When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So I'm in the process of building a 2004 L59 (flex fuel) Vortec. putting together the motor (machine shop did block/head work and bought me all the internals). Despite my telling the machine shop owner that the L59 originally came with dished pistons, he bought me flat top pistons (to match the .020" oversized bores he did. At any rate, I also got a slightly beefier cam (Elgin E-1839P). Not aggressive by any measurement. Stock connecting rods, stock crankshaft. Doublechecked the cam degreeing and it is within 1 degree of the stated centerline. Bolted on a head with check springs and when I got to 10 degrees BTDC had only .053" clearance. By the time it got to TDC I was in negative clearance land (valve smacking the piston). Also watched the dial indicator and noticed instead of the .575" advertised lift, only reached .405". Anyone else out there ever had this occur to them and what did you do about it? The machine shop says they don't have the capability of fly-cutting the tops of the pistons. Would purchasing pistons with a shorter compression height or already relieved tops help? Going back to the dished pistons I don't think would work because the dish is only .068 deep and wouldn't give me the minimum .080... I'm stumped... any help appreciated. Thanks.
How thick was the headgasket that you mocked it up with? I flycut a lot of mild builds when I’m not using a full-on custom piston, here in house. I use Lindy cutters. It’s a very easy process that anyone can do. Here’s a link to their site. Call them with questions…very smart folks. https://www.lindytools.com/ihpc
Camshaft Specs: 220/224, .575"/.575" 112LSA.....
Did you check the deck hgt?
"By the time it got to TDC I was in negative clearance land (valve smacking the piston). Also watched the dial indicator and noticed instead of the .575" advertised lift, only reached .405"
I'd suggest sorting this out b4 you start cutting/changing things.
Sumting wong.
Put the push rods in for one cyl and leave the rockers off. Rotate the engine through 2 full revolutions. As that piston passes through TDC, on one of the 2 revolutions, you should see the exh PR retract to its "rest" position, and the int one just start to move upwards. The other instance of TDC of course is firing, and no PRs should be moving anywhere near that time.
The exh valve should start to open as the piston passes through BDC, then reach full open as the piston reaches about halfway up the bore, then close as described above as the piston reaches TDC. Likewise, the int should begin opening just as the piston passes through TDC, reach full open as it descends through the int stroke to about halfway down, start to close, and close fully shortly after the piston passes through BDC. The valves on a cam that small shouldn't be open more than a few .001"s at TDC.
In case you can't tell, it sounds to me like the cam is WWWWWAAAAAAAYYYYYYYYY out of time with the crank; maybe using some wrong mark on one of the sprockets or something like that. I'm directing you how to verify that the cam timing is at least somewhat close to correct. In fact, if you bring the crank to #1 TDC, and rotate the cam by hand to where the valves are just "changing over" as described, then install the timing set, I'll bet you'll discover some marks on the sprockets that align, that are different from whatever you've been using.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
1966 C10 LS Swap (If I can get the thing built) 
