86 22re low compression and blow by after rebuild
01-13-2017, 07:39 PM
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86 22re low compression and blow by after rebuild
I have an 86 extra cab 4x4 that has developed some issues after a full rebuild about 6k ago.I am looking for advice on how to proceed. You know, besides burning it to the ground...
The truck is an 86 22re Xtra Cab 4x4 SR5. I got it with about 180K miles on it. Luckily I got the truck from the original owner and it was all original and untouched besides the timing guides and an injector connector. As best I could tell everything else was original, which was fantastic. I put about 35k on it before it burned a valve, from there I took it down to the block and rebuilt the motor. I planned on driving it across the country and back this coming summer so I didn't really skimp on anything. All fresh reputable machine work (Basko in Az), all new Toyota gaskets, over-sized NPR pistons/rings, Japanese bearings, LCE Dual row, new water pump, Toyota PCV, OEM cap-rotor-wires, new Denso plugs, all new vac. lines, all new coolant lines, new TPS, new oil pump, injectors rebuilt and flow tested, checked harness connections, I had ENGNBLDR build me a fresh head with 261 cam, all the sensors were cleaned and bench tested ETC....
Broke in the cam and engine (Zinc added, varied RPM, compression braking, changed oil) rechecked the valves hot after the first few heat cycles then at 500 miles, then 1000 then 3000 and 6000. Head bolts are new and were re-torqued after 500 miles. (Head bolts were backed off slightly one at a time in sequence and then re-torqued) After about 1100 miles started driving normally. From there I had no mechanical issues, the truck ran great and always started almost instantly every single time. Ran cool, even with the AC on and hauling motorcycles around Phoenix. Drove great, idle was ok. The IAC valve needs to be replaced and the 261 cam I think has a bit of overlap that the EFI really does not like under 900RPM but the thing runs great and is responsive and smooth all along the RPM range. No smoke, Good MPG. No issues. Everything was nice and consistent. Looking back I wish I would have ran a compression check but I figured that I would wait until 10K when the rings had more than enough time to seat. I have had no reason to suspect that the compression was low at that point, seat of my pants tells me it was not. I also wished I would have referenced sites like this because there is a wealth of knowledge on these particular engines.
Then these issues developed suddenly at about 6000 miles. I put about 20 miles on it one morning, shut it off to drop someone off and tried to restart. I was getting nothing almost as if I had no spark or fuel. My gut told me that the engine sounded a little different as it turned over. I made a phone call and ten minutes later tried again, started right up. Drove home with no issues. Next day no start no matter how much cranking, engine still sounded different. It sounded like it had low compression in a few cylinders. I had spark and fuel but no fire. So I checked compression, I was showing 60 120 60 122. Yikes.
Here is where it seems I had an intersecting issue that may or may not be relevant. After sitting for a week I pushed the truck into the garage, rechecked the valves hoping that the timing had somehow shifted or maybe it ate the cam for some reason? Cam was perfect, valve clearance was still spot on. Crank to cam timing was still good. Still no start, still sounded "uneven" while cranking. Double checked and it seems I was not getting fuel. Checked the EFI fuse in the kick panel and sure enough it was blown. The cause was known and fixed, I had started to replace the hot start VSV connector weeks ago but found it unavailable so the clips were just pushed onto the VSV and they had shifted and shorted the EFI. No big deal. Replaced the fuse and the truck fired right up. I took this chance to reset the ignition timing to make sure it was spot on and adjusted the TPS just to make sure. Idle was fine in the garage. I went for a short ride and it all seemed well. Got gas and.... hard starting and would not maintain idle without throttle help. I drove it home and flogged it to redline. Slight smell of oil, got it back home and sure enough there is oil on my hood from excessive crank case pressure. Enough to blow out the dipstick. I double checked to make sure the PCV valve was functioning. Popping the oil filler cap off while it ran also show excessive pressure, a lot of it. Crazy amounts. It has not had this pressure before it developed these issue. I cant imagine what else it would be beside severe blow by of the rings.
To verify the rings I threw some oil in the first cylinder and it went from reading 60 to 77. At this point I dug out the bore-scope to take a look inside and nothing is obviously jumping out at me. Crosshatch is still visible on all 4. The scope is not the best but I can compare them against each other and honestly they all seem similar. The "Good" look the same as the bad but I dont think the visual inspection is telling me much. I changed the oil out just to make sure that the oil was not saturated with fuel and washing the cylinders down? The oil did not smell like fuel and it maintained the same MPG until the issues arose. At this point I got so discouraged that I took a break. I have not done the oil-ring test to the rest of the cylinders.
I am using a cheap compression tester so I have no idea of its accuracy but having 2 cylinders reading half of the other two is obviously a huge issue. I would think 120 is obviously too low for the "good cylinders" even.
So, my question is, why in the HELL would the rings suddenly lose their seal? If this happened right after I put it together or the first 1000 miles I would understand but it is a little perplexing to me that the rings would seal great then seemingly lose their seal so suddenly after 6000 miles with no other issues leading up to clue me in. Even with the crazy blow by it does not seem to burn too much oil. There is no evidence that I have seen in the exhaust. The only other thing coming to mind is that the cylinders are getting washed down with gas but with runability and fuel consumption having remained constant right up until it was hard to start, it doesn't scream flooded cylinders and it was not running rich.
It would be a huge defeat to have to pull the engine again as I am working with limited space and money. I am trying to figure out what direction to go next. Lets say the engine oil somehow got compromised with fuel and washed down the cylinders, would I be able to re-seat the rings to an acceptable level by just running it? What could even cause that to happen in the first place? And more so in 2 cylinders? What would cause me to suddenly get so much blow by past the rings?
The truck is an 86 22re Xtra Cab 4x4 SR5. I got it with about 180K miles on it. Luckily I got the truck from the original owner and it was all original and untouched besides the timing guides and an injector connector. As best I could tell everything else was original, which was fantastic. I put about 35k on it before it burned a valve, from there I took it down to the block and rebuilt the motor. I planned on driving it across the country and back this coming summer so I didn't really skimp on anything. All fresh reputable machine work (Basko in Az), all new Toyota gaskets, over-sized NPR pistons/rings, Japanese bearings, LCE Dual row, new water pump, Toyota PCV, OEM cap-rotor-wires, new Denso plugs, all new vac. lines, all new coolant lines, new TPS, new oil pump, injectors rebuilt and flow tested, checked harness connections, I had ENGNBLDR build me a fresh head with 261 cam, all the sensors were cleaned and bench tested ETC....
Broke in the cam and engine (Zinc added, varied RPM, compression braking, changed oil) rechecked the valves hot after the first few heat cycles then at 500 miles, then 1000 then 3000 and 6000. Head bolts are new and were re-torqued after 500 miles. (Head bolts were backed off slightly one at a time in sequence and then re-torqued) After about 1100 miles started driving normally. From there I had no mechanical issues, the truck ran great and always started almost instantly every single time. Ran cool, even with the AC on and hauling motorcycles around Phoenix. Drove great, idle was ok. The IAC valve needs to be replaced and the 261 cam I think has a bit of overlap that the EFI really does not like under 900RPM but the thing runs great and is responsive and smooth all along the RPM range. No smoke, Good MPG. No issues. Everything was nice and consistent. Looking back I wish I would have ran a compression check but I figured that I would wait until 10K when the rings had more than enough time to seat. I have had no reason to suspect that the compression was low at that point, seat of my pants tells me it was not. I also wished I would have referenced sites like this because there is a wealth of knowledge on these particular engines.
Then these issues developed suddenly at about 6000 miles. I put about 20 miles on it one morning, shut it off to drop someone off and tried to restart. I was getting nothing almost as if I had no spark or fuel. My gut told me that the engine sounded a little different as it turned over. I made a phone call and ten minutes later tried again, started right up. Drove home with no issues. Next day no start no matter how much cranking, engine still sounded different. It sounded like it had low compression in a few cylinders. I had spark and fuel but no fire. So I checked compression, I was showing 60 120 60 122. Yikes.
Here is where it seems I had an intersecting issue that may or may not be relevant. After sitting for a week I pushed the truck into the garage, rechecked the valves hoping that the timing had somehow shifted or maybe it ate the cam for some reason? Cam was perfect, valve clearance was still spot on. Crank to cam timing was still good. Still no start, still sounded "uneven" while cranking. Double checked and it seems I was not getting fuel. Checked the EFI fuse in the kick panel and sure enough it was blown. The cause was known and fixed, I had started to replace the hot start VSV connector weeks ago but found it unavailable so the clips were just pushed onto the VSV and they had shifted and shorted the EFI. No big deal. Replaced the fuse and the truck fired right up. I took this chance to reset the ignition timing to make sure it was spot on and adjusted the TPS just to make sure. Idle was fine in the garage. I went for a short ride and it all seemed well. Got gas and.... hard starting and would not maintain idle without throttle help. I drove it home and flogged it to redline. Slight smell of oil, got it back home and sure enough there is oil on my hood from excessive crank case pressure. Enough to blow out the dipstick. I double checked to make sure the PCV valve was functioning. Popping the oil filler cap off while it ran also show excessive pressure, a lot of it. Crazy amounts. It has not had this pressure before it developed these issue. I cant imagine what else it would be beside severe blow by of the rings.
To verify the rings I threw some oil in the first cylinder and it went from reading 60 to 77. At this point I dug out the bore-scope to take a look inside and nothing is obviously jumping out at me. Crosshatch is still visible on all 4. The scope is not the best but I can compare them against each other and honestly they all seem similar. The "Good" look the same as the bad but I dont think the visual inspection is telling me much. I changed the oil out just to make sure that the oil was not saturated with fuel and washing the cylinders down? The oil did not smell like fuel and it maintained the same MPG until the issues arose. At this point I got so discouraged that I took a break. I have not done the oil-ring test to the rest of the cylinders.
I am using a cheap compression tester so I have no idea of its accuracy but having 2 cylinders reading half of the other two is obviously a huge issue. I would think 120 is obviously too low for the "good cylinders" even.
So, my question is, why in the HELL would the rings suddenly lose their seal? If this happened right after I put it together or the first 1000 miles I would understand but it is a little perplexing to me that the rings would seal great then seemingly lose their seal so suddenly after 6000 miles with no other issues leading up to clue me in. Even with the crazy blow by it does not seem to burn too much oil. There is no evidence that I have seen in the exhaust. The only other thing coming to mind is that the cylinders are getting washed down with gas but with runability and fuel consumption having remained constant right up until it was hard to start, it doesn't scream flooded cylinders and it was not running rich.
It would be a huge defeat to have to pull the engine again as I am working with limited space and money. I am trying to figure out what direction to go next. Lets say the engine oil somehow got compromised with fuel and washed down the cylinders, would I be able to re-seat the rings to an acceptable level by just running it? What could even cause that to happen in the first place? And more so in 2 cylinders? What would cause me to suddenly get so much blow by past the rings?
01-14-2017, 11:30 AM
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I put the pistons in. Before assembly I checked the ring gap in all the bores and they were all within spec. Ring gaps were staggered. Rings were installed facing the right way and in the right order. I had someone else put a set of eyes on it as well just to make sure before I stuck them in the bores.
