["QUICK-SILVER"]

Looks like you'll need a modified lifter bore brace for the dog bone to self center and rest on.

Noticed in some other vids that when the dog bone was slid all the way in one direction... The other end looked like about half engagement.

Have to go back and watch again, but looked like more lift/smaller base circle was possible. Would want longer flats on the lifter for the dog bone to work right.

Clay

[JC455]

Originally Posted by Singleton

Nice video. I guess I have the same question as JLMounce above about the dog bone and the lifter flats.
Also, at the 6:33 mark of the video I believe you might have misspoke about the base circle being larger for more cam lift. Smaller base circle would be more lift if lobe noses are the same height, right?

Darn it! I wasn’t thinking correctly on that.
Yes, a smaller base circle is going to give you more lift if the peak of the lobe remains constant.

I added a pinned comment to correct it.

[JC455]

Originally Posted by JLMounce

Great vid! Definitely helps illustrate some of the pitfalls here.

So the only thing that could possibly still be an issue is the height of the non-machined section of the lifter. It appears to be coming out of the lifter bore high enough to push on the dog bone. I believe that is why the other member here pointed out that he's notching the dog bones, to avoid that happening.

That said, considering the construction of the dog bone and have a ball and socket connection to the spider, I'm almost wondering if it's meant to pivot?

I was thinking about a pivot too.
I started pondering having the dog bones ‘floating’ on the ends of a retainer(spider)- that way, they are high enough to hold the lifters in line, but also held in place by a rigid retainer/spider vs. the thin sheet metal one...
maybe that’s what the guy on FB is making?

[P@blo]

Do you have the comp cams 31-1000 kit yet John? If you do it would be interesting if you did a video rotating the cam with two lifters and a dog bone in place to see the movement and if it lifts.

This mod is going to crush the retrofit market that currently exists as it is a better mousetrap, by far.

[shermanator2]

Thanks JC455 for the great video and thanks for listing me in the credits. I am very happy too that you pointed out with the straight edge and feeler gauge that the noses of various cams are all at the same height, although it seems that not everyone understands this concept yet.

I think that, as you have eluded to in the thread, the dog bones are our next interesting challenge here. Since with a properly designed cam, the fully round part of the lifter extends out of the lifter bore, the off the shelf dog bones are going to be lifted, which is not acceptable.

There seems two (at least) two different designs of dog bones out there. Even the pictures on Comp Cams web site do not seem to match what they are shipping. There are the ones with the tapered bottom which look like they are made to rock, which does not seem like a good idea, and the fully flat one that seem to be what Comp is shipping.

69HotBird had an interesting solution. With the fully flat dog bones, he milled the bottom with a carbide end mill to clear the fully round part of the lifter. The only thing that I did not like about this was that the flat part of the dog bone that was left seems pretty thin.

I had another thought. As long as carbide end mills are in play, can we mill the flats on the lifters longer, so that the fully round part never comes out of the lifter bore? Has anyone ever tried to mill a lifter? Then the off the shelf fully flat dog bones should work.

I am thinking that the ideal solution might be double thick dog bones that are relieved like the 69HotBird design. That would be a custom part though. Maybe not out of the realm of possibilities.

[tempest1964]

It's too bad no one knows an engineer at Ford and could discuss whether the dog-bone was designed to move slightly or pretty much stay stationary. Also wonder about the factory spring pressures for the HT 2148, seated and open. Someone had mentioned that because these sealed power factory style lifters are lighter, they would require less spring pressure. This is definitely a very interesting topic.

[JC455]

Originally Posted by shermanator2

Thanks JC455 for the great video and thanks for listing me in the credits. I am very happy too that you pointed out with the straight edge and feeler gauge that the noses of various cams are all at the same height, although it seems that not everyone understands this concept yet...

My pleasure! Since I’m NOT an expert in any of this, just a hobbiest, I try to take in other people’s thoughts and ideas, then apply them to my ideas/concepts.
I was curious about the relationship of the cam lobes vs the cam journal height, and was measuring gaps for my video...
Then I read your’s and others’ posts and knew I was correct in my thinking!
I’ve learned SO MUCH from people on this site- it’s amazing the amount of knowledge that’s floating around here, if one only asks.
Mr. P-body(Jim Lehart) got in touch with me, and has been very encouraging about this whole project— he seems like a really good guy!
I’m awaiting Randy Repp’s retainer/spider to evaluate whether the Ford/Comp piece or his will be more ideal for a no/low maintenance hydraulic roller setup.

[rohrt]

Subscribed

Great video.

Isn't there a few people already running this setup? I wonder what they did about the dog bone situation. If the dog bones can't lay flat without movement I would suspect that would be a whole lot rattling going on.

[firechicken]

Originally Posted by rohrt

I wonder what they did about the dog bone situation. If the dog bones can't lay flat without movement I would suspect that would be a whole lot rattling going on.

I have to wonder if it would be any worse than retro fit roller link bars bouncing back and forth?

[P@blo]

The dog bones are supposed to remain stationary as the 30-1000 kit instructions states, they must remain flat against the block at all times. I will see if I can upload the instructions.

Step 5– Final Check
Spin the engine over by hand at the crankshaft with a wrench and watch closely to movement of the lifters. As the lifters move up and down, the lifter guides should remain perfectly flat on the tops of the lifter bores. They should not be moved at all. If they do, the camshaft does not have the correct base circle size to be used with these retro-fit lifters in non-hydraulic roller cam engines. Stop here and replace the camshaft with the proper one before proceeding. Running the engine with this condition will surely result in major engine damage. The installation of your COMP Cams® hydraulic roller lifter kit is now complete. Refer to the camshaft installation and degreeing instructions that came with your cam for further instructions on pushrod installation and valve adjustment that are needed to complete your project. Please note that there are special length pushrods required for use with the retro-fit kit and depending on which Ford engine you are working with.

As mentioned on the original Youtube video comments, many guys using the Comp XR88HR without issues so you can check that out too. As far as I can see it you test fit each dog bone and rotate the cam a few times to verify the correct base circle is being used. The solution may be to only use certain cams with larger base circles as the instructions state instead of dog bone lifter interface modifications as I am not sure I feel good about going that route.

The Jim Lehart modification benefits are:

1) Cost (half or more)
2) Lifter weight savings
3) Durability (these HT2148 lifters are proven on many cars for many miles)

Great topic!

[shermanator2]

Originally Posted by P@blo

As mentioned on the original Youtube video comments, many guys using the Comp XR88HR without issues so you can check that out too. As far as I can see it you test fit each dog bone and rotate the cam a few times to verify the correct base circle is being used. The solution may be to only use certain cams with larger base circles as the instructions state instead of dog bone lifter interface modifications as I am not sure I feel good about going that route.

Does anyone have one of these Comp XR288HR cams that you can do the straight edge and feeler gauge test that JC455 demonstrated so well in his video? If you can get a feeler gauge thicker than 0.020" between the straight edge and the nose, then that is a compromised lobe design. For a given lift, it is either slowing the ramp rates or increasing the side loading on the lifters or both. I am not willing to put up with either of these compromises.

My guess is that the XR288HR will have the lobe noses at full height. Why would Comp not grind it that way? I don't think Comp is going to market a reduced base circle cam so that people can use lower cost lifters instead of their expensive link bar lifters. If the nose is not at full height, then I will assume that the "Comp" in Comp Cams name means Compromise, not Competition.

The base circle diameter for any correctly designed Pontiac cam will be very close to 1.899-2x(lobe lift+.010). It does not matter if it is roller, flat, solid, hydraulic, granny car, full race, low lift, high lift. Anything else is not optimal.

[tempest1964]

Just curious. I tried looking this Comp XR88HR cam up on their web site. Couldn’t seem to find it. Was curious about the lift of this cam. It would help to compare other HR cams with the same or less lift. Since these Sealed Power lifters have their limitations. Thanks in advance.

[P@blo]

Originally Posted by tempest1964

Just curious. I tried looking this Comp XR88HR cam up on their web site. Couldn’t seem to find it. Was curious about the lift of this cam. It would help to compare other HR cams with the same or less lift. Since these Sealed Power lifters have their limitations. Thanks in advance.

https://www.compcams.com/xtreme-ener...5-455-cpg.html

[Singleton]

There seems to be a fundamental misunderstanding concerning the different cams and the effect on these oem lifters.
These oem roller lifters will rise out of the lifter bores the same amount, (+- .010), regardless of camshaft used.
The larger lift cams have a smaller base circle, so that the lifters starting point is lower in the bore.
The lifter stopping point at its highest will be the same regardless of which camshaft is used, mild or wild.

[JC455]

Originally Posted by Singleton

There seems to be a fundamental misunderstanding concerning the different cams and the effect on these oem lifters.
These oem roller lifters will rise out of the lifter bores the same amount, (+- .010), regardless of camshaft used.
The larger lift cams have a smaller base circle, so that the lifters starting point is lower in the bore.
The lifter stopping point at its highest will be the same regardless of which camshaft is used, mild or wild.

Exactly! That’s why I was using a feeler gauge to show how the ‘top’ of the lobe was at the same height, regardless of cam type/design.
This is also why I was showing how much the lower oil band gets to the bottom of the lifter bore. As I said in my video,”The top of the oil band isn’t going to be our problem.”

[Singleton]

John, not sure if this was stated here or on the video, but what is the distance between the upper scribe line and the flat area on the lifter?

[JC455]

Point of reference: I’m using a Herbert hydraulic roller in this 455.
Its specs are as follows:
230/235 duration at .050
.525/.540 lift
112 lobe center
It’s part# CPH5
It looks VERY similar to an SD Performance Stump Puller, just less lift.
230/236
.590/.592 w/ 1.52 rockers. (.582/.584 1.5 rockers)
112 lobe center

The Comp XR288 is
236/242
.520/.540 lift
110 lobe center

So my lift is almost identical to the Comp stick.

[JC455]

Originally Posted by Singleton

John, not sure if this was stated here or on the video, but what is the distance between the upper scribe line and the flat area on the lifter?

Which lifter? Which flat area?
I’ll try to get some detailed pics of the lifters with some measurements.

[Singleton]

Originally Posted by JC455

Which lifter? Which flat area?
I’ll try to get some detailed pics of the lifters with some measurements.

The 2148 that interferes with the dogbone.
How far above the lifter bore does the non-machined area extend upward

[JC455]

Originally Posted by Singleton

The 2148 that interferes with the dogbone.
How far above the lifter bore does the non-machined area extend upward

Oh, gotcha. I’ll mock it up and get some measurements.