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About don_k

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  • Car Model and Year
    2002 Deville DTS
  • Engine
    Northstar 4.6L V8 (LD8/L37)
  1. On the N* the odd number cylinders are in the back. #'s 5 & 7 are rear drivers side. That area of the engine is also the hottest. I checked w/an IR thermometer, also it is furtherest from the water pump in the coolant flow path. Also, just to be clear, the cat was also presenting backpressure. The obstruction from the cat got worse with heatsoak and presented an ever increasing exhaust restriction with increasing exhaust flow and increasing temps. W/my IR thermometer, I was showing temps in the area of 500 deg throuout the cat area and all the way up to the rear engine bank exhaust manifold. Temps out of the front bank exhaust were in the 250 deg area.
  2. INFO FOR TROUBLESHOOTING OVERHEATING NORTHSTARS!! I would have posted this info earlier (right after I got my new engine running) but I wanted to confirm my results with a few more days of driving. When I was reassembling my engine I found that the "Y" pipe connecting the two exhaust banks just befor the cat had a significant obstruction (the pipe from the front exhaust portruded into the main pipe at the joint). The obstruction was significant enough that I felt it would create exhaust back pressure. I decided to assemble the new engine with the obstructed exhaust and have it tested at muffler shop for backpressure. After starting the new engine and assuring everything was operating normal, I drove the car in verying conditions for a little over 50 mi. The new engine displayed the same heating symptoms that I had w/the old engine. On long uphill pulls the coolant temperature would continue to rise as long as the higher than normal load was present. I did this a couple times to confirm what was happening (I stopped the test both times when I got the temp to 240 deg (I did not want to damage the new engine). I then took it to my local muffler shop for the backpressure test. At idle it showed a little over 1 to 1 1/2 psi in front of the cat. At 2,000 rpm it showed 3 1/2 to 4 psi. Behind the cat it measured 1/2 psi at both an idle and 2,000 rpm. They removed the cat and the Y pipe. They ground the Y pipe portrusion flush w/the side of the main pipe. The cat vissually appeared to have about a 25-30 percent blockage and was replaced. I can now drive uphill as long as I want to w/normal coolant temps. The new engine runs exactly as it should w/no temperature excursions. I have been attempting to solve this problem since I bought the Deville 3 years ago. When I bought it it was still under a factory warranty. I took it to the dealership w/the temperature problem 4 times in the first 1 1/2 years I owned it. They told me all four times there was nothing wrong w/the engine. The last time I took it in was after a 250 degree excursion while driving through the CA desert on I-15. The trans torque converter quit locking after the incident. The dealer repaired the trans and told me there was nothing wrong w/the engine. The warranty ran out, I replaced the radiator, water pump, themostat and all the hoses. The problem continued and worsened w/time. Last fall I had the coolant checked for exhaust gases and each cylinder pressure checked w/valves closed. The coolant showed there was exhuast gases present and the pressure check pushed coolant out the overflow bottle on #'s 5 and 7. Blown head gasket. I put together a new engine and reman trans and here we are. I believe the Y pipe and cat obstruction caused the high temps from the beginning. The high temps led to the blown head gasket and here we are, 3 years later!!!
  3. Well, the new engine fired right up, no problems. Everything is going fine w/the break in. Here is a recap of what I did: New engine block, heads, timing chains, gears and tensioners, new bearings, seals, gaskets (Cometic MLS headgskets), and rings; reused my original engine crankshaft, rods and pistons. Timeserted the new block and used ARP studs. Remanufactured transaxle. The engine and transaxle are changed from the from the original VIN 9 to VIN Y (VIN Y cams and VIN Y transaxle gear ratio). I had Westers program a PCM w/my VIN and all the VIN Y programing for the engine and transaxle. Everything is working perfectly, I am turning aproximately 1900 rpm @ 70 mph. My wife and I are leaving on a trip to South Dakota next Wednesday and will be gone for about 2 weeks (should be about a 3,000 mile trip). Will report back on how the engine trans are doing whe I return.
  4. My new engine and trans are back in the engine bay and I am completing the installation of thbe electrical harness. For those of you who are reluctant to remove an engine from the bottom, I say, don't be!!! Jump in there and do it. I started by raising the Deville approximately 12" at all four corners (I placed the rear wheels on raised wheel dollies and the front on jack stands under the uni-body frame). I followed the FSM proceedure for disconnecting everything, placed two floor jacks under the center of the engine trans cradle and lowered the cradle to minimum height on the two floor jacks. I then used my engine hoist to raise the front of the Deville high enough to slide the cradle laterally out the drivers side wheel well. I raised the front of the vehicle with the engine hoist approximately 10 additional inches to clear the top of the engine as it was moved laterally through the wheel well opening. The removal was no more difficult or time consuming than a normal removal from the top. Reinstallation is the reverse of the removal process and no more time consuming. I am planning to "fire" the new engine in the next two days with time allownces for my Grandson"s birthday and Mother's Day. Will give another update Monday or Tuesday.
  5. I understand you support other options for thread repair/stregthening, I have explained my reasoning for the route I took and obviously it differs from your preferences.
  6. Ranger, RE: Timesert + studs, you timesert the block the block which gives you the equivilant thread holding capability as a larger diameter bolt and then buy ARP studs w/M11 1.25 threads that screw into the timeserts (call ARP tech service, give them your engine info and they will give you the correct ARP studs, they do not make a North* labeled kit)
  7. Update on my project, I have removed the engine/trans, disassembled the engine, cleaned the pistons, rods, and crankshaft. I timeserted my new block, installed ARP studs, assembled the new block and heads w/new gaskets, bearings and seals. I purchased a remanufactured trans and am ready to install on the cradle for installation in the Deville. Am shooting for a completion date sometime next week. Will have some pictures to post soon.
  8. Answered my own question on rod bolt part number, 12552947, if anyone else is interested.
  9. I was able to buy ARP studs and a time-sert kit for less money, the time-serts do provide a larger diameter insert than the stock headbolts, but not as large as Jakes studs.
  10. I have decided to time-sert the new block, plus the ARP studs. Along with the MLS head gaskets, should prewty much guarantee a head gasket problem free engine.
  11. Yes they are the 275 hp cams, but they produce more hp and torque below some where around 4000 rpm. I owned a 2000 Deville w/"Y" engine and liked it more than the 02 w/"9" engine. I am reusing my stock 02 pistons w/new GM rings.
  12. Update on my engine project: I have decided to use the "Y" cams in my new heads. I will install the engine with a "Y" transaxle and am having the computer reflashed w/"Y" programing. I will end up with a new "Y" engine, rebuilt "Y" trans, and reflashed "Y"computer in my DTS w/235 55 17 in wheels & tires. Should slow the RPM's down substancially @ highway speeds and hopefully improve gas mileage.
  13. Sent PM RE timesert kit. If I am the lucky recipient I will send the kit on to another N** repairer.
  14. What years & model trans will interchange w/02 Deville?