Question about the stock 1970 426 Hemi hyd. lifters?

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427dart
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Question about the stock 1970 426 Hemi hyd. lifters?

Post by 427dart »

My brother was looking at his factory stock hydraulic lifters which had 10,000 miles on them from when the Hemicuda was new.
He noticed that instead of a raised radius crown which should be present on a good lifter....he saw what looked like an inverted radius when a straight edge was laid across the bottom of the lifter. Now he only had located one of the lifters and is looking for the box that had the others and they are numbered as they came out the block. No evidence of extreme wear and I have the factory camshaft that came out the engine and will look at the lobes.
I remember that the 69-70 440 6bbl engines came with a special low taper camshaft and special lifters to match and that the same design was used on the new 1970 426 Hemi with hydraulic cam. This was done due to the higher valve spring pressure the Hemi and 6 bbl. engines ran.

So would this be a failed lifter or did the low taper lobe design use an inverted radius for lifter rotation? Don't recall hearing about hydraulic lifter failures in the 70-70 Street Hemi of 440 6 Bbl engines. I'll see if I can get a picture of the lifter.
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by PackardV8 »

For the BBM, Johnson Hylift has P/N A-812 for '58-67 and A-976 for the '68-78. There are also a high-performance R version of each which must be used with adjustable rockers
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by mag2555 »

All you really need to know is that if you do not see the push rod spin every time the valve it power’s opens and closes then that cam and lifter combo will not live long!

You can see this action take place just by cranking the motor on the starter with all the plugs out even.
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427dart
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by 427dart »

Here is the picture of what the Chrysler "flat faced" looks like that came on the 1970-71 426 Hemi and 69-71 440 6 bbl engines.
This is after 10,000 miles of street use back in 1970-71. I guess it is designed to contact low taper lobe on outside edge for spin with no contact in center. Wonder how many 440's and Hemi engines that were being refreshed had still good lifters thrown out because the lifter failed the common crown rock test? 99% of gearheads didn't know this at the time!
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by HDBD »

I could be wrong but back in the day I seem to remember hemis having lobes go flat rather frequently. Or was that the excuse to tell dad to change cams? Its a blur now..
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by 427dart »

As you can see there is no wear marks in the center part of lifter face...just that narrow area around the O.D. The engine ran fine back then with no sounds of tapping lifters. We still looking for the box that the other 15 lifters were in and I will also look at the factory cam which I have on the shelf.
I am just posting this info for historical reference. Back in late 71 my brother pulled the Hemi to install the Race Hemi parts including the Racer Brown STX-22 cam which he still has.
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by 427dart »

Here is the 1970 Hemi cam with 10,000 miles of use from 1970-71. Little if any wear and can go right back in since we have the matching lifters.
Check out that little dab of Hemi orange paint on front of cam! No numbers at all on the camshaft.
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by Geoff2 »

The 440 Six Pack lifters [ & probably the hemi ] were of a low taper design, due to the stronger valve springs in the six pack engines. Presumably the side to side taper on the cam lobes was slightly less to work with the low taper lifters. While the radius on these lifters was greater, they still had a radius [ taper ] & were not concave if that is what is being suggested....
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by mag2555 »

It sounds like Mother Mopar with these two motors and there size lifter diameter found the happy medium between more contact area to live with greater spring loads and still having enough taper to spin the lifters and at least get them thru the factory warranty period.
Very interesting!

So this brings up the question do aftermarket Cams and lifters for these motors incorporate these same changes/ features?

Was it not the Hemi fuel cars of the 60s that lead Isky to devise the hard face lifter?
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427dart
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by 427dart »

Well I don't know what a new factory lifter of this design would look like. So would this be a lifter beginning to fail....go flat after 10,000 street miles?
Anyone out there that had a 440-6 pack or 70-71 Hemi car have there stock cam/lifters fail? There was no internet back then so any issues would have been read about in the car magazines or from dealer techs and word of mouth from other owners. Have sent these pictures in an email to Dave Dudeck and having him possibly forward to Mr. 440 Six Pack Bob K.

I checked the cam lobe lift and they are in spec at .311-.314 Intake and Exhaust. Going to set up a lifter fixture and check the .050 cam duration which I have wanted to see.

Of note the 1970-71 Hemi had slightly more spring pressure than the 66-69 solid lifter Street Hemi. Back in the 70's we used Kendall Race oil so it had all the good stuff. I still have a full can of it sitting on the shelf from 1971 !
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by Geoff2 »

The Hemis were noted for short cam/lifter life because the heavy valve gear reqd strong springs, aka Battleship springs. Those lifters in the pic are worn.
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by 427dart »

Machined up a .904 tappet and also a retainer block. Results Duration at .006 was 284 degrees and 228 at .050 for those who may want to know.
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by PRH »

Have you indicated across the lobe to see how much taper it has?

I usually check it on the base circle.

FWIW, which isn’t much........ in 42 years of messing with Mopars....... I’ve never seen a mention of the Hemi having a low taper cam & lifters.

I’ve measured quite a few stock and stock replacemt type cams(for various makes of engines) where the lobe taper was .0005-.0010”........ so, something in that range wouldn’t register as “low taper” to me.
Somewhat handy with a die grinder.
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Re: Question about the stock 1970 426 Hemi hyd. lifters?

Post by 427dart »

Well here is my guess on the lifters. For better durability Chrysler said they used a special low taper cam lobe and a special flat faced lifter to go along with the Street Hemi valve springs on the new 440 6 Pack engine. Why would they not use the same idea on the 1970-71 Street Hemi with the new stronger valve spring and hydraulic cam? I did also read that the hydraulic lifters used on the Hemi had limited plunger travel...this info found in the the Chrysler Direct Connection manual. Running the indicator across the lobes I saw .001 taper. I didn't have the one lifter to look at in my hand as my brother sent me pictures of it. He was looking for the box with the other 15.
All of this just for checking out what it was.
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