875-12 Comp Cams vs Stock/850 Lifters - Disassembled

[Quickstop [UK]]

I took them apart for comparison. Stock/850 on the top, 875 on the bottom.

Note the oil hole is 90* different to the 875s.

Same size of body - obvious if they are to be compatible.

Note that the 875 spring is a bit beefier. I couldn't tell if it was much stronger though. They seemed similar in strength.

The body design is very different.

At the bottom of each however is a check ball with a spring. This is the valve that allows oil in so that there is a 0 gap. If this check ball assembly fails, when the lifter is compressed or at rest, the oil can seep through the ball and the lifter will become loose. It is here that I believe the lifter failure problem is most common.

Again, the differences just beneath the push rod cup are pronounced.

This is a retainer from an 875. Unlike the 850, removing this will damage the retainer and it seems hard to do it any other way. I wouldn't mind putting in an 850 after reassembly but given this has to be deformed to remove it, I think it would be a bad idea to try and replace the retainer and use this lifter again. You can see the crease where it folded when I took it apart.

Hope this is interesting to someone!

 

[alwayscode390]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

I enjoyed that ... are the 875's rebuildable ? ---

 

[Quickstop [UK]]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

this is a retainer from an 875. ... Given this has to be deformed to remove it, i think it would be a bad idea to try and replace the retainer and use this lifter again. You can see the crease where it folded when i took it apart.

:tup:

 

[MoJo]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

The oil metering disc below the push rod cup is why you should use full roller rocker arms with CC-875 lifters. The CC-875 lifters severely limit oil flow to the rocker arms and production type ball pivot rocker arms require good oil flow to cool and lubricate the ball pivot. You may get by with ball pivot rockers and CC-875 lifters but I find it a good reason for concern especailly at the RPM that those lifters are designed to run. The oil metering disc limits oil to the rocker arms in order to maintain higher oil pressure on the rod and main bearings where it is needed most at high RPM. The GM high ball lifters were introduced in 1965 (actually in the 1962 Tri-power Pontiacs) and were called "anti-pump up" lifters by the racing crowd. They are still in use today and since 1987, they are a roller version. High ball lifters have a metering disc but the disc they have has a small hole in it for the limited passage of oil so it can be used with stock ball-pivot rocker arms. . The CC-850 lifter appears to be a replacement for a standard production low-ball hydraulic lifter because I don't see a second spring that is used to hold up the check ball and I don't see a oil metering disc

The oil feed hole in the body of the CC-875 lifter is in the correct location which is in parallel with the roller axle. That places the oil feed hole in line with the oil gallery passage rather than at a right angle to it. I have not seen a roller lifter with the oil hole at a right angle to the roller axle.

The retainer clip of the CC-875 lifter is supposed to be a heavy duty clip compared to the stock type "paper clip" design that the CC- 850 lifter has. I like the internal C-clip retainer that the obsolete Melling JB-951R (race) flat tappet lifters used. Melling JB-951 standard flat tappet lifters still use a HD C-clip retainer. I don't think the CC-875 stamped steel retainer can be replaced with a C-clip retainer because the C-clip is made of hardened and thicker steel and the retainer clip groove in the CC-875 lifter body may not be large enough to accommodate an internal C-clip retainer. If the CC-875 lifter had a C-clip it could be disassembled and cleaned if necessary. But why would anyone want to do that? Lifters are designed to last for the life of the engine and there is no reason to disassemble a lifter and rebuild it unless someone is really on a low budget rebuild.

I was going to check and see if I could replace the stamped steel push rod retainer in my CC-875 lifters with a internal C-clip but my engine builder had already installed the lifters as is. He told me I have nothing to worry about as long as I kept at least .004" - .008" (1/8 turn) pre load on the CC-875 lifters and locked.. Failures due to a weak retainer clip is what concerned me. , I know the CC-850 "paper clip" retainer must have plenty of pre load or the retainer can pop out at high RPM valve float. One thing I could not get out of Summit or from Comp Cams before I purchased my CC-875 lifters is the total lifter travel. It must be proprietary information or because the lifter travel varies due to production tolerances or they feel like no one needs to know that information???. Some people will attempt to bottom standard CC-850 lifters out and back off .005" in order to make a limited travel lifter out of a standard lifter. My CC-875 lifter travel were .060" when I checked them by hand on the bench with a push rod . That is about one half the total travel of standard CC-850 lifters.

Since Quickstop has a CC-875 lifter disassembled, it would be a good opportunity to check the CC-875 lifter and see if it will accept a internal C-clip retainer.

 

[dgoodhue]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

Even if their isn't potential oiling issues, it doesn't make sense to use stock stamp rockers with 875's anyways.

 

[MoJo]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

There are conditions where stamped ball pivot rocker arms are fine to use. GM used them until 2000 in all Chevrolet engines but switched to roller pivot rocker arms when they introduced the LS7 and retrofit LS6 lifters, both of which has restricted oiling. GM part numbers 12576400 for LS6 and 17122490 or 12499225 for the LS7 engines. Unlike the CC-875 lifters which have .060" travel and .004" preload, the GM LS6 and LS7 lifters have .160" travel with .080" preload, If your valve lift is low enough to work with standard travel lifters or less than .480" valve lift, the LS6 and LS7 lifters are the ones to use, but with roller pivot rocker arms, since those GM lifters have restricted oiling.

If the engine has a camshaft with a high lift lobe profile that requires a higher valve spring pressure, limited travel lifters with restricted oiling, the engine should also have roller pivot rocker arms that can run on marginal oiling and a high valve spring load.

 

[Quickstop [UK]]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

I'll see what I can do but I don't have any internal c clips lying around.

Interesting to hear that the disc is an oil metering disc. That makes sense. I have full roller rockers fortunately.

Also, I'm pretty sure that there is a spring and ball bearing in the 850 as well. That's essential to the mechanism to prevent the lifter from draining from oil and functioning properly.

 

[MoJo]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

I just recalled that the use of the so-called "low-ball" lifters were discontinued after 1967. The lifters themselves were not discontinued but they were not installed in any engines at the factory even the low performance engine with a 2-barrel carburetor was equipped with high-ball anti-pump up lifters. . Most aftermarket lifters, either hydraulic flat tappet or hydraulic roller lifters, are high-ball "anti-pump up" lifters and have been since 1975 for flat tappets, and 1987 for roller lifters. .

For example, I bought a new 1967 Firebird 400 and it was equipped with standard "low-ball" lifters. It had the standard production 325 HP, 400 CI engine and did not have the high-performance camshaft. Those lifters were just like a rev-limiter and would kill the power at 5,000 RPM. I rebuilt the engine in 1969 and installed a Crane solid flat tappet camshaft and 4.33:1 gears and that really woke that engine up. However, with the solid flat tappet lifters, I spun out rod bearings on two separate occasions due to excessive oiling to the rocker arms and drop in pressure at the rod bearings above 5,600 RPM. In 1971, I rebuilt the engine for the last time using ARP rod bolts, and installed a 1970 Ram Air IV hydraulic flat tappet camshaft, with BB Chevy valve springs, Melling JB-951R limited travel hydraulic lifters and I did not have any more problems.

 

[whooped]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

so you're saying that with valve lift of .498/.498 on a 1.5 rocker that low travel lifters, such as the CC875s need to be used but only in conjunction with full roller rockers due to their low volume of oil transfer?

 

[ItsMyTy]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

so you're saying that with valve lift of .498/.498 on a 1.5 rocker that low travel lifters, such as the CC875s need to be used but only in conjunction with full roller rockers due to their low volume of oil transfer?

No offense, Mojo may be saying that, but it's all HIS theory.

In real world use, I have had 875's in both of my trucks and there is PLENTY of oil flow to the rockers at very low oil pump RPM. I've seen it when priming both my engines. Both engines also have comp 1.52 roller TIP rockers with a ball pivot. I've never had a problem.

 

[MoJo]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

IMO...Anytime restricted lifters are used, the rocker balls are receiving less oil and can overheat. .High RPM and high valve spring pressure makes the problem more critical. Marginal rocker arm oiling with high valve spring pressure is why roller rocker arms were designed. Aftermarket grooved rocker balls help with the oiling problem by retaining oil, but they can only go so far. If your valve spring seat pressure is over 130 lb. and over 350 lb. open, and you are using restricted lifters, the use of full roller rocker arms should be considered.

The restricted lifters and marginal rocker oiling is why GM introduced roller pivot rocker arms in 1997 on the LSx V8 engines. The 1997 - 2010 GM style bolt down roller rocker arms must use different length push rods to adjust lifter pre load. In other words, the pre load is not adjustable with the GM roller pivot rocker arms.

There is no any need for "roller tip" rocker arms because valve tip and rocker arm contact has never bee a serious problem. The roller tip does not "roll" when the engine is running. The GM roller rockers do not have a "roller tip".

 

[MoJo]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

:tup:

Since you have the CC-875 lifter disassembled, try the following metric internal C-clip retainer that may replace the stamped type retainer.
Supplier: McMaster-Carr.
Part no. 98455A116
Pkg of 50: $8.22

Specifications:
Black oxide finish
Bore diameter: 16 mm (0.630")
Groove diameter: 16.8 mm (0.661")
Groove width: 1.1 mm (0.043")
Ring diameter: 17.3 mm (0.681")
Ring thickness: 1 mm (0.039")

Other industrial suppliers may have internal C-clips with the same measurements.

Install the C-clip with the sharp edge up so it will aid retention.

McMaster-Carr has a huge variety of internal C-clips in metric and standard sizes but the above clip is likely the best fit from what I can determine. I would check the fit but I don't have a spare CC-875 lifter.

 

[Quickstop [UK]]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

If you have a c-clip laying around, you could post it to me?

I will see if I come across anything in the UK. I looked at the collapsed 875 and it looks like the casing at the bottom, where the check valve and spring is, was compressed. If the valve was unable to open and fill with oil/ unable to close then that would explain why it failed. It may have been due to too much preload on installation. I'd need to compare it with a functional one though.

 

[Quickstop [UK]]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

I just installed new 875s and at idle, the rockers were well lubricated. 875s are fine to be used on a stock engine.

 

[MoJo]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

If you have a c-clip laying around, you could post it to me?

I will see if I come across anything in the UK. I looked at the collapsed 875 and it looks like the casing at the bottom, where the check valve and spring is, was compressed. If the valve was unable to open and fill with oil/ unable to close then that would explain why it failed. It may have been due to too much preload on installation. I'd need to compare it with a functional one though.

That happens all the time. Some people install CC-875 lifters and try to set them at .060" pre load like a regular production lifter. That will destroy the lifter as soon as the engine is started , if it can be started.

The CC-875 lifters and other restricted lifters get plenty of oil at IDLE. High RPM with high valve spring load is where the rocker arm wear and oiling problems start. If CC-875 lifters are not used like they are designed to be used they are more trouble than they are worth and no better than stock lifters. .CC-875 lifters were designed to be used with high lift camshafts, strong valve spring load, and roller pivot rocker arms so the rockers will survive at high RPM.

When using the CC-875 lifters it is absolutely essential that fully adjustable screw in or pinned 3/8"-24 rocker studs are used and the .005" lifter preload is positively maintained with the use of roller rockers and the supplied poly-lock nuts. The OE prevailing torque lock nuts or the lock nuts supplied with roller tip rocker arms should only be tightened once. The prevailing torque lock nuts locking feature wears down the rocker stud threads with continued adjustment and can make the locking feature ineffective. When 3/8"-24 studs are used, keep the open valve spring pressure below 360 lb. and use narrow body, self aligning roller rocker arms. Do not use SB Chevy V8 guide plates because 4.3L V6 valve spacing is different and the pushrods may rub against the plates. .

 

[MoJo]

Re: 875-12 Comp Cams vs Stock/850 Lifters - Disassembled

Lesson learned:

My 1956 Chevrolet had a 1965 GM 327 fuel injection engine with the 1965 Chevrolet fuel injection solid flat tappet 30-30 camshaft. Following a few events in NHRA D/MP, I found that the engine burned up a few rocker balls. After an investigation by the Chevrolet dealership and technicians who were sponsoring my car, it turned out that the lifters were oiling the rocker arms with so much pressure and volume at high RPM that the oil was shooting over the rocker pivot balls and valve springs. Th eoil was hitting the top of the valve covers and was running down the valve cover outer walls. I had 1965 Corvette aluminum valve covers on the engine and they do not have any oil deflectors. I removed the1955-1964 Chevrolet solid flat tappet lifters and replaced them with 1965 Corvette "edge oriface" fuel injection solid flat tappet lifters and had no more problems with burned rocker balls. I am glad I switched out the early style solid lifters and installed the 1965 Corvette restricted lifters because doing so probably saved the valve springs as well as the crankshaft. That problem was addressed in a 1967 GM Technical Service Bulletin for those customers who had 1965 Corvettes with 365 HP Fuel Injection engines. .

That is proof that too much oil volume to the rocker arms can create a problem to the rest of the engine. GM has bee trying to solve that problem since 1965 and so far the only way that is practical is with the use of restricted hydraulic lifters..