Masterspykiller

I blew it on my L98 high performance build. Newbie gotcha warning too late!

The block was professionally prepared (cleaned, magnafluxed, decked, bored, honed, etc.).

The bottom end was professionally assembled (balanced rotating assembly (crank, rods, pistons) and the cam installed).

I planned to do everything else. Then it sat in a sealed plastic bag for four years until I finally had both time and money to work on it (last week).

When I dropped in the well-oiled new lifters, UH OH, several would not slide in by themselves and stopped at almost the same height. A few of those needed thumb pressure to fully seat, but were then too tight to reseat without thumb pressure after cam rotation. And a few would not seat even with very firm thumb pressure.

I confirmed the CompCams 875 hydraulic roller lifters are correct for this block (850 lifters would also work).

I AM PRETTY SURE THE LIFTER BORES, at the very end near the cam, probably got peened over during one of the block preparation procedures and were not "rechecked" before bottom end assembly.

I know a cylinder bore, or trashed lifter covered in lapping compound, should be used to round out the bottom ends of the lifter bores so the lifters drop in with gravity assistance only, and rotate freely in the bores.

Even if I can put toweling at the bottom of the bores, and round out the bent ends with the block upside down (using gravity to encourage the grit to exit the top of the bore), I can't see any way to avoid getting grit into the oil ports on each side of the lifter bore, and I can't see any way to clean those with the block assembled.

HERE IS THE QUESTION: IS THERE ANY WAY TO AVOID DIS-ASSEMBLING THE ENTIRE BOTTOM END TO "CLEAN UP" THE LIFTER BORES?

All suggestions welcomed.

For those of you who have read this far, here is the fun part, our build list (any comments welcome on this too!) AREAS of concern are marked with *#*?:

1991 Corvette Coupe L98 automatic (daily driver plus some auto-x)
91-93 octane fuel only, oil changed diligently 5,000 miles

BLOCK
Freshened block, professionally machined, casting 10243880
350 bored 4.030
Crank and cam center distance reduced to 4.470 (measured)
2 bolt main
one piece rear seal
ARP 12 point fasteners everywhere possible

ROTATING ASSEMBLY
GM crank, balanced
Scat 2-cir5700 rods
Speed Pro R9902-30 rings
Speed Pro H100cp30 pistons 5cc valve reliefs (eyebrow)

CAM
TPIS ZZ9 cam, iron gear
duration i212/e226; lsa 112; i.483"/e.520" lift w/1.5rr (.515 intake lift w/1.6rr)
Cloyes True Roller timing chain 9-3145-5
Cloyes timing chain cover with adjustable cam button
CompCams 875 hydraulic roller lifters
GMPP lifter guides (dogbones)
GMPP lifter retainer (spider)
5/16" diameter chromoly heat treated _____
*#*? Push rod length to be determined after lifter, head install

HEADS
AFR 180 eliminator 0919 heads (AFR standard springs, retainers, valves, rod guides, lifter studs, 65cc combustion chamber)
CompCams ultra gold 3/8 roller rockers 1.5 exhaust, 1.6 intake
Stock valve covers
FelPro 1142-026 head gasket (to increase compression)
Compression calculation made with piston volume at TDC determined by burette with colored alcohol (piston is flush with deck)
Static compression 10.52; Dynamic compression 9.94
*#*? Quench area 0.026
(Thank you to Pat Kelley for creating and sharing the DCR calculator!)

INTAKE
Opened up air filter
52mm BBK throttle body
*#*? Stock plenum
Accel high flow runners
Accel high flow base

FUEL
Walbro 255 fuel pump with upgraded harness
stock fuel rails
Adjustable fuel pressure regulator (set to 50psi)
Bosch III flow matched 24lbs injectors, 26lbs output at 50psi
(Thank you FIC!)

EXHAUST
TPIS long tube headers
Random Tech high flow cats
X pipe
Borla 3" cat back

TRANSMISSION
4L60 This was rebuilt a few years ago with tighter, firmer shifts and new torque converter, no specifications known, no work planned
Will use ZF Doc beam plates when re-installed
stock drive shaft
3.06 stock rear end

COOLING
DeWitts radiator
(Thank you Tom DeWitt for so much help on this forum!)
Stock fans
Stewart high flow mechanical water pump 13403-HP
*#*? MAYBE add auxiliary electric water pump to keep flow up while sitting in Los Angeles summer traffic
Stewart high flow, calibrated 180 thermostat
Mishimoto hose set

OILING
billet aluminum filter mount with bypass BLOCKED OFF
Melling 55HV, IS-55E, M-55005, 55-S3 oil pump etc.

wydopnthrtl

I'd not be afraid to take it apart. Just make sure to put the parts back together in the exact same place and orientation.
Tip 1: Shim the rods so that they can't rotate and put a small deformation in the bearings when you loosen and tighten the rod bolts. (get multiple feeler gauges and shove them in the gaps between the crank and rods)
Tip 2: Measure torque to turn the the bottom end over and then when reassembling measure the TQ to verify nothing is binding (more than the original state)

Its not rocket science... get er done!

Tom400CFI

I agree. that the problem w/this job isn't getting contamination on the crank; you can flip it over to avoid that. The problem is flushing out the lifter bore when done, and not getting contamination into the lifter oil galley. I think you'll have to disassemble, do the work, get the block flushed again, put it back together.

Tom400CFI

Been thinking about this a little more;

What if you charged your lifter galley with compressed air or water, then honed out the lifter bores? If you plugged all lifter bores except for the one that you're honing, the velocity of discharge though the one lifter bore ought to be more than enough to keep the galley free of debris.

cudamax

I don't think its that big of a deal. Get in there with a die grinder and just hit the bottom on the lifter bore, maybe a 1/16 inch and up and flare it a real little at a time after sliding out the cam and stuffing oil soaked rags in there. Then trail fit each lifter until they slide in and out nicely

Sleazy Rider

if it was my block, i would take the time to dissamble it to do the work...just for piece of mind to know that contaminates were left in the block and oiling system. just be sure to mark each assembly coming out for cylinder/saddle number and direction. i just put my short block back together after getting 3 bad cranks.

LTxDave

Are you sure its a problem with machining and not just some corrosion in the lifter bores from sitting up so long? I'd look really close before taking it apart. If it is corrosion, some PB Blaster will disolve it pretty quickly.

Masterspykiller

Thank you all for taking the time to share your wisdom with me.

I am pretty sure it is not corrosion - all of the lifters stop or snag at almost the exact same depth, just about where the full diameter exits the bore near the cam.

As much as I am reluctant to dis-assemble the professionally installed bottom end, it appears I must. Even if I stuffed rags to avoid any contamination of the lifter valley and oiling ports 1/2 way down the bore and pressurized it, it is just too difficult and too obstructed to get to the open end of the bores with the rotating assembly installed.

So, I'll pull the entire rotating assembly and cam out tomorrow. I probably will stuff the bores and pressurize it all, and mask off the non-work areas to minimize contamination. I really don't have the facility to wash the entire block, so I will be very careful.

I guess I'll also radius the lifter valley oil returns at the same time.

Anything else I should do with my little Dremel tool while I am at it?
Cheers!

cudamax

A million things to do with a Dremel on an Engine. You can start with the intake valley drainback and then some simple screens placed there will save a motor if a valve train comes apart and then enamel the entire intake valley. I've seen nuts with a dremel and too much time on their hands get 5 to 10 pounds off of the entire.
Really if you are planning on a complete tear down at least work on 1 lifter bore first. Try opening up just the bottom lip of the lifter bore and or hit it quickly with a brake hone. Isnt there any kinda grinder with a vacuum? or a grinder and a real powerful vacuum or a reamer.
It's not going to take much to make them straight and if u keep it dry u can suck it out of there

mtwoolford

pull your cam; take a very small half round machinists file and gently deburr the bottom and top lip of the tight lifter bore(s); clean, oil reinsert lifter, check for freedomn of movement; all will probably be okay.

I would NOT attack the lifter bore with a brake hone or similiar device; go a little too far and you're screwed big time; a dremel ? naw, too aggressive. good luck

cudamax

Sure in the wrong hands. Otherwise it's a second or 2 per bore and ur done

Tom400CFI

C409

..... I'm still trying to wrap my head around any machining operations that would involve peening lifter bores from either side ... especially on an iron block ... its not something that could happen by accident ... get the micrometer out and measure the lifters ..........

rklessdriver

I agree and GM blocks, espc a used one is almost always going to be on the loose side of the spec for lifter bore clearance.

First thing I would do is check the OD on the lifters with a MIC.

OP once you get it apart, remove the front and rear lifter galley plugs...

Then do as mtwoolford suggested with a small round machinist fine tooth file.

Once all the lifters move free then take a garden hose and hook it up to HOT water out of your sink and use only HOT water and Tide detergent to blow thru the lifter bores and lifter galleys.

The detergent will get oil away from the small metal and grit left behind and the HOT water will be able to wash it away and then the hot water will evaporate fairly quickley.

Once the water has evaporated take a papertowel with WD40 or ATF and wipe all the machined surfaces and bores to protect them and get the block ready for re-assembly.
Will

Midnight 85

I am having a hard time believing there is any damage to the lifter bores as others have said. I would definitely give the bores a good dousing with PB and while it is sitting take each lifter and clean it up with carb cleaner and some scotchbrite, maybe the lube that was on the lifters when new has gelled a bit. I sure would give these things a try before tearing the engine apart and grinding something.

rocco16

First make sure it really is the lifter bores. Can you swap lifters around and still have the same bores give problems? How about turning the lifters upside down in the problem bores and seeing if they'll go in that way. At least you can determine if it's the bores or the lifters themselves.
That would be step one.

cv67

Look up CNC blocks goes by the name Carl not sure if hes still here used to post in the C3 section a lot. Or Chris Straub some lifters are sized a touch different maybe you can just swap brand lifters and be done with it. They would have the info I never bothered saving it but have seen them post it.

leesvet

Just roll up a green scotch-brite pad as suggested and run it up/down in the bore with some lube, WD or PD and that will clean off the gelled oil and/or lite oxidation. I'd pull the cam and stuff clean OILY rags under the bores. Why oily? so they catch and hold the debris better.

There's nothing wrong with the bores....bore. or the lifters.

what IS wrong is 4 yrs sitting in the corner. I'd expect to see other areas of oil/lubes gelled or gummed from time sitting with temp/humidity changing. Being in a plastic bag does not prevent oxidation on the metals OR the lubricants.
That just helps keep dirt/dust off.

Oxidation is simply the normal chemical break-down of a material from AGEING. Like rust is to iron. The effect of oxygen on a material...there was/is some amount of air trapped inside the bag with the block. There was only a little air in there but LOTS of time...
Thats why vacuum sealing is such a big deal.You can seal out both time AND oxygen.

None of these assembly lubes were meant to "sit" for years. They are designed to be short term lubes without the preservatives necessary to prevent gelling from time. There are special lubes made for long term storage.

Scotch brite the bores, wipe 'em out and go. Its a near-zero clearance bore so any amount of gel or gum inside will make it too tight.
I'd plan on the first oil change coming early to help rid the insides of the gum/goo that will be released from the first couple heat cycles. Call the 1st oil change a "flush" cycle and start the break-in with the 2nd oil fill. Even after some scrubbing on this motor it will still be cleaner than any build coming out of a "production" shop. Those seem to work ok...
Good luck, its not that bad. You're just a lil nervous with your million dollar build, as I would be too!

cudamax

Maybe u should measure the lifter bores and then measure the lifters and see were your at. Then see where ur at. Before u do anything

Tommycourt

Having an engine sit under a plastic cover and with the changes in humidity due to the highs and lows of summer and winter, IMHO I really might think of tearing it down and doing a thorough cleaning of the block. I know this sounds like a lot of work because it is, however it sounds as if you have a lot of money invested and it would be a shame not to make sure everything is correct. Just a small amount of condensation can do a lot of damage, however it is your motor and you have to do what you feel is right. Not trying to play with your head, it's just what I would do. I hate doing something over that I already done once.
Tommy