4.0L V6 with bad head gasket (repair or replace?)

I have nothing to add except that I'm following it intently, anxious for the final result! Great job so far, Man!

 

Quick update. I installed the rear water bypass joint, cams and timing components today. The rear water bypass is a real pain in the azz. How do you master techs do it? Do you guys climb onto the engine or get in the engine bay to reach it?

 

Sit on rad support feet on sway bar if I recall. Rag on hood latch for the plums.

Back pain, don’t forget back pain.

 

This is what I have at the shop, really saves the knees.
https://traxionproducts.com/products/topside-creeper

 

Ah yes...the good ol superman. That's what I call ours. Yeah, I use that as well. Always need to take everything out of your shirt pockets though.

 

This is exactly how I have been working minus the rag.

 

ayy guys, so turns out i dont need to get my heads or block machined because they are well within spec from Toyota! once I get done cleaning em up, I can put it back together. Currently working on em, ill go live on my IG if yall want to watch/ask any questions while im doing em!

https://www.instagram.com/wrdoverland

 

That’s good to hear. Btw, I took a look at your IG. Nice pics. I spent 2.5 months and 10,000 miles on the road back in 2020.

 

So I am hoping that one of the techs will respond here. I don't expect too many folks will engage on this post but who knows...


It looks like I made a mistake when ordering a new valve lifter for one of my exhaust valves that was slightly out of spec. I am pretty sure I have a way to solve my issue, but I don't quite understand how I managed to make an error in selecting a new valve lifter in the first place. Hopefully an explanation will help me and someone else in the future when looking to order new valve lifters.

Okay so one of my exhaust valves on cylinder #6 had a clearance of 0.016 in and the range is supposed to be 0.011 to 0.015 in. The FSM appears to offer two methods to determine what lifter to order. One method is to use a formula (listed below) and the second method is to refer to their selection chart (see attached).

The formula for an exhaust valve is listed below:

T: Thickness of removed lifter
A: Measured valve clearance
N: Thickness of new lifter
where the formula to calculate a new exhaust lifter is as follows:
N = T + (A - 0.30 mm (0.012 in.))

The thickness of the removed lifter is 0.2137 in.
So T = 0.2137
A = 0.016 (as measured with a feeler gauge)

N = 0.2137 + (0.016 - 0.012) * I used 0.012 since all of my measurements are in inches.
N = 0.2177 in. (or 5.53 mm.)

Since the lifters are only available in even millimeter increments I chose to order a 5.52 mm one. According to the FSM you should select the lifter thickness that is the closest. In my case, I am right in the middle of two sizes so I opted to size down.

In hindsight, I should have installed the new lifter and the other 15 lifters on the LH (driver's) side head before installing the heads in the car but I didn't. This would have allowed me to find the problem before I installed the timing components.

I just measured the exhaust valve with the new lifter and my clearance is now .010 which is out of range. The range for an exhaust valve is 0.011 to 0.015 in.

I just spent some more time re-reading the valve clearance section in the FSM. If you refer to the valve selection chart instead of using the formula I get a suggested lifter of "50". "50" would imply a lifter size of 5.50 mm from my understanding.

What's interesting is the chart gives me a suggested lifter of 5.50 mm as opposed to the formula giving me a target lifter of 5.53 mm. Since it is an odd size, it is suggested to order either 5.52 or 5.54 mm.

5.52 mm - 5.50 mm = 0.02 mm. This difference of 0.02 mm (0.0008 in.) would put me closer to 0.011 in.

Now it looks like I could order a 5.50 mm lifter to put me right in the range but I will play it safe and order a 5.48 mm lifter to comfortably put me back in the range.

Aside from discrepancy I encountered between the two methods, I am also puzzled by the original measured lifter thickness (T) of 0.2137 in. My micrometer was calibrated but I would have expected it to be smaller in thickness as the inside of the lifter has "40" stamped in it. I would expect this to correlate to a lifter of 5.40 mm which is 0.2126 in which would be thinner than my measured thickness of 0.2137 in (T).

So in summary my solution is to order 5.48 mm ("48") lifter just to safely put me in the range but I still don't feel comfortable explaining to someone who was planning to order these in the future.

Here is the valve selection chart below. I have highlighted in yellow my measured valve clearance range at the top and also the row nearest to my current measured lifter thickness of .2137.

 

I ran into an issue when test fitting the timing cover. The new o-ring on the bottom of the timing cover kept falling off.

Is there something that I can use to help keep the o-ring in place during installation?

Btw, I tried removing the two studs at the bottom and it did not give me any extra vertical movement of the cover as to avoid sliding the FIPG around when installing.

 

Use a dab of grease or Vaseline to stick it in place.

 

How did you end up with measuring valves? Headjob?

Usually exhaust valves gain clearance due to carbon the valve, and when the head is off it gives you a chance to clean off the deposits causing the clearance.

You do have it right with the math, 0.010 probably would have been fine, but specs are specs for a reason and you risk burning a valve if its not shutting properly.

 

^ This, but there's another secret method I use...

I reuse the originals, they are flat and slide across the pan better, no risk of them falling off. It's 100% the wrong way to do it, but it removes risk.

The right way to do this job is sub-pan off, but thats stupid. The 2016+ tacos need it, just miserable.

 

Well all of the valves, both intake and exhaust, measured at the larger end of the spec. Most of my exhaust valves had a clearances of 0.014 or 0.015. It was just one that measured 0.016. For what it's worth, I ran into an older mechanic who said larger tolerances are what he would expect as the camshaft lobes do wear over time and add to the clearance.

I ended up picking up a "48" or 5.48 mm lifter. I installed it yesterday and the clearance is at 0.011 inches now. So all good there.

I put both of the exhaust manifolds on yesterday. It took me several hours to do one as the. Only then did I realize that it becomes easier if you remove the manifold stay bracket. Bonus tip... Loosen both both bolts on the manifold stay brackets but only remove the bottom bolt.

It's a little disheartening to have put in so much time only to have to deal with the possibility of messing up the o-ring and FIPG between the oil pan and timing cover. I also tried to remove the 2 lower studs and did not give me any more room to lift the cover up a bit when installing it. It actually made it a bit tougher to keep the alignment between the oil pump and and crankshaft. I always knew that this part of the install would not be a ideal.

Btw, my existing o-ring was flat but it did have a crack in it. It was actually brittle and needed to be replaced.

 

I got the cover installed. I used some grease to hold the oring on the bottom of the cover. Hopefully it stayed on. According to the FSM it says to get the cover and water pump installed within 15 minutes after the FIPG. I can't say that I did that, so I suppose I get a C- for execution and an A for effort. Hopefully it is a non-issue.

Also, I tried to be slick and not install the 10mm bolts on the water pump in order to try and get all of the 12mm bolts torqued down sooner. Unfortunately I couldn't get the 10mm ones started so I had loosed up the 12mm that I just torqued down.

I'll continue on tomorrow. I would expect everything at this point to be pretty straight forward.

 

These timing chain covers on these engines are insane. Great job so far tho.

 

I used Permatex black for the sealant on my engine. I think it gives you more time to install the cover and torque the bolts. It takes longer to cure though 24-48 hours.

 

Hey guys. I was reviewing the pictures that I took of the timing cover that I installed. I noticed that I did not run the FIPG all the way to the bottom of the cover on both sides.

Do you think the FIPG squeezed enough to cover that gap or do I need to pull the cover?
I don't want to overthink it but wasn't sure if this would cause an oil leak. Thanks.

 

I'd call it good and hope for the best. Just what I would do. Hopefully someone else more familiar with that cover will chime in.

 

Leave it alone at 0.016 or order the next size larger than than the one that was in their to make the clearance .016".

I'd address it if it was tight on an exhaust valve.....but .001 out of spec? Just leave it.