Cam question?

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Re: Cam question?

Post  466cj on May 12th 2012, 6:15 pm

AUDIOADDICT02 wrote:
466cj wrote:
AUDIOADDICT02 wrote:
Ok, damn, then are the calculators really that inaccurate?

Calculators are only as accurate as the information put in.

This is what I put in & what I got:
Bore: 4.36
Stroke: 3.85
H.g.: 0.038
Head vol. 72cc

...and I get 11.58 compression..???

..I also read that with 71cc heads will bring the bbf up to 11:1 compression ratio?

Need more than that. Need to know the CC of the piston and the distance from the deck surface to the piston. Makes a big difference.

I used

Head gasket .041 x 4.5"
Head 97cc
Piston 22cc
Deck clearance .025"

Gave me a CR of 8.03

Now I did use a 4.39" bore which is .030" over

If I use a std. bore 4.36 I get 7.94 CR which is about right for stock 1984

Using the std bore get:

83cc 8.73, 75cc 9.28, 72cc 9.50, zero deck with 72cc 10.0 CR




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Re: Cam question?

Post  AUDIOADDICT02 on May 12th 2012, 7:12 pm

466cj wrote:

Need more than that. Need to know the CC of the piston and the distance from the deck surface to the piston. Makes a big difference.

I used

Head gasket .041 x 4.5"
Head 97cc
Piston 22cc
Deck clearance .025"

Gave me a CR of 8.03

Now I did use a 4.39" bore which is .030" over

If I use a std. bore 4.36 I get 7.94 CR which is about right for stock 1984

Using the std bore get:

83cc 8.73, 75cc 9.28, 72cc 9.50, zero deck with 72cc 10.0 CR




I would imagine my pistons are 4cc? they have a valve pocket?
That's what I don't understand, how do you know the distance from the deck to the piston?

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Re: Cam question?

Post  Barney on May 12th 2012, 7:15 pm

AUDIOADDICT02 wrote:
466cj wrote:

Need more than that. Need to know the CC of the piston and the distance from the deck surface to the piston. Makes a big difference.

I used

Head gasket .041 x 4.5"
Head 97cc
Piston 22cc
Deck clearance .025"

Gave me a CR of 8.03

Now I did use a 4.39" bore which is .030" over

If I use a std. bore 4.36 I get 7.94 CR which is about right for stock 1984

Using the std bore get:

83cc 8.73, 75cc 9.28, 72cc 9.50, zero deck with 72cc 10.0 CR




I would imagine my pistons are 4cc? they have a valve pocket?
That's what I don't understand, how do you know the distance from the deck to the piston?
So -4cc then, you have to measure to see how far the piston is I. The hole.
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Re: Cam question?

Post  rmcomprandy on May 12th 2012, 7:29 pm

AUDIOADDICT02 wrote:
466cj wrote:

Need more than that. Need to know the CC of the piston and the distance from the deck surface to the piston. Makes a big difference.

I used

Head gasket .041 x 4.5"
Head 97cc
Piston 22cc
Deck clearance .025"

Gave me a CR of 8.03

Now I did use a 4.39" bore which is .030" over

If I use a std. bore 4.36 I get 7.94 CR which is about right for stock 1984

Using the std bore get:

83cc 8.73, 75cc 9.28, 72cc 9.50, zero deck with 72cc 10.0 CR




I would imagine my pistons are 4cc? they have a valve pocket?
That's what I don't understand, how do you know the distance from the deck to the piston?

What 84 model has only a 4 cc piston...? That's probably what the volume of the valve notches may be as with a Flat-Top piston ... how about that bathtub dish in an OEM stock 1984 piston...? That usually has about 18 more cc's. plus that year engine usually has the pistons about .025" down the hole which is another 6 plus cc's.

This is the Kinda stuff you get when it is done with just a guess. Actual measurements are required to arrive at an accurate figure.

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Re: Cam question?

Post  466cj on May 12th 2012, 8:52 pm

rmcomprandy wrote:
AUDIOADDICT02 wrote:
466cj wrote:

Need more than that. Need to know the CC of the piston and the distance from the deck surface to the piston. Makes a big difference.

I used

Head gasket .041 x 4.5"
Head 97cc
Piston 22cc
Deck clearance .025"

Gave me a CR of 8.03

Now I did use a 4.39" bore which is .030" over

If I use a std. bore 4.36 I get 7.94 CR which is about right for stock 1984

Using the std bore get:

83cc 8.73, 75cc 9.28, 72cc 9.50, zero deck with 72cc 10.0 CR




I would imagine my pistons are 4cc? they have a valve pocket?
That's what I don't understand, how do you know the distance from the deck to the piston?

What 84 model has only a 4 cc piston...? That's probably what the volume of the valve notches may be as with a Flat-Top piston ... how about that bathtub dish in an OEM stock 1984 piston...? That usually has about 18 more cc's. plus that year engine usually has the pistons about .025" down the hole which is another 6 plus cc's.

This is the Kinda stuff you get when it is done with just a guess. Actual measurements are required to arrive at an accurate figure.

Randy,

What is your point???

All I have to do is use 8.0 CR and a 97cc head chamber to determine relative change. Now I know some of these engine are more like 7.8 CR. The numbers I have are from notes I have. You and I both know the decks vary, they aren't most times even same front to back...

So what is your point??? how about if you have something constructive to add do so...

To the OP I used a 22 cc dish in the piston NOT 4cc. Actaully measuring will give most accurate numbers, but what I have provided will be within a few points (tenths) of real...

Steve


Last edited by 466cj on May 12th 2012, 11:25 pm; edited 1 time in total

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Re: Cam question?

Post  dfree383 on May 12th 2012, 11:02 pm

AUDIOADDICT02 wrote:
dfree383 wrote:
Compression....... if you want to run a decent sized camshaft. If its a stock Long Block, your only at around 8:1 or Less..... to run decent with that cam you'll need to be in the 10:1 range. Plus you will need springs and rocker arms.

I'd suggest a Head swap. if you budget allows or go with a substantialy smaller camshaft.

That's exactly what I'm aiming at, at least 10:1 compression, I'm looking at some aluminum 83cc chamber heads that will put me at 10.2:1 compression according to a calculator.

If you want 10:1 you need to look at some ths streets or Edelbrock rpm heads in 72cc, 83cc heads arent going to get you there, besides only heads I recall the are at 83cc are tfs a460 heads and those are all wrong for what your doing.
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Re: Cam question?

Post  rmcomprandy on May 13th 2012, 12:00 am

466cj wrote:
rmcomprandy wrote:
AUDIOADDICT02 wrote:


I would imagine my pistons are 4cc? they have a valve pocket?
That's what I don't understand, how do you know the distance from the deck to the piston?

What 84 model has only a 4 cc piston...? That's probably what the volume of the valve notches may be as with a Flat-Top piston ... how about that bathtub dish in an OEM stock 1984 piston...? That usually has about 18 more cc's. plus that year engine usually has the pistons about .025" down the hole which is another 6 plus cc's.

This is the Kinda stuff you get when it is done with just a guess. Actual measurements are required to arrive at an accurate figure.

Randy,

So what is your point??? how about if you have something constructive to add do so...

Steve

My point was to the OP in that if you are merely guessing at what you have, (as in imagining 4cc OEM pistons in a 1984 engine), no one can get you an absolutely correct compression ratio.

I might have quoted at the wrong place but, I don't think so.

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Re: Cam question?

Post  466cj on May 13th 2012, 1:43 am

rmcomprandy wrote:
466cj wrote:
Randy,

So what is your point??? how about if you have something constructive to add do so...

Steve

My point was to the OP in that if you are merely guessing at what you have, (as in imagining 4cc OEM pistons in a 1984 engine), no one can get you an absolutely correct compression ratio.

I might have quoted at the wrong place but, I don't think so.

OK, that makes sense and is true. Sorry, just was not clear. I'd say can get close within 1/2 point of compression with some educated guessing. Many assume and don't measure, I've seen engine builders do this too as they done it hundred times before and always been right.

Is a good point also in that he could pull the heads and find someone has been into it. For all we know could have a set of domed pistons in it. Guess bottom line he should pull the heads before buying a set of head or cam so that he can make an informed choice.

Steve


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Re: Cam question?

Post  AUDIOADDICT02 on May 13th 2012, 1:51 am

rmcomprandy wrote:
466cj wrote:
rmcomprandy wrote:
AUDIOADDICT02 wrote:


I would imagine my pistons are 4cc? they have a valve pocket?
That's what I don't understand, how do you know the distance from the deck to the piston?

What 84 model has only a 4 cc piston...? That's probably what the volume of the valve notches may be as with a Flat-Top piston ... how about that bathtub dish in an OEM stock 1984 piston...? That usually has about 18 more cc's. plus that year engine usually has the pistons about .025" down the hole which is another 6 plus cc's.

This is the Kinda stuff you get when it is done with just a guess. Actual measurements are required to arrive at an accurate figure.

Randy,

So what is your point??? how about if you have something constructive to add do so...

Steve

My point was to the OP in that if you are merely guessing at what you have, (as in imagining 4cc OEM pistons in a 1984 engine), no one can get you an absolutely correct compression ratio.

I might have quoted at the wrong place but, I don't think so.

Ok, sorry, I've pulled the heads before, last time was just last week, I should've taken close-up pics of the pistons, they're flat, but have (like you said) a bathtub-shaped "pocket".

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Re: Cam question?

Post  AUDIOADDICT02 on May 13th 2012, 3:23 pm

Since I'm not allowed to post links, I'll post the product number: Sealed Power ZH418CP, my pistons are exactly like those, Idk how much more volume they add?

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Re: Cam question?

Post  rmcomprandy on May 13th 2012, 10:59 pm

AUDIOADDICT02 wrote:Since I'm not allowed to post links, I'll post the product number: Sealed Power ZH418CP, my pistons are exactly like those, Idk how much more volume they add?

That H418 piston has two opposed intake eyebrows in order to be used on either side of the engine with the offset 1.0402" diameter wrist pin. It has a .240" deep oblong dish with a compression height of 1.752" which is at least .020" down the hole and Ford says it is around 8/1 compression with a D3 type head.

Different 460 replacement pistons used in early F.I. engines are also offered in the same configuration, (H582P), with a .065" oblong dish and the same 1.752" compression height; Ford says 8.9/1 compression ratio with a E7 type head.

The later F.I. engines use a same configuration piston but using a metric ring pack with a .189" deep oblong dish, (H612P), however, it has a 1.772" compression height which is closer to the top of the bore; Ford says 8.9/1 compression ratio with a F3 head.
FRPP uses these pistons, (with one valve pocket machined for the use of bigger diameter valves), in their 460 crate motors.

All of these are also offered in "coated skirt" form with a part number suffix of CP instead of just P.

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Re: Cam question?

Post  466cj on May 13th 2012, 11:49 pm

AUDIOADDICT02 wrote:Since I'm not allowed to post links, I'll post the product number: Sealed Power ZH418CP, my pistons are exactly like those, Idk how much more volume they add?

Audio the numbers I used are very close to what you have if it is all original. If you go by the CR's I listed you will be within a few tenths (Bolting a 72cc head on will put you between 9.2 - 9.6). Main wildcard is going to be how far in the hole the pistons are. Hope this helps.

Steve

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Re: Cam question?

Post  AUDIOADDICT02 on May 14th 2012, 12:25 am

rmcomprandy wrote:
AUDIOADDICT02 wrote:Since I'm not allowed to post links, I'll post the product number: Sealed Power ZH418CP, my pistons are exactly like those, Idk how much more volume they add?

That H418 piston has two opposed intake eyebrows in order to be used on either side of the engine with the offset 1.0402" diameter wrist pin. It has a .240" deep oblong dish with a compression height of 1.752" which is at least .020" down the hole and Ford says it is around 8/1 compression with a D3 type head.

Different 460 replacement pistons used in early F.I. engines are also offered in the same configuration, (H582P), with a .065" oblong dish and the same 1.752" compression height; Ford says 8.9/1 compression ratio with a E7 type head.

The later F.I. engines use a same configuration piston but using a metric ring pack with a .189" deep oblong dish, (H612P), however, it has a 1.772" compression height which is closer to the top of the bore; Ford says 8.9/1 compression ratio with a F3 head.
FRPP uses these pistons, (with one valve pocket machined for the use of bigger diameter valves), in their 460 crate motors.

All of these are also offered in "coated skirt" form with a part number suffix of CP instead of just P.

Goddamn, you lost me bigtime there man, I don't know much about pistons at this point so your explanation confused me. confused

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Re: Cam question?

Post  AUDIOADDICT02 on May 14th 2012, 12:28 am

466cj wrote:
AUDIOADDICT02 wrote:Since I'm not allowed to post links, I'll post the product number: Sealed Power ZH418CP, my pistons are exactly like those, Idk how much more volume they add?

Audio the numbers I used are very close to what you have if it is all original. If you go by the CR's I listed you will be within a few tenths (Bolting a 72cc head on will put you between 9.2 - 9.6). Main wildcard is going to be how far in the hole the pistons are. Hope this helps.

Steve

Ok, thanks for that man. Do you think the 72cc Super Cobra Jet heads will work for me? I know there are also the tf & edelbrock heads, but the scj heads are cheaper & can handle the lift my cam provides.

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Re: Cam question?

Post  466cj on May 14th 2012, 12:41 am

AUDIOADDICT02 wrote:Ok, thanks for that man. Do you think the 72cc Super Cobra Jet heads will work for me? I know there are also the tf & edelbrock heads, but the scj heads are cheaper & can handle the lift my cam provides.

The FRPP SCJ-A heads would be a good choice. I would recommend getting a cam made to match your combination. As far as valve to piston clearance, always have to check it. WIth those grand canyons of a piston and as far down the hole they usually are I'd say you have a good chance of not having an issue.

Regardless, still have to check the piston to valve clearance. If you do need more clearance Isky makes a took that will allow you to cut the valve notch in the car. It uses the head as a guide.

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Re: Cam question?

Post  AUDIOADDICT02 on May 14th 2012, 2:00 am

466cj wrote:

The FRPP SCJ-A heads would be a good choice. I would recommend getting a cam made to match your combination. As far as valve to piston clearance, always have to check it. WIth those grand canyons of a piston and as far down the hole they usually are I'd say you have a good chance of not having an issue.

Regardless, still have to check the piston to valve clearance. If you do need more clearance Isky makes a took that will allow you to cut the valve notch in the car. It uses the head as a guide.

Those are the ones I have my eyes on, they're made for flat tappet cams & I have matching hydraulic lifters. The cam I have provides .582int. lift & .600exh. lift. If you don't mind me asking, How do you check piston to valve clearance?(I want to make sure I do things right)

I'm really trying to whoop my Chevy & Honda fanboy friends here! Very Happy

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Re: Cam question?

Post  466cj on May 14th 2012, 3:17 pm

AUDIOADDICT02 wrote:
Those are the ones I have my eyes on, they're made for flat tappet cams & I have matching hydraulic lifters. The cam I have provides .582int. lift & .600exh. lift. If you don't mind me asking, How do you check piston to valve clearance?(I want to make sure I do things right)

I'm really trying to whoop my Chevy & Honda fanboy friends here! Very Happy

That Lunati 61605 cam may not be the best with a low to mid 9 CR. It will run, just may be a bit soggy on the low end and be leaving something on the table.

A few ways to check valve clearance. Some put clay on the piston top, bolt down the head with the valvetrain operational (use a solid lifter) and turn the crank over twice. Then cut the clay in half and measure the clearance.

I usually put the head on with checker springs, put the piston at TDC or where ever I want know the clearance, push the valve down until it hits the piston and measure with a dial indicator how far the valve moved. If I need to know exactly where it is hitting may put a piece of clay on the piston for an imprint.

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Re: Cam question?

Post  AUDIOADDICT02 on May 14th 2012, 6:47 pm

466cj wrote:

That Lunati 61605 cam may not be the best with a low to mid 9 CR. It will run, just may be a bit soggy on the low end and be leaving something on the table.

A few ways to check valve clearance. Some put clay on the piston top, bolt down the head with the valvetrain operational (use a solid lifter) and turn the crank over twice. Then cut the clay in half and measure the clearance.

I usually put the head on with checker springs, put the piston at TDC or where ever I want know the clearance, push the valve down until it hits the piston and measure with a dial indicator how far the valve moved. If I need to know exactly where it is hitting may put a piece of clay on the piston for an imprint.

Well I'm aiming at 10:1 cr, would it not work with that or does cr have to be a bit higher?
I'm gonna have to check with the checker springs just to be safe.

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Re: Cam question?

Post  466cj on May 14th 2012, 7:22 pm

Certainly the more CR the better. It is not like if you are at 10.0 it will be a total dog, but at 10.5 it will be an animal, but 10:1 be a lot better than 9:1.

I was assuming you did not want to touch the short block. To get to 10:1 you likely will. If you have the deck cut so that the pistons are at zero deck you will just hit 10:1.

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Re: Cam question?

Post  AUDIOADDICT02 on May 15th 2012, 2:04 am

466cj wrote:Certainly the more CR the better. It is not like if you are at 10.0 it will be a total dog, but at 10.5 it will be an animal, but 10:1 be a lot better than 9:1.

I was assuming you did not want to touch the short block. To get to 10:1 you likely will. If you have the deck cut so that the pistons are at zero deck you will just hit 10:1.

Wouldn't 10.5:1 be a bit too much to run on pump gas, or would it be fine?

I'll probably have to since I want to change the rods to H-beam rods, I might as well do that while the engine is removed. Also, if the pistons are at zero deck, wouldn't that reduce the amount of valve lift?

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Re: Cam question?

Post  dfree383 on May 15th 2012, 2:28 am

10.5 with the aluminum heads and the cam you have mentions should be just fine. Providing you can tune and engine and are not just throwing everything together and hoping for the best.

What is this motor going in? What are you going to use it for?

Whats the Trans, Gearing and balance of the driveline?
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Re: Cam question?

Post  AUDIOADDICT02 on May 15th 2012, 2:36 am

dfree383 wrote:10.5 with the aluminum heads and the cam you have mentions should be just fine. Providing you can tune and engine and are not just throwing everything together and hoping for the best.

What is this motor going in? What are you going to use it for?

Whats the Trans, Gearing and balance of the driveline?

If there is something I'm unsure of I will have someone do it for me so I wouldn't be guessing.

It's for an f250, just street use, I'm not trying to race it, but I do want the power for when I need it.

C6 3-speed auto tranny(hoping to replace it with a powerglide when the funds allow it), 8.8 rear end, 3.54:1 gears.

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Re: Cam question?

Post  dfree383 on May 15th 2012, 2:52 am

You need to do a much smaller cam, for the street smaller is better.

also a Powerglide is not what you want for a street F250...... Stick with the C6.


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Re: Cam question?

Post  dfree383 on May 15th 2012, 2:58 am

Something like this is way more inline with what your doing

http://www.summitracing.com/parts/LUN-61601/

Stick with the the 9:1-9.8:1 range, don't worry about decking the block.

It will run alot better, with a stock type convertor, 3.54 gears and a heavy truck.
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Re: Cam question?

Post  AUDIOADDICT02 on May 15th 2012, 3:00 am

dfree383 wrote:You need to do a much smaller cam, for the street smaller is better.

also a Powerglide is not what your want for a street F250...... Stick with the C6.

It will see the track every once in a while though & I'm tired of driving down the highway at such high rpms, so idk what other 4-speed tranny will handle/fit the 460?

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