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-   -   Little tapping when start up (http://www.toyota-supra.info/forums/mkiii-supra/17964-little-tapping-when-start-up.html)

Sonyps307 10-15-2010 02:47 AM

Little tapping when start up
 
So when I first start up my non turbo I hear a little tapping going on but it stops about 5 mins of running and will not start tapping again intill the car has sat for a while could this be a header or exhaust leak or maybe a bad lifter Or does a bad lifter always tap as the car is running

Bru 10-17-2010 09:17 PM

You could take the heat shields off and look for black carbon tracks around the exhaust manifold. FelPro makes a nice thick beefy exhaust gasket. The exhaust nuts are notorious for rusting to the stud and then you end up stripping the stud in the head instead of tightening the nut. If you want to, apply a small amount of penetrating fluid to the nuts and let it soak awhile. Try loosening a quarter of a turn and see if they move together or separately. If they are frozen together try backing out the stud and nut together then soak in penetrating oil. Break them loose by grabbing the middle of the stud where there are no threads with a pair of vice grips. You may have to alternate using a torch and a cleaning with a wire brush then adding more penetrating oil it comes loose. When they separate clean the stud threads with a wire brush. Keep track of which end was in the head. Use a jam nut to reinstall the stud. This is easier done with the exhaust manifold off. Then you can tighten 2 exhaust manifold nuts facing each other temporarily to drive the stud in. Again, its aluminum so don't overtighten. Worst-case scenario is you have a rotten stud hole or threads are pulled. A repair consists of drilling out the hole and tapping new threads and using a "Heli coil" repair. Apply small amount of anti-sieze compound and torque than nuts gradually using the pattern in the repair manual and torque to spec.

Is your oil old or thined out? Use the proper viscosity for the temperature range are going to be in encountering. I also replace a quart of my oil with Lucas oil additive which is quite thick and a lot like STP but not that thick. The oil pressure with 20% lucas oil is a little bit higher than otherwise. Another thing that can make a ticking sound is a loose spark plug. Make sure they are torqued down to 13 - 16 ft. lbs. Another thing you can check is the valve lash. Since Supras do not have hydraulic valves, they are adjusted using a wafer shim that rides under the camshaft for each valve. It's best to have a manual to follow the procedure to get the measurement correct. Valve lash clearance measurement is accomplished using flat feeler gauges on a cold engine. Excessive clearance here can cause a ticking sound. If you're going to replace a shim, it's helpful to have the S shaped specialty tool to hold the valve opened when removing the wafer shim and a mechanic's magnet. You don't want to scratch the camshaft face with screwdriver or get your finger pinched. You also need either micrometer or vernier caliper (and know how to use one) to get a measurement of the thickness of the wafer in the cases where there is excessive clearance and want to calculate the replacement shim to order. If your cheap, like me, you can play musical chairs with the shims. Find one that's tight on the spec. and see if you can swap the loose one to bring them both in spec (or at least closer than they were). The thickness of the shim and the valve lash is the total distance. I have even sanded the backside of shims with worn emery paper on a flat surface to shave off one or two thousandths. Just be sure the sanded side stays down and not riding against the camshaft. Hopefully it's not a connecting rod bearing or wrist pin. Thicker oil could buy you a little time. Carbon buildup can cause preignition taping but that's more likely on a hot engine. I use redline SI-1 gas additive (Amazon.com). Try one bottle full in a tank of gas for a quick cleanup and then to 2.5 oz. per tank there after. It comes in a 15 ounce bottle.

Good luck

Green7mgte 10-17-2010 10:45 PM

+1 for the post..

good stuf there bru

Sonyps307 10-17-2010 11:39 PM

All the valves and lashes should be to specs the motor was just rebuild With all new pistons, rods, bearing and the head was redone to. Like a month or so ago just has alittle over 1000 miles on it and just had it first oil change about 2weeks ago and the tapping started around 300-400 miles after the build But I just found out they Torque they head bolts to 58lbs Could this cause any thing and I will check the spark plugs and header bolts tomarrow

Sonyps307 10-17-2010 11:43 PM

And It just started to burn alittle oil but I think thats ok for a new motor with new rings right

907mge 10-18-2010 12:13 AM

It can also lose a little bit into the pcv. When I had my intake apart, all parts where coated with oil on the inside.

Sonyps307 10-18-2010 12:16 AM

Would oil in the Pcv be bad or ok

Bru 10-18-2010 03:24 PM

The preferred head torque specification is above the 58 ft/lb book value at 70 ft/lb. You'll need a torque wrench and a Allen socket attachment. Follow the torque pattern in the book. A compression check couldn't hurt. I would expect to see some oil in the intake after an overhaul but if it's excessive it could contaminate the airflow sensor on a turbo car. Never clean one with solvent otherwise you could ruin it, and they are expensive.

Sonyps307 10-18-2010 05:50 PM

It's a non turbo and I will do the head bolts and compression check

Bru 10-18-2010 11:31 PM

Another condition that can cause a ticking sound is "piston slap". That is when the skirt of the piston slaps against the cylinder bore when tolerances are exceeding specification. Either a worn piston or a too large a bore for the piston. Piston slap is usually worse on a cold engine then gets quieter on warmup especially with aluminum pistons which have a greater coefficient of expansion than the iron block. That's why we have head gasket problems on the Supra. The aluminum head scrubs the top of the head gasket more than the bottom on each heat/cool cycle. A stacked metal head gasket solves this problem or increased clamping force on a standard head gasket.

Try this test for Piston slap: When the engine is cold and ticking the loudest, wear a pair of rubber gloves and pull the spark plug wires one by one and replace them in the distributor. If the ticking sound changes you have piston slap (excessive tolerances). Also have a ground wire handy to put in the distributor terminal as you are pulling the spark plug wire out to ground the spark. It may run rough but listen to the sounds. Piston slap means your engine rebuilder wasn't following proper procedures.


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