Internal lifter failure??

[Jack H.]

Re: Internal lifter failure??

Just my 2 cents.

The Federal Mogul/Sealed Power/Speed Pro number I'm used to is HT817. A high rev option was also available as part number HT817R. Those may be old numbers.

My understanding is that used lifters on a new cam is a NEVER, EVER, EVER, and new lifters on a used cam is a bad idea. In my younger/poorer days I got away with the new lifters on a used cam, but my applications were oldschool small block chevys and chevy 6 inline sixes. As Duke has mentioned big blocks have more force/stress so probably not a good ideas. As Dave has mentioned, I'd never take a chance on it with my pride and joy big block Corvette and best to replace cam/lifters together following all break-in procedures.

I wonder if you have a university or materials lab nearby that you could have one of your failed disks tested...university may do it for free as part of teaching lab if you ask the right person. I'd certainly like the peace of mind to be able to definitely point to the culprit, especially if it's your original born with engine. Maybe you'll get cooperation from the manufacturer, but I've grown more pessimistic and untrusting in such endeavors.

[Tom L.]

Re: Internal lifter failure??

This has been sitting for a while, I just didn't have time to get into it. this week I was able to contact Hy-lift Johnson's tech line. When I spoke with them they immediately said they could not help and referred me to an engineer at the factory. When I got ahold of him he said he never saw that type of failure either (???) and had no real suggestions other than coil bind, incorrect seat pressures or valve float.

To check for coil bind I checked the pushrods, they roll nicely on glass. I also used a solid lifter to check for coil bind at full lift. At full lift there was about .070" between each coil and there was no evidence of contact.

To address the spring pressure issue I took the springs off the motor from the cylinder that had the failed lifter, #1, and brought them to my engine builder. He pulled up the file from assembly that shows all the spring pressures (See the attached word document), tested the two I brought to him and compared. The intake valve had 109lbs. on the seat and 323lbs. at full lift. The Exhaust had 111 on the seat and 325 at full lift. Pretty much spot on.

Nether of these things seem to be the root cause and additional attempts to contact the engineer I was referred to have not been responded to. I'm getting the impression that he has no desire, or ability, to help out. Very frustrating.

Sooooo... Any other ideas out there???

[Tom L.]

Re: Internal lifter failure??

Can't seem to post the attachment so I'll type the data taken at initial assembly from the springs I mentioned

Intake 1: Seat lbs.- 110, Seat ht. 1.880, Open lbs 330lbs., Open height 1.400, Bind height 1.275, Clearance .125, rate 459lbs.

Exhaust 1: Seat lbs.- 111, Seat ht. 1.880, Open lbs 323lbs., Open height 1.400, Bind height 1.265, Clearance .135, rate 442lbs.

[Duke W.]

Re: Internal lifter failure??

Buy a new cam and lifters from one of the reputable aftermarket cam makers. Any of them will have a suitable grind for your application. Personally I use Iskidarian. They're 10 minutes from my house, they've been grinding cams for 50+ years, they come up with what I want, the price is reasonable, and I never have durability issues. The cams break-in and function just fine.

:02:

A couple of points... I don't know of any "aftermarket" cam company that sells an exact duplicate of the OE cam other many, maybe, Crane.

I had an Isky valve retainer fail on my EP TR3 back in the seventies. I was in their shop about ten years ago, and I would not recommend that anyone buy anything from them for a OE rebuild.

The Federal Mogul part number for the '66-'73 Corvette big block camshaft is CS1093M and VL43 for the lifters. I don't consider Federal Mogul to be "aftermarket" because they are a Tier 1 supplier for current production parts and still manufacture parts for vintage engines.

All their camshafts are Parkerized, which helps with break-in. The only aftermarket cam company that I know of the Parkerizes their cams as SOP is Crane.

Duke

[Duke W.]

Re: Internal lifter failure??

Aftermarket cams of similar duration usually have more overlap than OE cams, and that kills low end torque and roughens up the idle. That's why I always recommmend OE cam designs for restoration engines. More power and revs can be had with head massaging.

Federal Mogul parts are sold at NAPA and many other parts chains/stores. I'm sure they have a warranty.

I don't recommend roller cams for engine restorations. It's an expensive conversion and you typically end up with too much overlap. Also, everything in the valve train is heavier, which even with high rate valve springs limits revs. Head massaging is a better way to spend the money. Flat tappet cams that are built to the GM prints including Parkerizing with OE replacement valve springs and CJ-4 oil rarely result in any problems.

With careful attention to valve spring installed heights hydraulic lifters will go to at least 6500 and mechanical lifters to at least 7000 with OE design cams/springs, and if the heads are properly massaged engines with SHP cams will make useable power to those limits, and base engines will easily make useable power for another 500-1000 revs above the OE rated power peak.

The only thing to worry about is connecting rods, particulary on 283s and early 327s, but much more durable rods are available for about $250 a set. That is money well spent!

Duke