Building my first motor and I need help.

bigpoppa822

Registered User
Well my car has been down for almost 2 years now since snapping the crank and I finally have the funds to put the motor back together. I have pretty much all the components to build the motor but I'm nervous about getting the block machined right. The block going to the shop is from the reman. motor I had in my car and I want to make sure it's still usable after being machined once already.
The pistons I got from DD are .030 over, the pistons that were in the motor were .030 over. The reman. motor broke with only 15k on it so I don't think the cylinder walls saw much wear, but there wasn't cross-hatching present. Could this be a problem? I also already have rings for those pistons (once again supplied by DD.)

The pistons are made for a 9.225" deck height. Stock is 9.232". I also have MLS gaskets. I'm worried the machining for the gaskets would make the deck too short. Is this something I have to worry about with a higher than stock compression ratio?

I already have crank bearings and a 4.2 crank but the block has probably already been line honed when it was rebuilt. Will my bearings not fit if this is the case?

As long as none of this stuff is a problem the block is going out next week. Can you guys provide some insight on these potential problems? I am planning on doing assembly myself (with help from my dad who is an ASE master tech and gearhead but knows nothing about SCs)

Thanks for reading.
 
i have a unmachined engine block with the main caps you could have if there was a easy way to get it to you its gonna be scrapped next week
 
You should be ok with the deck height. I have always used 9.225" and it has always cleaned off fine for me. Generally the decks are slightly taller than factory spec. Factory spec is usually the minimum on a stock block.

As for the bore, it will have to be honed for a cross hatch finish, but the real determining factor for whether or not you can use it (assuming it's straight) is final size. The pistons were made for a 3.841" bore, any more than .001" bigger than that would be excessive IMO.

The block probably wasn't line honed - that's a rare operation. Look at the housings, if they machine marks like they were bored out then that is factory machining. If they show a cross hatch hone pattern, then it was honed aftermarket. Either way your bearings will fit though. Have the shop load up the bearings and check the final dimensions, then compare that to your crankshaft. This will tell you where you are at and let you know what needs to be done if anything. Are you using main studs? If so you'll probably have to have it line honed yourself.
 
He could have the pistons coated to add some extra material there on the skirts if the bores end up too big, right? Within reason anyway.

Usually you buy the pistons then they bore and hone the block to fit.
 
TwoTone thanks for the offer but if this block can't be done I have a lead on a local spare. I think shipping would kill me on that one.

Dave, looks like I need to get the bores checked before it goes in for machining. I did buy ARP main studs so I should just have it line honed anyway according to your post.
So I should also give the shop my crankshaft I take it? Can they measure deck height with just the crankshaft in the block and no rod/piston combo?
 
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