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Didn't degree the cam and this is what I found

moparbud66

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Ignoring everyone's advice, I was lazy and being a cheapskate and did not degree my cam. The instructions (Comp cams) said that many cams have the advance built in and in many cases, the stock timing position would be adequate. I lined up the timing marks in the stock location and the engine would not start. It didn't even sound right but I kept trying anyway. I concentrated on the body work for a while and now finally have the time and ambition to look into what I did wrong. I pulled the heads the other day and was surprised to find that some of the exhaust valves had actually touched the pistons. There doesn't seem to be any damage and I'm really glad it didn't fire up. I'm sharing this as a lesson and maybe some lecturing and advice will come back my way. There is way too much work in this bottom end to ruin it now. I have decided not to use the 906s that were bolted on, instead I will get some aluminum heads, roller rockers and a decent dual plane manifold, carb. etc. to compliment what's here. It's a 1970 440, .060 over, H beam rods, KB flat tops, all balanced. Suggestions welcome, keep them constructive, I learned my lesson!
 

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What cam did you use? Hydraulic or solid or roller? 1 bolt or 3? What timing chain? 3 way, 9 way adjustable?
What head gasket and how thick? What is your deck clearance?
Stock rockers and pushrods?
Details, then we can figure out the issue.
 
In my opinion, not degreeing the cam had nothing to do with what you see here. If you did degree the cam, and checked the valve to piston distance when the valve is open, you could have seen an issue. You might have meant this, and if you did, I misunderstood.

A cam (a lot are), that has advance already ground into it, is on the order of 4 to 8 degrees, and as long as you lined up the stock marks, with proper components, should not have a problem. You don't mention the head gasket thickness, piston compression distance, deck height of the piston, cam lift, rocker ratio, pushrod length, rod center-to-center. An error with any of these things will have the result you found.
 
Yeah, I find this suspicious too. If you did a bore and then added a stroker kit to the bottom end how could you not know the piston height and know if those 906 heads would work or not? When I was planning out my stroker build I had the pistons dished -24cc so the there would be clearance and help get the compression down to 9.6:1 for today's gas. Plus I used some putty on the pistons and mocked on the heads and rotated the motor taking note of the imprint of the valve on the putty. Did I mention I didn't degree my cam either? Lined up the marks with a 4A crank gear position and #1 piston up top and in it went. Was that the right thing? no but it works which means I think you have more of a kit combo issue than no degreeing you cam issue.




 
The dish on a piston has nothing to do with valve to piston clearance. I the OP is letting you all know that he skipped a step that would have avoided this issue as he would have felt the interference by hand on one piston rather than crashing all 8 exhaust valves.
 
I guess my old eyes are confusing me. Are you saying that the divots I see in your pistons aren't flycuts for exhaust valve clearance? Or are there marks in the flycuts that my eyes can't pick-up?
 
I guess my old eyes are confusing me. Are you saying that the divots I see in your pistons aren't flycuts for exhaust valve clearance? Or are there marks in the flycuts that my eyes can't pick-up?

There are marks in the fly cuts, you have to look closely. I only saw them because I used my phone to get a close up view.
 
I guess my old eyes are confusing me. Are you saying that the divots I see in your pistons aren't flycuts for exhaust valve clearance? Or are there marks in the flycuts that my eyes can't pick-up?

Those sure appear to be the flycuts. We should also always go through the process of checking piston to valve with any non-stock cam/piston/stroke combo. Sounds more like the chain was off a tooth. I had a timing chain set that really took CAREFUL examination to be sure the marks were lined up.
 
In my opinion, not degreeing the cam had nothing to do with what you see here. If you did degree the cam, and checked the valve to piston distance when the valve is open, you could have seen an issue. You might have meant this, and if you did, I misunderstood.

A cam (a lot are), that has advance already ground into it, is on the order of 4 to 8 degrees, and as long as you lined up the stock marks, with proper components, should not have a problem. You don't mention the head gasket thickness, piston compression distance, deck height of the piston, cam lift, rocker ratio, pushrod length, rod center-to-center. An error with any of these things will have the result you found.
You're right, you should not have a problem but that only happens in a perfect world. There are just too many variables not to degree in a cam. If you just align the dots, you are trusting who ever machined the cam and the sprockets and placed the key ways and the dots in exactly the right place. If the cam and both sprockets are on the money then you're in good shape but if they are not, then you can toast an expensive engine. In my 40 years of playing with this stuff, NO cam or timing chain assembly goes in any engine I build, stock or not without being checked with a degree wheel. It's must another tool that should be in an engine builder's tool box.....even if you use it one time and you find an error that saves the engine, it more than paid for itself.
 
i'm almost thinking as deep as those reliefs are that the cam was off a tooth or two late for the pistons to have caught up with the closing valve,....? another note, you can't check piston to valve clearance properly with a hydraulic tappet.
 
Just curious if you had new pushrods made when you changed the cam and added the stroker kit?
 
All the parts I used were bought the previous owner. It was the typical unfinished father and son project. The cam is not that radical (.488 int.,491ex) and is a hydraulic flat tappet design. At the time, I was pinching pennies and used stock replacement rockers by Elgin Ind. bought off ebay. Same for the pushrods. I used a set of stock head gaskets but can't tell you the actual thickness. I threw on the 906's that came with the package and they were all done up with new valves and seats. Interesting enough, only 5 valves left marks on the pistons which tells me that some of my components are not as equal as they should be. Also, the pistons come up all the way to the top of the bore. Is this proper? I'm gong to step back a bit, consult a builder in my area, and buy all new top end components per their recommendations. Does anyone think that these pistons could be damaged in any way? I'm in a much different position now than I was when I put this together so I'm willing to spend whatever it takes to make a healthy street driver. It' going in my 66 Satellite (automatic) and the rest of the car is nearly ready. Thank you to everyone for your replies and FBBO for making this forum available.
 
The pistons are fine. I'd check the upper rod bearings though.
 
i'm almost thinking as deep as those reliefs are that the cam was off a tooth or two late for the pistons to have caught up with the closing valve,....? another note, you can't check piston to valve clearance properly with a hydraulic tappet.
Right. Got to use something solid. I made something to put on the lifter and use an adjustable push rod to do this.

All the parts I used were bought the previous owner. It was the typical unfinished father and son project. The cam is not that radical (.488 int.,491ex) and is a hydraulic flat tappet design. At the time, I was pinching pennies and used stock replacement rockers by Elgin Ind. bought off ebay. Same for the pushrods. I used a set of stock head gaskets but can't tell you the actual thickness. I threw on the 906's that came with the package and they were all done up with new valves and seats. Interesting enough, only 5 valves left marks on the pistons which tells me that some of my components are not as equal as they should be. Also, the pistons come up all the way to the top of the bore. Is this proper? I'm gong to step back a bit, consult a builder in my area, and buy all new top end components per their recommendations. Does anyone think that these pistons could be damaged in any way? I'm in a much different position now than I was when I put this together so I'm willing to spend whatever it takes to make a healthy street driver. It' going in my 66 Satellite (automatic) and the rest of the car is nearly ready. Thank you to everyone for your replies and FBBO for making this forum available.
Pistons can vary a few thousandths and so can the block from front to back and corner to corner. Then you have rods that can be different by a couple of thousandths. If you get a long rod mounted to a tall piston and placed in a low corner of the block.....you see where this is going? And I didn't even mention the crank! Most shops that 'true' deck the block and align hone the mains and resize the rods never check their machining results nor do they check each and every piston as it comes out of the box. I use a bar in the mains to check blocks for square and .005" out of square is common even after machining. It takes a bunch of time to check everything like that and is why general engine shops would rather machine the parts and 'trust' that their machining is on the money. This is what they do even if the block is perfect....they won't check it and just machine it. Talk to someone who runs in the Stock Eliminator or even the Pro Stock classes (and several others) about why their engines are so expensive. The guys that are at the forefront are there for a reason. Everything is on the gnats ***. Just because it's new out of the box or fresh from the machine shop doesn't mean it's on the money.
 
the elgin parts and the stock head gaskets aren't an issue. i've used kb pistons several times and the the piston to valve clearance is generous. that cam's lift shouldn't be an issue either. i still believe the cam or crank sprockets were off a tooth or two.
 
I certainly will recheck that again. It is a 1 bolt cam. The cam sprocket has only one mark and the crank sprocket has 3. I installed it on the circle (stock position).
 
cam degree

Ignoring everyone's advice, I was lazy and being a cheapskate and did not degree my cam. The instructions (Comp cams) said that many cams have the advance built in and in many cases, the stock timing position would be adequate. I lined up the timing marks in the stock location and the engine would not start. It didn't even sound right but I kept trying anyway. I concentrated on the body work for a while and now finally have the time and ambition to look into what I did wrong. I pulled the heads the other day and was surprised to find that some of the exhaust valves had actually touched the pistons. There doesn't seem to be any damage and I'm really glad it didn't fire up. I'm sharing this as a lesson and maybe some lecturing and advice will come back my way. There is way too much work in this bottom end to ruin it now. I have decided not to use the 906s that were bolted on, instead I will get some aluminum heads, roller rockers and a decent dual plane manifold, carb. etc. to compliment what's here. It's a 1970 440, .060 over, H beam rods, KB flat tops, all balanced. Suggestions welcome, keep them constructive, I learned my lesson!


I have about the same set up you do in my 66 Satellite. It has a '75 440 that is .030 over, the same cam as you, stock LY rods, flat top pistons from a '70, steel shim head gasket (.020 thick), 906 heads. If I remember correctly my pistons are about .084 in the hole and my compression ratio is about 9.6. I don't recall the length of my push rods. Maybe I'm just lucky because I didn't degree the cam when I installed it and I've had no problems. It runs great on 93 octane.
 
I have about the same set up you do in my 66 Satellite. It has a '75 440 that is .030 over, the same cam as you, stock LY rods, flat top pistons from a '70, steel shim head gasket (.020 thick), 906 heads. If I remember correctly my pistons are about .084 in the hole and my compression ratio is about 9.6. I don't recall the length of my push rods. Maybe I'm just lucky because I didn't degree the cam when I installed it and I've had no problems. It runs great on 93 octane.
I have a 70 (69 casting date) that's still standard bore and the original pistons are .050 down. With 516 closed chamber pocket ported heads with 2.08 intakes and steel gaskets, the CR is 10.3-1. It has a Hemi grind cam, double roller chain with titanium retainers and moly rings. Right now it's just a long block with no rockers.....thinking about selling it.
 
I think the real lesson is always check piston to valve clearance. I know I do. Learned the hard way.
 
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