Spare parts engine build

[wyrmrider]

gvx
I'd call Joe before I'd call 1 666 Cam-Help for 383 400 sbc
interested in seeing what they come up with
hard to tell what the IVC points are with those cams from the specs given

[randy331]

It's a 20* duration change same lift. If there's 40 HP with a 3*-4* cam change there should be 200-266 HP with 20* shouldn't there ?? LOL

I would care to bet if you changed the lsa 20 degree,s you would see the 200 + HP loss as a mater of fact i think you may have difficult getting it to start. Or maybe you can twist this response into another if scenario that will turn my description of a cucumber into a water mellon if you resequence the gene strand for optimal nutricion lol

Never mind.

I thought by your post of a 40 HP difference from 3*-4* you had actually seen it, but I guess not.
Sorry if I offended you by asking for info on it.

Randy

[user-612937456]

Never mind.

I thought by your post of a 40 HP difference from 3*-4* you had actually seen it, but I guess not.
Sorry if I offended you by asking for info on it.

Randy

Actually that was not what my post was about I think I tried to stress 3 different times that this was a "as much as, could be, a hypothetical scenario, then directly saying I had no data to back up this specific number". You can't take the message I was trying to convey and put it into a bottle with specific application this was intended as a broad and generic.

[randy331]

Actually that was not what my post was about I think I tried to stress 3 different times that this was a "as much as, could be, a hypothetical scenario, then directly saying I had no data to back up this specific number".

Is hypothetical HP as fast at the track as actual HP ?

Seems hypothetical power is a lot easier to find.

Randy

[user-612937456]

It includes a 17% power factor

[Carnut1]

It includes a 17% power factor

I prefer 98%+ per factor but that is just me.

[phantomfab]

Randy

with lift and aggressiveness the same on both cams?

I was not specifically referring to duration change nor suggested "lift and aggressiveness the same on both cams" I didn't mean to be controversial and get anyone stirred up either. It was just a general emphasis on the importance of event timing (or choosing a random but similar specs camshaft) I have no specific data in mind so don't beat me up for using the alleged exaggerated #'s. If you move the intake lobe in particular 4 degree's wider from 108 to 112 separation in a hypothetical engine combination you can kill the peak #'s whether it be 23 HP or 45 Hp there are way too many variables to say what loss you will suffer by choosing the wrong camshaft spec's.

Not trying to take away from phantomfab intelligence or knowledge either. I was attempting to make an effort to steer him away from mistakes I had made 30-40 years ago by reasonong that I have this cam so I think I will just use it. Also considering not knowing more background than he initially shared.

Cams I have are a 300 crane, cant remember specs, ill check later and a cam that I'm unsure of the only thing on it is a 1z206 and its a 550/545 lift, both are solid lift cams and an isky sl2 details as follows

Although if they are cams he has had experience with he may very well be making informed decisions.

Just to come into this a little bit, the crane and the isky cam i have both run and had good results with, Just wasnt sure which to go with on this combo, since i ran the isky in a 9:1 engine and the crane was in a 360 with 13.5:1 with a set of overly worked double humps. And i understand that your not wanting me to make make mistakes you have i get that, but as i had said before this is a backup car i'm just wanting seat time and and was using most of the illegal bmod parts i had laying around to put an engine together since basically anything goes in the Amod.

[phantomfab]

I really do appreciate the replies from you guys. I do have a question though. If the pistons are rated at 11:1 with a 62 or 64 cc head like the double humps, then what would my compression be around with the 75cc head? I'm not sure of the dome cc.

It won't matter much what the pistons are rated for, only what the parts measure up to when installed. Install some pistons, CC them at TDC, and CC your various heads. Using advertised gasket volumes will get you close. 1 CC is worth about a tenth compression point, so any advertised piston volumes are usually off by a half compression point or more. Many of the 76 CC chambers are 80 CC or larger.

Thanks, i get this i ,was just shooting for a ballpark figure. I was figureing around a 9.8-10.2 range. Was just looking for a second opinion, basically what this thread is for was some second opinions.

[phantomfab]

I was not specifically referring to duration change nor suggested "lift and aggressiveness the same on both cams" I didn't mean to be controversial and get anyone stirred up either. It was just a general emphasis on the importance of event timing (or choosing a random but similar specs camshaft) I have no specific data in mind so don't beat me up for using the alleged exaggerated #'s. If you move the intake lobe in particular 4 degree's wider from 108 to 112 separation in a hypothetical engine combination you can kill the peak #'s whether it be 23 HP or 45 Hp there are way too manyvariables to say what loss you will suffer by choosing the wrong camshaft spec's.

Personally I think your exaggerating the effect small changes in cam have on the power.
And a 108*-112* LSA change doesn't mean you necessarily moved intake valve events. You can install both on the same ICL.

Soon I'll be testing a 20* duration difference in cams, I'll bet after we find best position on both, and tune them both up, there won't be 40 HP difference.
I'll be a little surprised at a 25 HP difference.

Not saying there are no very well developed engines that are sensitive to valve events, but very few are that developed.

As you can see from the detailed thought of parts going into this build it is a very developed engine, I'm just kidding, But i think i'm gonna go with the unknown in this engine and see how it ends up, i may take it to the dyno and see if small adjustments will dial it in a little better, I'm not too worried about getting it perfect. But when you do this test on duration, send me a PM so i'm sure i see the thread, I'm curious as to both peaks and how they move in the rpm range, also how it affects the overrall rpm range of the engine. Just from personal experience I'd think it would narrow the rpm range and move it up higher in the rpm range before peak with the higher duration. Also is this going to be a high compression engine that you test or???

Randy

[phantomfab]

Actually that was not what my post was about I think I tried to stress 3 different times that this was a "as much as, could be, a hypothetical scenario, then directly saying I had no data to back up this specific number".

Is hypothetical HP as fast at the track as actual HP ?

Seems hypothetical power is a lot easier to find.

Randy

i like the spirit guys but calm down lol don't get me wrong i love a good argument because a lot of good info is usually brought out in them. I like the input from both of you and i am curious on your testing Randy. GVX i get that a good custom grind is usually well worth the cost but this a "spare parts engine build" and i'm gonna go with Randy's advice to use a cam i already have, and to be honest i'm going to use all of them out of curiousity at this point. I run two tracks a week and this car is getting put together for some extra seat time. And i understand that horsepower can be lost from a poor cam choice but 40 hp is a little steep at 3-4* change and I believe that is why Randy came in a little hot and heavy. And lets be honest anybody that is in this kind of sport is competitive at heart and arguments start. I'm fine with that on my thread, just if ya'll are gonna argue put some facts out and let's all learn something, nobodies gonna be right or wrong most of the time, might as well teach someone something lol not just starts a dick measuring competition haha we all know a less than optimal cam is gonna be down on some power i'm fine with that i just wanna know which one i should go with, yet still nobody has given me an opinion on which one haha that's ok. I am actually building two 882 headed engines, a flattop 360 and a flattop 355, one is getting the sl2 cam and the other is a custom grind, The custom grind is going in my brothers car and mine is getting the sl2, He's a better driver but we're curious of how well the two will compete. Everything is the same in the two except the 5 cubic inches and the cams, heads flowed the same with both cc'd at 74cc's and the intakes are the same with all identical parts, these are our two primary cars. This is off topic of the post but so is a custom grind cam lol we'll find out in three weeks if the extra money spent on the cam was worth it. Will it perform better, most likely, was it worth it on the track? Well the track will tell. now with all that being said thanks for the input from everyone, happy racing, bench or track.

[phantomfab]

Off topic again, sorry but comparing two cams, this was when my brother bought the SL2 cam, he went from the 274 cam bellow and only turning around 5800 rpm max with a 6.0 gear in a 3400 lbs pure stock to around 7000 rpm. The difference was insane.... Went from a mid pack A-feature car that ran a b-feature every night to a car that usually won it's heat and was a top 3 A-feature car. The cam was a huge gain but the 274 was laying there when we put the car together and he had a ton of seat time and could drive the piss out of the car, we was BROKE back then and the cam just wasn't in the budget. Hell we barely made it to the track but ran every weekend. Now we've got around 10 cars and we both plan on running 2 cars a night two nights a week. The point is i understand a cam is big difference but this engine was basically the same idea as back then. Just now we've got better parts laying around, hell we've even got really good engines already built on stands, but i don't want a ton of nights on those engines just for me to have extra seat time. I hope this makes since to some of you. I just started this thread to get some different opinions on what to put together out of basically the scrap pile engine parts that i plan on beating the piss out of.


Summit Racing Part Number:ISK-201SL2

Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 2,400-6,800
Intake Duration at 050 inch Lift: 236
Exhaust Duration at 050 inch Lift: 240
Duration at 050 inch Lift: 236 int./240 exh.
Advertised Intake Duration: 276
Advertised Exhaust Duration: 280
Advertised Duration: 276 int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.390 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.410 in.
Valve Lift with Factory Rocker Arm Ratio: 0.390 int./0.410 exh.
Lobe Separation (degrees): 106
Computer-Controlled Compatible: No
Grind Number: SL-2



Summit Racing Part Number:SLP-Cs-274
Intake Valve Lift with Factory Rocker Arm Ratio: 0.390 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.410 in.
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: Stock
Intake Duration at 050 inch Lift: 194
Exhaust Duration at 050 inch Lift: 203
Duration at 050 inch Lift: 194 int./203 exh.
Lobe Separation (degrees): 112

[1972ho]

This may be a good example of power increase from,Joe may remember this engine.

[phantomfab]

This may be a good example of power increase from,Joe may remember this engine.

What was the difference between test 1 and test 2? And by looking at that, i'd take the cam from test 1 for the classes i'd be running lol. limited to 7800 rpm unless i wanna throw on some extra pounds to the car.

[phantomfab]

Pistons are .100 dome with zero deck height in a .060 350. head gaskets are 0.039 and the heads measure 74cc's, What kind of compression would that be, if someone is willing to do the math for me. I got 10.4:1 when i tried.

[Walter R. Malik]

Personally ... when comparing similar size aftermarket cams from different companies ... in order to gain even 25 peak horsepower, the first cam would have to be a really bad fit for whatever the application; especially on a 450 horsepower engine.

Going from a camshaft that is just close to one which is almost perfect won't see near a 40 horsepower increase.