Lifter noise after mods?

[SNK-BIT]

It's been awhile (http://forums.qwiksnake.com/showthread.php?t=2927) since I’ve posted but have finally made the mods to my Cobra. I went with the 165cc AFR's (#1402), 1.7 Scorpion rockers, and used all recommended hardware. The only place I deviated from was the cam. After talking to the AFR tech's I was "talked" into a Comp cam that was not "e" legal but both AFR and Comp tech said would pass a "sniff" test but of course couldn't guarantee it. It's a (Comp P/N 35-351-8) XE270HR 218/224 dur @.050 and .512/.512 lift (.534/.534 with Scorpions) and 114° LSA. AFR wanted a 4* advance on the cam and it came out to 3* so I left it at that. Of course it was close in the p to v area as I had .083 on intake! The exhaust at .122 was much better. I reused my stock roller lifters as they were making no noise and looked in good shape. Beings how I converted from non adjustable pedestal mounts to studs with poly locks I obviously had to do some adjusting. I went to base circle, took out all the play in the pushrod, and gave it 3/4 turn more. Fired right up and clacked "mildly" all the way to operating temp. I only took it off idle (1500-2000rpm) a couple of times on the way to operating temp and it never did quite up. I shut it down , pulled the valve covers, and gave all of the adjusters an additional 1/4 turn. It help but seems to clack on initial firing, and after reaching operating temp. It might just be me but it seems to be ok in between these two points. Ideas? Also two other items I've been troubleshooting...a rolling idle problem that has been there since I bought the car but was never (200-400rpm flux) bad enough to worry about. With the new cam? it would roll from idle (approx 750-800rpm) to almost 2000rpm repeatedly before settling down again. I think I’ve (IAC,salt n pepper connectors, etc) pretty much fixed that problem but this brings up the last issue. Unless I have a lite load on the accelerator the car in any gear (1500rpm and lower) wants to buck. I'm pretty sure the cam is not "big" enough to cause this but I’m thinking it has to do with my idle quality issue. If it wasn't for the noise and this lite bucking the car has really responded to the changes as it even sounds meaner and pulls waaaay harder than it used to. I need to get this fixed so I can get some new dyno and track numbers. Any and all help appreciated. Thanks for listening.

[coupe]

too tight. Go about 1/3 turn of "pre-load"...then, tighten lock screw and give a little "twist" on the outer nut again after that...snugs it nicely.

3/4 to a full turn is probably about .040-.050.

You only need .025 to .030.

[QWKSNKE]

Did you read this thread http://forums.qwiksnake.com/showthread.php?t=64 that is "stickied" to the top in this forum. It shows the proper procedure on adjusting the rockers.

On your bucking, what MAF are you running

[SNK-BIT]

Thanks for the replies. I went from stock pedestals that were non adjustable to afr's with studs and poly locks hence my "chebbie" 3/4 turn. I know on those engines a full turn doesn't hurt and I usually go 3/4 to a full turn. My understanding was that at high revs and 1/4 to 1/2 turn you took the chance of popping the lifter "clip" out. I've also heard going to tight will cause clacking. How? Is the lifter bottoming out? My lifter adjustment was with the lower intake off, the cam on "base" circle, a "slight" drag on the pushrods, then 3/4 turn. Obviously this didn't work. I mean I didn't change brand or weight of oil and other than the new rocker arms and pushrods nothing has changed. I can't say I've done an adjustment on a SBF as most are just torqued down. I will give it another shot (yep I read the "sticky" on how to adjust the rockers) and see how it goes. Should I also (after loosening the rocker) crank the engine over a few revolutions to "repump" the lifters befor adjusting or is it not necessary? Hey this also brings up the question I've heard from folks at the dragstrip about setting "lash" loose for torque and "tight" for rpm. Does this only apply to solid lifters? I'm running the stock 70mm maf. Is this too much cam for the computer? I surely don't think so as I've read were folks are running with TFS1 cams (larger than mine) and idle good at 850-900. Are my stock (24lb) injectors a problem? Thanks. (I know I have more questions in my head than corn in a cornfield).

[coupe]

TFS cam is not much different...a little more duration and less lift actually.
You're fine with all the stuff you have. Lash is only on solid's.

[SNK-BIT]

No luck. I did as suggested one cyl at a time. Loosened in/ex on that cyl and cranked eng over until I saw oil press come up to make sure lifter was "pumped" up. Ran poly's down 1/4 to 1/3 turn and locked set screw down. Did all cylinders that way. I'm sure i'm on "base" circle of cam. Initially it was completely quite then it acts like there is too much valve spring pressure and it bleeds the lifter down and they start clacking again. It's not oil pressure as before I did the heads etc it was at 35lbs idle and still is. I was told the clacking is "normal" by a couple of mechanics after changing heads, pushrods,rockers. I don't know but i'm not real happy with the way it sounds. It's not that it's "that" loud it just didn't make any noise before that I remember. I'm more concerned about the excessive lash beating the rockers or valve stem tips. Anyone else have "Scorpion" rockers? If so are they noisy? Somethings wrong!

[QWKSNKE]

mine gives off a little more noise than stock since I added the stud girdles last year.

Don't have any experience with the Scorpion rockers. All I have used are D.S.S. and Comp Pro Mags

[ncontt]

Anyone else have "Scorpion" rockers? If so are they noisy? Somethings wrong!


I have them on my car but I also have the turbos AND the noisy "EDEMBROCK" gear drive...so I can't really hear it if it is making noise... sorry.

[vristang]

I have had a fair amount of noise with my adjustable rockers since installing them.
As far as I can tell the noise is coming from the pushrod tapping on the guideplate.

I have tried all kinds of adjusting methods, none of which made any difference.

jason

[QWKSNKE]

I have had a fair amount of noise with my adjustable rockers since installing them.
As far as I can tell the noise is coming from the pushrod tapping on the guideplate.

I have tried all kinds of adjusting methods, none of which made any difference.

jason

That is probably true. I have the same problems on my car with the pushrods touching the guide plates. There is no way to move them around where they do not touch. They do wear a custom slot in the guide plate after a few thousand miles though :D

[vristang]

They do wear a custom slot in the guide plate after a few thousand miles though :D

:doh:

I guess I'll have to keep an eye on that. :chug: