Slight mess-up with a 393 build...question for people who build a lot of motors

[MadMikeyL]

Well I have built a few motors before, but prior to this 393 I'm building, I had never done a stroker before. Anyway, I made the mistake of not assembling everything and checking for clearance issues before I sent the rotating assembly out to get balanced. I had put the crank in the block, and made sure that I didn't have anything hitting there, but tonight when I put the first piston in, I found that the skirt of the piston hit the counterweight. This happens on all but 2 of the pistons, so I had no choice but to grind away some material off the counterweight so that everything would clear. I did this for piston #s 1-4 tonight, and I will do the other 4 tomorrow night. What I am wondering is if the material that I am grinding away will be enough to throw the crank out of balance and cause other problems. Should I send everything out to get rebalanced once the counterweights are ground down, or will it be OK to just assemble everything and run it with the material removed from the crank?

Mike

 

[tylerrocks]

I dont have the experience you are looking for, but any imbalance in the crank multiplies exponentialy with RPM. If you took a fair amount of material off probly needs rebalance.

 

[low5.0]

call the place you had balance it and ask them. it all depends on how much you ground off but I would rebalance it.

 

[bluevenom867]

My question would be why two of the pistons didnt hit. Do you got six incorrect pistons?

Check the skirt to crown hieght and compression hiegth first,make sure they are all the same.If they are,then the crank counter wiegth where either cast/forgered improperly,or that was not the correct crank for the application.If it is minimal interferance,it could be do to line boring,witch would slightly shorten the crank to deck distance.

As far as balancing goes,yes it will need rebalanced especialy if you plan on above 5,500 rpm opertation.

 

[vristang]

I'm no expert, but..
You have the wrong mix of parts

There shouldn't need to be an grinding done on the counter weights

Yes, you have thrown off the balance job


jason

 

[LEE93COBRA]

I'm no expert, but..
You have the wrong mix of parts

There shouldn't need to be an grinding done on the counter weights

Yes, you have thrown off the balance job


jason

+1

 

[fast97gt]

um take the piston skirts and grind some of the material off the pistons and you can balance the pistons while your doing this too.

 

[88mouse]

yeah if you were going to grind any thing i would have done the pistons. Did you order a stroker kit?If so shouldn't have been no need to grind anything but maybe the block.Yeah your crank will be out of balance now.

 

[vristang]

um take the piston skirts and grind some of the material off the pistons and you can balance the pistons while your doing this too.

Your joking right?




Guys,
Something is wrong with the parts combination.
There shouldn't be any issues with crank to piston clearance.

You shouldn't have to grind the counterweights or the piston skirts...


jason