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Discussion Starter #1 (Edited)
Hey fellas. Working on the motor out in the shop today, thanks to mandatory home time. I’m having problems with my cam install in my 302/11r build. I’m measuring for my pushrods and I’m having PTV contact after degreeing the cam in. I’ve tried it both 2 advanced and straight up. It barely kisses, but it does make contact. I feel like I’m missing something simple. My build:

302, SBE, new L2488F pistons
11R190 heads milled to 48cc chambers
Fel Pro 9333 gaskets
SA timing gear set
Custom FTI cam.
I am measuring for pushrods currently. 7.0” is what I’m coming up with.

Here’s the PTV contact on the #1 cylinder with the cam 2 degrees adv
1057893


Here it is with the cam Straight up:
1057894


What does it look like to you more experienced types out there..? Am I just off by a few degrees on my install somehow, or is my cam too big..? I know the heads are milled, can’t undo that. I’m hoping to make this combo work, should be rowdy as hell! Thanks for your input guys.
 

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Your piston to valve clearance was shortened by a lot when the heads were milled to 48cc.

Probably lost .075"-.080" (minimum) with that much being cut.

Fly cutting the piston is about the only fix right now.
 

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Discussion Starter #3
Thanks for responding, Ed. I’m going to PM you a few questions
 

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Flycutting pistons in the block is no big deal. I did it free hand with a dremel on a block back in the mid 90's. That engine ran for about a decade until I lunched a piston due to user error - I swapped ignition boxes and failed to double check the timing (distributor wasn't moved). I ended up with over 40 degrees of advance, and with a blower, that's instant piston death. And my flycuts were UGLY. Here's an old pic:
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Those are Badger brand hyper pistons. This is after 10 years and probably 500 dragstrip passes - probably 100-200 10 second passes. Don't judge me. I was young, broke and just wanted to go fast. And it worked. I assembled that engine in my mom's kitchen in a condo. My point is, renting a flycutting tool and going to town really isn't a big deal. You can do it with the shortblock still in the car. If you're particularly butch, you can do what I did (I also flycut those pistons in the car; I didn't find out about the P/V issues until after I put in the short block). Heck, you could use your heads as a guide (or a junked similar head) - just use a slightly oversized intake valve and grind cutting flutes into the face. Here's an interesting option:
 

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You can flycut them in the block if you're careful; and plan on pulling everything back apart to clean the junk out from between the pistons and bores.

HOWEVER....I can't say for sure how much "meat" is in the pistons; don't know how much you can safely remove. The good engine builder guys know that stuff, not me. I will say there's probably enough based on the fact that them old TRW's are thick and real heavy but don't take that as the gospel. Ed?

But here is a way to do it. Say you have 2.02 intake valves and 1.60 exhaust (for example). Grab an old valve and superglue some 36 grit (or 24 grit) sandpaper to it. I use an old sanding belt from the OLD (and I mean like 50+ years old) craftsman belt sander. Once the glue is set/cured, trim almost all of the excess off around the edges. I like to leave a little bit, say, .025" or so overhanging the OD of the valve. Throw it in the head with some lube on the stem, throw the head on, use a drill motor on slow speed and run it into the piston. Takes a few seconds and you should be able to get enough clearance assuming the pistons have enough meat to do so. I ran into a problem with a set of 4032 Mahles that didn't have enough meat in them, but keep in mind they were hollow dome pistons and I was shooting for about 15:1 (and actually overshot it a little).

Yeah that thing outta be fun.
 

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Discussion Starter #6
Thanks for the responses guys. Alex, those reliefs are gnarly! How deep were they, or did you ever care to measure them?! I don’t think I need to notch much. I’ve been looking at the Lindy tool but I don’t want to spend the money or make time to have the heads disassembled. Could a set of super thick MLS head gaskets get me clearance? I’m thinking a new cam or Dremel bravery are my best options. Any other ideas while I wait to hear back from Ed..?
 

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I had no good way of measuring them. I seem to recall using duct tape and dry cleaning bags (the thin ones when you get a shirt presssed and cleaned) and taping them around each cylinder one at a time. Remember - this was pre-forums, early internet days, so I have no ability to do research other than the old fashioned way. I just kind of guessed. As I zeroed in on where they needed to be, the "reliefs" got better as I went along. The one you see is the first one I did - the worst looking one. They did get better, but not a whole lot. The only reason that photo exists is because the piston next to it is missing a good chunk of the ring land (that's when I blew that motor up). Todd's suggestion is good, I dunno if I'd go as medieval as I did on nice, decent pistons. But there are ways to fly-cut in situ that can work just fine, without my degree of butchery. I certainly wouldn't do that to the custom JE pistons I run now. But now I own a mill, lathe, TIG machine, and bunch of micrometers and calipers. Back then I had a dremel, one socket set and a few screwdrivers; my only measuring instruments were plasti-gauge and rulers.
 

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Hey fellas. Working on the motor out in the shop today, thanks to mandatory home time. I’m having problems with my cam install in my 302/11r build. I’m measuring for my pushrods and I’m having PTV contact after degreeing the cam in. I’ve tried it both 2 advanced and straight up. It barely kisses, but it does make contact. I feel like I’m missing something simple. My build:

302, SBE, new L2488F pistons
11R190 heads milled to 48cc chambers
Fel Pro 9333 gaskets
SA timing gear set
Custom FTI cam.
I am measuring for pushrods currently. 7.0” is what I’m coming up with.

Cam card:
View attachment 1057892

Here’s the PTV contact on the #1 cylinder with the cam 2 degrees adv
View attachment 1057893

Here it is with the cam Straight up:
View attachment 1057894

What does it look like to you more experienced types out there..? Am I just off by a few degrees on my install somehow, or is my cam too big..? I know the heads are milled, can’t undo that. I’m hoping to make this combo work, should be rowdy as hell! Thanks for your input guys.
 

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Discussion Starter #9
So I think my cam will be for sale, unless I can get it reground. I don’t have the time, and a shop I trust, to go through with the Lindy tool route. ( I don’t have an extra, milled, bare 11r head to work with at home, either.) I can’t bring myself to freehand needed reliefs in fresh pistons. The bottom end is perfectly balanced, as is. If I can sell my current cam, I might only be out $50-$75.
 

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Based on what I see in that picture, changing the cam will not solve the problem. Your only option is to flycut or replace & re-balance. Flycutting (in this application) isn't going to be removing enough material to have to rebalance anyway.

On balancing, it used to be that some shops preferred to use a 50% factor, in other words they'd figure up the total rotating weight and 50% of the reciprocating weight. But some guys liked to over balance, use, say 52% reciprocating. Then some used a little less, say 45% for example. Many OEM old school engines aren't even in a ballpark--lot of them weren't even in the county (I've seen them 20-30g out of spec-right from the factory). Later model stuff is usually better, mainly because they have better equipment and better tolerances now. So removing a few grams from the crown ain't a big deal as long as they're all close. With that said, it takes a good bit of material removal to equal one gram of aluminum; which is very likely you'll never notice it.
 

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Hey, just to learn, is part of the problem that those pistons were not designed to really be used with twisted wedge heads? Thanks
 

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PS - Years ago I had to hand clearance pistons in a 289. I put grease in the piston to cylinder gap, covered everything else with taped plastic bags and ran the engine 30 years with no problems at all.
 

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By chance are you running 1.7 rockers? If so, you could go to a 1.6 and be ok, I would think.
Or if youre already running 1.6s, Scorpion makes a 1.5 set
 

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By chance are you running 1.7 rockers? If so, you could go to a 1.6 and be ok, I would think.
Or if youre already running 1.6s, Scorpion makes a 1.5 set
That's not going to do anything for this issue...
 

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Because at peak lift the piston is near the bottom of the cylinder. Duration determines how long the valve is sticking out and is the main cause if something is going to smack.
 

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Discussion Starter #20
Yeah those are just standard OE replacement forged SpeedPro pistons that I used when I thought it was just going to be a GT40 headed 302... I got a great deal on the heads/cam/rockers, etc., on here a while back (like 2 years ago..) Life happened for a while, and now I’m finally getting it together.
1058143
I sold the cam a few days ago to another member... I feel a lot better about getting a custom from Ed that’s specific to my car. It’s going to be backed by a T5z and a 3.50/70 geared 9” in my 2700 pound 64 Falcon. Can’t wait to see how it does.
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BIG thanks to Woody and the SBF building website!! Without the videos, I would not have realized the short block, that I had built locally, was all sorts of wrong! Now I know it’s built right!
Thanks to everyone that shares their knowledge on here as well. I don’t do FB, or any of that crap. This is my go-to place for info, and some good entertainment at times!!
 
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