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FE TALK
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http://www.clubcobra.com/forums/fe-talk/)
| RockBit |
12-16-2018 01:07 PM |
Great job Brent. Your ME education is showing. I’m sure there are lots of guys that will take advantage of this.
Whenever I get close to 6,000 in mine, its time to change my underwear.
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| blykins |
12-16-2018 05:07 PM |
Wear some depends and keep your foot in it. :cool:
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| redmt |
12-17-2018 08:29 AM |
Hey Brent, back in the day I had a pull truck FE go over 9k when the oil pump shaft broke and then it made a really big noise, and immediately disassembled itself.
Seriously though, we tried everything we could think of for more RPM. 62-6800 was doable but the valve train available to us at that time wouldn't hold up. It's great that you were able to take a good idea and using todays technology come up with a solution to a long standing problem.
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| redmt |
12-17-2018 08:36 AM |
Quote:
Originally Posted by blykins
(Post 1455323)
Wear some depends and keep your foot in it. :cool:
|
An old time buddy of mine and I used to spend a lot of money and time building these engines. His statement most every time I would blow one up was "Didn't you hear the noise". My reply was usually something like "F'k the noise, by the time you hear it it's already too late" I NEVER took my foot out of it. |
| Whodeeny |
12-17-2018 10:17 AM |
Quote:
Originally Posted by blykins
(Post 1455251)
High rpm FE's have never been a problem. High rpm hydraulic roller FE's have been the bottleneck.
Lots of my customers want a little more rpms without having to run a flat tappet cam or the risk of a solid roller. Now we have options.
I took it to 7500 simply because I wanted to prove my rocker arm design. It went there very easily with only 200 lbs seat pressure and 500 lbs open.
We turn 8500-9000 rpms with <400 lbs seat pressure and 1200 lbs open pressure on my BBF pulling truck engines.....with almost 2.5" valves. The right cam lobe makes all the difference.
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What are the risks of a solid roller? |
| cycleguy55 |
12-17-2018 10:54 AM |
Brent:
I appreciate your FE knowledge and experience, and this example only reinforces that.
On a related topic, what would be the rev limit for a 385 series with a similar setup - properly profiled hydraulic roller cam, light but strong rocker arms, etc.? Other critical components (e.g. titanium retainers)?
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| blykins |
12-17-2018 11:12 AM |
Quote:
Originally Posted by Whodeeny
(Post 1455350)
What are the risks of a solid roller?
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The lifters have needle bearings or bushings in them. Solid cams have lash, which means that the lifter is not always in contact with the cam lobe. Couple that with much higher spring pressures than normal (usually around 600-700 lbs) and you have a lifter that is constantly being beat up. The lifters have a short life span and if you don't keep up with it, you can end up with scattered parts inside your engine and a ruined camshaft. |
| blykins |
12-17-2018 11:14 AM |
Quote:
Originally Posted by cycleguy55
(Post 1455352)
Brent:
I appreciate your FE knowledge and experience, and this example only reinforces that.
On a related topic, what would be the rev limit for a 385 series with a similar setup - properly profiled hydraulic roller cam, light but strong rocker arms, etc.? Other critical components (e.g. titanium retainers)?
|
I would expect the same and it's more than likely easier to get to that result. Studded rocker arms are generally more stable than shaft mounted rockers and there are lots of rockers to choose from for the 385 series.
Biggest help is the cam lobe shape, correct spring pressures, and light as possible valves. |
| cycleguy55 |
12-17-2018 01:20 PM |
Quote:
Originally Posted by blykins
(Post 1455354)
I would expect the same and it's more than likely easier to get to that result. Studded rocker arms are generally more stable than shaft mounted rockers and there are lots of rockers to choose from for the 385 series.
Biggest help is the cam lobe shape, correct spring pressures, and light as possible valves.
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Sounds good. Thanks!
Merry Christmas! |
| Whodeeny |
12-18-2018 09:20 AM |
Quote:
Originally Posted by blykins
(Post 1455251)
High rpm FE's have never been a problem. High rpm hydraulic roller FE's have been the bottleneck.
Lots of my customers want a little more rpms without having to run a flat tappet cam or the risk of a solid roller. Now we have options.
I took it to 7500 simply because I wanted to prove my rocker arm design. It went there very easily with only 200 lbs seat pressure and 500 lbs open.
We turn 8500-9000 rpms with <400 lbs seat pressure and 1200 lbs open pressure on my BBF pulling truck engines.....with almost 2.5" valves. The right cam lobe makes all the difference.
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What is the risk of a solid roller? |
| blykins |
12-18-2018 09:52 AM |
I answered your question up above.
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| Whodeeny |
12-31-2018 10:48 AM |
Quote:
Originally Posted by blykins
(Post 1455353)
The lifters have needle bearings or bushings in them. Solid cams have lash, which means that the lifter is not always in contact with the cam lobe. Couple that with much higher spring pressures than normal (usually around 600-700 lbs) and you have a lifter that is constantly being beat up. The lifters have a short life span and if you don't keep up with it, you can end up with scattered parts inside your engine and a ruined camshaft.
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Brent - What would the expected life span (in miles driven) be for mechanical roller cam lifters for an engine driven on the street? Thanks. |
| blykins |
12-31-2018 10:53 AM |
Depends on the lifters, but generally anywhere between 3500-10000 miles.
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| Whodeeny |
12-31-2018 12:43 PM |
Quote:
Originally Posted by blykins
(Post 1455955)
Depends on the lifters, but generally anywhere between 3500-10000 miles.
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In your opinion who makes the best mechanical roller lifters, the ones that might run 10,000 miles? |
| blykins |
12-31-2018 01:02 PM |
Morel, Crower, Jesel, Isky.
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| Whodeeny |
01-01-2019 11:09 AM |
Quote:
Originally Posted by blykins
(Post 1455958)
Morel, Crower, Jesel, Isky.
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Thanks Brent.
Comp Cams has a mechanical roller lifter (96836B-16, $1000 for 16 lifters!) that replaces the needle roller bearings with a bronze bushing. Any experience with using this lifter? |
| blykins |
01-01-2019 11:18 AM |
I don’t run Comp lifters.
If you don’t plan on being over 6000-6500, there is no reason to run a solid roller on the street and take the risk.
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| Kit Coyle |
01-10-2019 10:24 AM |
My Cobra has a 1970 BOSS 302 Cleveland engine with a solid lifter cam and
lifters built in 2006 with new pistons in 2012. This thread has raised solid lifter longevity concerns so I thought I would run this by everyone to see where I stand. The block, crank, rods, heads and intake manifold are 1970 BOSS 302.
The pan is Milodon road race with windage tray. The cam is a Chrane solid
roller with duration 230/238 @ .50. Adv. duration is 280/288. Intake @ .50
opens 8.0 BTDC closes 42.0 ABDC. Max lift 107 duration 230. Exhaust opens
56.0 BBDC closes 2.0 ATDC. Max lift 117. Duration 238. Spring pressures
145 closed 345 open. Trick flow pushrods. Harland-Sharp roller rockers.
17,000 miles on engine with new pistons at 12,000. I am told heads must
be removed on this block to access lifters to check them. No bad noises
using stethoscope. Very strong engine. How radical is my cam and where do
you see my vulnerability and what can I do to mitigate future problems.
Thank you very much.
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| blykins |
01-10-2019 10:51 AM |
Kit, your cam is not radical and your spring pressures are light. You didn't mention what lifters you're using, but I would be doing a lifter inspection or even a replacement at your mileage level.
In the future, if you do a rebuild, there is absolutely no reason to run a solid roller for this type of build. What you have could have been easily accomplished with a hydraulic roller that could go 100000 miles without issue.
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| Kit Coyle |
01-10-2019 11:40 AM |
Thank you Brent. The lifters are Crane "Vertical Guidebar Roller Tappets"
circa 2006. If the heads have to come off to inspect the lifters then I might
consider putting in new. Or maybe think about a hydraulic cam and lifters at not a heck of a lot more money. Too bad there isn't an easier way to get access
to the lifters in this block, but such is life. I also might mention that this engine
has MPG port plates installed...both intake and exhaust. I don't know how
much difference they make but there is no mid-range flat spot. With such a
light car I wouldn't think there would be anyway. Thanks again, Brent.
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