I'm getting a crate L98 for my car soon. I don't want big power, but I want to keep it pretty close to stock. So far i'll be running a custom tune, AS&M runners, edlebrock base (all port matched), stock throttle body, and Dyno Don headers with a dual cat exhaust. Would 1.6 ratio roller rockers add anything to this set up? Would they interfere with anything? I've heard they are noisier and can lead to false knock.

 

They make self aligning rockers that fit under stock valve covers, they are narrower. If you are going stock but want all the stock you can get then look at 1.6 rockers and a zz4 cam. You can install a zz4 cam and it will run fine on a stock chip with no tuning. I ran one for years in my 89 350 iroc and it would out run an lt1 car. Thats what I am putting in my vert is a 350 with steel gm 1pc crank, 6 inch H beam rods with forged Mahle pistons (slightly dished) balanced. Probably going to get the ported pro comps.

 

Any word on if the ZZ4 cam will pass emissions? I'm in the PRK (people's republic of kalifornia)

 

u need to change the springs if going with that cam,especially with 1.6 rockers! maximum lift on stock springs is only like .470"

 

Where are you getting the crate motor? I have an L98 in my 91Z that is getting tired. Trying to figure out if I should do the valve seals-they are leaking- or pull the whole motor...

 

i wouldn't worry about valve seals,does it smoke a little upon startup?

 

1.6 rockers only work w/ stock cam specs, add a big cam and u better beef up the springs

 

All I gotta say is if your gonna get roller rockers, you still have to fix the geometry or you will destroy your engine if the valve train fails. ALso you need narrow body roller rockers or the stock stud guides on the valve cover will hit the rr and the valve cover will not mount flush. best narrow body rr are the CompCams self aligning Magnum RR's.... Picture of the magnums are below...


Another narrow body rr is the Scorpion RR below......


Not EVERYBODY will tell you about the "geometry" of the valve train. So if you wanna learn more about fixing the "geometry" of the valvetrain, here is the link.

http://www.compcams.com/Products/CC-...rods%27-0.aspx

http://www.pontiacstreetperformance....traingeom.html

http://www.carcraft.com/techarticles...h/viewall.html

 

narrow body,self alligning

 

I'm selling a set of Comp Cams Hi-tec stainless 1.6 RR right now on corvetteforum. I'm new here so I don't have my privileges to sell yet. let me know if your interested


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they will give a slightly throatier exhaust note too

 

Not to hijack the thread, but I HAVE to do the seals: it smokes A LOT on startup and I am oiling at least 2 plugs and dropping cylinders.
While I am doing it, given that the engine is bone stock, is replacing the springs and upgrading rockers worth the expense- what type do you guys recommend and why? I would be happy to get back the horsepower that 21 years of driving and 194,000 miles have robbed from her!

 

I already mentioned which rockers are best for the centerbolt valve covers. You have to investigate which valve springs can take the maximum a given ratio is applied (1.5 or 1.6 rr) before the springs begin to bind.

 

What heads?

Going to want a good TPI setup to use /need .544 lift on the exh ( ZZ4 exh = .510 lift w/ 1.5's ) as well as some good valve springs.
The GMPP ZZ4/LT4 springs that go with the cam are good for .525

 

I don't think you should be losing any hp from time.

 

I suspect new seals are not going to solve your oiling problem
@ 200K your rings are probably on the way out ( if not already gone on the cylinders with oily plugs ) and the majority of the oil in the cylinder is coming up past the rings;
not down from the valve seals

Once you loose the piston ring seal you loose compression so you are then down on horse power and it just slowly gets worse until the engine dies

 

I dissagree: these engines are notorious for leaking valve seals. If I was getting oil blowby, I would be burning it while the engine is running. I only get oil smoke on startup, not while it is running. Also, the plugs show wet oil coating if they are pulled after letting it sit and cool. That oil is coming down, not up...

 

These engines are notorious only IF the owners or PO never did an over haul. Any vehicle the has the similar style valve seals are and will leak if not replaced or maintained like how they should be. You gotta remember, you are focused on these f-bodies because you own one, but fail to realize that this occurs on a good percentage of cars of the 90's era.

 

Whatever

Is asking a bit much for them to still perform as new
Especially given your engine is 20 years old and has 200K on the clock , possibly will the valve seals it originally left the factory with

 

i would take vettoz words so far hi has not pointed me wrong this guy gets my a++++
hope you ok with me saying something vettoz

 

Vetteoz knows his stuff. Unfortunately for me, my advice goes poof as no has mentioned, "hey, Chevy86 has a point about the geometry of the valve train". I'm out.

 

Good luck actornoff. PS, I was born in Huntington Park. Big ups to the City of The Angels.

 

its just your valve seals if it does it on startup. No big deal

 

There's no need for 1.6 rr on a stock cam, and if you DO change the cam, most are spec'd with 1.5s. You can simply choose the appropriate cam specs without going 1.6.

....and even the zz4 cam gets a little on the big side for a LTR TPI with 1.6 rockers.

 

So there is zero benefit? Even just to free up friction in the valve train?

 

you will gain a few hp, and the exhaust note will be a bit more throaty due to the increased lift. Your engine will probably last longer too.

 

My point was simply addressing the lift difference. ...and I would say no. No benefit that you'll ever see. Obviously you're increasing lift, hence air in and out, and the dyno may see a difference, but the benefit of a PLANNED out engine cannot be overstated. Adding .1" of lift because your uncle's neighbor had a spare set of 1.6's sitting int he toolbox just isn't gonna make a worthwhile difference.

....now the fact that you're adding rollers and roller tips certainly helps. Also, stamped stock rockers can flex as much as .2" so a good quality set of rockers is a great addition. .....but pick your ratio and cam first. Then buy a good set of whatever ratio rockers you determined you needed. Anything you can buy in 1.6, you can buy in 1.5.

 

As for your combo, if you're limited on cash, get your motor in, as close to stock as you can, (exhaust is still a must-do however) and put the money into a torque converter. If you're running stock L98 heads, no cam, and no intake will come close to what you'll feel from a better converter.

.......but speaking just about the engine, assuming you're keeping the heads stock, a cam similar to the zz4 cam would certainly help. There are several good cams with similar specs. My zz4 cam passed (barely) in NC. I doubt it would pass CA. ...I did run a stock tune at the time (on a stock 89/MAF set up). You'll want the LT4 or comparable springs, and screw in studs too, although so far I've survived with press-ins. With that pretty mild set up, a good set of low cost (not cheap) roller tip rockers would be plenty. Remember, there are TONS of multi-hundred thousand mile small blocks still running stock stamped rockers. If ya spend 6 grand on a motor, what's a couple hundred more for full rollers. If you're just putting a stock replacement back in, ya gotta ask where's your money gonna get you the most return.

 

Whatever. Seriously? 'Is this the 5 minute arguement, or the full half hour?' I am not looking for a fight- just the input of someone with no axe to grind. Correct the following if I have it wrong:
1) Gen 1 SBCs are prone to valve seal failure over time.
2) if it blows oil smoke on startup, the consensus in the SBC community is 'valve seals'.
3) if it blows oil consistently during operation, it could be rings.
4) if it fails a 'leak down test' it could be rings.

Mine a) blows smoke on start up, b) doesn't blow oil smoke during regular operation, c) is fouling plugs with what looks like oil, d) I am getting a 'code 43':

Do you think if the valve seals are leaking, it will cause the computer to show a 'code 43'?
Don't think that is too hard a question... 'yes', 'no', or 'I don't know'.

 

Code 43 is a knock sensor. Make sure the connector didnt come unplugged too.Yes, I would say you are correct with statements 2-4

 

Thanks ninetyone!

 

Found a broken knock sensor lead! Anyone know how to test the sensor while I am at it?

 

Should meter out at 3300 - 4500 OHMS
Should have 4 - 6 volts on the supply wire with key on

 

You can test if it is working too ,by tapping softly with a wrench near the sensor. It should retard the timing. You will need to reconnect it first tho.

 

With 194K your guides are probably loose. Seals alone may not help.

 

True.

Also True.

If your going to remove all the stock rockers ANYWAY,..... install some RR's while your in there. I always add 1.6 rockers to every head I have to tear down when keeping a stock Cam. 1.6 opens the valve a bit more, reduce friction/heat & add a few ponies for cheap $$.

http://www.ehow.com/list_6730063_ben...-rockers_.html


If your planning on building a power-house engine, 1.6 rollers might not be the best fit. But on a 'mostly' stock SBC used for Street driving; Go For It !

 

Thanks guys! Added a new pigtail, connected it to the sensor, cleared the code and now it runs like it is supposed to! Seals are next!

 

White smoke on startup (not because it's cold outside) is valve seals, blue smoke on startup is rings. At least, that's what I've been taught. Metal expands when it warms up, so the rings could be contracted enough when they're cold to have some blow-by, but when they heat up they expand enough to fill out the bore and there is less or no blow-by.

 

Or perhaps the HEADS, CAM, INTAKE and tuning.....but sure....I'm sure the rockers helped. That's like discussing which has more calories, celery sticks or a quarter pounder, then saying that the sesame seeds on the bun added to the higher calorie count.

 

 

I felt a little increase.