Is there a problem with valve clearance using the 1.6 rockers on a stock engine?
I read about excessive wear with the 1.6 rockers. Is that a fact or conjecture?
It's a flat tappet system, so increased wear seems likely, yes. I don't know what the valve clearance is like on the stock engine. But increasing lift will result in decrease in whatever clearance there is. If you run at stock timing, it's probably not an issue. If the chain is stretched or you are installing the cam more advanced, it will likely become more relevant. I don't know the specs on the stock springs either, so they may be an issue as well. If you're just doing a throw n' go on a stock engine, you should be fine, but I'd check tolerances and springs just to be safe. Good time to replace valve seals and such too, since you're going to be in there.
Originally posted by RayOtton: Is there a problem with valve clearance using the 1.6 rockers on a stock engine? I read about excessive wear with the 1.6 rockers. Is that a fact or conjecture?
On the stock cam, you shouldn't have an issue. I think the stock springs support up to .450" lift...and you'd only be up to .437" on the exhaust which has more lift than the intake on the stock cam...
Spend the extra money on "full" roller rockers...also they'll be reusable if you decide to use a newer roller cam block for your next build... Summit has some aluminum ones - search for V6 narrow body aluminum roller rockers...
I read about excessive wear with the 1.6 rockers. Is that a fact or conjecture?
quote
Originally posted by dobey:
It's a flat tappet system, so increased wear seems likely, yes.
And for anyone who doesn't address the lack of zinc additive in modern engine oils, cam lobe/lifter wear could quickly become disastrous.
I've contemplated using 1.6 rockers in my Formula, but I'm concerned that the potential performance benefits would be minimal compared to potential excessive cam lobe/lifter wear.
I used 1.6 roller tips on my 2.8. The roller tips mean that there is no practical difference in wear. You get a lower exhaust note because the engine is breathing better. It is a cheaper way to increase your intake amount than a cam swap.
I used 1.6 roller tips on my 2.8. The roller tips mean that there is no practical difference in wear.
Arn, the roller tips would help ensure that there wouldn't be any excessive wear on the end of the valve stems or on the tips of the rockers themselves, but how do the roller tips help minimize wear on the cam lobes and/or lifters? There's still going to be added force on those areas due to the extra leverage of the 1.6 rockers.
I put the 1.6 roller rockers on my 2.8 several years ago and I could tell a difference in get up & go. I also use the Rotella oil which still has the zinc in it AFAIK. You can still by the additive on the web. I say go for it. Less work than swapping a cam.
Spoon
------------------ "Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
I also ran 1.6 rockers on an otherwise stock cam. It was a 3.4 Camarobird engine, but the 2.8 uses a cam with identical numbers. I had no trouble at all. There is no way that I would run a flat tappet engine without some sort of zinc additive or high zinc oil. I used to run Rotella T in my 3.4.
Having said all that... if you are into the engine anyway, and are replacing the cam, just get a cam with the lift numbers that you want, and use the 1.5 rockers. 1.6 rockers are, to me, a bandaid. They are an easy way to achieve more lift without going into the engine. If you already have a high lift cam, and are adding 1.6 rockers, you need to pay attention to the total valve lift, and make sure that you are not going to bind the spring coils. That's a sure way to start breaking stuff.
I preferred the Comp Cam roller tip rockers. They are a good compromise between stock, and full roller rockers, without destroying your bank account. They are available in 1.52 (which is actually stock spec) which I used with my 272 cam; and 1.6 ratios. I used the 1.52s because they are much more precise than the stamped steel stockers, and still had the roller tip.
------------------ Raydar 88 Formula IMSA Fastback. 4.9, NVG T550 Praise the Lowered!
Arn, the roller tips would help ensure that there wouldn't be any excessive wear on the end of the valve stems or on the tips of the rockers themselves, but how do the roller tips help minimize wear on the cam lobes and/or lifters? There's still going to be added force on those areas due to the extra leverage of the 1.6 rockers.
The change is so small, the engine won't even notice it. Sure in theory it is more pressure but a taller cam lob also increases pressure. It just doesn't make any practical difference.
Okay, I'm starting to feel a little less leery myself about possibly installing a set of 1.6 rockers. I wouldn't mind just a bit more power for my Formula at autocross.
These are the ones, right? CompCams 1414-12
[This message has been edited by Patrick (edited 01-30-2015).]
I have been running the Comp Cams 1.6 Roller Tipped, for the last ten years. Only use the Comp Cams, the Crane ones look horible in comparison. The Camaro (3.4) Guys claim 15 hp off of it.
I'm intrigued with the use of this style/application for the 2.8/3.4 as there are a lot of choices available for the SBC (and therefore potential good deals on eBay).
You had to swap out the studs from 10mm to 3/8"... anything else, like push rods and guide plates?
[This message has been edited by Patrick (edited 01-30-2015).]
For those worry'n about cam/lifter wear that then think roller tipped rockers,, are ok,, the rockers have the same issue as the cam/lifter.. in the ball socket, both blue then crack/fail. either run full rollers or don't waste your money.
I think the ones I quoted were normally used on 3800 motors... The difference is the stud: 10mm vs 3/8" ... Someone suggested to me that since 10mm is close to 3/8" that you may not even need the adapters and can stick with the 10mm nut since it's just there to hold the fixed base of the rocker down on the head - which I believe - but that was after-the-fact/installation.
As for worrying about wear - that's another reason I use roller-cam blocks exclusively now...
[This message has been edited by lou_dias (edited 01-30-2015).]
I'm still getting mixed signals as to the wear problem with 1.6 rockers.
Some folks think it's a problem but then one poster has had them installed for 10 years.
Also, I don't have any intention of pulling the engine to install a better cam. The performance rocker option is about the most digging into the engine that I want to do.
I'm still getting mixed signals as to the wear problem with 1.6 rockers.
Some folks think it's a problem but then one poster has had them installed for 10 years.
Also, I don't have any intention of pulling the engine to install a better cam. The performance rocker option is about the most digging into the engine that I want to do.
Some have issues with 1.6 rockers and they can be 1) piston to valve clearance.. not an issue on a stock 2.8v6 2)putting more pressure on the cam lobe, lifter face , todays oils have has the zinc al but removed, flat tappet cams need this zinc the wilder the cam the more it becomes a fast showing wear, as the lobe ramps are faster,taller and require stronger springs, the more pressure pushes the oil film off the lifter/lobe face and the parts run with less of an oil film, the zinc builds up on parts so the lifter nose and cam lobe face have a layer of zinc so even with the oil film being pushed out the zinc layer is still there, and gets renewed as the oil flows over the parts.. adding the 1.6 rockers won't add that much pressure as the stock springs are weak and after all this time are even weaker.. and the cam in the engine is mild, but that doesn't mean you shouldn't use oil made for flat tappet cammed engines, The biggest problem is people think they can add a zinc additive to todays oil and call it good,you can't todays oils are very high detergent that stuff cleans off the layer of zinc as fast as the zinc layer tries to build up a layer.. you have to use low detergent or non detergent oil.. and why the so called high zinc race oil is not always what it seems as many are high detergent oils,and ya they have high zinc levels the high detergent makes it's level a mute point.. 10 years ago you could just use diesel oil as it was high zinc.. but as soon as the epa added converters on diesels the oils had to become low zinc just like they did for cars.. to find the good oil diesel high zinc oil you are going to a big rig fleet part store, as the stuff on the local chain stores are for new diesels.. 3) non roller 1.6 rockers add side loading on the valve stem and guides as the stock geometry is set up if it was to blueprints, to not sweep across the valve tip,but to stay at the center, the 1.6 require different length push rods to get the same small movement at the center of the tip.. so they end up making the rocker tip sweep across the tip of the valve.. the farther from the center of the tip the more side loading on the valve stem and guide..
The good thing is the stock springs and cam are so lame the extra side loading isn't that big a deal.. but add a cam with fast lobe ramps and higher lift that require stronger springs and then it becomes a big issue.. the fast ramp ,high spring pressure is the reason ball and socket rockers have the same issues as flat tappet cams/lifter and need zinc.. or they blue from heat and the rockers then fail at the ball area..
1 - The car only has 48K miles and it was owned literally by a little old lady. I doubt the engine ever saw more than 3K RPM's and I know it was maintained according to the recommended schedule. So the valve train probably isn't too tired.
2 - Any oil manufacturers make "old style" oil or would a high end synthetic be acceptable?
I haven't used it, but I am told that Royal Purple produces an oil used in diesel motors that has zinc.
However, a good non-detergent synthetic will also work, however you will want good seals with synthetic.
I dyno'd my 2.8 at 132 at the wheels with 1.6 roller tips. The engine pulled very strong even with less than stellar rings.
The stock springs is all I ever used, and they worked fine right out past 6k rpm.
Watch the full roller rockers though. I used Scorpions and they did not clear the stock valve covers. I had to use S10 covers to get the clearance.
The fact is that unless you are doing high rpms the roller tips work just as well, albeit if you want that "little extra" top end you likely will want full rollers.
You'll want to port your exhaust logs and Y pipe if you are doing this work too. That frees up a good 6 hp.
Did the ones from Summit also required different valve covers from the stock ones?
Nope.
quote
Originally posted by Arns85GT:
All the aluminum rockers are too fat for the stock covers.
No they are not. The ones I listed from Summit worked fine. They are "narrow body" style.
My motor:
If you are truly worried about clearance, you can always run the gasket from other 2.8 motor as an "EXTRA" one - I'm talking about the thin flat one that looks like someone scrammbled cardboard and rubber together...
[This message has been edited by lou_dias (edited 01-31-2015).]
Can't speak to the 2.8 V6, but I use to have an Impala SS with an LT1. Guys would always swap the stock 1.5 rockers for 1.6, without batting an eye. No one ever mentioned any problems as a result of this.
So what did you end up getting? I can't find the 1.6 ratio, 10 mm stud, Comp Cams rockers kit that includes the pushrods, at any price.
I also ordered Crane 3/8" stud adapters... CRN-99148-2 and I ordered 6 of them since they are sold in pairs. The 10mm side goes in the head and leaves a 3/8" stud for the 1.6 roller rockers...
I have been running the Comp Cams 1.6 Roller Tipped, for the last ten years. Only use the Comp Cams, the Crane ones look horible in comparison. The Camaro (3.4) Guys claim 15 hp off of it.
edit to add: I run Mobil 1 oil.
Sorry sardonyx.. i have to differ on appearance.. I have the Crane 1.6 full rollers and they look beautiful!.. I love GOOOOOLD...!! I haven't had any problems running them. I included comps performance springs and running a 260/260 comp cam... Major difference from riding in other 3.4 swaps.. I'm also 9.25:1 compression (stock camaro compression for this engine) - i wanted to be reliable... but then I also have Ross forged pistons and ARI H-beam forged rods. - lighter weight and stronger than cast... to better performance. I am faster and more pep than a 4.6L mustang till about 3rd gear due to the breathing of the iron heads and other things...
I too run Mobil1 with lucas additive..
[This message has been edited by unboundmo (edited 03-05-2015).]
Originally posted by unboundmo: Sorry sardonyx.. i have to differ on appearance.. I have the Crane 1.6 full rollers and they look beautiful!.. I love GOOOOOLD...!! I haven't had any problems running them. I included comps performance springs and running a 260/260 comp cam... Major difference from riding in other 3.4 swaps.. I'm also 9.25:1 compression (stock camaro compression for this engine) - i wanted to be reliable... but then I also have Ross forged pistons and ARI H-beam forged rods. - lighter weight and stronger than cast... to better performance. I am faster and more pep than a 4.6L mustang till about 3rd gear due to the breathing of the iron heads.
I too run Mobil1 with lucas additive..
You are comparing apples to oranges, I have roller TIPPED you have full roller rockers, the crane roller TIPPED rocker arms are just crap. BTW the breathing MYTH, is just that, a myth, do the math. It has long been put out on here but yet I have no problem in the upper RPM. again do the math. (with the correct VE, etc the air flow is NOT the problem) The coil is the biggest problem past 4500 rpm. Just saying....
Sorry bro... But You don't have to be so rude about it.. Do the math crap. I wasn't saying that yours were in anyway bad.. Thought you mentioned appearance? Edit to say My mistake.. I see you are not comparing full roller
Also to come.. About doing the math...Maybe that's why in my garage I have the 3coil pack conversion, crank sensor, 7730 ecu and all the other things needed.. I'm just trapped with Cali smog and need a way around
Just sayin
and actually, I like my setup and have had no problems for years also so.... Just was putting it out there for others to decide
[This message has been edited by unboundmo (edited 03-05-2015).]
I love this shot... the way the rockers in the foreground are focused nice and sharp, and they get progressively blurry in the distance. Excellent framing and lighting as well.
2.8 pistons are flat top and the GM V6/60 performance book says iron heads with flat top pistons can support up to .510" of lift. 3.4 pistons are dished... I haven't looked at a stock 3.4 piston in a really long time but if the dish is wide enough, it could allow for more lift.
So adding 1.6 ration rockers on stock or mild performance cam will not cause an issue with piston-valve clearance. The real issue is your springs. I don't think stock springs support much over .460" lift. I think the Crane double springs support around .500" lift. So that's the issue you should pay attention to.
Originally posted by lou_dias: ... So adding 1.6 ration rockers on stock or mild performance cam will not cause an issue with piston-valve clearance. The real issue is your springs. I don't think stock springs support much over .460" lift. I think the Crane double springs support around .500" lift. So that's the issue you should pay attention to.
I found that to be the difference between using a Crane 260 or 272 cam. The lift for the 260 was .427/.454, I/E. The lift for the 272 was .454/.480, I/E. The 260 is widely reputed to work with stock springs. The 272 will not, without binding the coils.
(Strangely enough, if you add 1.6 rockers to a 260, you get the identical lift specs as a 272.)
With an iron head V6-60, I have never heard of anyone having piston/valve clearance issues with any of the commonly available aftermarket cams/rockers. Valve springs have always been the "gotcha" as long as I've cared enough to pay attention. (Which is not to say that it hasn't happened. But if it did, I missed it.)
[This message has been edited by Raydar (edited 05-30-2015).]
(Strangely enough, if you add 1.6 rockers to a 260, you get the identical lift specs as a 272.)
With an iron head V5-60, I have never heard of anyone having piston/valve clearance issues with any of the commonly available aftermarket cams/rockers. Valve springs have always been the "gotcha" as long as I've cared enough to pay attention. (Which is not to say that it hasn't happened. But if it did, I missed it.)
So would 1.52 rockers work with a 272 cam and get better performance than a 260 with 1.6's?
What he is saying is that both are the same. I used the 1.6 roller tips on the stock cam. Irrespective of whether I used a stock coil or big coil, the revs went clean right past 6k with lots of strength. I also used stock springs. No float, no problems. If you go to a higher lift you probably want the beefier springs
For streetability though, you want the cam that gives you torque in the 1k to 3k range and not the track version which gives you peak torque at 6k - 7k.
All that said, building a 2.8 is not something that is easy. As in all engine builds it has to be done exactly right. Much easier to swap, having done both.
I wouldn't mind just a bit more power for my Formula at autocross.
