: Fun with lifters



five10man
06-11-04, 09:25 PM
Hey yawl...
Beautifying the interior of my shop right now is a 97 Deville, vin Y. The customer brought it in due to a very light (IMO) tapping sound from the valvetrain. This noise has been present since she had the head gaskets replaced, block timeserted, and one lifter replaced about six months ago at another shop. After tracing the noise and trying the WOT / idle forever / Marvel Mystery Oil methods, I removed the right cam cover and intake cam.
Seven of the lifters (the OEM units) appeared OK, and would only release a tiny droplet of oil from their feed holes when squeezed. The eighth lifter, the one that had been replaced, was easier to compress, and gave up most of its oil, after which it compressed very easily.
The customer brought in an "extra" lifter she had been given, which I am assuming is the same as the one in the engine: a Sealed Power HT-2273. I soaked it in ATF, both standing up and lying on its side with the feed hole facing upward, and diddled it while it was submerged, but never have been able to get it to feel any better than the aerated aftermarket unit I took out of the engine. :banghead:
SO, THE BIG QUESTION: What is up with the lifters on these engines? :hmm: I have read quite a few posts with mentions of people's lifters getting airbound and ticking, but no mentions of long-term lifter problems. Can anyone out there with experience building these engines give me a solid pass / fail test for lifters on the bench? They should be close to rock-solid when fully bled, right? Is there a trick to bleeding them? Is there a good aftermarket supplier for lifters, or is GM the only way to go? Is it normal / acceptable for there to be a small "crack" where the hardened top is joined to the lifter body? Thanks ahead of time!

growe3
06-12-04, 12:20 PM
My experience with sticky lifters is that Marvel Mystery Oil can usually work them loose in a very short time. It is basically a very fine machine oil with penetrating qualities. On some engine it will work within minutes on others it may take 30 minutes or so.


I like it because it works without introducing any solvents into the oil system, that could break down the oil and cause scuffing.

Make sure that the proper weight oil is being used. Often people put in a heavy oil to try and mask the ticking, that is a mistake. While this may benefit a solid lifter it just makes it harder for the oil to enter a hydrulic lifter.


-George

five10man
06-13-04, 10:34 PM
I changed the oil, using 5w-30, about 1 month ago. I have already done the MMM thing, and it didn't help. I have also tried the WOT exercise regimen, and other than the revenue it generated for the local government, no one benefitted.


HAS NO ONE BUILT ONE OF THESE MOTORS? BBOB?

BeelzeBob
06-14-04, 11:47 AM
Honestly, there are very very few problems with the direct acting tappets in the 93-99 Northstar engines.


If a tiny bit of debris gets trapped between the check ball and the seat in the lifter (such as might be generated during an engine teardown....) then it can collapse under load and "tick"... Most every noisy lifter I have ever seen had debris in it causing the problem.

You are never going to "bleed" the lifter on the bench.....just too difficult to do. The hydraulic element in those lifters is "upside downwards" from the conventional lifter in a cam-in-block engine. Just the nature of the beast in an overhead cam engine like this. The down side to this is that it takes forever to get any air out of a lifter once it gets in there. It will usually take upwards of a 1/2 hour of engine operation to thoroughtly purge the air out of a lifter in a 93-99 Northstar...or any DOHC engine using those style tappets.


If you could identify the noisy lifter I would replace it with an OEM replacement (not a mystery lifter handed to you....LOL) and button it up and drive the car for an hour.

That engine uses 10W30 oil so if the weather is hot the extra viscosity may be needed to keep the valve train totally quiet.

I assume you are holding the cam chains taut during the cam removal to get the lifters out...??? If not, the front cover has to come off to reset the cam chain tensioners. They will rachet and take up the slack if the chains are simply left slack and it will be impossible to get thte chains back on the sprockets at reassembly. Don't be tempted to try and force them into place as the timing drive will be under severe tension and will break a chain or tear up the wear guides and wreck the timing drive.


It is normal to see a tiny line where the hardened foot of the lifter is welded to the lifter body. It can be there or not. It is just the weldline that is exposed when the OD of the lifter is ground to size. Perfectly normal.

five10man
06-14-04, 11:47 PM
Thanks... Just read your post after an afternoon of dead ISP servers and Caddy wrenching. The GM unit which arrived this morning was loads stiffer than the Sealed Power piece that I was going to install. When I submerged the GM lifter and squeezed it, feed port side up, it gave up about 20 small bubbles. After installation, the injectors are now the loudest tick this motor has.
Thanks for the info, and I can heartily NOT RECOMMEND Sealed Power lifters if you are building / repairing a Northstar.

BTW, I removed the fire blanket / noise reduction pad and there was a hole that lined up directly with the timing chain. This allowed me to keep the intake cam sprocket on the chain, pulled taut to the hole in the hood with a ratcheting tie-down. The hood struts were braced with two Thexton clamps made for that purpose. Wouldn't work on the exhaust side, I know, but it did the trick for no money spent on special service tools.