Can I Replace Lifter Bucket With Timing Chains On?

I rebuilt a 1grfe about a year ago and today it started misfiring on cylinder 3. Checked it out and I have 60psi of compression dry and wet, leak down test was pissing air out the intake. So I pulled the valve cover and sure enough the #3 valve bucket clearance is like .002". (kinda guessing because the bucket turns under the cam but my .004" feeler wont fit under it and thats the smallest one I have) So I know I need to replace the bucket with a smaller size thickness but I am wondering if anyone has tried to remove the cam caps with the timing all in tact. This may be a dumb question but if its possible it would save me a ton of work. Anyone seen or done this?

 

I saw that too but I believe that will only work for the engines that have the shim on top of the bucket, I am fairly certain that the 1grfe has the shim under the bucket. If it is under the bucket I need replace the bucket itself with the correct size.

 

I believe I have found my answer, I found this in case anyone is looking.
https://www.purefjcruiser.com/docs/2007 Toyota FJ Cruiser Repair Manual/1GR-FE Engine Mechanical/Camshaft/006002.pdf

 

The issue is why is the clearance so low, I'd be suspecting a burnt valve at that point, a bucket may not be the answer.

I'd suggest a borescope to check the valve visibly before you tackle the bucket.

But ya you can remove the tensioner and remove the cams with the timing cover still intact.

 

I agree with inspecting further, I had planned on doing a leak down with the cam off to make sure the clearance was my leaking issue. I dont have a scope that I can redirect to the valve faces so Ill have to rely on the cylinder holding pressure with the cam off to tell me if the valve is sealing.
I called the machine shop and they told me that they put in the same buckets when they did the valve stem seals. It ran perfect for about 9 months and 10k miles and just started misfiring on cold starts recently. Engine had 220k miles on it before the rebuild so I am guessing that it was just time for a clearance adjustment and it didnt get caught at the rebuild because it was in spec at the time.

 

Are you at .002 for measurement or zero clearance, or actually preloaded? Yes, the follower is the shim.

 

I cant tell for sure clearance, the smallest gauge i have is a .004 and it does not fit. The bucket spins easy enough under the cam but I believe the valve is being held open slightly and that is what is causing my loss of compression. My theory was to pull the cam and do the math for a new shim assuming that I was at .002, selecting a bucket that would put me either in the middle of the spec range or maybe even a thou towards the loose side. That way if I am in fact at .000 right now or even a thousandth loaded the valve would still seat. Bad idea? Maybe I'll look around for a smaller feeler gauge.

 

I will also do a leak down with the cam removed to confirm that the valve is seating completely.

 

Im gonna keep posting here in case anyone else is looking for answers since I couldnt find any anywhere.
Today I was able to get the buckets (lifters) out without taking the timing cover off. I removed the main timing chain tensioner, then removed the exhaust cam gear and loosened the intake vvt gear bolt enough to pull the phaser away from the camshafts locating dowel. I zip tied the exhaust cam gear to the chain so I wont lose the link it was on, also painted the links at the timing marks. I cant remove the intake cam bolt all the way with the timing cover on but it loosens enough to allow to rotate the camshaft freely of the cam gear. I also removed the secondary tensioner on the small chain to give me some room to move things. With that off I loosened the bolts for the cam caps in sequence and once they are removed the camshaft can be moved enough to get the lifters or buckets out.
On a different note I now came across a different issue. Alldata has an equation as well as a graph chart to help determine the size of the new lifter needed. I have 2 different size cups that were installed one a #39 (.2124") and the other #41 (.2130"), the numbers are stamped where the bucket shim is, on the inside of the bucket. The gaps are a guess for me at this point since I didnt find a feeler smaller than .004". Guessing as close as possible #39 had a gap of .001" (tighter of the two) and #41 had a gap of .002".
For the intake valves the calculation is x=y+(z-.008) where x is the new shim needed, y is the shim that was removed and z is the gap with the old shim.

So my calculation for #39 was as follows,
x=.2124+(.001-.008)
x=.2124+(-.007)
x=.2054
The equation shows I need lifter #20 with a thickness of .2047. (The next size up is #22 with a thickness of .2055 so I figure go with the looser/thinner #20.)

my calculation for #41 is
x=.2130+(.002-.008)
x=.2130+(-.006)
x=.207
The equation shows I need lifter #24 with a thickness of .2063. (The next size #26 has a thickness of .2071, once again I decided to err on the lose side with #24)

Then after all that they have a chart that also shows what bearing I would need based on gap and old lifter size, according to this chart I would need two #26 lifters. I dont have an answer to this yet but I went ahead and ordered #20, 24 and two #26 lifters, they will be here tomorrow. Ill install them and check gap to see if I am in spec. If anyone knows why I am getting different answers using the chart versus the calculation please let me know.

 

Don’t meant to sound like siri but here’s what I found.