Page 1 of 2

Highly PO'd at machinist

Posted: June 16th, 2013, 5:08 pm
by TR1Hemi
On what freakin' planet do they give you your block and pistons back, and when you get home are mocking everything up and the pistons jiggle in the bore? I was able to stick a .20" feeler gauge between the piston and wall, which when you get to that thickness of gauge they dont conform to the curvature as well meaning it is likely MORE THAN THAT! Oh BTW, these are .060" over pistons. Options? Other than making the local NAPA source another block and start from scratch.

Re: Highly PO'd at machinist

Posted: June 16th, 2013, 5:30 pm
by shawnxj
new block or sleeve the cylinders

Re: Highly PO'd at machinist

Posted: June 16th, 2013, 5:33 pm
by TR1Hemi
What bigger pistons are there? I have not really come up with anything.

Re: Highly PO'd at machinist

Posted: June 16th, 2013, 5:58 pm
by SilverXJ
Feeler gauge is no way correct to check the clearance. Not only that but pistons have a barrel shape or cam grind to them. There is a surprising amount of piston rock even in a cst piston.

To correctly check clearance you need a micrometer to fit the piston size (3"-4") and a dial bore gauge.

Re: Highly PO'd at machinist

Posted: June 16th, 2013, 7:46 pm
by Retlaw01XJ
TR1Hemi wrote:I was able to stick a .20" feeler gauge between the piston and wall,
0.20"?? That's a THICK feeler gauge!!! :shock:
I'll assume you mean 0.020"...Are you measuring at the skirt or at the ring lands?

Re: Highly PO'd at machinist

Posted: June 16th, 2013, 9:01 pm
by TR1Hemi
Yes, I did mean .020". I went back out because I remembered putting the rings in the bore, and they were good, so I measured the bore it was good, I measured a piston and it was only 3.910 near the pin not 3.935, BINGO there is my +.020". So then I remember to measure the skirt in the little oval area where there is no coating, and it was 3.935. So then I was a little less freaked out. I feel a little better now. Lol. I guess there is a lot of wiggle room.
My mains are all .002" except for the middle one which is .003" I can live with that being it is the middle one. Assembly continues.

Re: Highly PO'd at machinist

Posted: June 16th, 2013, 9:27 pm
by SilverXJ
Yeah, its surprising how much a piston can rock in the bore and how much different there is over various points on the piston.

Re: Highly PO'd at machinist

Posted: June 17th, 2013, 4:55 pm
by TR1Hemi
This point isnt talked about much on here. I mean once I calmed down and looked at the hard numbers, I realized it was ALL in the pistons, not the bore. I guess most have their short block built by their machinist. This is my first, but I am 45, have read about builds in mags since the mid 80's, worked in the Ar Force on fighter jets for 24 years, now work on locomotives for UP. Always been mech inclined, done ALL my own auto work except A/C and auto trannies, and have successfully rebuilt a Dana 44 with new gears. But I was in no way shape or form prepared for that!

Thanks for the reassurance Silver, you have no idea what your input means on these forums!

Re: Highly PO'd at machinist

Posted: June 19th, 2013, 6:51 pm
by TR1Hemi
Dropped the block back off at the shop for .008" taken off the deck, .035" wasn't enough. With my 68cc chambers and 2800' altitude I want a zero deck. He is also going to take a look at the cam bearings, I could not install the cam that came with the block or the new Mopar 229. They look straight, but it binds up in the last inch. i am going to mic both cams if they are the same I am going to give him the old one, if the new one has bigger journals I will have to give him the new 229. Meanwhile, Go Blackhawks!

Re: Highly PO'd at machinist

Posted: June 20th, 2013, 6:31 am
by SilverXJ
The journals shouldn't be bigger. Cam may not be straight, possibly a high spot on a bearing.

Re: Highly PO'd at machinist

Posted: June 20th, 2013, 6:08 pm
by TR1Hemi
The old cam that cam with the block, AND my new 229 cam stop at the same point, so I think I can rule out cam issues.

Re: Highly PO'd at machinist

Posted: June 20th, 2013, 6:11 pm
by TR1Hemi
When I said they look straight, I meant the bearings don't look cocked, he said he would measure them, and he may hone the blocks cam tunnel and install new bearings.

Re: Highly PO'd at machinist

Posted: June 20th, 2013, 6:34 pm
by SilverXJ
I don't think he can hone the block as I have not found larger OD cam bearing for ours. Unless one of the housings are way too small. I have found smaller ID bearings though.

Re: Highly PO'd at machinist

Posted: June 20th, 2013, 6:44 pm
by IH 392
my bet is he installed the front bearing from the front and screwed it up!, if he would have driven it in from the rear with the long bar and guide cone it would be straight!

Re: Highly PO'd at machinist

Posted: June 20th, 2013, 6:57 pm
by SilverXJ
Good point. I've seen this happen first hand. Nothing to guide the install tool on the front bearing if installed from the front.