Illustrated rebuilding of a L36 into a supercharged 3800... - Page 4 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

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Old 01-04-2007, 10:47 AM   #31
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Quote:
Originally Posted by clm2112
2.) Ask their advice and listen closely when they give it. Nothing pisses a machinist off more than being told their trade.
That'* good advice for any trade.

Great reading so far! Thanks again!!!
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Old 01-06-2007, 08:13 AM   #32
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Picking up where I left off...

The engine block is currently at Fred'* Fastrac Machine Shop being boiled out. I should have word back on Monday as to whether it got an overbore. (In the conversation I left the overbore to Frank'* descretion...if it needs one, he'll just go ahead an do it, if not, they will just hone the existing bores to remove any glazing and prep it to seal with new rings.)

With some free time on my hands, time to start cleaning up the lifters. And what a mess. The same spooge that was everywhere else in the motor was inside the lifters too, locking them in place (The spooge was too thick to pump through the lifter'* orifices, so the lifters just locked up, just like a collapsed lifter.)

Here'* an exploded view of the lifter. On the top row is a conventional Flat Tappet Hydraulic Lifter from a Small Block Chevy V8. On the bottom row is one of the Series II 3800 Roller Hydraulic Lifters. The parts from left to right: Lifter body, Return Spring, Piston, Reed Valve, Pushrod Seat, and Retaining Clip. On the right is just another assembled lifter.



Here'* a closeup of the lifter parts. If you have ever worked on motorcycle forks or taken a shock absorber apart then these parts should look rather familiar. The lifter works by sucking oil into the lower cavity, then metering a small amount into the upper cavity of the piston with every compression (cam lobe working to try to open the valve in the cylinder head.) The reed valve lets a little squirt of oil out through the pushrod seat where it pumps up through the hollow pushrod and lubricates the rocker arms and valves in the cylinder head. Without the oil in the lower cavity, the lifter is very spongy, but once the lifter "pumps up" full of oil, it becomes quite stiff and can transfer the force from the cam lobe to the rocker arm and valve. (This is why they are called "Hydraulic" lifters.)



Normally, to take a lifter apart you just pick the retaining clip out of it'* grove in the lifter body (keep your thumb over the end of the lifter to catch the parts and let off the spring tension.) These suckers were so gummed up that they needed to be manually pumped a few times just to get the parts out. Using a bench vise and a pair of appropriately size sockets, the lifter was gently, but firmly, squeezed repeatedly to force some of the gunk out of the cavities allowing someplace for solvent to get inside.



Once the lifter is dissassembled, the parts can be soaked in carb cleaner, kerosene, mineral spirits, or any other solvent to remove the cooked oil from the parts. DO NOT attempt to remove the roller from the lifter body. The pin is pressed in and the ends are deformed. If the roller is bad, or the rollerbearings inside are bad, the entire lifter goes in the trashcan.

Here'* the roller end of a roller lifter. What we are looking for is that the roller turns freely without any "clicking" (just like checking the wheel bearings on the car.) The surface of the roller needs to be free of any pits or burs. This one checks out and can be reassembled.



Putting the lifter back together is pretty easy. A few drops of oil on the machined surfaces and the parts all slide back together. A wood dowel rod compresses the return spring and the retaining clip pops back in place.



NOTE: When it comes time to actually reinstall these in the motor during assembly, I will be pre-oiling the lifters and manually pumping them up with oil before lashing the valves. This will be covered later. For now, the cleaned and reassembled lifters can be wiped down with oil and bagged to keep them clean till they are needed.

One down, eleven more to do....

Next stop, cleaning the rockers and pushrods.
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Old 01-06-2007, 12:04 PM   #33
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Good illustration Curt.
So besides the benefit of lower friction, the roller lifters can be reused on different cams.
Are you saying they are good as long as the roller tip bearings are good? How do you check orifice and plunger clearances?
Isn't is just good practice to replace them whenever you do a major overhaul like you are doing?
How much more cost than regular flat tappet lifters?
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Old 01-06-2007, 12:59 PM   #34
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Quote:
Originally Posted by 2000SilverBullet
So besides the benefit of lower friction, the roller lifters can be reused on different cams. Are you saying they are good as long as the roller tip bearings are good?
Exactly, flat tappet lifters are disposable items. The surface of the lifter in contact with the cam wears into the cam and vice-versa. They can only be reused on the exact same cam, and on the exact same lobe on that cam. (If the lifter was on #6 Intake lobe, then it MUST be reinstalled on #6 Intake on that cam.) If a new cam is installed, then all the flat tappet lifters go in the trash. Most cam kits come with a set of new flat tappet lifters.

A roller lifter is reusable, in any location on the motor and on any cam (provided the cam is ground for roller lifters.)

The internal orifices and springs do not actually need to be checked beyond the holes being clean and the spring is intact. The spring'* only function is to help return the piston to the top of the bore when the lifter hits the base circle of the cam lobe. There are no specs on how much tension it has or how big the holes are. Similarly, the retaining clip need only be check for it being seated, since it'* only function is to keep the lifter assembled when it is out of the motor. When we set the valve lash, one of the things we are doing is compressing the lifter enough to ensure the pushrod seat doesn't hit the retainer when the motor is running.

There is a spec on the diameter of the lifter body in relation to the block'* lifter bores. Until the block comes back, this will be an unknown number. (In other words, if the lifter bores are worn beyond the size this lifter fits, then an oversize lifter will need to be used, or the bore will need a sleeve to restore it to the proper diameter.) Too much slop between the lifters and the bores will result in low oil pressure and excessive wear over the motor'* life.

Note the flash from the camera exagerates the surface scratches in the polished surfaces of the lifter body. It looks severe in the photos, but is really quite minor.

More amusing facts: The Series II 3800 uses the exact same lifter as the small block chevy (LT1 and post 86 with roller cam, etc.) So, if your vendor doesn't list the 3800 in the charts, you can order lifters for the V8 and be good to go.

I haven't checked the lifter bore spacing on the block yet, but it is quite likely it is the same as the V8 as well (Meaning all the aftermarket Lock-Bar style roller lifters work too.)

Did a little comparative shopping. A replacement set of roller lifters (oem style locks) run about $150.00 at the low end, to about $250 for brand name Hi-Performance parts. By comparison, a set of Flat Tappet lifters runs about $40 for the low end. You can pretty much see the reasoning for reusing roller lifters whenever possible.

Another tidbit: You CAN use regular flat tappet lifters in this motor if you NEED to. For example, let say you want to run a camshaft that has a grind not available in a roller lifter. You can still run it if it fits in the block. You must however use flat tappet lifters and longer pushrods to do it. Flat tappet cams have their lobes ground at a very shallow angle. Flat tappet lifters have a very slight dome in the face of the lifter. The two work together to spin the lifter in the bore and even out the wear on the lifter. If you stuck a Roller lifter on that same cam, you would screw up the roller because of the side-load the angled cam loab would put on the flat roller.
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Old 01-06-2007, 01:56 PM   #35
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Well, I didn't think I would get this far without finding something that needed replaced, but here'* our first candidate for the trashcan.

I cleaned out the pushrods by soaking them in solvent, then blew out the inside of the tubes with compressed air.

I Inspected the ends of the rods for wear and most of them came up looking like this:



Take a good look at the one on the left vs. the one on the right. Notice how the ball on the left is worn and misshapened. This is the rocker end of the pushrod and a sign that the valve train wasn't getting enough oil. With all the goo inside the lifter bodies, this shouldn't have come as a surprise.

One rod will be kept as a reference for length, the rest get pitched in the trash.

If the rods ends had passed this inspection, the only other test would have been to roll them on a plate of glass to see if any were bent. (A good one will roll, a bent one would not roll.)

Follow Up Note: I'm going to use Crane One-Piece pushrods, pn 95621-16 which dimensionally match up with our existing rods. ( 7.050" long, 5/16th" diameter, heat treated for use with guideplates.) Another alternative is Crane 11628-16..same dimensions in a conventional ball and tube style pushrod.

Next stop is the rockers.
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Old 01-06-2007, 05:50 PM   #36
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Cleaning the rocker arms is much like cleaning everything else. Soak them in solvent, take them out and whipe them down. Check the trunion, it sould swivel freely on it'* bearings. Check the tip and the pocket the pushrod sits in for wear. After seeing the pushrods, I was expecting the worst, but the rockers look to be in good shape overall.



The rocker arm bolts need cleaning as well. The bolts are 5/16ths-18tpi and have thread locking compound on them from about halfway down the threads. Soak them in solvent as well. I ran a tap over the treads to clear them if debris and locking compound. When it comes time to reinstall them, the compound will need to be applied again.

This valvetrain setup is a little different from the usual stud & guideplate setup I'm used to. It also really limits what you can do for aftermarket rockers if you want to change to a higher ratio. You probably can convert the heads to run studs by drilling the bosses out, spot facing them down to a suitable height, and threading them for conventional studs. I'm not planning of making that kind of change, so I'm leaving the valvetrain in it'* stock form.
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Old 01-07-2007, 11:19 AM   #37
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Since I mentioned it in the previous post, I figured I'd better elaborate on it just a little more.

Cleaning fasteners is perhaps the most Mind-Numbing part of rebuilding a motor. Seriously, it is boring as h*ll. But it is important. Uniform torque values require uniform bolts in uniform holes. A lot of engine rebuilders simply discard the the old fasteners. Makes sense to them since time is money and new bolts are cheaper than the cost of labor to clean them for reuse. Home engine builders have a little more time, and a lot less cash, so cleaning up the fasteners is better than replacing every one.

Here'* the basics. Soak the bolts in solvent to get most of the gunk off. Lubricate the bolts with cutting fluid (Tap-Magic, Do-Drill, even plain old bacon grease will do in a pinch). Never cut a thread dry. Then thread the bolt through the appropriate sized die. In the following photo, all the gunk on the paper towel came off just the four rocker arm bolts in the background.



Another shot of the same fasteners. On the left is one that has been run through a die. On the right is one as it came out of the motor.



There are a few bolts that are harder to clean, like the massive harmonic balancer bolt. I don't have a die that size. I'll have to resort to brushing the threads manually with a wire brush to clean them out.

There may also be a few bolts that are tagged for only one use (A torque-to-yeild bolt that streches when torqued and should not be reused.) I haven't run across one yet on this motor, but I'll be reading the service manual carefully during reassembly, just in case they exist. (Typically, a head or rod bolt might fit in this category, the manual should state it clearly, otherwise it is assumed that all the fasteners are reusable ones.)
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Old 01-07-2007, 12:51 PM   #38
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Ok, time for a question. You clean up and re-use TTY bolts? I thought the rocker arm
bolts were one-time use? What'* the difference betweeen them and 'reusable' bolts?

My understanding was the rocker bolts and head bolts stretched after initial torquing.
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Old 01-07-2007, 02:14 PM   #39
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Quote:
Originally Posted by willwren
Ok, time for a question. You clean up and re-use TTY bolts? I thought the rocker arm
bolts were one-time use? What'* the difference betweeen them and 'reusable' bolts?

My understanding was the rocker bolts and head bolts stretched after initial torquing.
You could very well be right. If the rocker arm bolts are a one-time use, then they are going in the trashcan. I didn't see any notes in the service manuals I have indicating the rocker arm bolts were one time use. Just a reference on the rocker arm bolts to apply tread locking sealant and torque to 28ft-lbs.

On the head bolts, I haven't read up on the reassembly of the heads, so I can't answer that one just yet, though again it wouldn't surprise me to find they are torque-to-yeild bolts and are more trashcan material.
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Old 01-07-2007, 02:18 PM   #40
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Head bolts are TTY. I can verify that. I might be wrong on the rocker arm bolts.
I know some vendors sell higher ratio rocker arms and specify 'reusable bolts' which led
me to assume the stock bolts aren't reusable.

I'll check my manuals today on this also.
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