7 Bolt Endplay

[DSM Chase]

I have my motor out of my car and i figured hey why not check for endplay, so i took my oil pan off and using a dial guage i checked my play. Im getting 6 thousandths of endplay. Ive read spec is 3-6 thousandths? But basically i was having an ignition breakup issue and i think its because the crank is moving back and forth inside of the crank sensor due to endplay. Is it time to replace the main bearings? Also will the pistons come out of the bottom so i can put 1G rods in without taking the head off?

 

[Sebba]

I see no point in leaving the head on. You can remove everything from the bottom of the engine, but while you have it out, I see no reason not to do a MLS and ARP just for a little cheap security.

Yes, I would go ahead and change all the bearings.

 

[donniekak]

.006 of end play isn't going to cause ignition issues.

 

[DSM Chase]

So do you guys think i should go ahead and change the bearings? Or should i just put it back in the car with .006 of endplay?

 

[JayB12]

Service manual states standard value as .0020-.0071" with a service limit of .0098"

 

[bryanwheat]

I see no point in leaving the head on. You can remove everything from the bottom of the engine, but while you have it out, I see no reason not to do a MLS and ARP just for a little cheap security.

Yes, I would go ahead and change all the bearings.

The pistons WILL NOT come out thru the bottom of the engine.

I have my motor out of my car and i figured hey why not check for endplay, so i took my oil pan off and using a dial guage i checked my play. Im getting 6 thousandths of endplay. Ive read spec is 3-6 thousandths? But basically i was having an ignition breakup issue and i think its because the crank is moving back and forth inside of the crank sensor due to endplay. Is it time to replace the main bearings? Also will the pistons come out of the bottom so i can put 1G rods in without taking the head off?

.006 isn't enough to cause the crank trigger to hit the sensor. That is pretty well in spec. I wouldn't touch the bearings.

 

[Sebba]

The pistons WILL NOT come out thru the bottom of the engine.



.006 isn't enough to cause the crank trigger to hit the sensor. That is pretty well in spec. I wouldn't touch the bearings.

What's stopping you from pulling it all out the bottom?

 

[bryanwheat]

What's stopping you from pulling it all out the bottom?

The casting around the main bores.

 

[DSM Chase]

ok im probably just going to leave it all together, im in spec so be it.

 

[JusMX141]

My '97 GSX engine had the exact same amount when I had the pan removed- .006" as measured with a feeler gauge directly on the thrust bearing. I, too, elected not to change the bearings.

 

[DSM Chase]

Justin how Long did that motor last after you saw that it had .006 of end play?

 

[JusMX141]

No idea- it's still on the stand awaiting installation.

 

[JacksonAuto]

.006" is not out of line. Especially for an engine that has been run. Standard values are a guideline to use during initial assembly. Service limits are a guideline to use after the component has been in operation. Frankly, all the talk on the forums about "crankwalk" has everyone paranoid and looking for a propblem, that 9 times out of 10, doesn't exist.

As Bryan said, the pistons wont come out the bottom. Even if the did, there is no way to get them back in because of the rings. They must be installed from the top using a spring compressor of some sort. There's no half-ass way to do the job.

Don't follow the advice listed above about using an MLS head gasket. You'd first need to have the block and head milled to a surface finish of less than RA50 for it to seal. If you install an MLS onto an engine that hasn't been properly machined you will join the ranks of all the other people that have done it wrong, have a failure and then blame it on the gasket.

As for replacing the main bearings, only do so if there is a problem. And then be prepared to remove the crank and have it cleaned, inspected and polished to eliminate the problem from reoccurring. What I mean is a bad bearing is not the cause, it's the result so if you just put new ones in the problem will come right back.

 

[DSM Chase]

Thanks guys yep no were in my thread did I use that C word that all 7bolt guys are paranoid about. No worries about that mls junk I have an HKS 3mm head gasket with arp head studs. Thanks for the piston info anyways!