Telling Crankshafts apart

[ozconnection]

I looked at Kamerai USA and they have a spreadsheet PDF file that lists all of the metal headgaskets they have and their prices. They sell HG's for standard bore L28's. 86mm versus your 84mm isn't a problem as I see it. I ran an L24 HG on a L20A block 'cause I couldn't get an L20A HG. 83mm's versus 78mm's for the L20A. Ran perfectly with no leaks or problems at all. :classic:

http://www.kameariusa.com

Cheers!

[Diseazd]

I just talked to Z Doc in Roanoke. He brought up a good point. The machine shop should have attached the front cover when decking.......otherwise the block and front cover will not match up to the block deck......learning is fun!!!!:stupid:

[Zedyone_kenobi]

I do not envy you my friend, but I can thank you for sharing your experiences. We can all benefit from the lessons learned.

[70 Cam Guy]

http://www.napaonline.com/Search/Detail.aspx?A=FPG21157SP_0147184177&An=599001+101971+50018+2018010+11024+599999+109999+59999+2999999

You'll need to click to shop online to see the part but the 'head saver' or cylinder head shim may be an economical solution to canning the block. It's an option though I don't have personal experience with these

[Diseazd]

Talked to Carl Beck and Jim Frederick at the Mitty.......The 73 pistons come out of the block by .030". It's not the block! The .020 clearance should be plenty for a street car......They are currently building one in Florida with 73 pistons also. I'll build it onward and post pics of the finished product. Oh...by the way....we had breakfast with John Morton, Pete Brock and Les in Atlanta. A world of engine knowledge at that event. Guy

[zpizzaman20]

Guy,

I talked to the PO and he never did any machine work to the engine, at all.

Fred

[Diseazd]

Thanks Fred....seems the 73 flycut pistons are a slight different size than the 70,71 or 72. From what I extracted from the knowledge bank at the Mitty was that there's enough clearance on a street driven Z (no rod stretch) to bolt her up and run. I seem to have about .020 clearance and it's only around the outter edge of the combustion chamber. Andy (70 Cam Guy) found a .020 soft copper shim at NAPA if needed. Thanks Guy

[Gumby240]

I had a similar problem so I took it back apart and had the machine shop mill the pistons down just a little for clearence. Just another option .

[Diseazd]

Gumby.....Did they mill your piston with the rod attached?

[70 Cam Guy]

Gumby.....Did they mill your piston with the rod attached?

If it is necessary, I don't see why a machine shop couldn't (on a mill) if they have a good setup. I would imagine the setup would be on a tall side but it could be done. This, of course, doesn't address if the piston itself, has enough material. 20 or 30 thou doesn't sound like much though

I could see it being tough on a lathe with the rod attached.

[Diseazd]

My machine shop said they just did an engine exactly like mine (73 pistons in L24 block). Evidently 73 pistons need to be milled .030 inch for 0 deck height. They can mill the pistons with rods attached. I'm going to have them mill .025 inch for a positive .005 inch deck height ( most experts I've talked to including Dave Rebello say .035 to .038 inch clearance is minimum), so you could actually have plus .015 inch and still be OK.( gasket is .050 inch when torqued). As far as material available to mill......the valve fly-cuts are a lot more than .030, so that shouldn't be a problem. Looks like I'll be zipping it up shortly.....I'll update when I get the pistons back from the shop.

[Diseazd]

<a href="http://www.flickr.com/photos/14049800@N00/4608028862/" title="IMG_8438 by RVAE34, on Flickr"><img src="http://farm5.static.flickr.com/4037/4608028862_30d55756d7_b.jpg" width="1024" height="684" alt="IMG_8438" /></a>

The pistons were cut .030".....Deck height is now "0".....cost....$80.00.