3RZFE engine rebuild: How To---

The reason I skipped over valve shimming was because this engine was almost brand new in mileage, and the shims were already taken care of. This "rebuild" as stated in the OP is for a spun main bearing, so there was no need to mess with the shimming. However the shimming is a pretty simple job to take on.

Boring your engine over will not require anything really "special" other than making sure that the cylinder head is perfectly smooth, Boring an engine does tend to create "hot spots" where the cylinder head meets the block.

 

Bama, I'm about to overhaul my '97 3rzfe due to 50% leakdown and minor loss of power. It has 185,000 mi so could use it. May I use you as a mentor for stumbling spots?

 

I missed your post here, sorry. Feel free to hit me up for whatever you need.

 

Thought I would post my findings during overhaul here since so much is already covered.
Issue: Main and rod bearings.
When Toyota built the engine they matched journal sizes to one of three 'standard' bearing sizes. These are often referred to as micro-sizes. One crank may have a different size bearing on each journal. In replacing the bearings the Toyota Service Manual says to replace them with the same size unless of course you grind the crank. If you buy aftermarket (anything other than Toyota) bearings you can only get 'standard' which are an average of the micro-sizes or 'undersize' bearings. As pointed out to me, if your micro-size bearings are still in good shape you may have a better fit by reusing them than with an average size 'standard' new one. I was surprised that the bearings on my 3RZFE look brand new (no visible wear) after 185K. The crank doesn't have a mark but will be polished. There was almost no ridge buildup on the cylinders so I was able to pop the pistons out without any effort.
I am doing the overhaul due to a minor loss in power and a measured drop in compression of nearly 50%. During a leak-down type compression test I heard air coming from the oil filler, indicating a loss through the rings. However, when I removed the head I found the valves mistimed by one tooth and a lot of black soot at the intake. This could have been my leak and I'm doing a whole teardown due to a mechanics screwup years ago when I had new exhaust valves installed due to pulling too heavy a trailer from Alaska.
Something else to note: The exhaust cam has a driven gear and sub-gear. They both mesh with the intake cam gear but there is a torsional preload between the driven and sub-gear. This twist serves to quiet the timing train. The manual says to install a small 'service' bolt through holes in the gears before removing the cam to maintain this twist. You can install the cam without the twist and it will time and work fine, just noisier. I found mine in this condition. The holes were not lined up. I'll try to post some pictures.

 

Here is the bolt hole misalign.

 

I encountered this problem when I discovered I needed to grease and oil the cam before installing it (when I went to the FSM for torque information). I forgot to replace the bolt before removing the cam to grease it, and the gears twisted. I put it back in shape by placing it in a vise (protected by wood on both sides), prying it over with a screwdriver till I could insert a bolt from the valve cover (it's not threaded all the way to the end, so it allows for a little more adjustment). It was a nuisance, but it is fixed.

 

Not sure where this information came from. All crank journals are ground and polished to the same size. If one journal has to be .010" ground down, then all journals are ground down the same amount. This is standard practice at all engine machine shops, and factory machine shops as well. As for aftermarket bearings, I was capable of buying oversized bearings from the aftermarket all over the place. Not sure who sold you in the fact that Toyota is the only place that supplies oversized bearings. My bearings were manufactured by Melling, and they are .010" oversized.

So how is the rest of the rebuild going for you?

 

Oversize, yes , not one of three 'standard' sizes. The info comes from the Toyota Service manual.
The crank main bearings are either #1, 2, or 3. The rod journals are either #4, 5, or 6. All my mains are #2s. Three of my rod bearings are #4 and one is #5.

 

Got the gasket set, rings, oil pump, and water pump today. I just disassembled the oil pump and made the measurements. It's like new so will send the new one back. I checked the ring end gap and both #1 and #2 were almost .005 under minimum. That could have been disastrous. The company is sending a new set. Maybe I should have gone w/ Toyota parts.

 

That is truly strange. I guess Toyota just has to be different. lol. Good luck! If you need any info on putting it all together or setting it up, just let me know. The fun part will be getting your valves shimmed. That took me the longest.

 

I just got the head back from the machine shop. I had them do all that. They did have to order new exhaust valves because the margin was at minimums after grinding. That's two sets of exhaust valves in the life of the vehicle.
The head work, honing and cleaning the block, and removing the oil pump screws cost me over $900.

 

Wow. Did you look at the price of new? My brand new head was only $250, and I priced out new valves and buckets for only $300 more.

 

The new ones I found were more and a lot of the expense is for other than the head.

 

OK. Well Keep things updated! And take pictures! lol.

 

Lots of pix, mostly just for reassembly.
New development: I measured the timing chains and it appears both are worn beyond limits. I was surprised. Toyota gives very specific (to the .0001) for length and for diameter of the sprockets with chain attached. The sprockets seem to have wear also. I don't have calipers that reach that deep so will have the shop measure.
I don't remember the recommended replacement interval for timing chains and I vaguely recall that the chain and sprockets should be changed together.
This could get expensive!

 

If the chain is worn too far, then it is a good idea to replace those and the sprockets. They really are not that expensive. Kits can be found on eBay all day long. There is no actual "interval" for replacing the chain. It's like head gaskets: You don't replace them unless there is a problem. You can always do what I did and leave the balance chain off, and reinstall everything else! I do feel some vibration, but it's really insignificant to me. If you want to see more details and information on the engine and building it, find my "restoration" thread. Tons more engine pics and information there.

 

Cleaned and ready for rings. The oil drain holes can be opened with a 3/32" punch or a piece of wire coat hanger. Some of mine were blocked entirely.



I tried to add more than one picture and step to a reply but Int. Explorer keeps blowing up.

 

Rings installed. It is easier to install the oil ring expander first and then the top and bottom rails.