kingkarmann Posted January 3, 2015 Report Posted January 3, 2015 Sorry that this is a bit long winded... I have spent some time lurking and reading the great info on this site. The search function is pretty nice and I try and use it before I ask a question that has been asked 100's of times before. I do have a specific question about a 90 Regal with a 3.1L. I have read the intake manifold gasket material changed over the years. Some engines were equipped with metal/rubber gaskets while others had a plastic type gasket. The plastic gasket is prone to fail. As I understand it, a symptom of a blown intake gasket is frothy peanut buttery goo under the oil fill or radiator cap. Mine does not have that so I believe that for now the gasket is intact. Here's the question, should I believe I have a metal gasket or tear it down and replace it? The car was bought new then parked in 2005 with about 168k. It's been sitting for nearly 10 years. I never tried to start it during that time but have recently decided to see if I could but it back in service. I have rotated the engine and it moves freely. Knowing that all the systems (fuel, brake, tranny, cooling,electrical) need attention should I go ahead and replace the intake manifold gaskets too? I have the plenum and many ancillary parts removed. The intake is exposed. I found a couple of YouTube videos plus I have the factory service manual. It's not outside my skill set but right now I have the "if it ain't broke don't fix it" mentality. Pro's/con's?? Thanks! Oh, the power steering pump is a leaker but I'll save that for later:) Quote
Nas Escobar Posted January 3, 2015 Report Posted January 3, 2015 Well the real question is why was it parked, and if it was put away in good running condition. If it was running good, then the next step would be to do a pressure test on the radiator to see if you have any leaks. If you're not leaking the you're fine. I believe 1990 was metal, but I'm not too sure. Maybe someone that had a 3.1 LH0 will chime in. The replacement parts are made of metal according to this Auto Zone listing. http://www.autozone.com/external-engine/intake-manifold-gasket/felpro-intake-manifold-gasket/70062_233298_6647/ However, determining whether or not to swap is more or less dependent on seeing it run. These gaskets can also leak air but not water, and a tell sign of that would be bad idle and bad cold starts. Quote
RobertISaar Posted January 3, 2015 Report Posted January 3, 2015 the gen2(aluminum head, 87-94) 60V6 don't have common intake manifold gasket failures the way that the gen3(aluminum head, SFI, 94-05) do. I would say that unless you see a reason to mess with it, leave it alone. Quote
kingkarmann Posted January 3, 2015 Author Report Posted January 3, 2015 It ran pretty well when parked, having no real issues. Anyhow, I would hate to tear it down twice if the manifold starts leaking. I guess I'm sort of answering my own question. I have been doing some more surfing on this site about this potential problem. NAS, thanks for the reply! Any additional wisdom is most appreciated!! Quote
Crazy K Posted January 3, 2015 Report Posted January 3, 2015 the gen 2 used paper type gaskets. intake leaks would be hella rare. i'm guessing the following issues are likely having a car that sat that long: gas has gone bad and corroded the fuel pump into being inoperable fuel injectors have corroded and gone bad. crank sensor... check your injectors with a multimeter and post your results. they should all be in the near 12 ohm range. Based on some discussion, next 3.1 I tear down will used non stock injectors. The closest injector that can be supported with ease is the first version of the gen 3 (ie 94-99ish 3100 small port injectors) which only flow about 5% more than stock and are plug and play. RobertISaar, do you still concur with that thought? fuel pump. see if you get ANY flow. rental pressure gauge is available at autozone. tanks and excellent pumps are available through advanced autoparts. Quote
TravisP Posted January 3, 2015 Report Posted January 3, 2015 I don't know what kind of mileage you have on it, but I had a '93 Cutlass Ciera for a work car. They have the same motor and the Olds had nearly 300,000 miles on it and I never had any problems. Just did regular oil changes and maintenance. My son still has it and no mechanical problems yet. I wouldn't worry about changing it. Quote
RobertISaar Posted January 3, 2015 Report Posted January 3, 2015 check your injectors with a multimeter and post your results. they should all be in the near 12 ohm range. Based on some discussion, next 3.1 I tear down will used non stock injectors. The closest injector that can be supported with ease is the first version of the gen 3 (ie 94-99ish 3100 small port injectors) which only flow about 5% more than stock and are plug and play. RobertISaar, do you still concur with that thought? 17.5/16.7= ~105%. a perfect 128 BLM would need to drop down to 122 to maintain correct AFR, which isn't much of a change at all. some rebuilt/flow matched L82 injectors probably aren't a bad idea. might need to play with the calibration to get the injector offsets to match, but I would need to dig into them to see how different they are. Quote
GnatGoSplat Posted January 3, 2015 Report Posted January 3, 2015 check your injectors with a multimeter and post your results. they should all be in the near 12 ohm range. Based on some discussion, next 3.1 I tear down will used non stock injectors. The closest injector that can be supported with ease is the first version of the gen 3 (ie 94-99ish 3100 small port injectors) which only flow about 5% more than stock and are plug and play. RobertISaar, do you still concur with that thought? I doubt the 2.8/3.1 injectors are 16.7lb/hr as is commonly thrown around. I believe they're actually 15lb. They cross to Standard FJ105 which SMP sent me specs for, is a 15lb injector. FJ105s actually flow more than my stock injectors which could just be due to age. Rockauto on accident sent me some FJ95 injectors which are the proper SMP replacement for the 3100 and they flow considerably richer than even the FJ105s. Rockauto also lists gen 1 2.8/3.1 V6s as being compatible with most gen 2 injectors, and those engines definitely used 15lb injectors. Accel also lists the stock replacement for a gen 2 2.8/3.1 as being 15lb and 3100 as 17lb. I feel like this chart may be more accurate. http://www.nitrostreet.com/injectors.htm I haven't really experienced any problems with the paper intake gasket used on the gen 2 V6s. Quote
RobertISaar Posted January 4, 2015 Report Posted January 4, 2015 I'm going off of the injector flow constants in the calibration. both a 90 f and w-body 3.1 show 16.7lb/hr and have the same voltage offsets but different low pulse adders. Quote
Nas Escobar Posted January 4, 2015 Report Posted January 4, 2015 the gen 2 used paper type gaskets. intake leaks would be hella rare. Paper gaskets? That's a new one, I never heard of that before. I've seen em on other cars for different things, but never for the LIMG. I thought those were either metal or plastic. Quote
GnatGoSplat Posted January 4, 2015 Report Posted January 4, 2015 I'm going off of the injector flow constants in the calibration. both a 90 f and w-body 3.1 show 16.7lb/hr and have the same voltage offsets but different low pulse adders. Injector flow constants must be a bit different from physical static flow rate. 90 F-body injectors are definitely 15lb/hr. Paper gaskets? That's a new one, I never heard of that before. I've seen em on other cars for different things, but never for the LIMG. I thought those were either metal or plastic. Yep, same kind of material as used on the upper plenum on the LQ1 so you're probably familiar with the material. Feels like paper when new, but it hardens up to be plastic-like under engine temperature. Quote
Nas Escobar Posted January 4, 2015 Report Posted January 4, 2015 Yep, same kind of material as used on the upper plenum on the LQ1 so you're probably familiar with the material. Feels like paper when new, but it hardens up to be plastic-like under engine temperature. Yeah, I am... It's annoying to put on since moves around and rips very easily. I never realized they used it on the LIM too for the 2.8/3.1 . I though they originally used metal and switched to plastic around the time the LQ1 came out. Quote
GnatGoSplat Posted January 4, 2015 Report Posted January 4, 2015 Yeah, I am... It's annoying to put on since moves around and rips very easily. I never realized they used it on the LIM too for the 2.8/3.1 . I though they originally used metal and switched to plastic around the time the LQ1 came out. I hate that about the LQ1 plenum gasket. The 2.8/3.1 plenum gasket actually has little nylon retainers that prevent it from moving around. Very strange they didn't think to do the same on the LQ1. Quote
Heartbeat1991 Posted January 4, 2015 Report Posted January 4, 2015 2.8/3.1 LIM gaskets are metal, not paper, or plastic. They are a coated steel piece that covers the entire valley and both intake manifold mating surfaces. Quote
GnatGoSplat Posted January 4, 2015 Report Posted January 4, 2015 2.8/3.1 LIM gaskets are metal, not paper, or plastic. They are a coated steel piece that covers the entire valley and both intake manifold mating surfaces. I stand corrected. I have a spare Fel-Pro MS96041 gasket set, so I tried a magnet on it and sure enough, it sticks. It feels like that paper/composite material and hardly weighs anything so I wouldn't have believed it had I not tried a magnet on it, but they are for sure steel metal inside. Quote
kingkarmann Posted January 4, 2015 Author Report Posted January 4, 2015 I don't know what kind of mileage you have on it, but I had a '93 Cutlass Ciera for a work car. They have the same motor and the Olds had nearly 300,000 miles on it and I never had any problems. Just did regular oil changes and maintenance. My son still has it and no mechanical problems yet. I wouldn't worry about changing it. 300k, that's awesome! Ours has about 168k. Quote
kingkarmann Posted January 4, 2015 Author Report Posted January 4, 2015 the gen 2 used paper type gaskets. intake leaks would be hella rare. i'm guessing the following issues are likely having a car that sat that long: gas has gone bad and corroded the fuel pump into being inoperable fuel injectors have corroded and gone bad. crank sensor... check your injectors with a multimeter and post your results. they should all be in the near 12 ohm range. Based on some discussion, next 3.1 I tear down will used non stock injectors. The closest injector that can be supported with ease is the first version of the gen 3 (ie 94-99ish 3100 small port injectors) which only flow about 5% more than stock and are plug and play. RobertISaar, do you still concur with that thought? fuel pump. see if you get ANY flow. rental pressure gauge is available at autozone. tanks and excellent pumps are available through advanced autoparts. I have the plenum off and the fuel rail/injectors removed. I figure the fuel system from tank to engine will need inspected. Most of it, as you mentioned is probably beyond repair and will need replaced. I would like to know more regarding injector compatibility. I just figured any old GM 3.1 injector would do. I'm learning this isn't the case. Thanks for the insight! Quote
kingkarmann Posted January 4, 2015 Author Report Posted January 4, 2015 All this information has been truly helpful. Based on the info you have all provided I think I will leave well enough alone. I'm not touching the intake manifold. Now I just have to make sure I can find the correct injectors. Quote
kingkarmann Posted January 5, 2015 Author Report Posted January 5, 2015 I've been spending the evening cruising thru the forums and doing some searches on injectors. The weather here is lousy anyhow... I stumble upon Witchhunter.com. I like the idea that they can take the original injectors and in most cases restore them to original specs. Hopefully mine aren't too far gone. Witchhunter seems to get pretty decent reviews. Quote
Heartbeat1991 Posted January 5, 2015 Report Posted January 5, 2015 I've been spending the evening cruising thru the forums and doing some searches on injectors. The weather here is lousy anyhow...I stumble upon Witchhunter.com. I like the idea that they can take the original injectors and in most cases restore them to original specs. Hopefully mine aren't too far gone. Witchhunter seems to get pretty decent reviews. Make sure you ohm them first. Read everything they have on their site. I just sent mine there. Quote
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