comp cams thumper?? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 05-15-2012, 06:49 PM
ronbuhg's Avatar
Registered User
 
Join Date: May 2012
Posts: 35
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
comp cams thumper??

has anyone installed the comp cams "mutha thumper" cam,and how did it end powerwise and driveability? is it workable for a steet driven truck w/700R4 trans??would appreciate any and all thoughts on this.im sure i need to install screw-in studs/guide plates...extra vac source,stall converter???..anything else i need to consider ???will be a 350,4 bbl,iron heads{maybe aluminum heads}....headers,2.5" pipes,trual duals w/ flow masters 3 chamber mufflers,2 chambers too loud for my area unfortantly,would be cool if no restrictions on sound as im 85% deaf anyway!!!LOL !!!thanks for the time to answer..remember the dumbest questions are the ones you dont ask.....right??

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 05-15-2012, 07:50 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by ronbuhg
has anyone installed the comp cams "mutha thumper" cam,and how did it end powerwise and driveability? is it workable for a steet driven truck w/700R4 trans??would appreciate any and all thoughts on this.im sure i need to install screw-in studs/guide plates...extra vac source,stall converter???..anything else i need to consider ???will be a 350,4 bbl,iron heads{maybe aluminum heads}....headers,2.5" pipes,trual duals w/ flow masters 3 chamber mufflers,2 chambers too loud for my area unfortantly,would be cool if no restrictions on sound as im 85% deaf anyway!!!LOL !!!thanks for the time to answer..remember the dumbest questions are the ones you dont ask.....right??
I'll forgo the spiel about the thumpr cam line being poser cams and cut to the chase:

If after fully researching this cam you still want to run it, the cam requires a lot of initial timing (20 degrees-plus) to allow the carb to be adjusted for a decent idle w/o the primary throttle blades being opened so far the carb is idling on the transition circuit. This will mean the distributor may need work to the mechanical advance mechanism to keep the mechanical advance from adding too much timing. An adjustable vacuum advance will be needed in most cases as well.

There are many posts on this forum and elsewhere on these cams, you can do a search for more. Until then, these links may help:

Ignition advance

Cam installation

Adjusting the valves

Distributor installation

Valve train points to check
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 05-16-2012, 08:57 AM
ronbuhg's Avatar
Registered User
 
Join Date: May 2012
Posts: 35
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
thumper cam yes/no??

i think i'll heed what your not saying...dont sound like you like this cam for the street, so i'll think about a different cam??what would you reccomend as to what i'm looking for??steetable but would like a nice lope to it IF possible.i do understand i can't always get what i want both ways. sooooo???thanks &happy cruisin!!
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 05-16-2012, 09:30 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by ronbuhg
i think i'll heed what your not saying...dont sound like you like this cam for the street, so i'll think about a different cam??what would you reccomend as to what i'm looking for??steetable but would like a nice lope to it IF possible.i do understand i can't always get what i want both ways. sooooo???thanks &happy cruisin!!
I don't recommend cams per se, but I can give you a bit of info that may help you pick one:

A cam with a narrower rather than a wider lobe separation angle (LSA) will have more lope. A later intake closing point will tend to increase the overlap and cause a lope, same thing for an earlier opening exhaust.

Headers and a free flowing exhaust system will help the sound of a cam, stock exhaust manifolds like found on Gen 1 SBC engines inhibit the sound.

Also, I'm not totally discounting the use of a thumpr cam. They have their place and as long as you're willing to give up some performance for sound, then it may not be such a bad choice for you. It's just that many guys feel that if they are going to live w/a cam that has less vacuum and a lot of lope, they will go all the way and run a cam w/as much performance to offer as it can. One thing about the thumpr cams is for the sound they have, the vacuum isn't all that bad.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 05-16-2012, 10:27 AM
1971BB427's Avatar
Registered User
 

Last journal entry: Latest changes
Last photo:
Join Date: Dec 2010
Location: Portland
Posts: 1,570
Wiki Edits: 0

Thanks: 13
Thanked 239 Times in 208 Posts
There are cams that will work well with a stock converter and a fairly stock engine, and still give that lopey idle, but not lose useable bottom end. Crane has a nice cam that is 272/272 duration, with .454" lift and a LSA of 108. It's good right off idle at 1500 to around 5800 rpm's. You'll be much happier with this than any of the Thumpr cams.
Summit sells the same cam under their brand name for a lower price, so you can save some bucks and go with their's.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 05-16-2012, 12:18 PM
ronbuhg's Avatar
Registered User
 
Join Date: May 2012
Posts: 35
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
yeah??

sounds like the perferct cam for me.i didnt want to stick in something only to have one problem after another to deal with...what are your thoughts on "brand name" vs. "generic" if you will.dont mind saving $$$ at all.just dont want to have to go back into the motor 2 months later and do this all over again.reliability is uppermost in my mind..many years ago i built a 350 bored .030,4bbl,dual plane intake,headders,4 bolt main,"pink rods",true duals w/ the factory 327/350 hp cam.in a 75 camaro ,limited slip rear {you'll never believe this buts its true}a 2.56 gearset....also 350 trans w/shift kit.....burned not barked a mean 2nd gear {3rd if my ex-wife was driving and pissed off }that set-up i was very pleased with.this time i want to step up 1 or2 notches. the cam you recomended sounds perfect for my needs!!!!already got the p/n written in my wish list.thanks for getting rid a headache i've for some time...i have agonized over this prob. for a long time..glad i accidently found this website !!!sorry for being so longwinded. nobody closeby to discuss this with....happy cruisin!!!!!!
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 05-16-2012, 08:02 PM
BigEd36's Avatar
Registered User
 
Last photo:
Join Date: Nov 2009
Location: Auburn, IN
Age: 65
Posts: 386
Wiki Edits: 0

Thanks: 17
Thanked 43 Times in 39 Posts
Ronbuhg, you don't state what your truck setup is/will be but since you've said it will be street driven I'm going to make a few assumptions. I'm assuming a stock/near stock compression ratio, and you want a pump gasoline friendly compression ratio, so 9.5:1 or less static compression ratio (SCR). For a truck, which will be a lot heavier than the Camaro I would recommend a cam with a little less .050 duration than the ol' 327CI 350HP cam (even tho it's one of my all time favorites). That cam, and the 350CI 350HP cam, was designed for engines with 11:1 SCR, and both have a wide 114* LSA so they will idle smooth. With the lower CR's of the "smog era" engines, it really lowers the DCR (dynamic CR) so it loses a lot on the bottom, which is why the GMPP 350CI 290HP crate engine, with 8.5:1 and the ol' 350CI 350 HP cam, has a reputation as a slug til it's gets the revs up. I would stay with a milder duration cam, but with a tighter LSA as Cobalt327 recommended.

I'll recommend a few more modern cams for your truck.

First, the grind commonly known as an "RV cam". EVERY cam company has this, or an almost identical grind. Look for .420/.440 lift, 204*/214* @ .050, with a 110-112* LSA. A little more lift and duration than the ol' 350CI 300HP cam, and pulls hard in a heavy vehicle like a pickup or RV.

2nd, one of the most popular grinds, EVER. The Comp Cams High Energy HE268, .458 lift, 268* advertised, 218* @ .050, 110 LSA 106 ICL. I imagine the reason it's so popular is precisely because it has the right combination on lift and duration to work with the millions of "smog era" SBC's, and has a bit of choppiness for some of the "cam music" that we love.

2 very popular cams for SBC's with "smog era" static compression
ratio's (example 8.5:1 to 9.5:1) are the Crane 274HO6 (and versions by Summit and Elgin) and a grind I'll call the
K1103 (Sold by Summit Racing as the K1103 although every cam
company has this grind). These cams have mild .050 duration figures
to maintain dynamic CR for low end power. They will work well with
stock torque converters and "highway" gears, but will work even better
with higher than stock stall converters and lower (higher numerically) gears.

Crane 274HO6 grind, .450 lift, 274* advertised duration, 218* duration @ .050, 106LSA, 102 ICL Cam/lifter kit $209.60 at Summithttp://www.summitracing.com/parts/CRN-100072/ The 274HO6 is an equivalent cam to the ultra popular Comp Cams High Energy 268H, but is ground on a tighter 106* LSA. It has a choppy idle with mild 218* @ .050 intake duration. This cam is one of the grinds that Crane used to classify as "3/4 race".


Summit K00172 (Same grind as Crane 274HO6 -
supplied to Summit by Crane)
Cam/lifter kit $133.95
http://www.summitracing.com/parts/SUM-K00172/

Elgin CL1785PK (Same grind as Crane 274HO6)
Cam/lifter kit $99.95 at Northern Auto Parts
http://www.northernautoparts.com/Pro...tModelId=17034

YouTube video of 274HO6 idling in Shaun's '73 Nova with stock Goodwrench 350, Performer intake, 600 cfm Holley carb, open headers. Nova has hi-stall convertor, 3.73 open diff (no posi), has turned 13.86 1/4 mile with drag radials
http://www.youtube.com/watch?v=sDEthCakytU


Summit K1103 (same basic grind as GMPP 350HO and CT350 circle track crate engine.
Cam/lifter kit $99.95 at Summit. The "K1103" grind (.443/.465 lift, 214/224 @ .050, 112 LSA)
has just slightly more lift and duration than the cam used by GMPP in the "350HO" (350CI 330HP) crate engine and the "CT350" (350CI 350HP) circle track crate engine. .435/.460 lift, 320*/324* advertised
duration, 212*/222* @ .050 duration, 112.5* LSA. This is a little more "modern" split pattern cam, and has a wide flat torque curve, the idle is not quite as choppy as the 276HO6 but still has some choppiness so you can "hear the cam". The K1103 cam/lifter kit is $99.95 at http://www.summitracing.com/parts/SUM-K1103/

The 3 cams below are the same grind as the K1103.

Lunati Barebones 10001LK - C/L kit $99.95 at Summit
http://www.summitracing.com/parts/LUN-10001LK/

Elgin E-922-P C/L kit: CL-922PK
$137.15 at Northern Auto Parts http://www.northernautoparts.com/Pro...ntoryId=114312

SpeedPro CS1013R C/L kit CL1013PK $148.61 at Northern Auto Parts
http://www.northernautoparts.com/Pro...ntoryId=114312

Youtube videos with K1103:

'70 Chev C10 with 350 http://www.youtube.com/watch?v=_K-XV3Yum8k

350 with noisy gear drive http://www.youtube.com/watch?v=K-M45...eature=related

As for "name" versus "generic" grinds, the main difference is the label on the box and the price. Most all cams, no matters who's box it comes in, are ground by 3 cam grinding companies. The only cam companies, as far as I know, that grind all their cams in-house are Isky and Howards (both very good cams). The Crane 274HO6 part # is 10017. The last I knew Summit cams were supplied by Crane. The Summit part # for a cam/lifter kit is K10017 (looks kinda like Crane's number, huh?), but the part number for the cam only is 1785, the same as the part number for the Elgin boxed cam. Hmmmmmmm...

Hope I didn't muddy the waters too much in your decision makin'!

Ed

Last edited by BigEd36; 05-16-2012 at 08:21 PM.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 05-16-2012, 08:25 PM
1971BB427's Avatar
Registered User
 

Last journal entry: Latest changes
Last photo:
Join Date: Dec 2010
Location: Portland
Posts: 1,570
Wiki Edits: 0

Thanks: 13
Thanked 239 Times in 208 Posts
I wont buy junk to put inside my engine, but the Summit cams are nothing different than regular Crane Cams in a plain white wrapper. All you're giving up is a box that says Crane. I've used a lot of them, and as long as I can look up the specs and crossreference it to the same Crane Cam, then I know it's good.
There are a few Summit cams that I'm unsure who makes them, as I don't find equal cams in Crane's catalog. I steer clear of those until I know who makes them.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 05-16-2012, 08:45 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by BigEd36
I'll recommend a few more modern cams for your truck.
BigEd, this could make a good addition to the Crankshaft Coalition wiki. If you'd care to, you can put it there or if you'd prefer, I will.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 05-16-2012, 10:25 PM
1971BB427's Avatar
Registered User
 

Last journal entry: Latest changes
Last photo:
Join Date: Dec 2010
Location: Portland
Posts: 1,570
Wiki Edits: 0

Thanks: 13
Thanked 239 Times in 208 Posts
Quote:
Originally Posted by BigEd36
Crane 274HO6 grind, .450 lift, 274* advertised duration, 218* duration @ .050, 106LSA, 102 ICL Cam/lifter kit $209.60 at Summithttp://www.summitracing.com/parts/CRN-100072/ The 274HO6 is an equivalent cam to the ultra popular Comp Cams High Energy 268H, but is ground on a tighter 106* LSA. It has a choppy idle with mild 218* @ .050 intake duration. This cam is one of the grinds that Crane used to classify as "3/4 race".

Ed
I think you may have linked the wrong cam here. It comes up as Summit's 284/284, with 112 LSA
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 05-17-2012, 03:07 AM
BigEd36's Avatar
Registered User
 
Last photo:
Join Date: Nov 2009
Location: Auburn, IN
Age: 65
Posts: 386
Wiki Edits: 0

Thanks: 17
Thanked 43 Times in 39 Posts
Quote:
Originally Posted by 1971BB427
I think you may have linked the wrong cam here. It comes up as Summit's 284/284, with 112 LSA
1971BB427, you are correct, the correct link for the Crane 274HO6 cam/lifter kit at Summit is Crane 274HO6 at Summit. Not sure how I did that. I knew the part #'s for those 2 cams 'cause a lot of short track racers in the "hobby" classes use the 10007 cam, guess I saw the "7" and got in a hurry. Sorry for any confusion this may have caused. Maybe the mods can correct the link in my post, I can't edit it now.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 05-17-2012, 03:15 AM
BigEd36's Avatar
Registered User
 
Last photo:
Join Date: Nov 2009
Location: Auburn, IN
Age: 65
Posts: 386
Wiki Edits: 0

Thanks: 17
Thanked 43 Times in 39 Posts
Quote:
Originally Posted by cobalt327
BigEd, this could make a good addition to the Crankshaft Coalition wiki. If you'd care to, you can put it there or if you'd prefer, I will.
Cobalt, after I get off work I'll make the corrections to my original post so it has the correct link in it for the Crane 10017 cam/lifter kit before we add it to the wiki.

Ed
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 06-02-2012, 05:03 AM
ronbuhg's Avatar
Registered User
 
Join Date: May 2012
Posts: 35
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by BigEd36
Ronbuhg, you don't state what your truck setup is/will be but since you've said it will be street driven I'm going to make a few assumptions. I'm assuming a stock/near stock compression ratio, and you want a pump gasoline friendly compression ratio, so 9.5:1 or less static compression ratio (SCR). For a truck, which will be a lot heavier than the Camaro I would recommend a cam with a little less .050 duration than the ol' 327CI 350HP cam (even tho it's one of my all time favorites). That cam, and the 350CI 350HP cam, was designed for engines with 11:1 SCR, and both have a wide 114* LSA so they will idle smooth. With the lower CR's of the "smog era" engines, it really lowers the DCR (dynamic CR) so it loses a lot on the bottom, which is why the GMPP 350CI 290HP crate engine, with 8.5:1 and the ol' 350CI 350 HP cam, has a reputation as a slug til it's gets the revs up. I would stay with a milder duration cam, but with a tighter LSA as Cobalt327 recommended.

I'll recommend a few more modern cams for your truck.

First, the grind commonly known as an "RV cam". EVERY cam company has this, or an almost identical grind. Look for .420/.440 lift, 204*/214* @ .050, with a 110-112* LSA. A little more lift and duration than the ol' 350CI 300HP cam, and pulls hard in a heavy vehicle like a pickup or RV.

2nd, one of the most popular grinds, EVER. The Comp Cams High Energy HE268, .458 lift, 268* advertised, 218* @ .050, 110 LSA 106 ICL. I imagine the reason it's so popular is precisely because it has the right combination on lift and duration to work with the millions of "smog era" SBC's, and has a bit of choppiness for some of the "cam music" that we love.

2 very popular cams for SBC's with "smog era" static compression
ratio's (example 8.5:1 to 9.5:1) are the Crane 274HO6 (and versions by Summit and Elgin) and a grind I'll call the
K1103 (Sold by Summit Racing as the K1103 although every cam
company has this grind). These cams have mild .050 duration figures
to maintain dynamic CR for low end power. They will work well with
stock torque converters and "highway" gears, but will work even better
with higher than stock stall converters and lower (higher numerically) gears.

Crane 274HO6 grind, .450 lift, 274* advertised duration, 218* duration @ .050, 106LSA, 102 ICL Cam/lifter kit $209.60 at Summithttp://www.summitracing.com/parts/CRN-100072/ The 274HO6 is an equivalent cam to the ultra popular Comp Cams High Energy 268H, but is ground on a tighter 106* LSA. It has a choppy idle with mild 218* @ .050 intake duration. This cam is one of the grinds that Crane used to classify as "3/4 race".


Summit K00172 (Same grind as Crane 274HO6 -
supplied to Summit by Crane)
Cam/lifter kit $133.95
http://www.summitracing.com/parts/SUM-K00172/

Elgin CL1785PK (Same grind as Crane 274HO6)
Cam/lifter kit $99.95 at Northern Auto Parts
http://www.northernautoparts.com/Pro...tModelId=17034

YouTube video of 274HO6 idling in Shaun's '73 Nova with stock Goodwrench 350, Performer intake, 600 cfm Holley carb, open headers. Nova has hi-stall convertor, 3.73 open diff (no posi), has turned 13.86 1/4 mile with drag radials
http://www.youtube.com/watch?v=sDEthCakytU


Summit K1103 (same basic grind as GMPP 350HO and CT350 circle track crate engine.
Cam/lifter kit $99.95 at Summit. The "K1103" grind (.443/.465 lift, 214/224 @ .050, 112 LSA)
has just slightly more lift and duration than the cam used by GMPP in the "350HO" (350CI 330HP) crate engine and the "CT350" (350CI 350HP) circle track crate engine. .435/.460 lift, 320*/324* advertised
duration, 212*/222* @ .050 duration, 112.5* LSA. This is a little more "modern" split pattern cam, and has a wide flat torque curve, the idle is not quite as choppy as the 276HO6 but still has some choppiness so you can "hear the cam". The K1103 cam/lifter kit is $99.95 at http://www.summitracing.com/parts/SUM-K1103/

The 3 cams below are the same grind as the K1103.

Lunati Barebones 10001LK - C/L kit $99.95 at Summit
http://www.summitracing.com/parts/LUN-10001LK/

Elgin E-922-P C/L kit: CL-922PK
$137.15 at Northern Auto Parts http://www.northernautoparts.com/Pro...ntoryId=114312

SpeedPro CS1013R C/L kit CL1013PK $148.61 at Northern Auto Parts
http://www.northernautoparts.com/Pro...ntoryId=114312

Youtube videos with K1103:

'70 Chev C10 with 350 http://www.youtube.com/watch?v=_K-XV3Yum8k

350 with noisy gear drive http://www.youtube.com/watch?v=K-M45...eature=related

As for "name" versus "generic" grinds, the main difference is the label on the box and the price. Most all cams, no matters who's box it comes in, are ground by 3 cam grinding companies. The only cam companies, as far as I know, that grind all their cams in-house are Isky and Howards (both very good cams). The Crane 274HO6 part # is 10017. The last I knew Summit cams were supplied by Crane. The Summit part # for a cam/lifter kit is K10017 (looks kinda like Crane's number, huh?), but the part number for the cam only is 1785, the same as the part number for the Elgin boxed cam. Hmmmmmmm...

Hope I didn't muddy the waters too much in your decision makin'!

Ed
i apologize for taking so long to get back to you but thanks for the info.naahh you didnt muddy it too bad just narrowed down to cams that have proven to work in the areas i was looking for.all of you have been a big help and it is appreciated mucho !!!happy cruisin !!! Ronbuhg
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
? about the new Thumper cam from Comp. streetmaster42 Hotrodding Basics 19 01-17-2012 01:45 AM
comp cams " thumper" roller cam 67-4-fun Hotrodding Basics 3 06-05-2011 06:05 AM
comp cams ddpecka348 Engine 24 02-14-2008 07:41 PM
Anyone try Comp Cams Nostalgia Cams ? super_silent Engine 15 11-22-2007 03:01 PM
Comp Cams 46_stvblt Engine 6 01-22-2004 09:02 PM


All times are GMT -6. The time now is 02:15 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.