which LN's competition is doing.

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JFP,

what exactly will the center row of bearings do? They will never be in contact with the shaft. With the dual row, the opposing bearings on the second row will contact the shaft; increasing load capacity. But, the true solution is roller bearings with DOF. Which LN's competition is doing.

Actually they do make contact just fine. Because to do the triple row, you need to disassemble your engine, and send your IMS shaft to LN Engineering and have it modified to accept this multiple ceramic bearing system, there are relatively few of them on the street. But it is immensely strong (strongest of any design using a ball bearing) as all three rows are in full contact, and has been used in a handful of highly modified engines with total success (no failures, even with only a limited number were ever done this way).

Squirting oil onto the bearing may or may not help, depending upon where the oil is coming from. The "competition" you mention use an oil feed from one of the hottest and dirtiest parts of the engine to spray oil onto the ball bearing, which risks introducing debris and hot oil into an already fragile system. Both LN and Jake Raby have been quite vocal about why this is a bad idea and could actually lead to a failure that would not have occurred otherwise. If memory serves, Jake actually experimented with oil fed single row ball bearings, but went away from the design due to the additional problems it introduced, and eventually went to his patented ball bearing less Solution design for single row engines, which mimic's the style of oil fed solid surface bearing already in use in other similar Porsche engine applications, which if you think about it also totally puts to rest the concept that the shaft rocking is the problem.

Until (and if) they develop a "Solution" style solid bearing for dual row applications, with tens of thousands of successful installations, their splash oil fed dual row bearing system remains the proven way for dual row owners to go.

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