This Cam any good?

[Finallall]

Hi everyone,

I'm doing a 86 3.8 N/A build and am looking for a bit more performance. I'm trying to get 200hp and 250 tq out of this engine without boosting it. BTW this is an abandoned project that I inherited.

Here is what I'm working with:

- rebuild block 20 over pistons; 8.5 CR
- 4.1 intake with q-jet carb
- dual header exhaust
- mild porting done

The cam that I got is a Melling SBC-12. Brand new with lifters. This is the specks:
Cam Style: Hydraulic flat tappet
Intake Duration at 050 inch Lift: 180
Exhaust Duration at 050 inch Lift: 194
Duration at 050 inch Lift: 180 int./194 exh.
Advertised Intake Duration: 251
Advertised Exhaust Duration: 280
Advertised Duration: 251 int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.359 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.384 in.
Valve Lift with Factory Rocker Arm Ratio: 0.359 int./0.384 exh. lift
Lobe Separation (degrees): 104

So ... does this cam have what it takes to get me to my goal or shoud I start looking for something better? I'm more concerned with the TQ number then with the HP #'s.

Thanks for any advice,

Al.

 

[Freddie's Buick]

Never tried that cam....Melling does make quality parts though. Get with the manufacturer for more info and compare the specs with the traditional after-market cams for Buick V-6's, (Comp, Edelbrock, PAW), there are others but these seem to have a larger feedback here in this forum.

You may be able to get 200 HP with the Qjet and 4.1 intake. It was done with a 4.1. But the intake was higly modified.

 

[dr_frankenstein]

I would say that cam is small in duration and in LSA.

The buick is going to need more to make 200 HP.

I think something with around 218 to 224 @.050 would make a cleaner torque peak and using an LSA thats wider, more around 110* would help to keep you from winding the piss out of it to make the top end power.

A.j.

 

[Finallall]

Can anyone sugest a good cam for N/A application? I'm looking for off the line torque. I'd hate to put a cam in and then have to replace it.

 

[dr_frankenstein]

I think you should go after more Compression. You could do better on the intake however.........

For Compression a better piston will help you get to this, being your running a 4.1 - ive seen NA stage 2 flat top pistons for 250$ or less..... and there usually forged. But a buick 350 NA piston will work too.

For intake I would reccomend an Edelbrock performer with a 1" 4 hole spacer.

Id go to 10.0 or 10.5 to 1 and be slightly conservative on the timing to make it live on pump gas.

for cam i would use a a grind that is close to these specs, as these are some custom grind numbers from another cam I have.

DURATION @ 50
I 216
E 226

LIFT
I 512
E 512

LOBE SEPERATION ANGLE
112*

ESTIMATED ADVERTIZED DURATION
I 260
E 266

If you want more top end, narrow the LSA to about 110* or if you want alot of lope go as tight as a 108* but no tighter than that IMHO if torque is your game. a stall converter with about 500 to 1000 more than stock will really help with that off the line jump.

Good Luck
A.j.

 

[charlief1]

For the cost an edelbrock cam is a much better cam. The one you have is a stock 78 cam and isn't as big as the 86-87 GN cam. You don't need a .500 lift to make these engines perform but you do need a bigger cam for sure. As far as the intake I'm postings some pics for you to see what you can do with it. Very effective and if you add a 1 inch hiker you get better velocity in the intake. It works great and I did it back in my NA days.

 

[Finallall]

Thanks for the porting ideas. I will defenitly get a spacer for the carb but the cam I'm still contemplating. Is it a good match for the 4.1 intake? I want max torque from stand still till about 4,000 rpm. Not concerned about going fast as it's a city car. Maybe I should spend the $150 and buy the Edelbrock 5487 cam.

 

[charlief1]

Same grind as Edelbrock. Hope you're a member.
eBay Motors: NEW CAMSHAFT BUICK 231,196,252,181 IMPROVE POWER HYD. (item 220385445525 end time Apr-03-09 06:42:40 PDT)
Good to about 4800 and this one's cheap. If you need more info on porting the intake say so and I'll start a thread on how to do it. It will take a while to show but it's not hard, just time consuming.

 

[Finallall]

Awesome. I will buy it as long as he's willing to ship to Canada.

Yes a detailed thread about porting the intake would be awesome.

Also any advice on performance upgrades would be great as I'm in the process of assembling this block and want to do as many upgrades as I can. It'll stay N/A tho.

 

[charlief1]

For tech do searches and go to gn/ttype.org or add an S to the current site. You can find Earl Browns mods for the timing cover to help oil pressure and some other good info as well. You need to de-burr the block and releive some sections to keep stress risers from forming. I'll see if I have the time to post some pics later this week. As far as headers if you can (good luck) find a set of kenne-bell 1&5/8" headers and the 231/252 LOVES them. I still have 1 set.

 

[Freddie's Buick]

Thanks for the porting ideas. I will defenitly get a spacer for the carb but the cam I'm still contemplating. Is it a good match for the 4.1 intake? I want max torque from stand still till about 4,000 rpm. Not concerned about going fast as it's a city car. Maybe I should spend the $150 and buy the Edelbrock 5487 cam.

If for some reason you don't get that cam, get the Edelbrock combo. I've not heard anyone with the N/A set-up say anything bad about it. I still kept my Edelbrock intake and I also kept the 4.1, (between the both the Edelbrock way ouclassed the stocker).

Couple of years ago at the other turbo forum one guy went with the Edelbrock combo, (intake and cam), and was very happy with the results.

 

[charlief1]

I hope you haven't bolted the heads on yet. To use a bigger lift you need to cut the valve guides down some. Not expensive but you can't run more than .420 lift if you don't. Go the the engine section and start doing searches and READ A LOT. There is prep tips for the block and porting info there that will help you understand things a little better.

 

[Finallall]

Well I'm kinda on the fence here. I don't know if I want to put a lot of $$$ into it or just go with a V8. Anyone know the specks on the stock cam?

 

[charlief1]

What is the car exactly? The v8 may be cheaper to put together but the v6 is a little more unique and gets better gas mileage.

 

[Finallall]

84 fiero with a 4 speed manual tranny. 4:10 gears. Problem is the tranny can't take too much torque. It has a weak case. So I don't want to overbuild it.

 

[charlief1]

Fiero? You need to go to the hybred section and do a search. Which engine are you using? 231, 3800, or 3800 series II? There's a lot of info on converting a fiero on the web. Which engine did it come with from the factory? I'm guessing 4 banger? I've got the Fiero poncho book with some racing tranny part # for the racing 5 speed but it's so old I don't know if it would help you.

 

[dr_frankenstein]

84 fiero with a 4 speed manual tranny. 4:10 gears. Problem is the tranny can't take too much torque. It has a weak case. So I don't want to overbuild it.

you need that Getrag 5 speed out of an 87 GT.............if you go with a V8 I suggest you build a chevy 302.

the mild bottom end torque of the 302 makes it ideal for the weak transverse box, but the high rpm HP punch of the 302 will blow your doors off!

Try it......... you will be amazed.

:biggrin: A.j.

 

[Finallall]

Interesting but I want to try this combo first. 3.8 231 with the 4 speed manual tranny. 4:10 gears. Should climb up quick. I have 99% of the parts I need for this swap already. 4.1 intake + Q-jet, balanced flywheel and redrilled for 231 crank, clutch, PP, headers (2" streight through), 8.5 compression pistons, block honed 20 over with 20 over pistons, heads machined, dual timing chain, new oil pump + thrust plate and the cam I have in questrion, etc. It's all there just need to put it back together. Next I will be porting head and intakes and headers but ... before I close the timing cover up I wanted to make sure cam is the right one for my set up and not a bottle neck. Seems like it's a bit of work to change it afterwards.

So my question is ...what's the best cam to use with the 4.1 intake and q-jet + dual headers with minimum ill effects on daily driveabuility? Looks like the Edelbrock cam will be a bit hairy without the supporting components.

Any and all advice is greatly apprciated,

Alex.

 

[charlief1]

Again...WHICH 3.8 LITER....It make a bit of difference. Post a pic of the the heads ect so we know what you're using please.

 

[Finallall]

It's an 87 FWD block. I think I'm gonna go with the Edelbrock cam. 204/214. I will get the head #'s from it tonight.