measuring piston to deck clearance on 440 source dished piston

[Paul_G]

Straight up is a bad term, but dot-to-dot is worthless.

Lets see, dot on the cam gear gear is aligned with the dot (0) on the crank gear. no advance, no retard. Been like that forever.

 

[BSB67]

If you don’t measure it, you don’t know where it is. Saying “Dot to Dot” equals “I don’t know”.

 

[Paul_G]

If you don’t measure it, you don’t know where it is. Saying “Dot to Dot” equals “I don’t know”.

Understood. Degreeing the cam looks like rocket science to most people, me included. Special tools are needed, which a lot of people do not have. Thats why the average person lines them up dot to dot and done. It is a starting point.

I have to dig deeper with this engine. I have a degree kit. I am learning how to use it. I do not want to open this engine up again in the future to find burnt pistons and carnage. That gets real expensive. What frosts my nuts is I paid a pro shop to build this for me. Yet here I am doing it again myself.

 

[BSB67]

Sounds like you’re on the right path.

 

[PRHeads]

Just to be clear, about the only disassembly required to determine the cam timing is pulling a valve cover and the rockers off.

If all the front accessories are on, you’ll also need to remove enough stuff to mount the degree wheel and pointer(unless you have a damper with 360* markings).

 

[Paul_G]

The engine is on a stand. Heads are still off. I am done playing with it, just setting the ICL back to 108. I played with the timing set till I finally just mapped out the different positions. Put some match marks on the block and cam gear to see how much the gear was actually moving in each position, and in what direction. That helped. R8 is where I get the closest to 108. To go with more retard I will have to start playing with offset keys. How it came out;
Dot to dot - 115 ICL.
R4 - 110 ICL
R6 - 109 ICL
R8 - 108 ICL

This is a Summit brand timing set. Makes no sense as to why each position from R4 to R8 is only 1°? I did not bother trying R2 position.

I have a Summit brand graduated harmonic balance on it too. Sliding it on the crank I noticed the outer sleeve with the timing marks on it can slide around. Not having much faith anymore in Summit branded products.

 

[davidplymouth1@]

I'm hoping it goes well for you sir. Even with all of the great guys here to help me along, there's just so much to consider. I just got a kit from 440 source that arrived just today. But my machinist has had the block for 2 weeks. I've never done a kit like this before and it was very confusing to get an agreement between my machinist and 440 source Mike and Terry. I had an interesting talk with my machinist. If I have him mill the deck to just be clean only - He will cut it however the deck sits now - square? unsquared? He can't say until he gets the kit. He squares decks after the bore sizing is done by setting all four corner pistons to get a "read" for squaring the deck. because my machinists tools/machines are on the older side of things compared to modern computerized machines. Things were done differently then; as compared to now. So, I'm gonna wait till I see what the new piston height comes out to be before I have anything done to the deck. I ordered 10.00 pistons which both Terry and Mike say that means 10-1 with an 84cc head chamber. I'm hoping it will only need to be cleaned up a little - like 3-5 thousandths - but I got no problem with running it untouched either. The deck is virgin w/no visible issues. He wants $80 to clean it - and up to $700 more to square it depending on how many passes it takes - which may make it too low for the kit I ordered. very frustrating dealing with this old timer. I can't order the kit from 440 source unless I know the bore size after the cut and hone is done - but my machinist can't hone the cylinder without having the piston there to fit it correctly to the cylinder 440 source only has certain size pistons for certain size bores with certain size chamber heads. You cant just order a 10-1 pistion for a 4.375 bore unless you have the right heads for that particular kit. 440 source might not have a 10-1 piston for a 4.330 piston at 30 over to fit my heads. I might have to go .55 over to get a piston kit from 440 source that'll fit my head. Or what ever it may be. And there's no returns if the bore is wrong. I'll have to pay to have it bored out larger again and have to pay 440 source another $3000 for a different kit. My machinist can't simply go from 20 over to 30 over he'd have to go to 40 over but 440 source might not have a piston for 40 over. BLAH BLAH BLAH. If I buy a scat kit from my machinist - he'll make it right if he's wrong about where the final bore might end up at and exchange the pistons at his cost. But that costs $7000 and I still have to put it all together. $10,000 if he assembles it and ZERO warranty anyway I look at it. It shouldn't be so complicated. I feel like no one can man up and take responsibility for their words between those 2 companies.

 

[BSB67]

R8 is where I get the closest to 108. To go with more retard I will have to start playing with offset keys. How it came out;
Dot to dot - 115 ICL.
R4 - 110 ICL
R6 - 109 ICL
R8 - 108 ICL

Retard = larger ICL number.

108 ICL is the most advanced of all numbers you posted.

The R4 position, 110 ICL is 2 degrees retarded relative to 108 ICL.

 

[BSB67]

I'm hoping it goes well for you sir. Even with all of the great guys here to help me along, there's just so much to consider. I just got a kit from 440 source that arrived just today. But my machinist has had the block for 2 weeks. I've never done a kit like this before and it was very confusing to get an agreement between my machinist and 440 source Mike and Terry. I had an interesting talk with my machinist. If I have him mill the deck to just be clean only - He will cut it however the deck sits now - square? unsquared? He can't say until he gets the kit. He squares decks after the bore sizing is done by setting all four corner pistons to get a "read" for squaring the deck. because my machinists tools/machines are on the older side of things compared to modern computerized machines. Things were done differently then; as compared to now. So, I'm gonna wait till I see what the new piston height comes out to be before I have anything done to the deck. I ordered 10.00 pistons which both Terry and Mike say that means 10-1 with an 84cc head chamber. I'm hoping it will only need to be cleaned up a little - like 3-5 thousandths - but I got no problem with running it untouched either. The deck is virgin w/no visible issues. He wants $80 to clean it - and up to $700 more to square it depending on how many passes it takes - which may make it too low for the kit I ordered. very frustrating dealing with this old timer. I can't order the kit from 440 source unless I know the bore size after the cut and hone is done - but my machinist can't hone the cylinder without having the piston there to fit it correctly to the cylinder 440 source only has certain size pistons for certain size bores with certain size chamber heads. You cant just order a 10-1 pistion for a 4.375 bore unless you have the right heads for that particular kit. 440 source might not have a 10-1 piston for a 4.330 piston at 30 over to fit my heads. I might have to go .55 over to get a piston kit from 440 source that'll fit my head. Or what ever it may be. And there's no returns if the bore is wrong. I'll have to pay to have it bored out larger again and have to pay 440 source another $3000 for a different kit. My machinist can't simply go from 20 over to 30 over he'd have to go to 40 over but 440 source might not have a piston for 40 over. BLAH BLAH BLAH. If I buy a scat kit from my machinist - he'll make it right if he's wrong about where the final bore might end up at and exchange the pistons at his cost. But that costs $7000 and I still have to put it all together. $10,000 if he assembles it and ZERO warranty anyway I look at it. It shouldn't be so complicated. I feel like no one can man up and take responsibility for their words between those 2 companies.

It’s not complicated. It’s just new to you so it seems like it is.

It sounds like your machine shop has antiquated equipment. It’s okay. The last time I had a block decked not off the crank centerline was 35 years ago.

Also, the machine shop can inspect and measure your block now and tell you with 100% certainty what the final bore will be and the deck height. You should be able to estimate the compression ratio within +/- 0.10 before you buy anything.

 

[PRHeads]

At this point my suggestion would be-

Put the timing set dot to dot on the zero position…….take a pic of it.

Now put it on one of the advance or retard positions, take a pic of it.

Dot to dot - 115 ICL.
R4 - 110 ICL
R6 - 109 ICL
R8 - 108 ICL

The above only makes sense if you’re measuring the ex lobe.

 

[Paul_G]

OK guys, this is a quote from the insightful Forest Gump, "stupid is as stupid does". Yes, I am the stupid. I was on the exhaust lobe. At least I was on the odd side of the engine.

I got on the intake lobe and measured everything again.
At 0 - 108.5 ICL
A2 - 106.25
A4 - 103.5
A6 - 101.75
A8 - 100.5

I am putting it back to 108 as the cam card wants. Guess "I aint smart enough" to play games with it.

This was not the only mistake, but I am not confessing everything. Got more work to redo now.

 

[PRHeads]

At least I was on the odd side of the engine.

Baby steps.

 

[PRHeads]

Now for degreeing the cam. It wants to be on 108 ICL. That's where I put it last time. It was not straight up to get it there. I don't remember if it was advanced or retarded, but I think it was advance. The torque down low was outrageous. I would like to move the power up the rpm band and loose some of that torque down low. That would mean to retard the cam this time, which would change the ICL right. Is that ok to do?

Was the cam in fact previously installed using one of the advanced key ways, or was it in the 0 position?

I wouldn’t decide on the cam installed position this time around until after the actual final CR is determined.

Here’s my math on the CR with .051” gaskets and the pistons sticking out .012”:

1035- swept
78- chamber
27- piston
12.8- gasket
1- crevice(top ring down)
-2.9- deck
————
1150.9 total
115.9 total minus swept
————
9.93cr - 1150.9/115.9

 

[not so famous bob]

Paul that cam has 4* advance ground into it. Straight up would be ICL @112*. With your 500ci and a potentially high compression ratio (did you ever get that figured) I think straight up would be beneficial or you could split the difference at 110.
Edit: I have no experience installing cam on 112 ICL. I have most always installed around 108 to maintain bottom end power. Because all of my engine builds or <400ci

a 500' engine with good heads "flow354@.600" , 10;3 comp. , .600 lift solid roller , fuel inj. , does not have any worries about low end torque ,
zero deck , .036 head clearance (steel rods) ..will have no problem with low end torque !!!-ask me how I know>>>

 

[Paul_G]

Was the cam in fact previously installed using one of the advanced key ways, or was it in the 0 position?

I wouldn’t decide on the cam installed position this time around until after the actual final CR is determined.

Here’s my math on the CR with .051” gaskets and the pistons sticking out .012”:

1035- swept
78- chamber
27- piston
12.8- gasket
1- crevice(top ring down)
-2.9- deck
————
1150.9 total
115.9 total minus swept
————
9.93cr - 1150.9/115.9

The heads are not 78cc any more. They might be less then 70. I bought a CC kit to check the heads myself when I get them back from the machine shop. The cc kit arrived a few days ago. I opened it up to see what I bought only to find the buret broken. Summit is sending another buret. I bought a Holley fuel pump rebuild kit on that same order. The card is supposed to have a rotor, 4 little vanes, and a gasket. The card I got had the rotor, thats it. Summit is sending another one of those too.

 

[PRHeads]

If the heads are 70, and everything else is the same, you’d have 10.6cr.
1142.9/107.9

Heads @66 = just under 11cr.
1138.9/103.9

 

[Paul_G]

If the heads are 70, and everything else is the same, you’d have 10.6cr.
1142.9/107.9

Heads @66 = just under 11.1cr
1138.9/103.9

Thanks for doing that.

 

[PRHeads]

If the heads end up under 70, you could add a little thickness to the gasket to mitigate that some.

A .060” gasket is 2.2cc bigger than a .051”.