I'm running some hydraulic Lunati linkbar LS1 lifters the retrofit style similar to the high rpm lifters. I've got ETP heads so the pushrod length is not normal LS range. Anyway I'm running stock rockers with the ETP stands.

First let me say I didn't pre-soak the lifters I'm not sure if that's the cause of my trouble I usually do that but I've only run stock style lifters before now.

I assembled my engine checked pushrod length with an adjustable pushrod. At zero lash I read 8.090 on my length checker. This seemed reasonable so I went with 8.150 pushrods lunait recommened .030 preload the best I could do was .060.

When I went to start it fired barely on two cylinders but for the most part wouldn't run. The valves were hanging open and I was getting zero compression. I didn't hit any valves.

I swapped to 8.100 pushrods thinking I couldn't be off that much valves stayed open on base circle. So I put some 8.050 on it and they closed and it started runs fine and valvetrain is quiet.

Here's the part I don't understand when I first put the 8.050's in it the exhaust valves weren't opening the pushrod wasn't even moving with the engine turned over by the starter. I pulled the rocker arm and the took the pushrod out and then put it back in and then all of sudden the pushrods starts moving again. Now the engine will start and run normally and that problem hasn't returned after a few days of sitting.

One more thing it feels like when I that I'm not even at zerolash when the cam is on the base circle. It's like the lifter collapses or something but just a slighlty longer pushrod would cause the valves to hang open.

So what's going on here did I screw everything up by not pre-soaking the lifters. Did I install way to long of pushrods and smash my lifter cup down into the lifter. Why would the pushrod not move up and down with the lifter when the engine is turned over. I'm hesitant to do anything about it because it's running fine and the valvetrain is very quiet. I'm just to confused I've never had this problem with lifters before.

Thanks

 

My guess is that all the problems are from lifters with no oil in them. It can several seconds for the lifters to fill with the motor started. It would take lot of just cranking the engine to get the lifters filled.

 

When I installed my Morels for the first time (I believe your Lunati lifters may be Morel) the plunger would move very easily and it was difficult to measure for pushrod length. You have to be very gentle or the plunger would simply depress. When you didn't see any lifter motion you may have just been moving the plunger within the lifter. Now that you have it running, re-check the pushrod length as the lifters should be filled. That way you know where you are with regards to pre-load.

 

Thanks for the help. I assume it's all related to oiling I tried to check again last night after I ran it for awhile but it felt like the pushrod was too short again any longer of a pushrod cause the valves to hang open.

It's running nice and quiet and low RPM's but from what I can tell my pushrod is either nearly bottoming out the lifter or it's too short. It feels like it's too short but like I said when I had the longer pushrods on it wouldn't even start because the valves were hanging..

 

Blardy heck - I've got the EXACT same problem at present. I had ETP215s installed on my last LS1-engined car and have put the heads, new cam and Morel Link-bar lifters onto the new engine. The cam is VERY similar to the last one, head gaskets are the same spec and pushrods were the same - 8.10". Only 'new' component are the lifters.

I have had BAD misfiring - most cylinders - on the car and also discovered that with the roller on the base circle, the 8.10" pushrod opens the valve at least .030" when the rocker bolt is tightened - no wonder I wasn't getting any combustion!

It has been driving me crazy and I'm so glad I saw this thread.

I'm going to check with an adjustable pushrod and will most likely order a set of 8.025" (at a guess, although I will measure to confirm) as soon as I can.

I'll let you know what the outcome is.

cheers

 

My Comp Cams adjustable pushrod has become worth it's weight in gold to me since I picked it up 5 or 6 years ago...I'm also very fond of their valve spring height micrometer I bought at the same time...very nice to know exactly how much to shim each spring seat.

 

You can get custom pushrods from Manton very quickly and to a precise length if you need an in between length. You may also want to consider larger OD as well at these longer lengths.

 

Been there.. Too long a pushrod and no compression and misjudging zero lash because of no or little oil in the lifter (the lifter spring is really light).

 

Yea must have been the no oil for me won't do that again. Had to go through three sets of pushrods and I have a freakin length checker it was about worthless. 8.050's seem to be working perfect. Good luck!

 

You have to be careful when putting the pushrod in,It happened to me on the linkbar lifters.I missed the lifter putting in the pushrod and didn't notice till I was turning the motor over and the rocker wasn't moving,Panic set in Then I noticed the pushrod on a slight angle,All is good now.

 

Well, measured it all up today and am going to go with 8.00" pushrods, as they provide me with the .020" - .030" of preload.

If it does turn out too noisy, I may go to 8.025", but we'll have to wait and see.

cheers

 

Just a further update. I tried a few different measuring methodologies, using a pushrod length checker and came up with a requirement for a pushrod at approximately 8.035". Set at 8.025" the rocker ticked, so I opted for the 8.050" pushrod, which gives me approximately .035" preload on the intake and .045" on the exhaust.

Started the car up and it is running A-OK.

Much happier now.

cheers

 

yea 8.050 worked for me too

 

Are these 8.050 pushrods being used with a stock or stroker crank?