2.8L/3.4L Oversize Lifter

[Canyonero]

So my brain finally made a connection when I was driving around...

I've read somewhere along the line that occasionally an oversize lifter is used out of the factory if the block is slightly out of spec and they have to overbore a lifter opening. The block should be stamped at that opening with the size of the overbore. Where do I buy an oversize lifter?

Here's why I think I need one:

I have a salvage yard 3.4 that I did not rebuild. I dropped it right in and drove it as a multiport engine before I pulled the intake, installed the cam, and converted it back to TBI (long story). It did NOT tick with the stock cam and lifters. I even went back in and replaced the lifter (intake on #2) thinking I just got a bad one. But, it still ticks.

So, I pulled the valve cover and started the engine. Sure enough, no oil out of the intake pushrod on cyl #2 at first, when all others were flowing great. It did eventually start flowing oil, but a much lower volume than all the rest. The first lifter (that I installed with the cam) was shot, I could compress it with the pushrod where with the rest couldn't. Like it wasn't holding oil anymore, I think all those dry starts ruined it.

The engine was disgusting inside, I spent a while with a screwdriver and shop vac chipping away the deposits. I thought I was careful about preventing those deposits from falling into the engine when I was cleaning, but until now I assumed that a bit somehow found it's way into an oil passage and was causing the starvation of that lifter. But I got to looking at the passages on a trash block I have and don't see any way just ONE lifter could be starved in that way.

So. Oversize lifter bore? Makes sense to me. I just hope I can find a replacement... I just wish I hadn't tossed my old lifters, I could at least compare them to confirm this theory and maybe reinstall that lifter if I'm unable to source a new one. But, moot point, I'm almost certain I discarded them at some point over the last year.

[geoffinbc]

Yup they do exist in old blocks. But that was do more to old machining tools and mistakes. In the late 80's machining practices were vastly improved and I don't think lifter bore machining was an issue. The only way to know for sure is to check your block.

Don't overlook the fact that cam lobes can get damaged and tick, springs can tick and loose valves can tick.

The fact you don't see much oil flow could be due to the lifter, push rod or spring sup oil hole being partially blocked.

[Canyonero]

Well, I did replace the lifter with no improvement. The problem STARTED with a cam and lifter change. Damaged cam lobe wouldn't explain the oil starvation. Ticking is much louder on a cold start when it would seem that the oil has drained from the lifter and it's not getting enough oil to pump back up (when all other lifters/pushrods flow immediately). It's not my pushrod either, I checked and installed new comp cams pushrods anyway.

I obviously knew about oversize lifters, but I didn't make the connection of that possibly being MY issue until just recently. It makes the most sense given my symptoms and what I've already tried.

Question is, where do I get one!? Of course, I have to pull my intake to find out if that is indeed the issue, but there's no point to doing that if I can't get a replacement... Putting in another normal lifter will gain me nothing and I might as well NOT waste the time taking it apart if it's something I can't fix. If that's the case, I'll just have to try to tolerate the ticking (as I have for the past year) until I find a Northstar V8 to put in there instead. :P

[Canyonero]

Here's another thing I'm going to investigate tonight or tomorrow:

Maybe the lifter was fine, not oversize...but the rocker is hitting the valve cover. I never checked that. Lots of noise at first, then less noise when the lifter finally collapses under the beating.

I'm using Comp 1.6 ratio rockers and Comp springs and pushrods, but I have a Crane H260-2 cam. Far as I know, everyone else has used the Comp 252 cam. Maybe this combination just doesn't clear the Fiero valve covers. Pretty easy to check, just pull off my left cover and look for a dent...

[Canyonero]

No evidence of the rocker hitting anything...

I'm out of ideas. Anyone else?

I haven't pulled the intake yet, but that's up next. We'll see if this thing is supposed to have an oversize lifter after all.

[Canyonero]

Struck out again. The lifter appears to be correct.

[Canyonero]

Replaced the lifter. Again. Lashed valves to 1-turn past zero, was doing 3/4-turn before. Primed and started. So far so good...

[Superdave]

I was going to say... Curtis was running a solid roller cam with a ton of lift under Fiero covers..lol

I'd think if you had a standard lifter in an overbored hole you'd have seriously low oil pressure overall. Good luck with adding preload, have you checked the contact pattern on the valve?

[Canyonero]

I didn't look for anything specific with the contact pattern, but I didn't notice anything unusual. They have a few thousand miles on them now.

I'll start the truck after work today, see if it ticks. It would tick pretty loudly after sitting a day or so.