Base circle

Just put a ta 212 in the stock engine in the car. Cloyes timing set, ta front cover, and the rockers and shafts are a year old. Had 60 psi oil pressure for the entirety of break in, has 25 at hot idle. Front cam bearing looked fine, and it is running fine, unlike my prior experience with wiped cam lobes. Nevertheless, I have a noisy valvetrain. I did not check for pushrod length, I just stuck stock back in. Has anybody measured a difference in either base circle diameter of ta cams, or height of their lifter vs stock parts? That'd give me a no preload situation, which would act how it's acting I think. Ultimately I'll just have to dig to the root cause, and I probably shoulda checked before hand, but I didn't, and landed myself here, LOL.

Appreciate any input guys
Ethan

 

Have to check the length, it sounds like your one the correct path. Any time valve lift goes up, basecircle get smaller too......and so many time manufactures are consolidating parts to save money and product flow and stocking. I haven't see a new lifter have the correct cup height in so long for buick motors I dont know if a true spec lifter is even made anymore

 

Thanks guys, yeah this is a classic I knew better but did anyways situation. Should be fun when I get it sorted, I deleted what had to be almost 10 degrees of variable cam timing when I took the stock timing set off. I've never seen one so loose.

 

When Cam cores are ground for more lift then stock the way that added lift is achieved is with a lower base circle.

 

Took valve covers off today. Playing with valves that are shut, I can turn the pushrods with my fingers, but there's no perceivable lash in them. All 16 are getting a steady flow of oil. I would expect to see some slack in them to cause a noise, any guesses? I inspected pushrods and didn't see signs of contacts with their guide holes either.

 

LOOK at the lifters--either pull the manifold, or poke a videoscope into the lifter valley. SEE how far the lifter plungers are depressed.

Wild Guess: Defective lifters (excessive leakdown) not improper pushrod length.

 

I might be right at 0 lash and lacking the preload needed, but I don't have a measurable, quantifiable amount of positive lash. I'll get a bore scope in there and check it out to be sure. These are the Johnson lifter that TA sells, as they told me they could no longer get the Delphi. Potential exists that they're bleeding off too quickly, but I am getting plenty of oil to the rockers. Only one way to know for sure I guess. Thanks for the help guys

 

If those lifters have the plunger retained by only a round wire clip and not a flat type C clip then you do not want to run them even within .010” of fully extended, otherwise you stand a good chance of popping those clips out, and some valve springs can have fuss points in which at rpms well below peak the spring has lost control of its own mass with the same out come of valve float taking place.
This can pop out round clips and make for more issues !

 

No such thing, its either lash (looseness/clearance) or preload (any point past zero lash)
Being TA can no longer get the Delphi lifters and only has the Johnson HT 969 (Im assuming thats what they are) flat tappet lifters I think I'd go back to using a Chevy type lifter, the reason being is everyone and your neighbor has a Chevy their rebuilding right now and theres a HUGE market for Chevy stuff, so big companies cater to Chevy stuff, not so much Buick stuff, they dont care.
I used to run Chevy lifters with a longer pushrod, valvetrain was quiet, much more choices out there for the Chevy style lifter.
The Johnson flat tappet lifters are pretty generic for Buicks anymore, 30 years ago they were ok. I had issues with Johnson flat tappet lifters, thats why I switched to Chevy type.
I have since changed to a roller cam, initially used the Morel roller lifters, complete JUNK!
I called TA and ordered the Jonson roller lifters, another 700 plus dollars, they came in the Johnson box marked SBC, but they're quiet, and stay pumped up

 

There are two companies, entirely different, named Johnson, that manufacture Lifters..

"Johnson Lifters" is based in Taylor MI has been around for over 60 years, but was mainly an OEM supplier until fairly recently, when they started focusing on the aftermarket.. It's very possible that the original lifters in your Buick were manufactured by this company. The were a huge GM supplier, starting in the mid 50's. This company makes everything in the USA, and is the outfit that makes the "good lifters".

"Hylift Johnson" is an entirely different company that manufactures lifters, based in Muskegon MI. They too have been around for decades, and have been thru several different ownership groups.. they were/are an OEM supplier. This company actually made what was, up until the 90's, the preferred aftermarket lifters. And although they boast about their USA manufacturing, word on the street is most of the stuff is made offshore.. they only manufacture select lines here in the US. They sell under many brand names, and you won't have to look far to find negative stories about these products. Most of the lifters that you will find these days are marketed by Melling, and they are in fact Hylift/Johnson products.

They actually make a slow bleed down lifter, that would work and be quiet in most applications, but not for the 969 line, which is the 350/455 base part number.

http://toplineauto.com/wp-content/uploads/2019/04/Lifter-Application-Catalog.pdf
JW

 

I'm aware of that. Just trying to put into words that I could be right close to 0 lash, but that I don't have any lash.

 

I have come up with pushrod length as my issue. I am not getting the preload that I need, looks like I'm getting maybe .005" or so. My understanding is that stock pushrods are 9.350 (I don't have a caliper that big to confirm), so will the Comp 7896-16 do for me? They advertise as 9.378, but I want to be sure there isn't just a difference in how they're measured, since they claim to be stock length.

 

Buy or borrow a pushrod length checker.
Your machine shop should have one you can borrow, take home to measure, then return it and they can measure the checker to see what length you came up with.

 

Go to harbor freight but a cheap long caliper to fully verify the length your starting with......dont assume the pushrods you have are a certain length, you need to measure to know.........I ordered gm pushrods for a 454, advertised as 1 length, measured another.

 

I have a couple lengths in that style pushrod checker; if I had it to do over, I'd have bought the more-expensive, direct-reading versions. (Their "Hi-Tech" line, instead of the "Magnum" line.)

For example, https://www.summitracing.com/parts/cca-7704-1

The difference is that the "Hi-Tech" line has the measurement scale inscribed on the pushrod, you don't need a caliper or tape-measure to determine the REAL length (measured the way Comp Cams does.)

Thanks for that. I've posted the same thing on other forums. There's AT LEAST three different ways to measure pushrod length; be sure to use the same method that your pushrod supplier uses; or at least get within .025 of "correct" since pushrods tend to be shelf-stock in .050 increments.

 

I love my hi tech checkers. I bought the full lineup. I love that they direct read, I love that they dobt have the big clunky nuts that get in the way other things. You can drop in rotate the motor and get a good read and pattern. Some with the cheaper ones you can't fit the around things up top and have to remove the intake. The better ones you can measure without doing that.

I also have used them to measure other things inside of openings that need a good measure that are too big for small calipers or too far inside to have the room.