How far should I go? 2L eng mods

racydave · Post by **racydave** » Sat Aug 05, 2006 9:20 am

Im not at this point prepared to replace my pistons w higher compression ones, or doin the 1800 head for more compression, but I still want to tweek her. Has Bosch spark plugs. I may re adj valve clearance to gain more valve overlap. And I will order a cat replacment pipe. I would consider some re machined cam gears. At some point I would like to replace ignition system. A coil over plug system sounds interesting. Eng mods at this point- Webber 36 ADL, 1800 intake, have tweeked timing curve, has 4-2-1 exhaust. How bout some ideas? Thanks Dave

TVST*R · Post by **TVST*R** » Sat Aug 05, 2006 11:23 am

Great Q Dave, as I am considering my next engine mod. Now have
Marks Python header, exhaust, Magnaflow muff, 32/36 carb,advanced
timing...

If I put a race cam (I am leaning that way) in it, what else
should be done (ie, what is a next, good, reasonable mod)?
T

Gerard Del Monte · Post by **Gerard Del Monte** » Sat Aug 05, 2006 12:15 pm

Four years ago Guy Croft answered this question at length on this forum. He was replying to a guy who had a carb'd '81, but I assume that his Rx works for yours too:

CYLINDER HEAD
CARBS
CAM
COMPRESSION RATIO

These were his " 4 C's".

His suggested bolt-on mods in order of preference ( i.e. best HP per $ spent) were:

Single or twin silencer exhaust sysem with 4-2-1 header
Pair of Weber 40 IDF carbs on a down draft manifold
Modified cyliner head if it's on carbs
Set of Euro spec 2 lite camshafts
Engine strip and rebuild with 9.5-10/1 compression ratio pistons
Competition cams and valve spings, but for carbed cars ONLY
Upgraded clutch to go with competition cams and springs
Big radiator, low temp thermostat and oil cooler

I might also personally suggest that a K&N filter will help free up breathing as a free-flow exhaust will free up the back end.

As Guy's comments were from January of 2002, I don't think Mark's header was developed then, so I have to assume you could put Mark's 'snake' header in with Guy's recommendation for a 4-2-1 header.

Good luck guys, hope this has helped-

TVST*R · Post by **TVST*R** » Sat Aug 05, 2006 1:53 pm

Thanks Gerard-
For me then, I have to decide between head work and
cams.

I wonder where ignition changes fall in the priority list.
T

racydave · Post by **racydave** » Sat Aug 05, 2006 2:24 pm

tommy, at some point you must decide, ultimatly it sounds like you should go full blown. What goes into the heads must also go out. you need a balance, do the pistons, cams, Install some lower CC heads, then tune her up. Im staying closer to stock hardware since for one point, I can still burn lower octane fuel, and secondly I need to get my attentions back to my other "resto". I probably already answered my own Question, but, given the parameters does anyone have any good ideas? And how about ignition choices?

So Cal Mark · Post by **So Cal Mark** » Sat Aug 05, 2006 3:39 pm

to begin this discussion you need to determine two things; budget and performance level desired.
The budget will always be the deciding factor, but remember, when you add performance you're going to sacrifice something. It may driveability, emissions, reliability or gas mileage. For a street car, I don't recommend race cams. For most people the loss of low end torque and driveability is not a good trade-off for more power.
Once you determine how much you can spend, then you can calculate what conditions the car will operate in and decide what mods will deliver the results

Spyderbuddy · Post by **Spyderbuddy** » Sun Aug 06, 2006 11:12 am

ok and don't forget the rest of the drivetrain, supension, and brakes most people want a hot engine but fail to take the rest of the car into fact just remember 150 -200 hp in front of a stock drive line may not handle the added power. then the brakes may need attention. along with the supension. i've seen a lot of guy's drop in a 400 - 500 hp engine in front of a stock trans and two to three weeks later have to replace the trans because they burnt it up.

TVST*R · Post by **TVST*R** » Sun Aug 06, 2006 11:51 am

For me, I am not driven by budget or performance level, but rather
a reasonable progession of improving the power and performance
of this mighty car. I want to do one thing every 2-4 months,
drive it, evaluate it, and then do some more.

It sounds like my next step is head work and cams. Can someone
speak to those, ie what is head work, what are some specs
on cam performance (how do I keep low end torque
and increase the redline), who makes cams for this purpose, etc...

I find myself in the zone of 4500-5000 rpm very
often and that is where I want more power. I don't
want to keep feeling like I can't push it past
the 5500 rpm mark (where power drops).

T

So Cal Mark · Post by **So Cal Mark** » Sun Aug 06, 2006 12:23 pm

To increase the redline, the first step is better valve springs. Then lighter valve train parts. But, to increase the power band you don't need to raise the redline. Perf cams will increase hp within a given rpm range, and unless you're going racing, operating within the factory rpm limits are good enough. Even my street perf cams make good power over 6000rpm and don't sacrifice the bottom end much, mostly getting into the power curve at about 3000rpm. Remember, putting in radical cams to create power at the top end will detract from the low end, and that means poor driveability on the street. Next drive, try to pay attention to how much time is spent in the various rpm ranges. Unless you're constantly driving like a madman, most of the time you'll be in midrange.
Leave head work for last, the main reason for porting is to flow enough at new, higher rpm limits. Perf cams will give good hp increases at mid and top end.

racydave · Post by **racydave** » Sun Aug 06, 2006 2:55 pm

My eng runs great with my mods so far, real strong leading into shifting. Its probably the carb.

TVST*R · Post by **TVST*R** » Sun Aug 06, 2006 3:41 pm

Mark, with the perf. cam (not race), the power comes on at 3k, right?
What does it do at, say, 4500 rpm? Is it still pulling there?

Also, what are the cam options, ie, is there just one perf. cam,
or is there one that is "hotter" than others but still not considered
a race cam?
T

So Cal Mark · Post by **So Cal Mark** » Sun Aug 06, 2006 4:10 pm

there are several different grinds, but keep in mind you have to pass smog checks. The more radical the cam, the tougher it'll be to pass. The street perf cam has a slightly lumpy idle and will make power to about 6500 rpm. The next cam up would be questionable for smog checks, idles about 1200 rpm and has a similar power curve to the street cam, 3000 to 6500rpm. Not quite as tractable at low speeds as the street cam. If you drive in traffic on a regular basis, might not be the best choice but it is do-able if you realize there will be a trade-off for the perf gain

Joe Clemente · Post by **Joe Clemente** » Mon Aug 07, 2006 2:58 am

I would not recommend cams unless you are prepared to augment your motor's compression.

Even with a relatively moderate profile such as the 40-80s a new set of cams would not be very cost effective or powerful without an increase in compression. You cannot just bolt on a pair of cams and whip up a dozen or so more hp. The reason they will need more compression is because aftermerket cams are designed with more overlap than your stock cams. During overlap your motor isn't building any compression, it has to happen during that portion of piston travel that remains once both valves closed. The more overlap your cams have, the more static compression the engine will need in order to make horsepower. If you are bolting cams onto a stock low compression 2 liter, you'll end up with a breathless gutless pig with nothing down low in the revs where most of your driving is done and then gain little if anything at all up high where the cams are generally designed to make more power. A proper set of pistons and billet cams on the other hand will really wake up your car and put a nice grin on your face.

You can try looking at some regrinds but they are often a bigger compromise.

TVST*R · Post by **TVST*R** » Mon Aug 07, 2006 10:01 pm

Joe Clemente wrote:I would not recommend cams unless you are prepared to augment your motor's compression.

Even with a relatively moderate profile such as the 40-80s a new set of cams would not be very cost effective or powerful without an increase in compression. You cannot just bolt on a pair of cams and whip up a dozen or so more hp. The reason they will need more compression is because aftermerket cams are designed with more overlap than your stock cams. During overlap your motor isn't building any compression, it has to happen during that portion of piston travel that remains once both valves closed. The more overlap your cams have, the more static compression the engine will need in order to make horsepower. If you are bolting cams onto a stock low compression 2 liter, you'll end up with a breathless gutless pig with nothing down low in the revs where most of your driving is done and then gain little if anything at all up high where the cams are generally designed to make more power. A proper set of pistons and billet cams on the other hand will really wake up your car and put a nice grin on your face.

You can try looking at some regrinds but they are often a bigger compromise.

Is this true? I mean, my whole point of adding cams is to get some
easy, significant, noticable, added performance...
T

So Cal Mark · Post by **So Cal Mark** » Mon Aug 07, 2006 11:44 pm

that's why I was advising against big lumpy cams for the street. Most people are disappointed with the results. But a milder grind can be very effective, and I've got several cars running around that can prove it.