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gamellott

VG30E Top End overhaul

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As some may have read, I'm having an issue with the coolant on my 92 Pathfinder VG30E and I'm working on getting the heads off to see what the deal is. Symptoms are a bad misfire when cold and coolant vomit when the engine is running when taking off the radiator cap (This has never happened before) This is the first time I'm tearing into it. It's not what I would call a reliable driver anymore so I can't make it any worse (Or so I think I can't), so I figured WTH.

 

What I didn't realize is how much of an immense pain in the butt this is.

 

First things first, when I pulled the spark plugs, I found  No. 1 cylinder showed signs of where the problems were coming from. The rest of the spark plugs were nice and clean. They were relatively new, so clean they should be.

 

1. It took me some time, but I finally got my intake plenum off. I didn't quite realize that there was coolant lines going to a couple of places in the back of the plumbing attached to the plenum. Has anyone completely bypassed those for ease of re-installation, or is that a MUST to reattach? If so, did you completely bypass the hard tubing and run lines under the intake?  What would be suitable replacement hoses? I can't imagine it would be as simple as a cheap vacuum hose or fuel line.

 

2. Although I believe my EGR is fine, has anyone successfully blocked this off without having running issues?

 

3. My distributor base is free and spinning, yet I cannot pull it out. Is there a trick to pull it that I may not be aware of? I'm sure it's a 20yo hard as rock rubber O-ring that's holding it in place, but if someone has a trick up their sleeve, I would appreciate some insight.

 

I gave up for the day after I figured out that I can't get the harmonic balancer off because I don't have the correct bolts to attach my puller to, in order to pull it. And I cant remember what I did the last time I did it 5 years ago when I simply changed the timing belt.... off to whatever parts store now.... More to follow. I look forward to everyone's insight on the topic 😝

 

I had a quick look at the bottom of the water pump and I didn't notice any signs of leaking... but I didn't get in there with a light either, so it could be that I'm simply not seeing it yet.

 

Thanks,

Geoff

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On 12/4/2020 at 5:11 PM, gamellott said:

It's not what I would call a reliable driver anymore so I can't make it any worse (Or so I think I can't), so I figured WTH.

That's the spirit, Its already F#*&@% so what are you going to do perhaps F it up worse big deal.

 

I re attached all the coolant lines but ordered all new ones and still had to go down to napa an rummage through their wall of coolant hoses to pick one or two out, I purchased a large piece of gates heater hose to replace the crankcase vent hoses.

 

Blocking the EGR should not cause any runability problems unless you have to pass emissions, even then if it was blocked and all the equipment was there you would probably be ok. 

 

Distributor should pop out , just the one bolt holding it in . 

 

If you end up needing any top end bits or pieces I have some misc odds and ends laying around.  

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Ya, it took a lot of work to get the distributor out of the hole. It did not pop out at all. The 2 bolts holding the base plate in place were loosened and it eventually popped out. It appeared as though the o-ring was seized in there. 

 

Considering the hoses were in place for the last 28 years, that's what made those incredibly difficult to remove as well. 

 

The No.1 cylinder was the one leaking coolant into the cylinder. The heads do not appear to be warped more than a couple thousandths. The lip seals on the head gasket for 1, 2, and 6 were all cracked. Again.... 28 years... No way of knowing when/why they developed cracks, but that was likely where the water intrusion came from on No. 1. Does anyone have any insight on if I should get these milled?

 

I'm not in a huge hurry to get it all together. I'm gonna be painting the top end so it looks better than a rats nest of grey and black and oxidized crap and smudges of permatex.

 

No emissions tested in WA anymore, so the EGR is gonna go 😝

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The bolts I use to pull the balancer is a couple of 6x1.0 about 80mm long. I have a couple small fender washers on the head end to keep things from binding in my puller. 

 

I simply cut those 2 little rubber hoses at the back and replace them with new on reassembly. My local dealer stocks them and they don't cost much. 

 

With the heads, I would have them surfaced and the valve seals replaced at the very least. I would also use new headbolts since they are torque to yield and supposed to be replaced. That said, I did get away with just a new head gasket and bolts on my 1980 280zx when the 2.8L injested about 3L of water and blew out the gasket at #6 while crossing a flooded road. 

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14 hours ago, Mr_Reverse said:

The bolts I use to pull the balancer is a couple of 6x1.0 about 80mm long. I have a couple small fender washers on the head end to keep things from binding in my puller. 

 

I simply cut those 2 little rubber hoses at the back and replace them with new on reassembly. My local dealer stocks them and they don't cost much. 

 

With the heads, I would have them surfaced and the valve seals replaced at the very least. I would also use new headbolts since they are torque to yield and supposed to be replaced. That said, I did get away with just a new head gasket and bolts on my 1980 280zx when the 2.8L injested about 3L of water and blew out the gasket at #6 while crossing a flooded road. 

Great advice. Thanks!! 

 

Do you get the preformed hoses or just bulk 5/16" hose? Looking at Rock Auto, I see a few preformed ones, but I suspect I could make most of the bend radius' without kinking, or put in a good service loop.

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Another observation/question while I'm thinking of it....

 

When I took the top end apart, I noticed that there was a good buildup of sludge everywhere in the engine. The oil galleys that go up to the heads are pretty small and it has me wondering if I should find a way to blow that out. Does anyone have any advice on how to accomplish this without pulling the block or dropping the oil pan? 

 

I didn't notice any indications of oil starvation on the valve train. Should I even bother??

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Sludge build up like you describe is usually an indication of neglect, though coolant leaking into the oil can also be a factor. A PCV system that isn't operating correctly can cause it too. 

 

If you have the heads off, go on and clean them up and put some assembly line on the cams and valve lifters when you reassemble. Then I would probably do a full with ATF and new filter. Let the engine idle for a while, drain and change the filter and refill with some 5W-30. Run it for a few hundred miles and change again. That should clean it out. Something the old timers would do is replace a quart of oil with kerosene or diesel fuel and do the idle routine. You don't want to put a load on the engine while cleaning it out, the lube will be too light and allow damage. 

 

One thing that concerns me is the condition of the bottom end. The main and rod bearings might be damaged by coolant contamination. 

 

My niece bought herself an 05 Altima last September. A couple weeks later either the head or head gasket let go, something the first generation 2.5 suffered from. I told her it would be cheaper and better to just replace the engine with one from a wreck. It wound up costing just under $200 for me to swap the engine. Can get them pretty cheap here, about $130 is what hers cost and a few hours of my time that she paid me for. 

 

My 93 Pathfinder has a 3.3 from an Xterra in it because it was cheaper and easier than repairing my original 3.0. Fits fine and runs well. 

 

With the 2 coolant hoses at the back, bulk hose will work fine for the straight one, but the space and bend is too tight, you need a molded one and I have found in my area at least the dealer part is competitive in price and the easiest to use. 

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11 hours ago, Mr_Reverse said:

Sludge build up like you describe is usually an indication of neglect, though coolant leaking into the oil can also be a factor. A PCV system that isn't operating correctly can cause it too. 

 

If you have the heads off, go on and clean them up and put some assembly line on the cams and valve lifters when you reassemble. Then I would probably do a full with ATF and new filter. Let the engine idle for a while, drain and change the filter and refill with some 5W-30. Run it for a few hundred miles and change again. That should clean it out. Something the old timers would do is replace a quart of oil with kerosene or diesel fuel and do the idle routine. You don't want to put a load on the engine while cleaning it out, the lube will be too light and allow damge. 

 

One thing that concerns me is the condition of the bottom end. The main and rod bearings might be damaged by coolant contamination. 

 

My niece bought herself an 05 Altima last September. A couple weeks later either the head or head gasket let go, something the first generation 2.5 suffered from. I told her it would be cheaper and better to just replace the engine with one from a wreck. It wound up costing just under $200 for me to swap the engine. Can get them pretty cheap here, about $130 is what hers cost and a few hours of my time that she paid me for. 

 

My 93 Pathfinder has a 3.3 from an Xterra in it because it was cheaper and easier than repairing my original 3.0. Fits fine and runs well. 

 

With the 2 coolant hoses at the back, bulk hose will work fine for the straight one, but the space and bend is too tight, you need a molded one and I have found in my area at least the dealer part is competitive in price and the easiest to use. 

Thanks Again, You are a great wealth of information.

 

If I had the means, I would be swapping the engine, but I don't. Right now, I'm looking at roughly $300 in parts for starters of what I KNOW I need. Then there is the milling that is recommended which is around $100 from what I am told... Sooo... $400 is what I'm looking at so far... None, of which, has been actually ordered or done yet...

 

I'm going to have to look into what has to be done in order to get that 3.3L and how much more Hp it has vs the 3.0.... Future project 😜

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Ok, a some progress since I last posted anything. The heads came back from the machinist and they were good. They milled .006 off of them. I don't expect that I will have any issues with that little amount being taken out upon reassembly. 

 

Right head reassembled.... mostly. I haven't applied full torque to the rocker arm shafts and I notice that the valves don't close all of the way. This is the first time I have overhauled an overhead cam engine. Is this Normal? I'm assuming that the lifters will eventually come to rest at a shut position. I have made several rotations on the camshaft and there is little change to the amount of valve remains open. 

 

I have one new lifter being replaced because the face of it appeared as though it had cleaved off where it contacts the rocker arm. I purchased one of those $20 sealed power lifters from Rock Auto. What's your take on the ones that are $1.50 each? The rocker arms and shafts appear to have normal wear for the age and mileage. Nothing screams "I'm Fooked" aside from the one lifter. Seems to be a likely candidate why there was occasional valve clatter on startup. All of the rocker arms appear fine.

 

Since I will be putting in one new lifter on an old camshaft, and I'm not 100% confident that I kept proper track of all of the lifters; is there any suggestions to breaking it in. I have found the procedure in the SBC world, but these are not the same, and I don't want to ruin my efforts.

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I don't recall any special break in process. It is said that when reinstalling used ones that they should be put back in the same spots they came out of. 

 

I know when I worked at the dealership there was nothing special we did when replacing lifters. 

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On 12/25/2020 at 7:10 PM, Mr_Reverse said:

I don't recall any special break in process. It is said that when reinstalling used ones that they should be put back in the same spots they came out of. 

 

I know when I worked at the dealership there was nothing special we did when replacing lifters. 

Was that before or after the oil manufacturers removed the zinc in the oil? Flat OHV Lifter rebuilders warn of this problem without zinc in the oil. I really don't want to flatten a camshaft in my, first ever, OHC rebuild. 

 

Again, I'm not 100% confident that I put the lifters in the same place.... Close, but not positive. Round @!*% rolls 🤣

 

I really do appreciate your experience and insight. Don't give it up!!

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New Update.... I got the heads all assembled and ready to install. I got the head bolts as recommended. They were shipped from Rock Auto.

 

I was putting on the RH head and going through the torqueing sequence and I was putting down the final torque for the one head, when SNAP!!! The head bolt sheared off in the block. So I guess the head bolts are fragile compared to what they could be....

 

Rock Auto is sending me a new head gasket and I will be sending back the bolts in exchange for new ones... Yay me... a bit of a delay in a driveway in the PNW.... I have a sneaky suspicion that I won't have this all together before it starts snowing here....

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Well, I was working at my local Nissan dealership until almost 2 years ago. Not sure about the Zinc deal and how much it changes things. My 93 Pathfinder had a bit over 200k miles before I replaced the engine due to the woodruff key for the timing belt sprocket destroyed the crankshaft and the pistons and valves got to know each other. My 85 300zx had over 200k miles too before I suspect the oil pump broke. I was tired of working on that car so never bothered to figure out what went in it. Neither one showed any noticable wear in the lifters or cams. I did have a cam failure in a Z20 engine, but that was caused by a broken rocker arm. None of my other Nissans or the ones I worked on have shown problems with wear on the lifter faces or lobes. 

 

Where I work now, we see a few failed cams per year in GMs and Chrysler engines. Almost never caused by the oil though. 

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11 hours ago, Mr_Reverse said:

Well, I was working at my local Nissan dealership until almost 2 years ago. Not sure about the Zinc deal and how much it changes things. My 93 Pathfinder had a bit over 200k miles before I replaced the engine due to the woodruff key for the timing belt sprocket destroyed the crankshaft and the pistons and valves got to know each other. My 85 300zx had over 200k miles too before I suspect the oil pump broke. I was tired of working on that car so never bothered to figure out what went in it. Neither one showed any noticable wear in the lifters or cams. I did have a cam failure in a Z20 engine, but that was caused by a broken rocker arm. None of my other Nissans or the ones I worked on have shown problems with wear on the lifter faces or lobes. 

 

Where I work now, we see a few failed cams per year in GMs and Chrysler engines. Almost never caused by the oil though. 

Based on your experience, what others have told me, and what I have read, I get the impression that the oil with zinc (at least during the break in period) is for the traditional pushrod engines. 

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Latest and greatest... The heads are back on. I torqued the sprockets down while the heads were still off. Little did I realize, then, that I had to install the belt cover/housing behind them. I got the RH sprocket off no problem. I was attempting to take off the LH sprocket and I could not get the bolt to budge. Cranked up the air pressure to 140 PSI and destroyed my socket and goobered up the bolt head in my efforts. 

 

Now... I need to figure out how I'm going to get it out without removing the head again. 

 

I have an angle grinder and could grind it off, or I can try to take the cam out by removing the bolt on the back of the head... 

 

Suggestions/Recommendations??

 

And... I need to find a replacement bolt too... 🤪 Maybe I should quit while I'm ahead 🤣

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You can try a bolt extractor for rounded heads or weld an open end wrench to it.

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14 hours ago, Cuong Nguyen said:

You can try a bolt extractor for rounded heads or weld an open end wrench to it.

Unfortunately, I do not have a welder. Good idea though.

 

I don't believe I would get anywhere with a bolt extractor. If I couldn't get it off with a good 6 point 14mm socket and an impact, I don't think a bolt extractor would work either. I have some of those available, so I'll give it a try anyway 🤣

 

I did, briefly, try to use a map torch to heat it up to try to get it free. I believe I may have annealed the bolt which probably facilitated the destruction....

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old fashioned pipe wrench will either get it out or shear the head off... either way you get the cam gear off then you can get a bite on the bolt shaft. If you cant find a replacement local, pm me, I've got several.

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Oh, that sucks. Did you run the bolt in with the impact? Loctite? Or just an unlucky slip with the socket that rounded the head?

 

Welding a nut or something to it would've been my go-to. Without a welder, cover anything you don't want abrasives in (plan to wipe stuff down afterwards) and go after it with the angle grinder. Just be careful not to mess up the sprocket. You might get away with cutting a slot in the bolt head and using a slotted screwdriver bit in the impact, if you have something like that. Otherwise just grind the head off the bolt until it's not holding the sprocket anymore. Once the pressure's off, remove the sprocket, slot what's left of the bolt with the grinder, and back it out with a screwdriver (using the sprocket to hold the cam). Go slow so you don't cook the cam seal, and/or pack a wet shop towel in behind the sprocket if you can. (Given the thermal mass of the sprocket, bolt, and cam, I'd be surprised if you changed much with the torch.) Then remove the bolt from the other side, work out the diameter/thread/length, and order two.

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@Rockclymr, I think I have a way forward on getting a replacement. First big task is to get it off. We have a Tacoma Screw local here where I can likely get a suitable replacement.

 

@Slartibartfast, I used my impact in order to get it on. It was cold when I did it, and maybe simple thermal expansion made it even tighter when it warmed up a little bit. I doubt that I could have stretched that bolt like I did the head bolts. I started out with a lightly used 6 point socket. By the time the bolt head failed (probably something like 10 minutes of off and on wrenching, I probably slipped off a little) and it rounded the corners of the bolt and the socket is now a wobbly 6 points 😜 . Sounds like good advice for keeping the camshaft safe from heat. I'll have to take my time and keep everything covered for sure. I'm pretty confident once I get the head removed, the bolt should simply back out. Everything was clean, dry and there was no sign of corrosion.

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So, In the event that I damage the sprocket getting it off, it appears as though I will be heading to a Junkyard in order to find them.... I keep seeing a common theme here with a 28yo truck.... The upgrade to the VG33 engine may be coming sooner than later with these options available... although I see the same options with the VG33 😜🤣

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Impacts are great for taking things apart, but also great for screwing things up when putting them back together. The service manual specs 58-65 lb-f on the cam sprocket bolts. I welded up a tool to hold the cam sprocket while I tightened the bolt with the torque wrench, but I've read that you can hold it well enough with the old belt and vise grips.

 

If the threads are okay, then yeah, I imagine it'll back out pretty easily once there's no tension on it. I ran into that recently replacing the water filter in the house. Turns out it's a lot easier to unthread the housing when it doesn't have 50-60 psi jamming the threads together!

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@Slartibartfast, Ya, I don't do much assembly with the impact except when I don't believe I'll be able to get enough torque on it (as it was in this case) when I was trying to put on the rear bolt, which has a significantly higher torque spec. This, if nothing else, has been a long learning event. As stated before, this is the first time digging this deep into this engine. Or any other OHC car/truck engine for that matter. I have worked on OHC motorcycles, but this is clearly not the same critter. Same Concept maybe...

 

Provided I resurrect the engine, One good thing out of this is that I should be eliminating all of the exhaust leaks now that I will have all broken studs replaced. No, I didn't upgrade to the 10mm studs. Give me a couple of years, and I'll have the VG33 upgrade... maybe 

 

When I discovered the broken studs, I only replaced the passenger's side gasket. I couldn't seem to get anything on the nuts on the driver's side and that became apparent why when I took off the heads... 3 studs had backed out somehow, 1 was broken and the manifold was only being held to the head by 2 studs.... Which is apparently why I couldn't find any of them by feelsies 5 years ago.... With the upper intake off, I believe I should be able to get a better angle of attack on those nuts to tighten them down properly.

 

Speaking of exhaust manifolds.... What's everyone's take on those oversized washers under the manifold stud nuts? I was planning on re-using the ones I have, should I get more for the ones that were missing? Or does it even matter? I think it wouldn't hurt.

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Making lots of progress. The small water hoses on the back of the intake manifold are proving to be a bit of an issue. Does anyone have any suggestions on how to get a good handle on them in order to get them on with the manifold on?? A dab of grease, I suppose.... They're kinda on/installed, but not as secure as I would like.

 

Bolt extractor worked for the cam bolt like a champ. Thanks for all of the suggestions. I wouldn't have thought an extractor would work considering the bolt head got destroyed with an impact, but it did. New cam bolts torqued properly, not with an impact this time 🤪 Hopefully, this will be the last time I ever have to do all of this with this engine.

 

Almost everything on the engine is assembled. All that is left is the nuts on the LH exhaust manifold to pipe, belts, hoses, radiator, fan, oil and coolant. Should be firing it up and setting the timing tomorrow. Just in time for it to snow next weekend 😝

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Ok, lots more progress, it's running, the exhaust is leaking, and the timing is WAY OFF. I believe that I clocked the pulley on the Harmonic balancer incorrectly. With the timing light, it's indicating about 120 degrees out. Does anyone have an illustration of where the pulley should be clocked on the balancer?

 

Edit... Turns out I had an idiot moment. I was setting the timing on cylinder No.3. Timing set, runs good. Gonna do another oil change again since there's likely lots of water contamination in the sump. The alternator does not appear to be charging now; will be looking into that later... Oh, and... my heater now works!!! Well, We'll see if the heat keeps pumping out. That has been an intermittent issue that may have been a symptom of the bad head gasket... At least, that's the theory 🤪😝

Edited by gamellott
Update and I was an idiot
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