1993C4LT1

I have low compression on cylinders 1 and 5 due to bad valves. I figure since all that stuff will have to come off, itd be a good time to install 1.6 roller rockers. I've done a search, but want up to date info.

Will I need a tune if I install them?

My trans was rebuilt about 5 months ago(auto) to factory specs. Can my trans cope with the extra power safely?

What all do I need when installing the roller rockers?

Self aligning?

Are there any specific 1.6 roller rockers you recommend?

Thanks
Brandon

John A. Marker

You will not need a tune. Extra power will be 7-10 max. No issue for your transmission. You need to get narrow self aligning. I am looking at the Scorpion RR myself. Basic tools to replace, 5/8 socket and wrench.

You will also have to replace the stock springs. Many have suggested the LT4 springs about $50 or so. Replacing the springs with the heads off would be easy, especially if your having the valves machined. Just supply the new springs to your machinist. Suggest you replace the valve seals while your doing this.

1993C4LT1

Thanks! Yes, it will be getting new everything.

Edit, will I need different pushrods?

JrRifleCoach

Talk to the guys at Comp Cams. They're pretty savy on these conversions.
Might even think about a cam and tune to make those rockers work better.

1993C4LT1

Thanks. Might end up buying the scorpion rr's.

THE 383 admiral

your Push rods will be fine. you should always check the roller tip to stem tip location.. Trick flow push rods. Are the best value to performance ratio. Scorpions have a good Rep. Do NOT purchase anything like proform!!!! RR's

mtwoolford

here's where longer ratio rockers can bite you in the ****; of course the valve opens further, that's why you installed them right? Check for coil bind, with a mild cam that's probably a non issue, but you also have to consider whether or not the valve retainer is gonna smack the valve stem seal...and this could be a real issue...it's easy enough to solve early on but a bitch later on.

WW7

Push rod length will have to be checked...This is a pretty easy process, let us know when you get to that point and we can explain how to check them...You also have to check that the new rockers don't touch the spring cap , there needs to be a few thousands clearance between the two...WW

1993C4LT1

Thanks everyone. I won't be doing any of the work, but I'll let the shop know who will be doing my heads. Will keep you all updated.

C4vettrn

You can go with non-self aligning if you go with hardened pushrods and run guide plates. You might want to look at getting the larger rocker arm studs installed also. You will get some RR "taping" noise that is normal and pretty noticeable if you have a quite engine.

Rocky Capone

I was under the impression that if you did go total roller rockers something had to be done to the knock sensor. The sensor will will retard timing when it senses the "clatter" from true rollers. I thought I read it wasnt as simple as installing a 96 sensor but a resistor in the wiring. Can anyone confirm this.

cardo0

If u have lower compression u should try a squirt of oil and retest that cyl again. If compression recovers the rings are worn and bad - rebuilding the heads with a vlv job wont fix that. But if compression is still low in those cyl after a squirt of oil then it the heads that are not sealing.


Something that is over looked when swapping vlv springs is the LT1 heads have solid vlvs which are much heavier (20%) than the hollow stem LT4 vlvs. Going to LT4 vlv springs with LT1 vlvs can mean vlv float at high rpm.

I think the ticket now is the LS6 beehive spring which has both a higher closed press and full open press than the LT1 spring. They also fit inside the same spring pockets as they are smaller diameter. Since u are taking the heads for a rebuild u can have the machine shop install them correctly. But u well need different retainers for these springs. Oh and they are cheap too.

1993C4LT1

Rocky, I've read the same in other threads also. cardo, yes, I was concerned about that and will be doing a wet compression test.

WW7

Like Rocky says, the roller rockers will be much louder then the stock rockers were... Some people it bothers (like me ) others it doesn't..But I will say, If I had it to do over again I would stay with stock rockers because of the noise factor..To me getting the 8 to 10 hp isn't worth putting up with the added noise....WW

96 lt-4

People used to use a LT4 knock module when doing the swap but those are impossible to find these days.LT4 motors used composite valve covers to help limit the noise as well IIRC.

You could always go with the comp(or the like)1.6 roller tip rockers and that may be a good compromise.

1993C4LT1

I won't mind the noise. Thanks ww7 and 96-lt4 for clarifying it.

WW7

When I was having my car tuned, the guy doing my tune said he desensitized the knock sensor in my chip/tune to compensate for the extra noise..Maybe you can check into having this done..WW
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1993C4LT1

Not about the roller rockers. But I went to check on my car, and now my compression is high. 140 psi. I don't get it. Mechanic thinks it could be the opti. All I know is if it the opti, I can change that. And I am lean as hell on the left bank. BLM is at 140-150. Almost perfect on right bank. BLM at 124. I highly doubt the opti is bad.