To shim or not to shim valve springs
02-13-2015 | 02:59 PM
#32
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From: bel air, md
02-13-2015 | 04:10 PM
#33
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From: Vancouver BC
It depends which side of the spring you're looking at, they have yellow and blue stripes on them.
F'in, I believe it was answered by S30 but in case it was missed, you should definitely run a locator/cup, or hardened shim under your springs. However, I would never recommend only running a .015" shim, I've seen lots of them come apart when used as the sole shim under that kind of spring pressure. Use whatever lock/retainer combo you need to get enough height to run a locator, or at least a thicker shim.
F'in, I believe it was answered by S30 but in case it was missed, you should definitely run a locator/cup, or hardened shim under your springs. However, I would never recommend only running a .015" shim, I've seen lots of them come apart when used as the sole shim under that kind of spring pressure. Use whatever lock/retainer combo you need to get enough height to run a locator, or at least a thicker shim.
02-13-2015 | 04:13 PM
#34
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From: Pasadena, MD
Think about it, do you think a program that in its time had waaaaaaayyyyyyyyyy more money than any Nascar team of its time is going to put the wrong locks in their heads???? (Kiehaefer had 5 teams at one time in Nascar) Not to mention the motor I took apart and rebuilt was a motor that had been run and there was nothing wrong with the locks or the retainers and they all went back. So why should I change things?
No on the guide plates. I’m in deep enough building 2 motors over the last 14 months. Once that sting passes I will start thinking of upgrades.
The springs are dual springs with a damper and have 3 stripes. Blue, yellow and I think red. You just see whatever side is facing.
And this is a reason not to drink before noon time.
02-13-2015 | 04:22 PM
#35
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From: Pasadena, MD
It depends which side of the spring you're looking at, they have yellow and blue stripes on them.
F'in, I believe it was answered by S30 but in case it was missed, you should definitely run a locator/cup, or hardened shim under your springs. However, I would never recommend only running a .015" shim, I've seen lots of them come apart when used as the sole shim under that kind of spring pressure. Use whatever lock/retainer combo you need to get enough height to run a locator, or at least a thicker shim.
F'in, I believe it was answered by S30 but in case it was missed, you should definitely run a locator/cup, or hardened shim under your springs. However, I would never recommend only running a .015" shim, I've seen lots of them come apart when used as the sole shim under that kind of spring pressure. Use whatever lock/retainer combo you need to get enough height to run a locator, or at least a thicker shim.
With the new lock Bob mentioned we figure we could use a .030 shim.
02-13-2015 | 05:06 PM
#36
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From: bel air, md
So you do understand that I’m gonna pass on changing my 482 that may have even helped win an offshore championship (one of 40 made) that was designed by a guy way smarter than about any of us, with the heads being built in house by Crane (when they used to do that stuff) for Chevrolet / Kiehaefer offshore racing program and just because a couple guys on here see a picture I should do as they say?
Think about it, do you think a program that in its time had waaaaaaayyyyyyyyyy more money than any Nascar team of its time is going to put the wrong locks in their heads???? (Kiehaefer had 5 teams at one time in Nascar) Not to mention the motor I took apart and rebuilt was a motor that had been run and there was nothing wrong with the locks or the retainers and they all went back. So why should I change things?
The poly locks are two rounds past what H/S calls for but they always could be 1/8 longer.
No on the guide plates. I’m in deep enough building 2 motors over the last 14 months. Once that sting passes I will start thinking of upgrades.
The springs are dual springs with a damper and have 3 stripes. Blue, yellow and I think red. You just see whatever side is facing.
And this is a reason not to drink before noon time.
Think about it, do you think a program that in its time had waaaaaaayyyyyyyyyy more money than any Nascar team of its time is going to put the wrong locks in their heads???? (Kiehaefer had 5 teams at one time in Nascar) Not to mention the motor I took apart and rebuilt was a motor that had been run and there was nothing wrong with the locks or the retainers and they all went back. So why should I change things?
The poly locks are two rounds past what H/S calls for but they always could be 1/8 longer.
No on the guide plates. I’m in deep enough building 2 motors over the last 14 months. Once that sting passes I will start thinking of upgrades.
The springs are dual springs with a damper and have 3 stripes. Blue, yellow and I think red. You just see whatever side is facing.
And this is a reason not to drink before noon time.
02-13-2015 | 05:23 PM
#38
MarineKinetics
Joined: Oct 2002
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From: Rochester, NY
F_s,
I appreciate (and share) your enthusiasm for the preservation of a significant piece Offshore racing history. While most of your short block and the cylinder head castings are from the original Kiekhaefer/Chevrolet 482/496 program. It is difficult to define whether they are from the original 482 “Turbo Jet “program (1970) or the 482/496 offshore FI effort. (1972).
That said, I have cam sheets for both programs and I can tell you with certainty that your current valve train;
Crane Cams - Part #:138091 Mechanical roller tappet / Grind Number:TR-252/400-2-10, Basic Operating RPM Range:3,500-7,000 / Duration at 050 inch Lift:252 int./262 exh. Advertised Duration: 290 int/300 exh, Lift .680/.708
spring, retainer, and valve locks are not original or correct to the Kiekhaefer package. In fact, the lobe family the Crane 138091 cam is based on was not designed and brought into production until 1980, some 8-10 years after the original build. This certainly speaks to the criticism of the current cam valve train set up (obviously done after the engine left Kiekhaefer) and not the man himself.
I know many of the GM based Turbo Fire 482 were flat tappet, sent to KK, and subsequently converted to roller cams. I have the lobe numbers, but I am unsure the masters still exist.
Some history from a previous thread;
[ATTACH=CONFIG]537025[/ATTACH][ATTACH=CONFIG]537026[/ATTACH]
I appreciate (and share) your enthusiasm for the preservation of a significant piece Offshore racing history. While most of your short block and the cylinder head castings are from the original Kiekhaefer/Chevrolet 482/496 program. It is difficult to define whether they are from the original 482 “Turbo Jet “program (1970) or the 482/496 offshore FI effort. (1972).
That said, I have cam sheets for both programs and I can tell you with certainty that your current valve train;
Crane Cams - Part #:138091 Mechanical roller tappet / Grind Number:TR-252/400-2-10, Basic Operating RPM Range:3,500-7,000 / Duration at 050 inch Lift:252 int./262 exh. Advertised Duration: 290 int/300 exh, Lift .680/.708
spring, retainer, and valve locks are not original or correct to the Kiekhaefer package. In fact, the lobe family the Crane 138091 cam is based on was not designed and brought into production until 1980, some 8-10 years after the original build. This certainly speaks to the criticism of the current cam valve train set up (obviously done after the engine left Kiekhaefer) and not the man himself.
I know many of the GM based Turbo Fire 482 were flat tappet, sent to KK, and subsequently converted to roller cams. I have the lobe numbers, but I am unsure the masters still exist.
Some history from a previous thread;
Attached is a photo of your connecting rod. (Credit unknown).The parting line on the forging is hand ground smooth the full length of the rod. Areas around the bolt seats are given a generous radius to reduce the potential for stress risers. GM had a design sheet for race preparation of the dimple rod. The Kiekhaefer rods are prepped in identical fashion.
There were 25 of these engines assembled at GM in cooperation with Kiekhaefer. At that time all production Chevy big block packages were designated “Turbo Jet” engines. These development engines were designated 482 Chevrolet “Turbo-Marine” engines even though none were ever turbocharged.
The architecture of packaging a 4.25” stroke into a Std. deck block was much more challenging in the late 60’s, early 70’s than today. There were no aftermarket 4.250” cranks or shelf stock piston pin heights raised .125” or 6.385” connecting rods available at that time. That left two choices for an engine builder. Sourcing a costly custom crank from Moldex or Hank the Crank, or welding and offset grinding a OEM crankshaft, using a Std, piston pin height, a long rod, and a raised deck block. Kiekhaefer , had semi finished rod forgings made that would accommodate the necessary 6.405” c to c length of the rod to package the assembly. The packaging of the assembly is why a tall deck block had to be utilized, in spite of its inherent design disadvantage.
What is a routine 482/489/496 build today, utilizing parts sourced from the aftermarket, was considerably more difficult in 1969.
Block deck dimension Std Deck (454)____ 9.800”
˝ stroke/stroke radius_______2.00”
Rod C to C________________6.135”
Piston Compression Ht._____1.645”
Piston to Deck_____________.020”
Total_____________________9.800”
Block deck dimension Tall Deck (482)____ 10.200”
˝ stroke/stroke radius_______2.125”
Rod C to C________________6.405”
Piston Compression Ht.______1.645”
Piston to Deck_____________.025”
Total_____________________10.200”
[ATTACH=CONFIG]515555[/ATTACH]
There were 25 of these engines assembled at GM in cooperation with Kiekhaefer. At that time all production Chevy big block packages were designated “Turbo Jet” engines. These development engines were designated 482 Chevrolet “Turbo-Marine” engines even though none were ever turbocharged.
The architecture of packaging a 4.25” stroke into a Std. deck block was much more challenging in the late 60’s, early 70’s than today. There were no aftermarket 4.250” cranks or shelf stock piston pin heights raised .125” or 6.385” connecting rods available at that time. That left two choices for an engine builder. Sourcing a costly custom crank from Moldex or Hank the Crank, or welding and offset grinding a OEM crankshaft, using a Std, piston pin height, a long rod, and a raised deck block. Kiekhaefer , had semi finished rod forgings made that would accommodate the necessary 6.405” c to c length of the rod to package the assembly. The packaging of the assembly is why a tall deck block had to be utilized, in spite of its inherent design disadvantage.
What is a routine 482/489/496 build today, utilizing parts sourced from the aftermarket, was considerably more difficult in 1969.
Block deck dimension Std Deck (454)____ 9.800”
˝ stroke/stroke radius_______2.00”
Rod C to C________________6.135”
Piston Compression Ht._____1.645”
Piston to Deck_____________.020”
Total_____________________9.800”
Block deck dimension Tall Deck (482)____ 10.200”
˝ stroke/stroke radius_______2.125”
Rod C to C________________6.405”
Piston Compression Ht.______1.645”
Piston to Deck_____________.025”
Total_____________________10.200”
[ATTACH=CONFIG]515555[/ATTACH]
02-13-2015 | 07:08 PM
#39
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From: Pasadena, MD
Bob, once again thank you. Maybe what I thought was a total original is a modified K motor or a clone or a clone of a clone. All I know it a 1969/70 - 427 tall block block, forged stroked GM crank matching the same years, Kiekhaefer rods and LS6 pistons makes a 482. Crane had their name stamped all over the heads and most everything inside the heads came from Crane all the way to the cam. Not to mention the marine flywheel, oil pan, etc, etc. The motor looked like it had never been opened with the timing chain cover still being wired shut and such.
It is what it is and if its not a total K motor makes feel a bit easier about knowing that I plan on beating crap out it the 3 or 4 hours I may get to use it a year.
On a side note you all keep saying that they are not the right springs and being the cam is out of production but Summit still has an old listing and says the springs are a required part for the cam. http://www.summitracing.com/parts/cr...commendedparts
It is what it is and if its not a total K motor makes feel a bit easier about knowing that I plan on beating crap out it the 3 or 4 hours I may get to use it a year.
On a side note you all keep saying that they are not the right springs and being the cam is out of production but Summit still has an old listing and says the springs are a required part for the cam. http://www.summitracing.com/parts/cr...commendedparts
02-13-2015 | 07:30 PM
#40
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From: Western Michigan
Hey Bob....awesome post on the history on the Kiekhaefer 482cid engine! Was that engine something like 680hp? If so, do you know what the peak RPM range was?
I think Betty Cook used those in her race boat back in the day and when I was a kid in high school I remember reading an article about her and her race boat/team in a boating magazine back around 1975 or so. I remember those Kiekhaefer engines with the FI velocity stacks.
I think Betty Cook used those in her race boat back in the day and when I was a kid in high school I remember reading an article about her and her race boat/team in a boating magazine back around 1975 or so. I remember those Kiekhaefer engines with the FI velocity stacks.
