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Re: Cold startup rattle? [Re: lewtot184] #2897134
03/08/21 02:53 PM
03/08/21 02:53 PM
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kwikblownhemi Offline
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Originally Posted by lewtot184
doesn't make any difference what rockers are used; preload factor remains the same. the question may be is "there any adjustment in the valve train?".


That was the point and it's obviously going to make a difference in how he increases pre-load. He said he had custom pushrods made to achieve his desired pre-load.

If the pre-load is 0.020" now and it bleeds down enough to be noisy on start-up after 6-7 hours, how long will it take to bleed down with pre-load at 0.090" ?

The lifters are bleeding down fast. Is air-entrainment an issue? Sloppy clearances in the lifters?

Re: Cold startup rattle? [Re: kwikblownhemi] #2897137
03/08/21 03:14 PM
03/08/21 03:14 PM
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Originally Posted by kwikblownhemi
Originally Posted by lewtot184
doesn't make any difference what rockers are used; preload factor remains the same. the question may be is "there any adjustment in the valve train?".


That was the point and it's obviously going to make a difference in how he increases pre-load. He said he had custom pushrods made to achieve his desired pre-load.

If the pre-load is 0.020" now and it bleeds down enough to be noisy on start-up after 6-7 hours, how long will it take to bleed down with pre-load at 0.090" ?

The lifters are bleeding down fast. Is air-entrainment an issue? Sloppy clearances in the lifters?
could be crummy tappets, who knows? but, just from my experience this is just part of the mopar tappet with a lot of plunger travel. i'm out of this one.

Re: Cold startup rattle? [Re: lewtot184] #2897141
03/08/21 03:22 PM
03/08/21 03:22 PM
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Posts: 142
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Originally Posted by lewtot184
Originally Posted by kwikblownhemi
Originally Posted by lewtot184
doesn't make any difference what rockers are used; preload factor remains the same. the question may be is "there any adjustment in the valve train?".


That was the point and it's obviously going to make a difference in how he increases pre-load. He said he had custom pushrods made to achieve his desired pre-load.

If the pre-load is 0.020" now and it bleeds down enough to be noisy on start-up after 6-7 hours, how long will it take to bleed down with pre-load at 0.090" ?

The lifters are bleeding down fast. Is air-entrainment an issue? Sloppy clearances in the lifters?
could be crummy tappets, who knows? but, just from my experience this is just part of the mopar tappet with a lot of plunger travel. i'm out of this one.


Don't take it personal, Lew. I've had these same issues, sometimes the cause and the cure aren't easily found. I built a 318 with a moderate hydro Comp cam and lifters that was possessed. It would go weeks without noise. Sometimes it would start cold like the OP's engine and quiet right down. Others, it would go ten miles before it got quiet.

Re: Cold startup rattle? [Re: kwikblownhemi] #2897173
03/08/21 06:01 PM
03/08/21 06:01 PM
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Keymar, MD
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On the last motor my dad built for my sisters car (360 with comp cams hydraulic cam, stock steel rockers, edelbrock heads) it would make a noise similar. It would do it on start up, sometimes it would go away in a few seconds, other times it would continue. Sometimes the noise would stop and after 30 secs start again. Finally determined it was the lifters. The block was a "newer" block (I think in the 80s, but can't remember for sure so not sure if that had anything to do with it or not) but anyways the center part of the lifter that is smaller in diameter was taller/bigger than other lifters we used in the past. Ended up buying a new set of lifters that had the smaller / normal size center part and the engine hasn't made the noise since.

Re: Cold startup rattle: Update [Re: Cab_Burge] #2897200
03/08/21 07:16 PM
03/08/21 07:16 PM
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Bend,OR USA
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Originally Posted by Cab_Burge
I finish breaking in a new pump gas motor on my motor run in stand today, I had set the lifter preload at room temps. and knew that I would need to reset it with the motor warmed up, hot.
The heads and rocker arms are the Speed Master brand and version of the Eddy Victor with Speed Master bushed extrude aluminum 1.6 ratio rocker arm kit with 7/16 adjuster screws, the heads are CNC ported to 325 CC but they are not M.W. size intake ports.
I set the preload at 1/3 of a turn cold, I had free play on most of the rocker adjuster when warmed up and tried using 1/3 turn preload hot, that didn't work shock
That amount of preload would hold the valves open shock
I ended up having to use 1/8 turn preload hot to get it to start and run. I'll see what it does in the morning cold luck
I'm thinking the heads will shrink down when cold adding more preload and I'm hoping it starts and runs okay luck

My Motor didn't make any lifter noise this morning when cold, it does have some piston to cylinder wall noise (rattle) though when cold whiney I should have had those pistons made with the tighter street piston alloy instead of the race piston alloy realcrazy


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Cold startup rattle? [Re: lewtot184] #2897617
03/10/21 04:15 AM
03/10/21 04:15 AM
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Originally Posted by lewtot184
.020" preload won't work if you're not using a race hydraulic tappet. plunger travel in the tappet should be around .210". the preload needs to be around 50% of plunger travel. if you have adjustable rockers with 3/8"-24 thread adjusters set the preload between 1 1/2-2 turns. that will give you somewhere between .060"-.090" preload. treat .060" as a minimum. factory pre-load with non-adjustable rockers was at least .100". a performance hydraulic cam will make a little noise due to the fast closing ramps and that can't be adjusted out. setting the preload to .090" should make a noticeable difference.

I've never seen any stock production hydraulic lifter or after market Hi Po, not anti pump ups, that wanted to have anywhere close to .100 or more preload.
I remember when the first Hi Po anti pump up race hydraulic lifters came out in the mid 1970s that the instructions said to set them at zero preload to .0020 lash shruggy
I was dyno testing several NHRA legal 340 stocker motors and ended up testing them at .0020 lash and then at .000 and again with right at .010 to .015 preload on them using stock blueprinted ductile iron rockers 3/8 inch X 24 thread adjusters so a 1/4 turn preload was right at .011 lifter preload.
I have heard of guys recommending adjusting all the travel out of the lifter so it is bottom out, I won't do that tsk


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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