my1994z28

I just got my forged 383 short block back from the shop yesterday,its a true lt1 4 bolt main block...Here is the problem,the block sat out in the cold garage last nite,I went out and started to assemble the oil pump,pan etc...turn the motor over to install the lifters that were in my previous short block,and they are a tight fit in the lifter bores..was there a difference in lifter bores between the lt1 2 bolt main and 4 bolt main blocks??Or could it be that the cold has something to do with it??Any help is appreciated..

ZZ

Were the lifters warm? Let it all stabilize to the same temp and try again. Also check to make sure there's no flash rust in the lifter bores. They are the same size unless they were honed or resleeved wrong somewhere along the line,

my1994z28

The lifters were also cold,they were soaking in oil...4 out of the 16 lifters fit as they should...I never ran into this problem before..Needless to say it has put a stop to me finishing up the assembly...Maybe I should bring the lifters in the house for the nite and let them warm up?

ZZ

Did you try one that didn't fit on a bore where one did fit? You can see if it's a lifter or lifter bore problem that way.

Injuneer

Letting the lifters warm up, while the block stays cold will make the problem worse.... the lifters will expand as they warm up.

Rob94hawk

Uh, last time I checked the periodic table of elements iron expands when its hot so if the lifters are REALLY tight when the block is cold what do you think is going to happen when the block reaches operating temp?

Just sayin....

my1994z28

I talked to my builder today and told him the problem I am having,he said usually after having a block shot peened that it can create a vey slight lip on the lifter bore..He also told me to roll the motor over by hand and they would loosen up..Well just came in from the garage and they now are moving freely......Problem Solved..

Kevin Blown 95 TA

The block expands, too as do the lifter bores. Just like if you heated up a harmonic balancer hub to get it on a tight crankshaft shout.