jhall Posted January 23, 2005 Report Share Posted January 23, 2005 Here's a short story of a Timersert operation on a N*. It took about an hour to do four of the head bolt holes. Hope to pick up speed now that I've got the process down better. Link to comment Share on other sites More sharing options...
adallak Posted January 23, 2005 Report Share Posted January 23, 2005 Nice pictures. Thank you for posting. Now I see why it takes so long to make new threads. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
cetheri Posted January 23, 2005 Report Share Posted January 23, 2005 Outstanding series of photographs. I've always wondered how this was done. Thanks-a-million jhall! A picture is indeed worth a thousand words. Link to comment Share on other sites More sharing options...
adallak Posted January 23, 2005 Report Share Posted January 23, 2005 OMG! There are some 20 threads to be treated which means the template must be repositioned 20 times and bolts should be screwed and unscrewed 60 times! It would save a lot of time and labor if the template were reshaped as it shown on the picure attached. One can make 5 threads at a time and then just rotate the template 180 degrees. Just my $0.02 imesert.tif The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
adallak Posted January 23, 2005 Report Share Posted January 23, 2005 oops The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Scotty Posted January 23, 2005 Report Share Posted January 23, 2005 Really good idea Adallak! Link to comment Share on other sites More sharing options...
adallak Posted January 23, 2005 Report Share Posted January 23, 2005 Really good idea Adallak! Thanks, Scotty! The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
yenko Posted January 23, 2005 Report Share Posted January 23, 2005 Those are some really great detailed pictures! I was wondering how that was done! IMPORT CRUSHER Link to comment Share on other sites More sharing options...
Dloch Posted January 23, 2005 Report Share Posted January 23, 2005 Adallak that's a great idea.... I have a spare N* that I need to timesert I'll look into making one of those jigs. You have to remember that when Timesert and GM devised this fix I'm sure they weren't thinking that people would be doing every head bolt, only the ones that pulled or were damaged. Even when a dealer had fix one under warranty they wouldn't do every hole, only the one that was bad. They would charge the car owner an up charge to do the rest. Dennis Link to comment Share on other sites More sharing options...
adallak Posted January 23, 2005 Report Share Posted January 23, 2005 Adallak that's a great idea.... I have a spare N* that I need to timesert I'll look into making one of those jigs. You have to remember that when Timesert and GM devised this fix I'm sure they weren't thinking that people would be doing every head bolt, only the ones that pulled or were damaged. Even when a dealer had fix one under warranty they wouldn't do every hole, only the one that was bad. They would charge the car owner an up charge to do the rest. Dloch, Thanks. I personally would take care of all threads after the engine has been taken out, but, sure a dealer would have a different approach. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
jhall Posted January 24, 2005 Author Report Share Posted January 24, 2005 Hi all, Glad to see the pics were helpful / informative. I finished the LH head tonight and will start on the RH side this week. While I was in the process of installing the Timersert kit, I noted that most of the threads on the left head were already damaged from engine disassembly. Some did not actually start to fail until I tightened the securing bolts for the Timersert alignment jig, so it reinforces the need to Timesert a N* whenever the heads are removed. As far as removing / reinstalling the alignment plate, this is really easy. The steps that take most of the time (maybe the reason for the name Timesert ) is clearing the hole of chips during the drilling and tapping operations. In a bolt hole that still has a full set of threads, the drill has to be pulled out and the hole/drill bit cleaned at least twice. The tap also has to be cleaned at least twice. Chip build-up is a problem since the drill and tap tools need to remove material and not regrind the cuttings it in the hole (causes jamming, tool dulling and may oversize the hole/threads. I used a liberal amount of CRC (non-flammable) brake cleaner which did an excellent job on removing the WD-40 oil (used as a cutting fluid) and the chips. A compressed air nozzle with a 8" length of tubing was used to blow out the holes and clear all chips. I used a flashlight for inspection as recommended. One tip - I have the engine on a stand and I rotated the engine so the head being modified was slightly beyond a horizontal position. This prevented chips from falling into the engine and allowed the cleaning / cutting fluids and chips to fall into a pan under the engine stand. I know a jig for drilling multiple holes at one time would be big $$ if you had to buy it. The $350 cost for the kit (w/10 additional inserts, including shipping) was fairly high. Overall, the experience is tedious, but not nerve-racking. Timersert did a good job on the selection of the tap and the drill bit. Both cut very cleanly. I'll defer comment on the quality of the alignment jig until I try to bolt the heads back on! Link to comment Share on other sites More sharing options...
wreldo Posted January 25, 2005 Report Share Posted January 25, 2005 A picture is worth a thousand words. Is this procedure a one time replacement operation? For example, you have a new situation that causes the head to be removed again after its been timeserted. WR Link to comment Share on other sites More sharing options...
KHE Posted January 25, 2005 Report Share Posted January 25, 2005 The Timesert repair is usually a lifetime repair. If the head(s) need to be removed in the future for any reason, the block does not need to be re-Timeserted. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
jhall Posted January 25, 2005 Author Report Share Posted January 25, 2005 I'm not so sure on the durability of the block threads even after Timeserts are installed. While the Timesert insert can handle the install/removal torque and tension, the block threads may fail from the tension during a second assembly, causing the Timesert to pull out from the block. I did note that Timesert asked if the engine I was reparing was a first time or second time repair. They sell oversize Timserts for second time repairs. I have not heard of anyone who had to tear down an engine after installing Timeserts. Hopefully I won't be one of them! Link to comment Share on other sites More sharing options...
Dloch Posted January 25, 2005 Report Share Posted January 25, 2005 When I timeserted my motor I used masking tape and taped everything closed except for the headbolt holes. I modified a shopvac hose end with a drilled hole in it for a section of 1/4" tubing I had connected to an air gun. After drilling I would turn on the shop vac put the modified vac end over the hole and stick the air gun tip through the drilled hole in it. When the air gun was pressed the only place the chips could go was into the shopvac. Did the same after tapping and then after spraying brake clean in the tapped hole to be sure I got all the oil out of it. Dennis Link to comment Share on other sites More sharing options...
TDK Posted January 28, 2005 Report Share Posted January 28, 2005 This discussion begs the following questions... 1. How much cost would Timeserts have added to the original NorthStar engine build by GM? 2. Does the new 440hp supercharged 4.4 NorthStar use Timeserts or some other head-bolt system? 3. Are the headbolts/gaskets, the most common reason a NorthStar is retired? Please keep in mind that the BRD (big Red Dog) has over 172,000-miles on original everything... (except 1-set of plugs, 1-set of belts, 1-coolant change, 1-tranny fluid change, many lube oil/filters, tires and mucho fuel at 23.5mpg @82.5 mph). And I'm very pleased with any machine the can take it like I've dealt it out! Thanks in advance Add power to leave problems behind. Most braking is just - poor planning. Link to comment Share on other sites More sharing options...
32v_dohc Posted January 28, 2005 Report Share Posted January 28, 2005 1. If it were $5 per engine it would be too much at 1000 engines a day. The bolts are plenty strong and the threads are typically damaged taking the bolts out. Beside who's to say that if they had timeserted every block that we wouldn't be cussing the timeserts they used when they get stuck to the bolt and strip out the hole. 2. The thread pitch was changed for all northstars. No factory timeserts unless they are repairing a block. 3. I vote for money. They are retired because the cost to repair is more than the car is worth to the owner. Headgaskets are probably most common as oil consumption and leaks are easier to live with. HTH John Link to comment Share on other sites More sharing options...
jhall Posted January 28, 2005 Author Report Share Posted January 28, 2005 Hi Guys, I agree with the cost issues on the Timerserts if they were added at the factory. It does not make sense to provide this insurance for the few cars that last well over 100K miles that are actually refurbished. Essentially, these are "throw-away" engines in most cases. Bbobynski - Thanks for the great technical info. These details are great insight to the "nuts and bolts" of the engine design - much beyond what the repair manual can provide. I agree with comments on the bad rap given to N* engines simply because they run great beyond 100K miles and then may suddenly experience a major repair event - such as a head gasket. If the car body is in good shape (as usually is the case), where else can you get another 50K+ miles out of a decent looking car for $5K - $6K? This still is not as much as a new car payment for 5 years! Link to comment Share on other sites More sharing options...
Ranger Posted January 28, 2005 Report Share Posted January 28, 2005 The "preventive maintenance" of a set of head gaskets is not too much to expect on an occasional engine in my opinion. People take them apart and report that there is NO cylinder wear, no timing chain or sprocket wear, the heads do not need any work, etc. Just the head gaskets. Then the proper procedures are not followed and it results in thread damage to the block....or the threads are damaged due to old age. Timesert them. It is not that hard, expensive or time consuming. I think the ultimate answer of money is the final straw. If it costs more to fix than it is worth then walk away.... That is the deal and gamble with used cars at high miles....and over 100K is high miles in anybody's book. Bill, I think you need to step back and look at this through our eyes. You are in the unique position of knowing the Northstar intimately and probably have all the neccessary equipment to do a head gasket job...... in a weekend. The average person doesn't and then is looking at somewhere around $3500 to fix it. Those that do, like myself, don't have the ability to drop a drive train in the garage. This is a major undertaking, not simple preventive maintenance. True, they may last much longer than older engines but the heads could be removed and gaskets replaced without worring about re-tapping threads for less than a hundred dollars, assuming you DIY. Even if paying for the job, it was open heart surgury, not organ transplant. I think the frustration comes from the cheapest part "costing" so much. Like you said, a perfectly good, no rust, sharp, clean car has to get scrapped with a perfectly good motor because of a $100 gasket or pulled thread and you can't justify putting $3500 into a $5000 car. Kinda like loosing a space shuttle because of a lousy "O" ring. It just shouldn't happen, unless it is from lack of cooling system maintenance, then you get what you deserve. Link to comment Share on other sites More sharing options...
32v_dohc Posted January 29, 2005 Report Share Posted January 29, 2005 "throw away engine" ROFLMAO This from the guy that is rebuilding his northstar. What did you throw away? I mean besides the head gaskets. As far as DIY goes the engine will come out through the top. Rent an engine hoist and pull it. Buy the time sert kit on ebay, then sell it when you are done. This repair can probably be done for 3-400 dollars for both heads. Im also not convinced that you can't do this repair in the car although access to the rear bank could get dicey. John Link to comment Share on other sites More sharing options...
TDK Posted January 29, 2005 Report Share Posted January 29, 2005 Well then. Thanks guys, but I think the questions were dodged just a tinsy bit or maybe mis-interpreted (my fault also). 1. Timesert original build cost: If estimating an original build cost with Timeserts is too painful or embarrsing...(although I'd bet that the cost/benefit analysis was probably done at some point)... then how about: Rephrase the question as: If Timeserts were an option or that specific failure could be insured - then how much would you pay? I'm guessing there are a lot of folks who hate the idea of tossing the whole car and would be tickled to pony up another few hundred bucks for another 50,000 miles maybe. Maybe the Marketing Gurus' over-ruled on this one and something like this was stated in the think tank: "What? are you Engineers all nuts! Why raise the cost 160$ for those Timesert thingies - that will simply cost us new car sales in the long run. We don't need (or want) a bulletproof engine! The performance is more than enough to sell it. Hook 'em and they'l buy another - just to have the new features. Let's move on to those silly sunroof and trunk leak problemsl. Golly, you Engineers all worry too much and if we waited until it was just perfect - we would never market it". 2. Design changes or Timeserts: Great answers thanks. However, does this mean that if a "new" head is removed, there is no reason to Timesert? I don't think the answer will be "Yes - no problem". I think the answer might be "Better Timesert just to be safe". The factory service manual for the newer engines would be the definitive answer I suppose. 3. #1 Retirement cause: Sure, to repair or retire - always relates to the money involved to fix. I'm sorry if that was not implied in the question. I guess what I meant was: Does this particular, specific failure and required repair - trip the money scales the most times - in favor of retiring the entire car (where warranty has expired). Based on this forum (which is not a valid owner sample or scientific study by any means) I would say yes. PS, my boss is a Mech Engineer and one of his early college studies was funded by an auto company to research cars in salvage yards. They examined a wide range of parts and reported on early failures for sure. However, the real point was to determine which parts were over-built and could have been manufactured more "cost-effectively" - with consideration of how long the overall package was viable. Note that I did not mention "planned obsolescence" oops Again, many thanks to all respondents. I also apologize for hijacking the topic from the starter "jhall". You are doing one heck of a fine job on that engine and really helping a lot of others (me included) keep in mind what overheating etc - potentially costs. Add power to leave problems behind. Most braking is just - poor planning. Link to comment Share on other sites More sharing options...
adallak Posted January 29, 2005 Report Share Posted January 29, 2005 bbobynski, The poll (a local one ) shows only some 10% of Cadillacs still running have more than 175 kmiles. Is it common number for other luxury makes? The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
32v_dohc Posted January 29, 2005 Report Share Posted January 29, 2005 1. Don't think of it so much as dodging the question but skipping ahead to the real answer. The problem is that additional clamping load will not help most head gasket problems. The problem with factory timeserting is that when the gasket fails you may pull the time sert out with the bolt. Chances are if it was even discussed that engineering shot it down. If the bolt lacked sufficient strength then the correct solution is a bigger bolt or longer threads. Basicly more thread engagement. Time serts are recommended because there is no way for a DIYer or even a tech to evaluate thread quality after removal. Sure you can clean a bolt up and run it down in the hole but you only get a feeling for how loose it is in the hole. You would feel one that is really screwed up but maybe not one that is slightly loose. Effectivness here depends on experience. A properly tensioned bolt will never see combusion load. Basicly what I am saying here it that the tensile stress (preload) in the bolt should be greater than the load imparted by combusion pressure trying to lift the head. The tinsile load in the bolt will only change due to thermal expansion of the parts. One of the big problems with damaged threads is that the bolt can't reach the designed preload. This issue is made slightly worse when you consider the torque spec for the bolts. The 22 ftlbs + 180 degrees is meant to insure the proper bolt stretch. However the threads can fail by shearing out totally or minor movement. Any movement reduces the bolt strech and the preload. This may allow combustion pressure to load the bolt at a higher load than the preload. The end result is that the threads are pounded out by cyclical fatigue loading. Again it should be said that this is very rare from the factory and will show up very early. It is very unlikely that an 8 year old 50000 mile headbolt pulled out. It was damaged during removal. Most headgaskets fail due to coolant system problems. The thermal cycling of the parts cause relative movement in the head and block the gasket moves with it and develops small cracks. These cracks are minor, normal and hurt nothing but they do fill with coolant. In the absence of corrosion protection the steel core is attacked. You end up with a spiderweb of rusty cracks (similar to what you might see after removing laquer checked paint) that rot away the core. Eventually the core is gone and the head drops (bolt loose preload from reduced gasket thickness). The end result is reduced clamping force and headgasket problems. 2. If the threads are undamaged then there is no need to timesert. The rub comes from the how do you know when the threads are damaged. The factory is in a better position to determine this than the diy guy. 3. I misunderstood you before. If you talk about the whole car then it is collisions. The engine is normally retired when the cost to repair is more than the cost to install used or when the owner cannot / will not pay for repairs. Again timeserts won't solve the headgasket problem. Regular coolant changes are about the best thing that can be done hear. The most cost effective thing the factory could have done would be a change coolant message. Even if it was only time and mileage based. This probably would have saved more than a few. I also like the idea of a corrosion sensor. So that if corrosive conditions are present the change coolant message comes up. This would prevent incompetant fills as the car would tell you that corrosion protection is insufficient. I seriously doubt any planned obselesence is present. They built the whole engine to go forever. To rebuild you pull it apart clean everything up and replace gaskets and rod bearings. Do the time serts and ride it for another 200000. Cost on these is all labor. Also on the 175000 thing. The first northstars were in 1993 cars. 2005's are out for a 12 year difference. At 15000 miles a year a 12 year old car will have 180000. Newer cars will have less. In that light I think 10% is probably a good number when you consider that most cars will be less than 180000 over the 12 years (most car dont beat the average year over year) and that Cadillacs numbers will be skewed due to the fact that grandmas don't drive as far. John Link to comment Share on other sites More sharing options...
crich8136 Posted May 11, 2005 Report Share Posted May 11, 2005 I am about to timesert the left head on my 98 Deville. There are two index bushings in the upper left and upper right headbold holes. What do you do about those because they interfere with the timesert jig. Do you have to pull them? Thanks, Claude Link to comment Share on other sites More sharing options...
jhall Posted May 12, 2005 Author Report Share Posted May 12, 2005 I am about to timesert the left head on my 98 Deville. There are two index bushings in the upper left and upper right headbold holes. What do you do about those because they interfere with the timesert jig. Do you have to pull them? I had some luck with inserting a socket that had an external diameter very close to the internal diameter of the dowel. I used a wrench to grab the dowels and twist / pull them out. There were some wrench "bite" marks in the dowels, but they went back in nice and tight after a little polishing. I did this after I realized I forgot to buy new ones. If they didn't clean up OK, I would have needed to replace 'em. If you don't forget like I did, go ahead and buy new ones! Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.