farmdawg

I have noticed a rather annoying tick that has developed in my engine lately. I think when I changed the heads and cam for the maggie, I had a few lifters go flat or something.

I have checked the torque on the rocker arms many times to make sure that they are all tight and have found no up or down movement, but plenty of side to side movement on the shaft, could this be causing the tick that I'm hearing? It's mostly on the driver side of the car and is quite loud if you put you head down behind the front tire.

I have checked many times for exhaust leaks as well and have found none. The warmer the car gets, the louder the noise is, it doesn't go away. I can hear something in the header tubes, but can't make out what it is. My cam is exhaust biased with 226/234 duration 598/599 lift on a 117 lsa, it's not a mild cam, but not that aggressive either.

This is driving me crazy, it didn't make this much noise with the stock exhaust manifolds and broken valve springs before the maggie install. It's not in the blower, nor is it imcompatibility, just noticed it after the blower install, and it sizzles my sac. The block is a TSP prepped forged 347 that had about 7k miles on it when I bought it, and I have since put about another 4.5k on it, and changed the oil three times, it sat for the last six months while I was in Iraq, so I changed it when I got back.

I was thinking about upgrading to some Yella Terra rockers, or something like that, should I also consider some new lifters as well, and which ones? Any and all help is greatly appreciated.

stevieturbo

So you fitted a camshaft with much higher lift, and didnt check lifter pre-load, and fit suitable pushrods ?

You need to ensure your lifter pre-load is correct. If its too little, then it will tick forever....well, until a pushrod falls out or breaks.

farmdawg

I didn't think of that. They're stock lifters as far as I know, and hardened 7.4 pushrods. I checked with the previous owner and he had used a bigger cam with the same rockers, lifters, and pushrods and didn't have any issues. His lift was over 605 and lsa was 112 on the cam he used.

So now a dumb question, refresh my memory on how to check the lifter preload.

BadgeZ28

iTrader: (28)

The main point to check is that the 7.4 pushrod is still ideal. The camshaft might have a different base circle diameter? Our stock rocker arms are non adjustable and the pushrod length must be very close. A milling of the heads will cause the same concern. You can check for proper length by measuring pre-load with a dial indicator.

01ramair500hp

if you go with 7.450 there will be no valvetrain noise. we did that on a vette. went from 7.400 to a 7.450 and the noise went away. just a thought

farmdawg

It's worth a try, i guess, but shouldn't I be concerned about clearance issues between the valve and the piston then? The engine is assembled and in the car now, I'm not really wanting to tear the car apart any more than I have to at this point since it's my daily and limited time/space to tear it apart right now.

The cam that came out of the car for the maggie was an MTI Stealth II so I'm not sure if the base circle was a different diameter or not. I notice the noise mostly on the driver side, it seems more pronounced there and not as loud on the passenger side.

kwiksilverz28

iTrader: (7)

If it is the same base circle, and the heads/block have not been milled/are exactly the same height as stock, 7.40 should be correct. There is a tool somewhere that is basically an adjustable length pushrod checker...

farmdawg

To the best of my knowledge neither the heads nor the block have been milled. I've seen the pushrod length tools before, I'll try to get one and check that out too.