3RZFE engine rebuild: How To---

For those who know me, you will know that about a year ago I installed a new 3RZFE engine into my 1997 Tacoma 4X4, as well as some other detailed engine work. Well as is prone to happen, bad luck seems to strike when least desired. Back in March the Alabama group got together for our annual get together of modding and wheeling. shortly before this event my oil pressure sensor literally blew itself out and dumped my engine oil out while I was going down the highway. By the time I realized what had happened it was too late, and I had a bit of an engine knock. I had crossed my fingers and hoped that I could salvage things by replacing the engine bearings from below (Remove front diff, drop oil pan, replace bearings, reassemble) but unfortunately this did not work. The knocking returned just 30 miles later.

So now what to do? The engine itself was too new to throw away and replace it, so I did what any technician who repairs engines daily would do: I pulled the engine and tore it down in order to replace the failed parts.

Well here is my thread on it. I am not done, so posts will be added as I reach each step. Feel free to ask questions, or offer ideas, but I will greatly appreciate it if you would keep your comments oriented towards the thread itself, and not "shoulda-woulda-coulda" comments. I am making this thread so that those who might want to tackle a job such as this themselves might be able to get some helpful information, as well as give people who have never actually seen inside one of these engines a rare opportunity to do so.

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So the engine was removed and prepped for dis-assembly. If you are going to attemt ANYTHING like this I suggest you get an engine stand. While it is POSSIBLE to do a job like this without one, it is an invaluable tool to have, and is worth the small investment. You can buy them from Harbor Freight on sale most any time for $50. Trust me, it is WELL worth it.

When installing to engine bracket to the engine itself you must first "prep" the engine. This means removing ANYTHING that may need to be removed during dis-assembly. So off came the clutch, pressure plate, and flywheel. Next came the rear main seal housing. If you don't remove this housing you will NOT be able to remove the crankshaft from the block. Also if you look at the below photos you will see a correctly aligned bracket, and one that is incorrectly installed. To maintain safe balance of the engine on the stand you need to be sure that the centerline of the crankshaft and the centerline of the bracket are true to each other. The first picture I intentionally installed incorrectly so that you can better see what I mean.







now that the engine is installed I decided to save some time and money by removing the cylinder head with the intake manifold and exhaust manifold still attached. This saves time, and some money, as replacement gaskets will not be needed.

NOTE: WITH THE INTAKE AND EXHAUST MANIFOLDS STILL ON THE HEAD, THE ENTIRE ASSEMBLY IS HEAVY AND AWKWARD. USE AN ENGINE HOIST TO ASSIST IN REMOVAL. DO NOT ATTEMPT TO REMOVE BY HAND!



I don't have all the photos ready, so some will be added inside this post as I go, so reference back if you don't see something that is mentioned.

In order to remove the cylinder head as a unit you first need to remove the valve cover. This gives you access to the camshafts and the head bolts. Once the valve cover is removed use a 10mm swivel socket and a long extension to remove the bolt that holds in the camshaft position sensor. This needs to be removed to access one of the head bolts. After that you can use a 12mm socket to remove the two smaller head bolts that are in front of the timing chain. These bolts go into the top of the front timing cover. Next you should remove the timing chain tensioner from the head. This tensioner is located behind the ignition coils. Once that is removed you can take a 19mm socket to loosen the camshaft timing sprocket bolt. In order to do this you will need to use something to set in place to prevent the camshaft from turning. I used a long 3/8 drive extension slid into one of the many holes of the sprocket. Once you remove the sprocket it is ok to allow the timing chain to slide down into the front timing cover. You will recover this later.



Next comes the camshafts. They must be removed because the head bolts are located underneath them, and you will be unable to loosen or tighten them later otherwise. Pay careful attention to which lobes of the camshaft are pointed downward, as these are the ones under load. In order to safely remove the camshafts you will have to loosen the camshaft cap bolts a small amount at a time, working from the ones farthest from the ones under load towards the ones NOT under load. A couple turns at a time will be fine. You are just working carefully to keep from binding the camshafts. Once the camshaft caps are loose, carefully place them aside, making note of the order and direction they are removed. Each cap is actually labeled for direction and location, but if you keep them in the same order, it just makes things easier. Now remove the camshafts themselves and place them in a safe location.

So far I have seen no signs of damage or wear, but I expected this. I know the major part of the damage is in the lower end. Once the camshafts are out of place you will need a 14mm 12-point socket to remove the head bolts. Use one that is a 1/2 inch drive, as the 3/8 inch drive ones may not be able to handle the stress if they are of lower quality sockets, as well as a 1/2 inch drive breaker bar is much easier to use. Remove the bolts from the center out. I always remove them in the same order as you are supposed to torque them down in. This aids in reducing any abnormal warping from stress. After this I was able to hook a chain to the head and apply a small amount of lifting pressure with the engine hoist, and the head came off without a hitch.



Next comes the timing cover. I removed the AC compressor, and alternator, as well as their brackets from the engine , as this is required to remove the front timing cover. Next I removed all bolts EXCEPT those that were 10mm socket sizes. The 10mm socket bolts are not needed to be removed for removal of the timing cover. After that I removed the oil pan. The timing cover on the 3RZFE engine will not come off until you remove the oil pump pickup tube. This is done after the oil pan has been removed. Once that is done the timing cover will slide off, and your engine is pretty much disassembled down to the crank, pistons, and balance shafts.



At this point you can turn the engine over where the lower side of the engine is face up and get started on the lower end of the engine. Care has to be taken at this point because if not, you can nick the crankshaft, or a cylinder wall. This can cause you some SERIOUS problems, so be careful!!!!!

NOTE: PISTON CONNECTING RODS, AND MAIN BEARING CAPS ARE POSITION-SPECIFIC. THIS MEANS THAT THE ORIENTATION AS WELL AS THE LOCATION OF THESE CAPS IS VITAL FOR PROPER ASSEMBLY. FAILURE TO PROPERLY INSTALL THESE PARTS WILL MOST LIKELY RESULT IS A SEIZED ENGINE. PAY ATTENTION TO HOW THEY COME OFF, AND WHERE THEY COME OFF OF.

The piston connecting rods are bolted to the crankshaft by 12mm 12-point nuts. Remove these nuts and you can use a SOFT FACED hammer to gently tap the studs. This will help break loose the cap from the connecting rod, allowing for it's removal. Paying attention to orientation remove the caps one at a time, and gently push the piston out of the block in the direction of the head surface. Pay attention to the connecting rod so that it does not nick or score the cylinder wall. You will have to do these two at a time due to the orientation of the crankshaft which has #1 & #4 pistons matched, and #2 & #3 pistons 180 degrees opposite.

Once the pistons are removed and the caps carefully reinstalled, you can move on to the main bearing caps. These are the caps and bearings that hold the crankshaft into the block. The caps are held in place by 14mm 12-point bolts. Each cap has 2 bolts. Since there is no load on the crankshaft the order in which you remove the caps is irrelevant, but I like to start from the front and work towards the back. Again be aware of the location and orientation of the caps. Once they are removed you can remove the crankshaft itself. It is VERY heavy, so be careful when removing it.

So there you have it, the engine is essentially disassembled. I will include more photos later, as well as photos of the failed part(s).

 

Pass some over here

 

Going into this job I already knew that I had an issue with the #1 rod bearing. At this point I didn't know how severe, but I had a pretty good idea. Prior to this dis-assembly I had already taken the old crankshaft out of my old engine and took it to Precision Automotive in Birmingham, Alabama to have it machined and prepped for installation. The people there, were very knowledgeable in machine work, and their shop looked quite busy. They were the ones who initially mentioned that they would measure the journals and inspect the crankshaft first to determine if they could save me some money by a simple polishing. A couple of days later they let me know that the crankshaft was in great condition and simply needed polishing. This saved me $50 in machine work. I think that speaks highly of their professionalism and integrity.

After I disassembled the engine and removed the crankshaft, this is what I found for #1 cylinder:

Wide view:



View of a good rod journal:



View of #1 rod journal, and what is left of the bearing:



View of the rod itself, with the bearing removed: (note this should be smooth and not discolored)





So What was the next step? I took one of the good connecting rods from the old engine and swapped it to the new engine's piston. The old wrist pin pretty much just slipped out of the old piston and rod after I removed the retainers. The new piston had to have the wrist pin pressed out after removing the retainers.

(Note photos are of old piston, and bad rod. New piston and rod have already been installed)





After swapping out the rods I then cleaned the entire rod/piston assembly and liberally lubricated it with engine oil. I then took a piston ring compressor (available for rent from local parts stores, or can be bought at Harbor Freight for less than $10) and compressed the rings. Then I positioned the assembly carefully into the engine block, being sure to orient the piston correctly. On the 3RZ engine, the "3FE" that is engraved on the top of the piston is placed towards the rear of the engine. This is due to piston face shape, and to prevent valve contact when engine is running. If you look at the photo you will see this mark easily.




Side bar:

This is a piston with the ring compressor installed:





This is the piston installed in a cylinder opening. No, this is not #1 cylinder of course, but I forgot to take pictures of things when I installed the #1 piston. When tapping in the piston use ONLY a rubber or wooden mallet or handle. Do NOT use a metal hammer or any other metal faced tool.



Now that the replacement connecting rod and the piston has been installed properly, I am ready to install the crankshaft. At this point I am still waiting on delivery of the new rod and main bearings, which should arrive on the 28th or 29th of May.

 

Were you planning on doing anything performance wise while you are in there?

 

Not really. I really don't have the $$$ to do anything major, and really I am quite happy with the engine as it was as far as power. Was there something specific that you were thinking of? I always say I am open to suggestions.

 

I was wonderng about aftermarket cams or such?

 

Sub'd

 

Ah. Not too much can really be gained on these as far as cost v/s HP gains. I can't see throwing that kind of $$ into a daily driver for such a minimal gain in HP. But good thought.

 

Sub'd

 

Did you forget about the thread or are you still waiting on parts?

 

My mistake. I had gotten tied up with a large amount of other things at the shop and never got around to finishing this thread. The work has been completed, and I now have about 1000 miles on it. I will work on continuing the write up this week.

 

Thank you sir

 

Hi, this is my first post to the site, I mostly browse for threads related to what i am working on. I have just finished tearing my engine down, and a couple of things I am curious about this engine. (the last time I rebuilt an engine, it had a carburetor and points). The balancing shafts seamed to not have any bearings. where they went is just a cutout hole for the shaft, with a plate to hold it in the hole. from what i have read, they turn at 2x the rpm of engine. shouldent there be bearings here?

 

Sorry for the delay in responding to you Greg. Actually this engine DOES have balance shaft bearings. They are pushed in and pushed out in the same way that the GM camshaft bearings are done since the 60s. If you have no bearings at all, then they were wore out and need replacement anyway. What have you done so far in tearing down your engine, and rebuilding it?

 

Sorry about checking the site, I have been in the garage for the last 4 days, I figured it would go back together quickly (ha). So far I have taken the engine apart, had the head rebuilt, crankshaft miked and polished, and the block dipped and new balance shaft bearings pressed in (they also painted it,and put on new freeze plugs in, all for 150 bucks, crankshaft and head for 225). Got all parts and rings, bearings, and I have gotten everything put in except the main seals, distributor, and all the outside stuff. I am having trouble now trying to figure out how to time the distributor. If I understand the manual, it picks up signals from a crank and camshaft sensor. So, does it need to be timed or does it just start the spark from when the signal hits, irregardless of its position? any help would be appreciated.

 

There is still a base timing situation that you have to concern yourself with. You will need to have valve cover removed.

Bring engine to TDC based on timing mark on harmonic balancer and timing cover.

Verify that engine is at TDC of #1 compression stroke by verifying that timing marks on back of the two camshafts are properly aligned.

If these marks are not properly aligned then rotate the engine crankshaft 360 degrees and recheck.

Turn distributor shaft to align mark on gear to mark on housing of distributor.

Carefully install distributor and install mounting bolt.

 

Bama,

If I can ask a dumb question please...

Its more theoretical, but since we are talking about the 3RZ-FE, interference engines, and timing...

I understand how timing and timing marks work in general. But in a case where you are assemblying an engine from the bare block, putting on the head and cams, how do you ensure that you set it up so that timing is correct? Do you rotate the crank to #1 TDC before installing the head?

Im just asking for my general knowledge, I am nowhere near attempting an engine rebuild, but would like to one day.

 

Yes, The basics is to put the block at TDC of #1, then set the camshaft(s) on the head to the proper marks and install. Then do the fine tuning of the chain.

 

you make it seem so easy. but i think that because you skipped over valve shimming. thats the only thing that scares me about tearing my engine open.

also if i bore it .040 over do any of the steps change or do i need to do anything extra?