Dalee1104 Posted July 13, 2017 Share Posted July 13, 2017 So I was looking into a couple threads on here about compression testing. When I completed my engine build I did a compression test to ensure nothing was wrong. All the cylinders read 170 psi except one. One of them read like 158 to 164, I can't remember the exact number. Looking at the repair manual it said that this was still within the okay range of 12 to 15 psi difference so my engine was still good. According to the Chilton manual The engine has also always had this sort of deep internal knock. Increases with rpms, seems to get drown out ij the high rpms. Not as loud as a rod knock, and not as quiet as valves. Somewhere in the middle, but it's done it ever since i bought the car and even after the engine was gone over. It sounds the worst at idle, or that's when it's most noticeable. I've tried different things with the knock sensor to see if that was an issue and it doesn't seem to be making the engine change in any way due to this knock. And sometimes I swear it's louder than others. The engine runs fine other than just horrible gas mileage and sometimes a little rough with the pedal to the floor (assumed it's due to the 14 mpg over-fueling) is there any way this knock could be related to the one cylinder having lower compression? Also having lower compression is there anything I can Do? I saw on Thors wagon build he did the motor medic and it helped the numbers significantly, is that still holding up? Should I consider That? If so how do I go about it? Link to comment Share on other sites More sharing options...
Dalee1104 Posted July 13, 2017 Author Share Posted July 13, 2017 I would post pictures but I'm not sure how to do so through the phone Link to comment Share on other sites More sharing options...
Dalee1104 Posted July 13, 2017 Author Share Posted July 13, 2017 Figured it out. This is the problem child, a 97 legacy gt Sent from my SM-G930R4 using Tapatalk Link to comment Share on other sites More sharing options...
Thor294 Posted July 13, 2017 Share Posted July 13, 2017 Leakdown test will tell you if it's valves. You can also add oil to cylinder and see if it helps. If oil makes it go way up then you have bad rings. Motor medic helped me because I got lucky and possibly had a frozen ring or something. I have to check it again to see how it's holding up Link to comment Share on other sites More sharing options...
Dalee1104 Posted July 13, 2017 Author Share Posted July 13, 2017 Whenever you do check it be sure to update your thread I'd like to take a look at it Link to comment Share on other sites More sharing options...
Brighton96 Posted July 14, 2017 Share Posted July 14, 2017 I'd pull the plugs out and put 1-2oz of marvel mystery oil in each of the cylinders and then let it soak overnight. Then do an oil change with more marvel in it and see what that gets you. Link to comment Share on other sites More sharing options...
Dalee1104 Posted July 14, 2017 Author Share Posted July 14, 2017 The only issue is I'm leaking a bit of oil. Like kind of a lot. When I went to install the rear main seal it must not have gone right but I leak a lot of oil. Just no time to pull the engine back out yet. Do you think the marvel would just kinda be a waste at that point being as it'll leak out? Or is it still worth a try? I'm always making sure oil levels are good Link to comment Share on other sites More sharing options...
doublechaz Posted July 15, 2017 Share Posted July 15, 2017 It should still help get things moving. When you do get that engine back out, if you didn't go to the newer metal oil separator cover, do so. Link to comment Share on other sites More sharing options...
Brighton96 Posted July 15, 2017 Share Posted July 15, 2017 I'd still do the marvel treatments, it's pretty cheap if you get it from Walmart so I wouldn't worry about leaking most of it, it's not like it's super expensive or hard to find. Link to comment Share on other sites More sharing options...
Dalee1104 Posted July 15, 2017 Author Share Posted July 15, 2017 Okay cool, and you guys just drop that into the cylinder through the spark plug hole? Also my rear wrist pen was leaking a ton of oil when we pulled it at first and we rtv it to try and help but is there a more permanent solution to stop the leaking such as there is with the aluminum oil separator plate? Which I still need to do Link to comment Share on other sites More sharing options...
Brighton96 Posted July 15, 2017 Share Posted July 15, 2017 Yeah, normally the procedure is to pull the plugs, put 1-2oz in each cylinder through the spark plug hole, put the plugs back in and then let it soak for 12+ hours. Once it's done soaking, fire it up to burn off the residual oil and that's it. Link to comment Share on other sites More sharing options...
xxBLOOD88SHOTxx Posted July 15, 2017 Share Posted July 15, 2017 What kind of other maintenance have you done to the car? Weird that I haven't noticed your car around town before. Link to comment Share on other sites More sharing options...
Setnev Posted July 16, 2017 Share Posted July 16, 2017 The sound you're describing actually sounds like piston slap in that cylinder with the weaker compression. That's due to piston rings with a lower gap than the others that causes the skirt of the piston to "slap" the cylinder wall. Piston slap seems to occur most at midrange RPM when the engine is most "unbalanced". My friend had piston slap on his old EJ22 after seafoaming the oil and changing it, but his had well over 200k miles on it and he beat it worse than a pimp on a cheap hooker. When you change your oil, probe it with a magnet (like one of those cheap pickup magnets) to see if it has any metal in the oil. Basically put the pickup magnet in the stream of oil to see what it picks up. If you see a high concentration of metallic particles, you could be looking at something weak internal. If it is piston slap, a full rebuild will be necessary and it's a good idea to have the block honed to remove the scoring from the bottom of the cylinder walls. If you can, take a good quality video of the noise and upload it to YouTube or something so we can hear it. Link to comment Share on other sites More sharing options...
Dalee1104 Posted July 16, 2017 Author Share Posted July 16, 2017 Maintenance I've done involves the top end rebuild. Didn't go in depth in the connecting rods or crank or anything but had the heads resurfaced and everything and also checked the cylinder walls to ensure they are true and they were all in surpringly very good condition, the cross hatching in them from when they were built was still in very prominent shape and there were no divets or anything in any part. The oil I actually have checked before and there's almost nothing magnetic coming out of it. But the sound would kind of add up. Bad comes to worse I have another engine bored and stroked to a 2.7 litre with supposedly forged internals (haven't gotten that far into looking at it, bought it from some rich kid) Other then the deeper internals such as valves, crank, cams and things like that, everything has been replaced, I listed everything when I bought the car and so far all i have left that hasn't been replaced with oem factory parts is rear sway bar end links, coil pack, MAF, and steering rack bushings. It's been a very long time coming and I've put about 2500 into the maitanence (got the car for 1000) This being said the car is reaching the 250,000 mile mark. My dad says I just overthink it and that's just what an old worn out engine sounds like I just barely graduated highschool, naches and grew up in Chinook so my car kinda reflects that rough rugged off-road look, so if I'm anything it's definitely not a professional on any of this and i still have much to learn. My dad on the other hand used to build cars all the time with his buddies ranging from big v8 to turbo bikes, anyways talking with some of them today they were saying it's most likely the bearing clearance on my crankshaft? I'm unsure to what that even is but they brushed it off like it wasn't much to worry about as the engine is getting in it's age anyways and I'll probably swap soon Link to comment Share on other sites More sharing options...
Dalee1104 Posted July 16, 2017 Author Share Posted July 16, 2017 What kind of other maintenance have you done to the car? Weird that I haven't noticed your car around town before. I maybe have seen yours around lol you don't have any pictures up man but I do notice most 4th gens just because I think they are quite attractive Link to comment Share on other sites More sharing options...
xxBLOOD88SHOTxx Posted July 16, 2017 Share Posted July 16, 2017 Mine is silver on RPF1s. Link to comment Share on other sites More sharing options...
Dalee1104 Posted July 17, 2017 Author Share Posted July 17, 2017 Huh I'm in west valley area a lot as i work at Meadowbrook and live around yvcc but yeah I can't recall seeing yours either Link to comment Share on other sites More sharing options...
Setnev Posted July 17, 2017 Share Posted July 17, 2017 FYI piston slap damage won't show in the cylinder bore above the stroke of the piston, it'll show up in the bottom of the bore below where you can see it. Link to comment Share on other sites More sharing options...
xxBLOOD88SHOTxx Posted July 17, 2017 Share Posted July 17, 2017 Huh I'm in west valley area a lot as i work at Meadowbrook and live around yvcc but yeah I can't recall seeing yours either Very odd, I go to Perry Tech so I'm down the street 4 days a week lol. Not in West Valley as often as I use to be though, but I did have breakfast at Waffles Café yesterday. There are a couple really clean 4th gens in the area but I don't think any of them are on this forum. Link to comment Share on other sites More sharing options...
Dalee1104 Posted July 18, 2017 Author Share Posted July 18, 2017 FYI piston slap damage won't show in the cylinder bore above the stroke of the piston, it'll show up in the bottom of the bore below where you can see it. Oh, damn okay I was not aware of that. I was really just curious if that could be related to the horrible gas mileage and low power if maybe a valve wasn't working correctly or something Link to comment Share on other sites More sharing options...
Dalee1104 Posted July 18, 2017 Author Share Posted July 18, 2017 Very odd, I go to Perry Tech so I'm down the street 4 days a week lol. Not in West Valley as often as I use to be though, but I did have breakfast at Waffles Café yesterday. There are a couple really clean 4th gens in the area but I don't think any of them are on this forum. Well damn, I have Monday and Tuesday off but if your in the area any other day swing by Meadowbrook, you'll see my car parked over near the batting cages and I'll be working out at the go karts Link to comment Share on other sites More sharing options...
xxBLOOD88SHOTxx Posted August 9, 2017 Share Posted August 9, 2017 Finally saw your ride on 16th. Shoot me a PM I have a brand new radiator that Ill let go for cheap if it fits your 97 (It didn't fit our 97) Link to comment Share on other sites More sharing options...
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