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-   -   Cam LSA question (http://www.hotrodders.com/forum/cam-lsa-question-226019.html)

tjet 11-12-2012 05:06 PM

Cam LSA question
 
I have a question regarding the lobe seperation angle on a cam.
Will a cam with 232* @ .050" with a 112 LSA have a similar idle as a cam with 224* @ .050" with 110 LSA?

ap72 11-12-2012 05:57 PM

nope. They are 2 completely different cams and will behave in two completely different ways.

There's a LOT more to a cam than LSA, and damn the man who passed a long the idea that it is the most significant number involved in cam timing- it is no more significant than duration or lift. They ALL affect the manner of a cam.

tjet 11-12-2012 06:08 PM

I want to run the biggest hyd flat tappet cam possible without changing the torque converter or gears. The stall on the tq converter is around 2500. I'd like to install a comp magnum 280H, but I think the 230 dur + the 110 LSA may be too choppy. I'm thinking it may behave better with a 112 LSA

(355, 10:1, Dart 200 heads, Streetmaster intake, Q-jet, Tri-y 1-5/8 headers w/2.5 pipes, 3.54 diff, 3500# truck)

hcompton 11-12-2012 06:16 PM

Quote:

Originally Posted by tjet (Post 1610479)
I want to run the biggest hyd flat tappet cam possible without changing the torque converter or gears. The stall on the tq converter is around 2500. I'd like to install a comp magnum 280H, but I think the 230 dur + the 110 LSA may be too choppy. I'm thinking it may behave better with a 112 LSA

(355, 10:1, Dart 200 heads, Streetmaster intake, Q-jet, Tri-y 1-5/8 headers w/2.5 pipes, 3.54 diff, 3500# truck)

2500 stall should be good for that cam. Usally if it needs more than 2500 it will state it in the cam specs. But best to call and ask. But its a big cam for gears and 3500# truck.

ap72 11-12-2012 06:20 PM

Quote:

Originally Posted by tjet (Post 1610479)
I want to run the biggest hyd flat tappet cam possible without changing the torque converter or gears. The stall on the tq converter is around 2500. I'd like to install a comp magnum 280H, but I think the 230 dur + the 110 LSA may be too choppy. I'm thinking it may behave better with a 112 LSA

(355, 10:1, Dart 200 heads, Streetmaster intake, Q-jet, Tri-y 1-5/8 headers w/2.5 pipes, 3.54 diff, 3500# truck)

WTH are you trying to accomplish? Why not just go with a cam that matched your application instead of the "biggest cam I can"?

tjet 11-12-2012 06:24 PM

I'm concerned the 10:1 & iron dart heads may cause pinging. I'm thinking 230 & 112 LSA may bleed down some compression

ap72 11-12-2012 06:32 PM

Quote:

Originally Posted by tjet (Post 1610492)
I'm concerned the 10:1 & iron dart heads may cause pinging. I'm thinking 230 & 112 LSA may bleed down some compression

Call up a cam company and tell them what you did and tell them you need a way to fix it while giving up as little power as possible. I'd call Isky or Howards or Jones- they're all good at unusual applications.

Also be sure you have 10:1.

vinniekq2 11-12-2012 06:37 PM

go to a none flat tappet and or none hydraulic for a smoother idle and more power

hcompton 11-12-2012 06:45 PM

Did you calculate the dcr and base the larger cam on the numbers.

United Engine & Machine Co. Incorporated

I use this one its seems to be ok. Sorry dont have a suggestion on the dcr of your combo but with alum heads you canusally run a dcr of 9:1 and be ok a little less for good iron heads. But also depends on the area and temps the car will be drivien at. A car built to run in 100 degree temps needs to have some consideration of these extremes when building.

Not really the best with describing dcr but maybe someone can recommend a safe dcr number for your combo mine was truly a WAG. Since i have never run those heads.

hcompton 11-12-2012 06:53 PM

Guessing your engines numbers looks like the comp 268h should keep you in the safe zone. Also has a power band starting at 1600 rpm much more suited to a large truck and still deliver plenty of punch to get it moving.

But of course its all a guess since i do not have your engine in front of me to measure.

tjet 11-12-2012 06:53 PM

72 cc Iron eagle 200's, SRP flat-tops #138085 for 6" rods), Felpro 1094 shims

I have the exact same engine in my vette (355 10:1). The only difference is that I'm using Dart aluminum heads, XE268H cam & a 4 speed.

ap72 11-12-2012 07:00 PM

Quote:

Originally Posted by tjet (Post 1610509)
72 cc Iron eagle 200's, SRP flat-tops #138085 for 6" rods), Felpro 1094 shims

I have the exact same engine in my vette (355 10:1). The only difference is that I'm using Dart aluminum heads, XE268H cam & a 4 speed.

yep, not 10:1- about 9.6:1 assuming measured volumes are the same as advertised and you didn't take much of the deck.

tjet 11-12-2012 07:21 PM

Quote:

Originally Posted by ap72 (Post 1610496)
... I'd call Isky or Howards or Jones- they're all good at unusual applications.

Forgot about howards - will check.

F-BIRD'88 11-12-2012 07:23 PM

Try this cam. Comp cams Dual energy 275DEH-10 it is a much better choice for your truck
and will not cause pinging problems. makes lot of truck torque and power and will work very well with your 2500 stall. You'll like this one.. Ditch the old school obsolete Streetmaster intake manifold.
A modern dual plane manifold will do everything better.

The cam is comp cams part # 12-209-2 275-279 219-229 @ .050" .462-.482 110 lsa

tjet 11-12-2012 07:41 PM

1 Attachment(s)
Quote:

Originally Posted by F-BIRD'88 (Post 1610523)
Try this cam. Comp cams Dual energy 275DEH-10 it is a much better choice for your truck
and will not cause pinging problems. makes lot of truck torque and power and will work very well with your 2500 stall. You'll like this one.. Ditch the old school obsolete Streetmaster intake manifold.
A modern dual plane manifold will do everything better.

The cam is comp cams part # 12-209-2 275-279 219-229 @ .050" .462-.482 110 lsa

Will look into it. I'd like to stick with a single pattern cam if possible (single pattern has a more old school "rhythmic" sound unlike the dual pattern cams like my XE cam IMO) The streetmaster intake I have on my vette pulls harder than the Weiand 8004 I had on it, plus it has an oil fill tube which is a feature I need. Another intake option I may consider is an Edelbrock C-26 dual quad.

Trying to achive a 60's hotrod look & sound with this engine - it's going in my 59 Chev pickup


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