1FZ-FE cylinder bore tolerance for taper and out of round? Toyota spec and practical experience? (2 Viewers)

[dylancw]

Hi All,

I have a 266k mile 1994 Land Cruiser and I'm trying to decide how badly my engine needs the cylinders bored out. I pulled the head because I had a head gasket leak at #6 cylinder. The head has been rebuilt with new valve seals.

The block looks like it was honed at some point by the previous owner, I can see cross hatching on all 6 cylinders all the way down the bore, almost zero vertical lines. I have a dial bore gauge and I'm getting between .0005" and .0012" difference between the axial and thrust directions at the 10mm below top of cylinder mark. Is Toyota spec .0004" or another number? Any practical experience on whether I can get away with this for a while longer or whether I'm going to have a smoker on my hands? I know it consumed a little bit of oil prior to the head gasket blowing, but I was thinking that may have been from valve seals mostly.

Thanks!

Dylan

 

[scottryana]

This is going to be pretty hard to give a reasonable answer for. The cross hatching is probably OEM, many engines over 200k have stock cross hatching intact. Your measurements might be different if you were measuring with a torque plate. I bet you could add new rings and run it.

 

[flintknapper]

In almost every case we find that the OEM cross-hatching is still present (mine was, even at 316K miles). So that alone tells you there shouldn't be much wear. IF you have a noticeable 'ridge' at the top of the cylinder bore....then yes measure the bores....otherwise run it.

You didn't tell us what kind of dial bore gauge you have and how you zero'd it out. Very important to get it right. IF you are skilled at using a Dial Bore Gauge (getting it zero'd, rocking it and reading) then please disregard the above, but many folks don't measure/read accurately.

 

[dylancw]

That seems crazy to me that 200k plus mile blocks still have cross hatching. Did Toyota use softer rings than typical? I’m used to vintage American cars with lots of cylinder wear by 30k miles.

In almost every case we find that the OEM cross-hatching is still present (mine was, even at 316K miles). So that alone tells you there shouldn't be much wear. IF you have a noticeable 'ridge' at the top of the cylinder bore....then yes measure the bores....otherwise run it.

You didn't tell us what kind of dial bore gauge you have and how you zero'd it out. Very important to get it right. IF you are skilled at using a Dial Bore Gauge (getting it zero'd, rocking it and reading) then please disregard the above, but many folks don't measure/read accurately.

View attachment 2619061

 

[dylancw]

In almost every case we find that the OEM cross-hatching is still present (mine was, even at 316K miles). So that alone tells you there shouldn't be much wear. IF you have a noticeable 'ridge' at the top of the cylinder bore....then yes measure the bores....otherwise run it.

You didn't tell us what kind of dial bore gauge you have and how you zero'd it out. Very important to get it right. IF you are skilled at using a Dial Bore Gauge (getting it zero'd, rocking it and reading) then please disregard the above, but many folks don't measure/read accurately.

View attachment 2619061

Yes I have a Mitutoyo. Unfortunately I don’t have a setting ring or micrometer big enough to calibrate it with, so I could only use it for out of round and taper.

 

[flintknapper]

Yes I have a Mitutoyo. Unfortunately I don’t have a setting ring or micrometer big enough to calibrate it with, so I could only use it for out of round and taper.

Right.

Without zeroing the gauge and knowing the standard and service limit diameters....you can't assess wear. But as previously stated...IF your cylinder bores still show hatch marks it is minimal.

 

[Irish Reiver]

This is going to be pretty hard to give a reasonable answer for. The cross hatching is probably OEM, many engines over 200k have stock cross hatching intact. Your measurements might be different if you were measuring with a torque plate. I bet you could add new rings and run it.

Would the fact that the cross hatching is still visible across the full surface of the bore be an indication at the bore is not out of round or am i jumping to conclusions?

 

[dylancw]

My concern was that I’ve only owned it for the past 30k miles, and I don’t have a lot of service documentation, so I was concerned that someone in the past tried honing and replacing the rings rather than boring out and getting new pistons. I guess knowing the absolute diameter numbers would give me that answer. I can try getting a micrometer to calibrate against. Good setting rings are expensive! Mitutoyo 100mm ring was like $479 used.

 

[flintknapper]

That seems crazy to me that 200k plus mile blocks still have cross hatching. Did Toyota use softer rings than typical? I’m used to vintage American cars with lots of cylinder wear by 30k miles.

No. It's the result of quite a few things, in no particular order.

• With an inline Six, each cylinder that’s undergoing a combustion stroke is balanced out by another cylinder that’s undergoing an induction stroke. These ‘paired’ cylinders are located symmetrically around the center point of the crankshaft. A very efficient arrangement.
• The 1FZ-FE has a relatively long stroke (though under-square to the bore), the pistons have 3 sets of rings and a generous piston skirt...providing good support. These engines are not unlike some diesel counterparts you might see.
• The 1FZ-FE has a very good oiling system, both in routing and the use of oil nozzles.
• The 1FZ-FE typically does not see a lot of high rpm use, though they are perfectly happy to run at 4,000 rpm all day if you wish.
• The torque curve with this engine is flat in a very usable rpm range. Basically coming in strong at about 1800 rpm and maintaining it well through 3,000 rpm where it will see most of its use (on highway).

 

[flintknapper]

My concern was that I’ve only owned it for the past 30k miles, and I don’t have a lot of service documentation, so I was concerned that someone in the past tried honing and replacing the rings rather than boring out and getting new pistons. I guess knowing the absolute diameter numbers would give me that answer. I can try getting a micrometer to calibrate against. Good setting rings are expensive! Mitutoyo 100mm ring was like $479 used.

Don't buy a setting ring. You can zero your dial with a micrometer or even calipers that open wide enough. After selecting the correct anvil for your dial, set your micrometer/caliper to the nominal standard bore diameter. Place the caliper in a vise to hold it still (pad it, and lightly clamp).

Then just like you were measuring a bore rock the gauge back and forth and watch the dial needle for the position where it no longer changes directions (that is your zero point). It takes a little patience and finesse but it is accurate. Move the dial to zero at that point OR just slide one of the markers to that point. Then you're ready to go.

From my '97 FSM if it helps.

 

[ppc]

That seems crazy to me that 200k plus mile blocks still have cross hatching. Did Toyota use softer rings than typical? I’m used to vintage American cars with lots of cylinder wear by 30k miles.

As @flintknapper stated upon it's all about the design criteria and the Land Cruiser is totally different from most vehicles sold in the world. There have been a few historical posts in this forum related to the engine block being designed to allow two rebuilds after 300,000 KM resulting in a 900,000 total life. Most vehicles and motors are designed/built with a finite obsolescence very shorter than the LC. If GM/Ford/Chrysler built all of their motors to last as long nobody would be buying new cars and those companies would go out of business.

 

[dylancw]

Here's a short update. I ordered a setting ring 100.0 mm (measures 100.010mm according to my optical CMM). With the dial bore gage zeroed on that, the maximum measurement I got was on cylinder 2, 100.03 mm in the transverse axis (perpendicular to the crank) and 100.01 mm in the longitudinal axis (in line with the crank). Measured toward the top of the bore. Measurements in the other positions were more like 100.01 mm.

The top of the block needs to be decked slightly, as there is pitting from around the cylinder head gasket. The main and rod bearings look good. And the cylinder honing still looks great.

 

[SNLC]

Here's a short update. I ordered a setting ring 100.0 mm (measures 100.010mm according to my optical CMM). With the dial bore gage zeroed on that, the maximum measurement I got was on cylinder 2, 100.03 mm in the transverse axis (perpendicular to the crank) and 100.01 mm in the longitudinal axis (in line with the crank). Measured toward the top of the bore. Measurements in the other positions were more like 100.01 mm.

The top of the block needs to be decked slightly, as there is pitting from around the cylinder head gasket. The main and rod bearings look good. And the cylinder honing still looks great.

Yup, no need to bore that.

I would do BEB and call it a day.

Cheers