Multiple misfires after rebuild ** FIXED **

I haven’t quit yet.

 

Here’s a thought… on one of the heads I was very careful with making sure the lifters got back where they were originally put on the intake and exhaust side. On the other head I took all the lifters and threw them in a bucket and I don’t know which ones were for the intake side and which ones were for the exhaust side. My question is, are the lifters specific to the intake and exhaust side? They seemed to be exactly the same.

 

Did you do a valve clearance check? There are shims iirc.

If one side has some valves that are stuck partway open it could do all sorts of funny things.

 

I don’t know what that is. All I did was take the retainer off with the keeps and replace the valve stem seals. Then I put the retainers back on and made sure they were seated. I didn’t see any shims.

 

Wouldn’t a compression test show if there was a valve issue?

 

They go on top of the valve retainers and under the bucket.

Leakdown test would show if held open. Won't show if gap is too large tho.

 

Wow, hopefully hopefully hopefully this is the issue!

 

Yes, I put those back on. But they all seemed to be the same size. Are the different thicknesses?

 

From what I see online it is the same part number for the shims and the buckets. So it would seem they are interchangeable.

 

That is what I found as well, but the shims have to be selected individually to place the valve clearance within its tolerance band. You will definitely want to check all of the clearances and swap around / swap out your shims to achieve this.

 

So you think the shims could be different thicknesses in the head? That would explain it, but I still don’t know why the compression test would be so high if there were valve issues.

 

There very well could be several different thickness shims in there, and the thickness needed for a particular valve location could have changed as well as the engine has accumulated wear. Here is a screen snip from Yotashop with the thicknesses for the 4.7. I think the issue will be if any of the intake shims are mixed with exhaust shims, since the valve clearances are different.

I get your point on the compression test numbers and I don't have a good answer. Valve clearances are important though, so running through them and verifying that they are all within spec is probably a good thing to do just to be sure.

 

How would one go about checking valve clearances? I assume it would have to be done with the head on the block?

 

Well, I have watched a few videos online about the caps and shims. I am pretty sure the shims are not where they are supposed to be. My struggle is in wondering how the difference in clearance can cause misfires but the compression test had all the cylinders over 200 psi. I just don't want to waste a few days pulling the head off to check all the shims. Unless I won't have to pull the head, but I don't know if I can do it in the truck.

 

Did your friend do head work before he had his issues? Has he checked the shim clearances?

 

A mechanic online told me that my compression numbers are too high. The only number I found online for compression is around 195 or higher. Is over 210 psi too high for these engines?

 

You can check clearance by removing valve covers and using feeler gauges. The FSM is on this site and has the procedure.

210 is fine, it may be just the gauge.

 

The same mechanic told me he thinks my timing is off half a tooth on the drivers side. He told me to do what he did in this video and to ignore the fact it has vvti:

https://youtu.be/3-3ghs8tvcw

does this look like the correct way to do it and how could I be off half a tooth. It’s not like I have adjustable cam gears.

 

This picture he says shows I am half a tooth off:

 

How can you be half a tooth off? Teeth are rather binary in nature. 1s and 0's....no half teeth on the belt to be off by, unless the belt was defective....which would be an interesting twist to all this.

 

I don’t think he did. He is over 200000 miles though, so they may be out of spec just from wear. I sent him an email this afternoon about your insight.

 

Tomorrow’s the day. I have a Toyota brand timing belt, just in case, but I am going to start by removing the intake manifold and installing factory fuel injectors, Toyota brand intake manifold gaskets, and new denso brand coils and spark plugs. With the intake manifold off I should have more room to check the valve clearances.

then I will remove all the timing stuff to take the belt off so I can remove the cams. And I will fix the shims that are in the wrong place and put it all back together. I sure hope this fixes it.

 

The more I research it the more I think it may be the shims are the problem. When my truck is cold and I start it for the first time it sounds terrible. Once it warms up and the shims expand it sounds better and runs better.

 

I was also thinking that if the valves don’t open as far as they’re supposed to due to the wrong shims being installed they would still close all the way so the compression would still show super high. That makes sense in my head but I don’t know if that’s true or not.

 

So I have pulled the head, it’s a long story, I lost a shim. Can I just reuse the head gasket? It doesn’t have much mileage on it.
Or should I buy a new one?

 

This gasket looks weird. It seems to block a lot of the ports on the head. Is that normal?

 

@empty_lord

 

Never reuse a head gasket. That appears aftermarket too. And yes some ports are normally covered

 

It is aftermarket. Is Toyota brand better?

 

No, you can never re-use a headgasket.

How are you still...alive? You must have the patience of a saint. Just reading this thread over the last few weeks has driven me to drink. I can't imagine how you are still going. I did a HG on a subaru last year, only to have it start burning oil afterwords, and basically spent a month in bed I was so depressed. Parked the car, and still haven't gotten up the courage to touch it again.