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Thread: Refreshing the engine (rebuild and aftermath)

  1. #41
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    Re: Refreshing the motor of my 87' van.

    If the engine has quieted down since that video was taken, then perhaps it was just due to the lifters not being "pumped-up" yet. If however it still sounds the same, then there is a problem. These are hydraulic lifters and there should be zero lash. This means there should never be any space between a lifter, a push-rod, the rocker arm or a valve. Matter of fact, there should be about .090" pre-load on the "self adjusting" piston inside the lifter. If the lifter is at the base of a lobe and you can move/rattle a rocker arm by hand (in it's normal direction of travel), then there is too much slack and something should be done to correct it.

    When I said possible machining error I was refering to things like decking the block, shaving the head, grinding valves, etc. If the camshaft is new, then it's very unlikely it's defective (it's almost unheard of to see machining errors on these type parts). Still if you have excessive valve noise, part of the troubleshooting process is to rule things out. Cam lobe condition and lift can be checked with engine assembled if you have the proper instruments. If you don't have these things they can be picked up on Amazon and eBay for a reasonable cost (your time is likely the bigger investment). I use a dial indicator with a long extension. I have a mount bracket I made to bolt the mounting arm to the engine and it can be adjusted into place for each lifter. Specs for the camshaft are in the service manual. Tim

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    Re: Refreshing the motor of my 87' van.

    Finally got around to the van again. And you are absolutly corret Tim, the push rods are all to short. OEM are 6.380" in length all of mine are roughly 6.366 to 6.368". I think I am going to just order new OEM push rods and hope that does it.


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    Re: Refreshing the motor of my 87' van.

    did the longer push rods fix your problem?

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    Re: Refreshing the motor of my 87' van.

    That is way noisy. I have had about 8 different Vans and not heard a 4Y sound like that except for really cold starts and lasting about 10-15 seconds and that is on high mileage engines. Kind of reminds me of the sound a playing card would make in the spokes of a bicycle wheel

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    Re: Refreshing the motor of my 87' van.

    Push rods finally came in; no difference. I shot another video of the van idling. It's just as loud and sputters a lot.





    After running for a few minutes I noticed the low coolant light was on. And, well this is what my oil looked like:




    It wasn't there the last time I worked on the van. I checked compression on all 4 cylinders and it's around 130psi on each one so I didn't blow a head gasket. But it's getting in there some how. I changed the oil and filter with some cheap crap just to flush it. I also took the valve train out again to inspect the rocker arms and shaft. The shaft had a lot of debris and gunk built up inside it so I cleaned it with mineral spirits and put it back in. I have installed the valve train so many times I have a pretty good system now. I ziptie the rocker arms together to keep them where they need to be on the shaft and then bent a bunch of old wire to hold the push rods in place. It works like a charm and makes the job really simple.





    I don't really know where to go from here. I have replaced and checked everything in the valve train at this point and the problem is still there. Plus now I have coolant leaking into the engine. I have had pretty bad luck with this van and the idea of cutting my losses and selling it may have to be an option. I have sunk a lot of time and money and I don't want to have to do that, but I don't have much time or money to throw at it anymore.

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    Re: Refreshing the motor of my 87' van.

    I'm very sorry you're going through this. I know what a disappointment it must be. If you had this professionally rebuilt, then this should be on them...........all of it. I suspect the coolant in the oil is most likely due to a crappy aftermarket head gasket, but it could also be due to it overheating (I recall you saying earlier it was getting extremely hot). Other ways coolant and oil can mix is crack(s) in the head or casting flaws (if it's a new one). Another thing that can happen is cracks or pinholes in the block between the water jacket and the cylinder bore(s). That last one is not uncommon on some high performance engines, but I've never seen it on a 4y. The 4y is a heavy duty industrial quality engine so I don't think that's likely. Still, if there was a casting flaw, and the block was bored, it's possible a breach could have occurred.

    Regardless, whatever the reason, none of your options are that great. With all these issues, it it were mine I'd probably pull the entire engine, disassemble, and go over everything with a fine tooth comb. If I had paid somebody to do the work and they wouldn't make it right, I would probably return the engine to them via a trebuchet (not advocating any violence here).

    As for your push rods, when you posted above I was afraid the old ones were not off far enough to make a difference, but without measuring/checking all parts & geometry before making changes it's all random (it's better to measure twice and replace parts once). Tim

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    Re: Refreshing the motor of my 87' van.

    Terrence

    You mentioned that you were getting 130 PSI compression on each cylinder. 128 psi is the minimum. The spec range is 128-178 PSI I would expect a newly rebuilt engine to have at least 175 PSI per cylinder. I would think faulty head gasket is the cause of the low compression uniform in all cylinders and thus coolant getting into the oil

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    Re: Refreshing the motor of my 87' van.

    Quote Originally Posted by timsrv View Post
    I'm very sorry you're going through this. I know what a disappointment it must be. If you had this professionally rebuilt, then this should be on them...........all of it. I suspect the coolant in the oil is most likely due to a crappy aftermarket head gasket, but it could also be due to it overheating (I recall you saying earlier it was getting extremely hot). Other ways coolant and oil can mix is crack(s) in the head or casting flaws (if it's a new one). Another thing that can happen is cracks or pinholes in the block between the water jacket and the cylinder bore(s). That last one is not uncommon on some high performance engines, but I've never seen it on a 4y. The 4y is a heavy duty industrial quality engine so I don't think that's likely. Still, if there was a casting flaw, and the block was bored, it's possible a breach could have occurred.
    Quote Originally Posted by timsrv View Post

    Regardless, whatever the reason, none of your options are that great. With all these issues, it it were mine I'd probably pull the entire engine, disassemble, and go over everything with a fine tooth comb. If I had paid somebody to do the work and they wouldn't make it right, I would probably return the engine to them via a trebuchet (not advocating any violence here).

    As for your push rods, when you posted above I was afraid the old ones were not off far enough to make a difference, but without measuring/checking all parts & geometry before making changes it's all random (it's better to measure twice and replace parts once). Tim




    Quote Originally Posted by JPERL View Post

    You mentioned that you were getting 130 PSI compression on each cylinder. 128 psi is the minimum. The spec range is 128-178 PSI I would expect a newly rebuilt engine to have at least 175 PSI per cylinder. I would think faulty head gasket is the cause of the low compression uniform in all cylinders and thus coolant getting into the oil



    That's my suspicion as well, so I pulled the cylinder head...




    I don't see any immediate issues in the head gasket (other than it needs to be replaced now) but I also haven't checked the head for any cracks or warping. While I have everything apart again I am going to just bite the bullet and replace the rocker arms and shaft since everything else in the head is new. As well as there was some scoring on the shaft from oil starvation. I think I will pull the crank shaft and check to see if it's the correct one since the builder installed it when the motor was rebuilt.

    One thing that really caught my attention when I pulled the head was that there is a lot of carbon build up on the pistons for a motor with only 600 miles on it. I think that it may be from the valves not opening all the way if the lifters weren't function correctly, but I could be wrong. I am also going to replace the radiator while I'm in there and put in an oem thermostat since it over heated the last time I drove it and it has me concerned.





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    Re: Refreshing the motor of my 87' van.

    Well, it's been awhile but I finally ordered parts and tried my luck at this van again.

    I ordered a Chinese made cylinder head off ebay from a reputable seller since it came with valves, valve springs and all new rocker arms and shaft installed. Everything looked good on it and overall I was pleased with the head.
    The only issues I ran into were the holes for the exhaust/intake manifold studs were off just a hair and I had to enlarge the hole on the manifold to clear the studs. Also a hole for one of the fuel lines was missing but it's secure enough for it not to be a concern. I replaced all the gaskets and installed a Toyota head gasket this time around.







    After new filter, oil and coolant I fired it up. It hesitated but finally ran. And... nothing changed. Same noise coming from the motor, same sputtering at idle. Only thing that has changed is that the oil is clean of coolant. I let it run for 5 minutes and it never got quite or anything else. So I let it sit for a few days out of frustration. Went to start it again to check compression and now it won't run at all. Cranks all day but won't fire. Timing may be off but I'm pretty well fed up with this thing. The only thing I haven't replaced or checked in the valve train is the camshaft which the engine shop said they replaced. I guess all I can do is check timing, compression and after that I am out of ideas honestly. Such a bummer.

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    Re: Refreshing the motor of my 87' van.

    Quote Originally Posted by timsrv View Post
    Flat camshaft? Check travel with a dial indicator. Also, make sure the rocker shaft is right side up.

    http://www.toyotavantech.com/forum/s...roubleshooting

    Bringing back this thought, but how would you go about measuring the travel exactly?

  11. 05-30-2017, 09:57 AM


  12. #51
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    Re: Refreshing the motor of my 87' van.

    It's a shame you had the head off and didn't do it then (easy). It can still be done, just a bit more complicated. I'd pull the rocker assy back off, then use a dial indicator on the push-rods while rotating the engine by hand (removing spark plugs will make rotation much easier). Cam specs are in the FSM. Tim

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    Re: Refreshing the motor of my 87' van.

    Could I not just do it on the rocker arms? The clearance should be the same since they are on the pushrods.

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    Re: Refreshing the motor of my 87' van.

    You could, but there will be the variable of the lifters potentially compressing with the spring tension and the lack of oil pressure. It would be more accurate to take the load off the lifters before measuring.

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    Re: Refreshing the motor of my 87' van.

    Aww, that does make since. Alright I'll give that a go.

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    Re: Refreshing the motor of my 87' van.

    Sucks having the van sit while you bang your head against the wall over and over like that - keep at it and it will all be worth it once its running again

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    Re: Refreshing the motor of my 87' van.

    The only specs I could find for the Cam are the lobe height. I can only measure the lobe lift.

    Edit: Well, I found online the "OEM" specs for lobe lift on the parts description for a replacement camshaft. According to there specs OEM lobe lift is .239" on intake and exhaust. I am measuring from .228" to .236" on mine.

    So if I am understanding this right, and OEM intake lobe height should be from 1.5205" to 1.5244"; or on average about 1.5224" and the minimum lobe height being 1.5063" (according to FSM).
    Thus the difference in height being .0161"

    Therefore if the lobe LIFT of an OEM spec'd cam is .239" and the lobe lift of my intake lobe is .228", then my cam is .011" shorter than OEM cam lobe lift.
    Last edited by terrence; 06-01-2017 at 05:18 PM.

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    Re: Refreshing the motor of my 87' van.

    One in the same. Lobe height is the difference from the base to the tip............which is also lift (as measured from the lifter or the push-rod during engine rotation). Just remember that it takes 2 crankshaft revolutions to complete 1 camshaft revolution. Tim

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    Re: Refreshing the motor of my 87' van.

    I just zero the dial gauge and turn the crank over by hand until the dial hand stops increasing and goes back to zero and record where it peaked at.

    Edit: I just measured them all. Out of all 8 lobes all but one is within tolerance. There are a few close to the minimum height allowance and one is .0002" away from it. But would that be enough to be causing my issue?
    Last edited by terrence; 06-01-2017 at 06:05 PM.

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    Re: Refreshing the motor of my 87' van.

    No. With hydraulic lifters there's quite a bit of leeway. The cam lobes would need to be much worse to make that kind of noise. Camshafts are case hardened, meaning the hardening only penetrates down into the metal a few thousandths of an inch. Typically it takes years and many hundred thousand miles to wear through the hardened surface, but once that happens, the lobe(s) will go flat amazingly fast (like in ~ 50 miles). Since yours all measure so close, I would think the cam is fine.

    About the only thing left is to check (if you haven't already) is play/looseness between the rockers and the push rods. In that video it sure sounds like valve train noise........but hard to zero in on it from a video. Tim

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    Re: Refreshing the motor of my 87' van.

    Huh, well if the lifters, pushrods and rocker arms are all brand new then where would the play be coming from? Also, thanks Tim for all your expertise and input. I really appreciate it and would have probably thrown the towel in awhile ago without it.

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