Rebuild and Swap 391,000 Mile D16A1 in Pictures

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Rebuild and Swap 391,000 Mile D16A1 in Pictures

Postby trent » February 5th, 2015, 4:55 am

Five Main Bearing Halves Seated in Cylinder Block
The machine shop cleaned off stains on the main bore surfaces under the bearings to make sure the bearings would stay round in shape. There was not enough taken off the bores to affect bearing clearance.

The slots where the two thrust bearings go are visible on the sides of the second crankshaft bore. I put in new ones from Acura.

Everything was washed thoroughly with brushes and soapy water after the machine shop bored out the cylinders 0.25 mm. I bought some different size brushes from a webstore, one which just fits the cylinders. I think searching for "cylinder bore brush" will find them. One brush I used from Home Depot was sold as a dryer vent lint cleaner.

The reused cylinder head bolts squeaked a little when torquing them down. Maybe some kind of thread cleaning chase would have made them go in smoother. I couldn't find anything for that purpose. It's not the same tool as in a die and tap kit.

The machine shop also checked the crankshaft and bore dimensions and told me to just use standard size bearings. There was some uneven cylinder wear. The shop said I could go with either standard pistons or 0.25 mm oversize. There was no ridge for a ridge reamer to remove at the top of the cylinders.

Acura has also discontinued the oil pump. My oil pump looked fine on the inside, and clearances were within the specified ranges. I replaced the oil pressure regulator spring and piston, but I'll bet the old ones were fine. Many people who also routinely replace perfectly good water pumps will be horrified that I didn't buy a new oil pump.

If you carefully maintain your coolant, the Honda water pump will last a very long time. There is a cylinder block drain plug for coolant on the side facing front that will drain much more than what the radiator petcock will. Replace the sealing washer with a new one, and be careful not to overtorque the plug in the aluminum block.

Also do all your own motor oil changes to make sure the oil pan plug sealing washer is properly replaced each time; otherwise, someone will strip the plug threads trying to fix a leaky drain plug.

The crankshaft got only a little polishing, and standard size bearing were fine. My crankshaft had over 400 thousand miles with 7500 mile oil changes.

Main Bearing Clearance

Molybdenum Disulphide Paste
Honda Moly 60 Paste dissolved well in motor oil so I used it as assembly lube.

You'll need to buy some correctly sized bolts to mount the block to an engine stand. They go into the transmission mounting bolt holes. One of the four holes I used is a different size than the others.

Main Bearing Caps
The loose oil galley plug in the top of the picture was torqued down after mounting the cap to the block on an engine stand.

Four New Honda P29 Pistons (0.25 mm oversize)
The machine shop told me that factory oversize pistons have altered domes to maintain the same compression ratio.

Also shown are a ring expander, a good ring compressor and packaged rod bearings and piston rings. Clevite bearings have the same style date code stamped onto them as the original Honda bearings and are made in Japan. Go with these.

The different colors of Honda bearings vary in steps of 0.003 mm. That is the same as 0.118 thousandths of an inch. There are size codes stamped on the block and crankshaft and connecting rods. A chart tells what color Honda bearings to use. Honda main bearings are discontinued. Have the machine shop take measurements and tell you if the standard size Clevite bearings are good to use.

The piston pins were not exactly centered after the machine shop put them in with a machine that pops them in quickly. None of the pins extended far enough to touch the cylinder walls. There are some tools shown in the factory service manual for installing pins that may get them centered more precisely. The off center pins leave me with a bit of uncertainty that I would have rather avoided. I reused the old piston pins, because the service manual implies that old ones can be reused if they measure within specifications. The machine shop said the pins as they installed them would be fine.

The two pieces of rubber hose go over the connecting rod bolts to keep them from scratching the crankshaft when installing the pistons.

Another type of piston ring compressor that looks like a band clamp tends to leave a scratch on pistons where the edge of the band is.

My Honda rings came gapped within the specification for the oversize bore that the machine shop made. There is an up and down direction for the top two rings. The small dot goes up. The top ring and the second ring have different cross section outlines. There is a notch along the edge of the second ring. The end gaps should be positioned at specific angles around the circumference. The factory service manual (pp. 7-15,16) has all the details clearly written. I used plenty of motor oil over the pistons, rings and wrist pins as well as the cylinder walls before inserting the pistons into the bores using the ratcheting piston ring compressor in the picture.

Rod Bearing Clearance
I reused the old connecting rods, caps, bolts and nuts.

Felpro Head Gasket
I threw this Felpro gasket out after a valve stuck open after five miles. It is bowed out a little between the pegs, but worked fine as far as I could tell in five miles. The shop gave me another one with a reddish-orange outline around some of the corner holes where oil leaks tend to develop above the "D16A1" stamp on the block. Maybe the shop gave me a slightly thicker one because my compression numbers were a little high after milling the head. Compression was, of course, zero in the cylinder with a stuck exhaust valve. Somehow the valve left no marks on the piston.

There is an oil metering jet between the block and the head that is sealed with an o-ring. Its hole is in the center of the block on the top in the picture. The jet and o-ring can be removed by tapping the jet from behind through a passageway to the underside of the block. The jet is discontinued and must be reused. The o-ring can be replaced with a new one.

Tell your machine shop not to bother installing camshafts and setting valve lash because you will need to remove the camshafts to bolt the head to the block. The proper procedure for removing and installing the camshafts starts with backing off the rockers all the way to minimize the risk of bending a valve when bolting down the caps which should be done gradually in a criss-crossing pattern so the camshaft stays level and the rockers don't bind.

The camshaft has no bearings. If the camshaft bore sizes are out of spec, the head must be replaced. I was able to reuse my old 400,000+ mile cylinder head. The machine shop ground the valves and valve seats and put in new exhaust valve guides. Some valves were replaced and most reused. The 400,000+ mile motor's only problem was excessive oil consumption that caused an emissions test failure for visible smoke. After rebuilding I could tell power had been low, but it was hard to realize that before because it happened so gradually over time.

I also reused the old camshafts and valve rockers. I had done valve adjustments myself every 15,000 miles above 100,000 miles. I don't know how to check the lift and duration on camshafts to see if they're in spec. The rebuilt motor gets good mileage between 27 and 30 mpg for the around town driving I've been doing lately. The highest so far was 34 mpg. It will zip up to the redline smartly and smoothly. I don't have the inclination for a dynomometer test. Would it give a number to compare to the 118 hp factory spec?

The intake and exhaust valve seals in the Felpro kit are the same. Honda has different ones because the intake and exhaust valve stems are slightly different diameters. I recall reading that less oil consumption will occur with differently sized intake and exhaust seals.

Removing the camshaft caps takes some wiggling and light tapping being careful not to deform the caps or damage the mating surfaces. I wiggle a pin-punch tool in the bolt holes and tap the sides of the cap taking it along slowly while pulling up on the cap and being ready to hold on to the cap if it should pop off suddenly. I use the same pin-punch in the camshaft holes near the cam wheels to hold the camshaft in place for installing a timing belt.

Long Block
The machine shop used a red colored assembly lube on the camshafts.

I used crank oil seals from Acura because I had a leak with an aftermarket drive axle seal once.

Stock D16A1 Motor Swap
The new motor is hanging from a lift, the old motor is sitting on a tire and the Integra has an empty space for the new motor. I used the load leveler to angle the transmission downward while initially lowering the assembled motor and transmission. I adjusted the leveler as needed and rolled the engine stand in from the side. The hood is removed and sitting upside down on a surplus army blanket on the roof. Since the garage floor is level and the car is on four evenly adjusted jackstands, the hood will not slide off the roof.

The procedure for removing the motor and transmission given in the factory service manual worked well for me. I had fitted a bolt into the lifting point on the power steering bracket prior to starting the project. I ended up paying the weekly rental rate for a hoist because I had it for three days. It still cost less than buying a hoist and load leveler.

I borrowed the old worn out tire. It is size 215/45R17 for a 17 inch wheel, and the hole is too big. Two inches smaller would have been better.

The rubber gaskets around the timing belt covers are discontinued so the old ones need to be reused. I think one of those covers is vibrating at around 3400 rpm.

Correction: I found some emissions inspection records and discovered that the actual odometer mileage was 391,000 plus or minus 250 miles when I stopped using the original factory build on this motor.

Update: I continue to astonish people on a daily basis with my rebuild. A Cusco strut tower brace, Tokico HP struts and shocks, and standard size BF Goodrich Super Sport tires are the only performance upgrades.
Last edited by trent on October 30th, 2015, 2:29 am, edited 14 times in total.

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Re: Rebuild and Swap 400,000+ Mile D16A1 in Pictures

Postby MinkelR » February 5th, 2015, 7:23 am

Nice write up! Fel-Pro's tend to fail a lot on these engines so better sooner than later that you changed that out.
My cylinders were pretty egg shaped after my rebuild at 210k miles. I can't imagine what 400k miles looked like.
1987 Acura Integra LS (Rest in Pieces)
1989 Acura Integra LS Daily Driver
1992 Mazda 323 (Sold)

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Re: Rebuild and Swap 400,000+ Mile D16A1 in Pictures

Postby evtsteward » February 6th, 2015, 2:10 am

When did your teg turn white bro? it's always been black. Anyway, very nice write up and call me when you have a moment. Nothing special. Just like to hear from my co admin once in a while.
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