Big solid flat tapet cams.

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Berserk
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Big solid flat tapet cams.

Post by Berserk » Thu Nov 02, 2017 4:33 pm

Do the large solid flat tapet cams work well or are there a lage risk of them going flat? I se comp listing cams at 260-270 degree intake duration at 050 and 640 lift. Seems to me that it would be a very cheap way to make some desent power in a big block chevy. will a cam like that last on the street?

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Re: Big solid flat tapet cams.

Post by pdq67 » Thu Nov 02, 2017 6:12 pm

You might want to hunt up the late UDHarold's BBC solid flat tappet lifter cams and chat with some of the BBC guys that run them.

And I really miss Harold on the boards.

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MELWAY
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Re: Big solid flat tapet cams.

Post by MELWAY » Thu Nov 02, 2017 10:20 pm

It's no so much the big duration that would make it in reliable but high lobe lift with fast ramps with cause early wear
3370lb Sedan 9.89@136MPH 358chevN/A

Geoff2
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Re: Big solid flat tapet cams.

Post by Geoff2 » Fri Nov 03, 2017 3:28 am

High lift = more spring tension to control valve train
More spring = more wear
More lobe lift = smaller overall lobe, 'peakier' nose, less area to carry the load at max lift

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Re: Big solid flat tapet cams.

Post by DaveMcLain » Fri Nov 03, 2017 7:34 am

Geoff2 wrote:
Fri Nov 03, 2017 3:28 am
High lift = more spring tension to control valve train
More spring = more wear
More lobe lift = smaller overall lobe, 'peakier' nose, less area to carry the load at max lift
More lift does not necessarily mean that you need higher spring loads to control the valvetrain. Often a lobe with more lift can have lower negative accelerations and actually require less load.

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CamKing
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Re: Big solid flat tapet cams.

Post by CamKing » Fri Nov 03, 2017 10:15 am

It depends on the lobe design, but the longer the duration for a given lift, the less spring pressure you need, and the more reliable the cam will be.
We have a 260@.050" design with .615" lift, and it's very reliable, but I could design a cam with the same lift and duration that would require 100 more pounds of spring pressure, and it wouln't be very reliable.
Mike Jones
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Re: Big solid flat tapet cams.

Post by Steve.k » Fri Nov 03, 2017 10:22 am

We currently running two engines with flat cams. One is .657 and 260-266 @.050. The other .640 and 255-260@.050. Seem fine for reliability. Cam builder calls for 120-320 spring pressure! Hardly aggressive.

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Re: Big solid flat tapet cams.

Post by Geoff2 » Sat Nov 04, 2017 5:53 am

Dave,
Maybe you should read the OPs post...again.

Berserk
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Re: Big solid flat tapet cams.

Post by Berserk » Mon Nov 13, 2017 12:53 pm

How do I tell if it is a reliable cam or not? If I would like a cam with slower less agressive ramps that will live on the street. How about something like this?

Brand:COMP Cams
Manufacturer's Part Number:11-613-5
Part Type:Camshafts
Product Line:COMP Cams Drag Race Camshafts
Summit Racing Part Number:CCA-11-613-5

UPC: 036584540151
Cam Style: Mechanical flat tappet
Basic Operating RPM Range: 4,500-7,500
Intake Duration at 050 inch Lift: 270
Exhaust Duration at 050 inch Lift: 280
Duration at 050 inch Lift: 270 int./280 exh.
Advertised Intake Duration: 310
Advertised Exhaust Duration: 320
Advertised Duration: 310 int./320 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.638 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.638 in.
Valve Lift with Factory Rocker Arm Ratio: 0.638 int./0.638 exh.
Lobe Separation (degrees): 110
Intake Valve Lash: 0.028 in.
Exhaust Valve Lash: 0.030 in.
Computer-Controlled Compatible: No
Grind Number: CB 310C-10

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Re: Big solid flat tapet cams.

Post by statsystems » Mon Nov 13, 2017 2:27 pm

Berserk wrote:
Mon Nov 13, 2017 12:53 pm
How do I tell if it is a reliable cam or not? If I would like a cam with slower less agressive ramps that will live on the street. How about something like this?

Brand:COMP Cams
Manufacturer's Part Number:11-613-5
Part Type:Camshafts
Product Line:COMP Cams Drag Race Camshafts
Summit Racing Part Number:CCA-11-613-5

UPC: 036584540151
Cam Style: Mechanical flat tappet
Basic Operating RPM Range: 4,500-7,500
Intake Duration at 050 inch Lift: 270
Exhaust Duration at 050 inch Lift: 280
Duration at 050 inch Lift: 270 int./280 exh.
Advertised Intake Duration: 310
Advertised Exhaust Duration: 320
Advertised Duration: 310 int./320 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.638 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.638 in.
Valve Lift with Factory Rocker Arm Ratio: 0.638 int./0.638 exh.
Lobe Separation (degrees): 110
Intake Valve Lash: 0.028 in.
Exhaust Valve Lash: 0.030 in.
Computer-Controlled Compatible: No
Grind Number: CB 310C-10

Depends on lifter diameter.

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Re: Big solid flat tapet cams.

Post by CamKing » Mon Nov 13, 2017 2:56 pm

statsystems wrote:
Mon Nov 13, 2017 2:27 pm
Depends on lifter diameter.
????
That cam won't know what lifter diameter is on it, as long as it's bigger then .842"
Mike Jones
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
(704)489-2449

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Re: Big solid flat tapet cams.

Post by Newold1 » Mon Nov 13, 2017 7:39 pm

Beserk

Your Comp Cams choice for a camshaft with durability for the street seems a bit of a contradiction?

How well does any engine become durable on the street when the operating range is 4500 to 7500rpms??

Think you better ask some one like Mike at CamKing and find a workable design for your application.

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Re: Big solid flat tapet cams.

Post by pdq67 » Mon Nov 13, 2017 8:27 pm

Like I said earlier, hunt up UDHarolds cams here and then talk to the guys that run them.

Might try going over to Team Chevelle and asking because imho, they have more BBC engines in their rides than Team Camaro and NastyZ28.

pdq67

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Re: Big solid flat tapet cams.

Post by Berserk » Fri Nov 17, 2017 4:43 am

lifter diameter would be stock chevrolet. Yes I will ask at team chevelle to.

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