JasonA Posted December 27, 2007 Report Share Posted December 27, 2007 I didn't want to hijack Marika's thread, but my curiousity was raised when I read about the cylinder liners being retained by a rubber o-ring. Where, exactly, is this rubber o-ring, and how does it not get burned up during normal engine operation? Seems like a "fragile" material for such an important function. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 27, 2007 Report Share Posted December 27, 2007 Keep in mind that they use rubber o-rings in the solid rocket boosters, while the 4.9 is a powerful engine, my guess is that the solid rocket booster is a little bit more powerful If I recall the guru's description, the cylinder sleeves are surrounded by coolant, the sleeves are pressed down into the block against the o-ring that seals the coolant in from getting into the crankcase. As the rubber ages, it becomes brittle and shrinks and coolant can leak into the crankcase, this is one of the reasons the cooling supplement was used. I do not think the rubber takes a lot of heat abuse as its far away from the combustion chamber and the bottom end is near the crankcase Since Marika has coolant in her oil, it can come from a few places the o-rings, a head gasket or the intake manifold which has coolant running through it (or a cracked sleeve but not likely). Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
joeb Posted December 27, 2007 Report Share Posted December 27, 2007 i wondered about the o-rings myself. so a rebuilder has to pull out the sleeves and reinstall to change the o-rings? hmm, sounds like fun. which is harder, replacing the o-rings or timeserting a northstar block? Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 27, 2007 Report Share Posted December 27, 2007 i wondered about the o-rings myself. so a rebuilder has to pull out the sleeves and reinstall to change the o-rings? hmm, sounds like fun. which is harder, replacing the o-rings or timeserting a northstar block? Special equipment is needed to pull the sleeves, I have never heard it being done. I would be curious how the reman guys do it Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
JasonA Posted December 27, 2007 Author Report Share Posted December 27, 2007 If I recall the guru's description, the cylinder sleeves are surrounded by coolant, the sleeves are pressed down into the block against the o-ring that seals the coolant in from getting into the crankcase. As the rubber ages, it becomes brittle and shrinks and coolant can leak into the crankcase, this is one of the reasons the cooling supplement was used. I do not think the rubber takes a lot of heat abuse as its far away from the combustion chamber and the bottom end is near the crankcase. Thanks -- that makes sense. So the o-rings are at the BOTTOM of the sleeves. I also guess that's why they call the 4.9L sleeves "wet sleeves". The Northstar sleeves are "dry sleeves", is that correct? I know the guru always said that the two engines were designed such that one could more easily pass coolant to the oil as compared with the other; I guess this is the reason. Thanks again. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 27, 2007 Report Share Posted December 27, 2007 This is a good question about the NS, I know they are wet sleeves also, but I believe the sleeves are cast into the block, not pressed in like the 4.9, maybe someone with more info regarding this will know. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 27, 2007 Report Share Posted December 27, 2007 Look at the space around the sleeves in this NS, coolant flows around the sleeves Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Ranger Posted December 27, 2007 Report Share Posted December 27, 2007 This is a good question about the NS, I know they are wet sleeves also, but I believe the sleeves are cast into the block, not pressed in like the 4.9, maybe someone with more info regarding this will know. Correct. Link to comment Share on other sites More sharing options...
Ed Hall Posted December 31, 2007 Report Share Posted December 31, 2007 According to the guru, the wet sleeves on the 4.1/4.5/4.9 engines were made of very hard material so even on an engine with high miles, often there would be very little ring groove. As a result, he recommended just replacing the rings and main bearing on engines with over 200k miles. Does the NS 4.6 engine also have wet sleeves made of very hard material? Link to comment Share on other sites More sharing options...
KHE Posted December 31, 2007 Report Share Posted December 31, 2007 I believe the sleeves in the Northstar are cast in place. They are also a very hard material - at 200,000 miles, there won't be a wear ridge in the cylinders. When I Timeserted my '97 STS, there was NO ridge and the factory hone pattern was visible at 105,000 miles. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 1, 2008 Report Share Posted January 1, 2008 I believe the sleeves in the Northstar are cast in place. They are also a very hard material - at 200,000 miles, there won't be a wear ridge in the cylinders. When I Timeserted my '97 STS, there was NO ridge and the factory hone pattern was visible at 105,000 miles. We have heard over and over again how the cross hatch hone was still in the bore when the pistons are pulled. That is incredible if you ask me. Your statement kevin about the sleeves being hardened makes sense. I did rings on a Cadillac 429 and the ridge was substantial enough at 68,000 miles that I needed to use a ridge reamer to remove the ridge in order to remove the pistons from the top. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
JasonA Posted January 1, 2008 Author Report Share Posted January 1, 2008 The longevity of engines (and in particular, cylinder honing) may be getting better as a whole, not just with Northstar engines. A friend of mine pulled the heads off his 1998 Dodge Grand Caravan (3.8L cast iron V6) because he thought he had a head gasket problem. Turns out he didn't, but the original cross hatching was still very visible, and the engine as a whole was clean as a whistle. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 1, 2008 Report Share Posted January 1, 2008 Who knows maybe its improvements in metallurgy? Maybe the ring and piston design or coatings minimizes friction? They changed the pistons at some point to add teflon on the skirts to reduce scuffing, so some sleeve/cylinder wall damage can be done if the piston is poorly sized and cocking in the bore. I think there were problems with this in the 2000 model year, but dont quote me. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Ed Hall Posted January 1, 2008 Report Share Posted January 1, 2008 Also, better carburation. The old carburetors would over enrich and dump too much raw gas down the cylinders which would wash away lubrication. Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 1, 2008 Report Share Posted January 1, 2008 Also, better carburation. The old carburetors would over enrich and dump too much raw gas down the cylinders which would wash away lubrication. Good point! Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
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