["QUICK-SILVER"]

Originally Posted by Singleton

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

Good visual on that near the end of the video. Skip to about 14:15.

Flat guide area could be cut nearly to the oil hole. Just can't go as low as the oil hole in the bore.

If a lifter can be machined to work better... A mission specific Pontiac bone wouldn't be that hard to make.

Clay

[Scarebird]

We went thru this last year - .

That said, why not a rigid spider in the valley which uses the SS454 truck roller lifters?

Those flats are rotated 90° for the different angled valves so a Pontiac variant could grab them like an open end wrench from the center of the lifter valley? The would not have to sit flat on the top of the lifter bore either.

[shermanator2]

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.

Thank you, thank you, thank you. I have been trying to say this on three different threads about this subject, but some, including significant contributors, have not seemed to get it.

The instructions from Conp Cams that someone quoted on one of the threads that said in essence if your lifters stick out too much, buy a different cam from us did not help. That is just plain silly. I do not know if those instructions came from the Ford kit or what, but it would be silly there too. If you can install the cam into the tunnel, the lobes are not too tall.

[shermanator2]

Originally Posted by "QUICK-SILVER"

A mission specific Pontiac bone wouldn't be that hard to make.

Clay

This is what I am leaning toward as the best solution. The SBF lifters are 1.73" apart (at least according to the internet, which never lies). Pontiac lifter bores are 1.82" apart according to some measurements I had laying around. That means the bog bones are going to be pretty loose fore and aft. I am wondering if when a dog bone is slid fully toward one lifter, if it still extends far enough on the other lifter to cover the flats.

Another thing is that the SBF lifters are .875" diameter compared to the Pontiac/Chevy .842". The reason I bring this up is that I am wondering how the measurement across the flats (open end wrench size) compares between the 2148 lifter and the Ford lifter. JC455, can you measure the 2148 lifter across the flats and can someone measure a dog bone?

If we make Pontiac specific dog bones, we can make them extra thick so that we can relieve the bottom like 69HotBird did and still have plenty of width on the flats, we can make the the right width, and we can get the right wrench size.

[shermanator2]

Originally Posted by Scarebird

[COLOR="Navy"]We went thru this last year - .

That said, why not a rigid spider in the valley which uses the SS454 truck roller lifters?

Those flats are rotated 90° for the different angled valves so a Pontiac variant could grab them like an open end wrench from the center of the lifter valley? The would not have to sit flat on the top of the lifter bore either.

My concern with this would be the tolerance of the lifter spacing from the front to back of the engine. there would have to be enough slop in the open end wrenches to handle all of the production variation and thermal expansion differences. To me that does not seem doable with old production blocks where we do not even know what the production tolerances were when they were built.

[P@blo]

https://www.summitracing.com/parts/cca-31-1000

Click the "instructions" link. Not sure what to say as I was just relaying manufacturer's installation instructions. To me this did not make sense from what I read other guys posting.

Dog bones do not move if they do comp says wrong cam base circle is all I know thus far but could be on the wrong track.

[JC455]

I'll get some measurements tonight.
Thanks, guys!

[JC455]

Scarebird-
I don't think those 454 rollers will work because the pic shows them having the high oil-fill port/scalloped-out area, like an LS lifter does.

[Scarebird]

That me be an issue...

[shermanator2]

Originally Posted by P@blo

https://www.summitracing.com/parts/cca-31-1000

Click the "instructions" link. Not sure what to say as I was just relaying manufacturer's installation instructions. To me this did not make sense from what I read other guys posting.

Dog bones do not move if they do comp says wrong cam base circle is all I know thus far but could be on the wrong track.

OK, I guess Comp Cams really means Compromised Cams then. Maybe they do this to lock people into buying a cam that only they make. Maybe they can pull this off with Ford people, but I hope that Pontiac people are smarter.

With a properly designed dog bone or a properly designed lifter, they could use a properly designed cam with faster ramps and/or less lifter side loading.

It is also interesting that the dog bones that 69HotBird posted pictures of are not the same as what is shown in these instructions. I thought those were from this kit, but maybe I misunderstood.

[P@blo]

It could be that the instructions are for a different engine and that the lifter would drop too low in the lifter bore on certain smaller base circle cams?

Here's the confusing part for me. The other member removed material (0.035") from the beveled edge (top portion of dog bone) to create the added clearance to allow the lifter not to move the dog bone during operation. But the lifter will travel up the lifter-bore the same even on low lift cams so why is added clearance needed?

We have a lot of wiggle room for the bottoms of the lifters on a small base circle cam so it might be a non-issue but if the highest point of a lifter only travels so high in the lifter bore despite cam lift choices, why is clearance being added so the dog bones do not move on certain cams? Would this not support comp cams instructions?

Again I apologize if I am coming across stupid but unless I can make sense of something I am unable to process information.

[shermanator2]

Originally Posted by P@blo

It could be that the instructions are for a different engine and that the lifter would drop too low in the lifter bore on certain smaller base circle cams?

Here's the confusing part for me. The other member removed material (0.035") from the beveled edge (top portion of dog bone) to create the added clearance to allow the lifter not to move the dog bone during operation. But the lifter will travel up the lifter-bore the same even on low lift cams so why is added clearance needed?

We have a lot of wiggle room for the bottoms of the lifters on a small base circle cam so it might be a non-issue but if the highest point of a lifter only travels so high in the lifter bore despite cam lift choices, why is clearance being added so the dog bones do not move on certain cams? Would this not support comp cams instructions?

Again I apologize if I am coming across stupid but unless I can make sense of something I am unable to process information.

The way I read the instructions is that Comp Cams makes a special series of compromised cams for small block Fords just to go with that kit.

What 69HotBird did was cut a relief in the bottom, not the top, of the dog bone so that the fully round portion of the lifter could protrude into the dog bone. This would be required for any properly designed cam using the HT2184 lifter in a Pontiac. High or low lift will not effect this. It is not for certain cams. It is for any cam.

As you point out, based on JC455's measurements we have plenty of room at the bottom, so high lift cams should not be an issue.

[242177P]

If the 2184 is THE lifter to use, would it make sense to source round .875 ID shims?
Like the dogbones, they'd still need to be fitted to the block, but that's a lot easier
than milling a step into the bottom of a dogbone.

[JC455]

I used the adjustable table of my drill press as my base. I placed the lifters in the slot for more stability, then placed an adjustable combination square vertical so I’d have a consistent 90* angle to measure from.
1) From the base of the flat tappet lifter to the upper line I scribed, which indicated the upper limit of lifter stick out, is about 1”-25/32”.
2) From the base of the Sealed Power roller lifter to the upper edge of the oil feed port is about 1”-21/32”.
This leaves us with 4/32” or 1/8” of clearance.

[JC455]

3) From the top of the oil fill cut out to the base of the machined flats on the top side of the lifter is 8/32”
4) From the base of the lifter to the base of the machined flat is 1-30/32”
5) From the base of the machined flat to the top of the lifter/machined flat is 20/32”

[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

Looks like 8/32”-4/32”= 4/32” so about 1/8” of unmachined, round lifter sticks out.
I’ll try to get an actual measurement to verify the math(hopefully no stack up error) after I figure out what’s going on with the cam bearings(see my other post from this evening)- I’m not real hip on putting my brand new roller cam in those crappy bearings again.

[pmd400]

I tested an ls7 lifter on a cam that had the maximum lobe lift .030" under the cam journals. The round part of the lifter comes about 0.125" out of the lifter bore

[shermanator2]

Originally Posted by pmd400

I tested an ls7 lifter on a cam that had the maximum lobe lift .030" under the cam journals. The round part of the lifter comes about 0.125" out of the lifter bore

What manufacture and part number of lifter did you test? And out of curiosity, what cam had the noses 0.030" below the journals?

[shermanator2]

Originally Posted by 242177P

If the 2184 is THE lifter to use, would it make sense to source round .875 ID shims?
Like the dogbones, they'd still need to be fitted to the block, but that's a lot easier
than milling a step into the bottom of a dogbone.

Unless these were epoxied to the block I don't think this works. If they are floating, the "corners" of the lifters will catch these and lift the shim washer and the dog bone up.

[shermanator2]

It is a PONTIAC lifter!!!

The Sealed Power HT-2148 is a Pontiac lifter first and foremost. I looked at the application list on Sealed Power's web site and the earliest application that I can find is for the 1984 Pontiac built Iron Duke 2.5L 4 cylinder used in Fieros and other GM cars as the standard 4 cylinder. It was used in 4.3L V-6 starting in 85 and various other V-6s in later years up until 2009. It was used in SBCs (not all, some use flat until 95) from 87 until their demise. It was used in various LS motors in cars, including the 7.0L until 2013, but apparently not later. The last application I found was in 6.0L truck engines in 2018.

Let's stop talking about LS7 lifters. If we want to call it something other than the HT-2148, let's call it the Iron Duke lifter.