1993 3.4 DOHC "Lifters"

[Schurkey]

As part of the repair to my '93 3.4, I'm wanting to disassemble and inspect the hydraulic "lifters".

I don't see a snap-ring; and I can't find lifter disassembly in the service manual.

HOW do they come apart?

[RedZMonte]

dunno if these pics help... but this is what came up on a search.

http://60degreev6.com/forum/showthread.php/32394-LQ1-Lifter-disassembled-photo-s

[Schurkey]

THANK YOU!

I think the deal is that they just pull apart, there is no snap ring. I guess I'll be finding out this afternoon...

[Schurkey]

Not so easy as I had hoped. Requires considerable internal pressure to pop the hidden snap-ring. Must trap the plunger with a vice and some padding or the internal parts will fly away, and you'll have to hunt all over to find the two plungers and coil spring.

Hydraulic lifters have traditionally been the most-precisely machined and mated parts in an engine. Disassemble ONE AT A TIME because you do not want to mix-and-match the internal pieces. Do not allow any dirt or lint to remain in the lifter. These things have to be CLEAN. Slight discoloration is acceptable, as pictured. Heavy varnish must be removed. Assure that the check ball seals one way but allows fluid flow the other way. As pictured, the fluid would flow out the "nipple".


(Top) Lifter body
(Lower) Internal plunger with check ball, coil spring, external plunger with snap-ring retainer. Note "polished" circle in the center of the external plunger, from contact with valve tip.


Spring stacked on top of internal plunger as it would be when assembled.


Lifter body showing contact circle from internal plunger, and machined depression that allows oil to flow into plunger.


Internal plunger and coil spring, positioned as they would be when assembled. REFERENCE ONLY--Don't try to force external plunger over this, assemble the plunger first, then install complete plunger assembly into the lifter body.


External plunger with snap-ring. Snap ring is totally inaccessible when assembled into lifter body.




Note oil hole in groove of lifter body. Grease needle re-purposed to blow compressed air into hole. CLEAN THE NEEDLE before injecting air into lifter. Air pressure pops external plunger out of lifter body




Rubber-tipped blow gun used to pressurize lifter body. 100+ PSI will not always pop external plunger free--but if it does, it'll fly across the shop unless you trap it.

[Schurkey]

Update: 8 out of 12 lifters in the first head came apart with air pressure. Two more came apart with air pressure after soaking in carb cleaner; whether that actually helped or it was just coincidence, I don't know.

The last two would not come apart even after I cranked the air pressure to 140 psi. I had to re-assemble the grease needle and pop them apart with the grease gun. Not my first choice as the grease is harder to clean out of the lifter than air.

At this point the first twelve are all apart, all cleaned, re-assembled and ready to go back into the cam carrier.

[Later edit] I've popped another 24 lifters (from my spare pair of heads/cam carriers) apart for cleaning and inspection. All lifters so far seem to be in essentially the same condition--some varnish; but nothing terrible. No real wear to speak of on the lifter face that the cam lobe rubs across, but the wear surface is "polished". Some lifters seem to spin in the bores, the wear surface has a circular pattern. Others appear to not spin, and the wear pattern is oblong with minor varnish on the part of the lifter face that the cam isn't rubbing on.

Of this group of 24 lifters, only seven came apart with air pressure. All the rest had to be popped with the grease gun. Cleaning the grease back out of the lifter is the worst part of the whole deal.

The spare pair of heads/cam carriers came to me with the lifters in a separate cardboard box. I have no idea which lifter went in which lifter bore. I don't think it's hugely critical because the valve springs are fairly weak, the cam lobes and lifter faces are huge, and therefore the pressure per square inch is way less than, for instance, a typical V-8 engine cam and lifter set. It's not like the lifter faces are showing a wear pattern that should be matched to the cam lobe. If I knew which lifter went in which bore, I'd keep them in order. That's what I did on the heads that came on the engine. This spare set is going together at random...and I'm not losing any sleep over it.

The remaining head/cam carrier will be pulled off the engine this week. With a little luck, the car will be drivable by this time next week.[/Later edit]




Modify LQ1 cam shafts per service bulletin 57-61-09. (Lifter tick oil pressure "fix".)

http://60degreev6.com/forum/showthread.php/49738-LQ1-Service-Bulletin-57-61-09-Lifter-tick-%28cold%29?p=450416#post450416

The head gasket that started this whole mess:

http://60degreev6.com/forum/showthread.php/49657-Losing-coolant-into-2

LQ1 Block heater warning:

http://60degreev6.com/forum/showthread.php/49839-3-4-VIN-X-LQ1-Engine-Block-Heater-Warning