Did a 5 speed to my GS and has a PROBLEM! Won't Crank! need some Ideas/Suggestions.
03-29-11, 09:28 PM
#16
I just built six 2JZ engines in the past two months, this info is still fresh in my head lol.
A quick checklist for building an engine:
Did you have the head and block machined?
If yes answer these:
Did they bore or hone the block? If so, how much extra wall clearance was added? Did you make sure piston to cylinder wall gap is still within tolerance?
Did you check if the head and block are true and completely flat? Maximum block warpage spec is .07mm. Max head warpage spec is .1mm. If it exceeded that, then you need the head or block milled to get it back in spec.
Did they deck the block and head? If so, how much material was cut off them? You need to know this because it will raise the compression ratio.
Did you have the crankshaft journals cut undersized or micropolished? If so, how much material was taken off? If it was undersized, make sure you have the oversized bearings to fill in the gap to get it back into clearance spec.
If they messed with the crank did they rebalance it? To how many grams tolerance was the balance?
Did you put in new piston rings and rod/main bearings?
If yes answer these:
If you put in new rod bearings. What are the clearance measurements? This should be done by using a bore gauge to check the connecting rod's inner diameter of the big end, then using a micrometer to check the crank journal. Also measure the thickness of the bearing. Subtract the crank number from the rod number and then subtract the bearing thickness. You should get a number of .023-.041mm range to be within acceptable tolerance. Max rod bearing clearance is .07mm.
Do the same for the main bearings, but take the inner diameter of the main caps then subtract crank journal diameter and then subtract bearing thickness. You should get a range of .026-.040mm. Max main bearing clearance is .06mm. Also, make sure to measure the thrust washers to see if they're in spec. If they're not, throw a new set in there.
Did you put in new piston rings? Did you check the end gap and piston groove clearance? They groove clearance for the top piston ring needs to be .011-.07mm for top ring. And .030-.070mm for the second ring.
Piston end gap should be set to .30-.47mm for top ring, .350-.520 for second ring, and .130-.450 for oil ring set.
Also, don't forget to stagger the piston rings so the end gaps do not all face the same side, this will cause excessive blowby.
Did you tighten down all the bolts in the correct order? Also, if you upgraded to ARP studs, did you torque to their specified values? They typically specify a 3 stage/3 pass torque sequence on their hardware.
Next thing is the head and valvetrain. If you had any machine work done to the head, answer the following:
Did you have a valve job done on the head? If yes then did you go back and re-tolerance all the lifter shim clearances?
The intake side shim clearance should be within .15mm-.25mm. If you are out of this range, you will have excessive valvetrain noise or the engine won't run properly.
The exhaust side clearance should be within .25mm-.35mm. The intake/exhaust shim clearance is VERY important if you want to build a quiet engine. Sometimes I take a good 2 hours or so just doing the shim tolerances so I can have a whisper quiet engine.
Remember, all the measurements here are spec'd with the parts cold or at "room temp" of around 70-80F.
There are several other things to check such as runout and such with a dial gauge, but those typically don't go out on a 2JZ very often so I didn't mention them here.
A quick checklist for building an engine:
Did you have the head and block machined?
If yes answer these:
Did they bore or hone the block? If so, how much extra wall clearance was added? Did you make sure piston to cylinder wall gap is still within tolerance?
Did you check if the head and block are true and completely flat? Maximum block warpage spec is .07mm. Max head warpage spec is .1mm. If it exceeded that, then you need the head or block milled to get it back in spec.
Did they deck the block and head? If so, how much material was cut off them? You need to know this because it will raise the compression ratio.
Did you have the crankshaft journals cut undersized or micropolished? If so, how much material was taken off? If it was undersized, make sure you have the oversized bearings to fill in the gap to get it back into clearance spec.
If they messed with the crank did they rebalance it? To how many grams tolerance was the balance?
Did you put in new piston rings and rod/main bearings?
If yes answer these:
If you put in new rod bearings. What are the clearance measurements? This should be done by using a bore gauge to check the connecting rod's inner diameter of the big end, then using a micrometer to check the crank journal. Also measure the thickness of the bearing. Subtract the crank number from the rod number and then subtract the bearing thickness. You should get a number of .023-.041mm range to be within acceptable tolerance. Max rod bearing clearance is .07mm.
Do the same for the main bearings, but take the inner diameter of the main caps then subtract crank journal diameter and then subtract bearing thickness. You should get a range of .026-.040mm. Max main bearing clearance is .06mm. Also, make sure to measure the thrust washers to see if they're in spec. If they're not, throw a new set in there.
Did you put in new piston rings? Did you check the end gap and piston groove clearance? They groove clearance for the top piston ring needs to be .011-.07mm for top ring. And .030-.070mm for the second ring.
Piston end gap should be set to .30-.47mm for top ring, .350-.520 for second ring, and .130-.450 for oil ring set.
Also, don't forget to stagger the piston rings so the end gaps do not all face the same side, this will cause excessive blowby.
Did you tighten down all the bolts in the correct order? Also, if you upgraded to ARP studs, did you torque to their specified values? They typically specify a 3 stage/3 pass torque sequence on their hardware.
Next thing is the head and valvetrain. If you had any machine work done to the head, answer the following:
Did you have a valve job done on the head? If yes then did you go back and re-tolerance all the lifter shim clearances?
The intake side shim clearance should be within .15mm-.25mm. If you are out of this range, you will have excessive valvetrain noise or the engine won't run properly.
The exhaust side clearance should be within .25mm-.35mm. The intake/exhaust shim clearance is VERY important if you want to build a quiet engine. Sometimes I take a good 2 hours or so just doing the shim tolerances so I can have a whisper quiet engine.
Remember, all the measurements here are spec'd with the parts cold or at "room temp" of around 70-80F.
There are several other things to check such as runout and such with a dial gauge, but those typically don't go out on a 2JZ very often so I didn't mention them here.
Last edited by JeffTsai; 03-29-11 at 09:37 PM.
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