[MrArt2u]

I’m sad to report that the Flat Tappet Hydraulic Lifter Catastrophic Failure Club has a new member. The 400 in my ’64 Bonneville convertible chewed up the number 7 exhaust lifter pretty good. The motor was built just about 20 years ago but only has about 4,000 miles on the clock. I got tons of advice back then from this very forum. Old Man Taylor, TATodd, Tom S. And so many more, all answered tons of questions. So I’m back for fresh advice. Reading through the forum, it looks like a lot has changed in the high performance Pontiac world over the last 20 years.

I’ll need some advice on what may have caused this and what to do next. So far, I’ve only gone so far as pulling the intake and valley cover and pulling the bad #7 exhaust lifter. There was close to a quarter of an inch ground off that lifter so I know the motor has to come out for proper cleaning, how far do you guys go? Complete strip down? Do you typically replace all the bearings? Rings?

Does the fact that it was the last camshaft lobe mean anything?

Part two: Need new cam advice.

I’m also looking for new cam selection advice. I was considering a roller cam but, wow, what a price difference. Is it worth it? Stick with Flat Tappet? I’m strictly a street, no strip driver and getting older so much more of a cruiser these days. I’m looking for a reliable motor that pays respect to the legendary Pontiac power.

Here are my current specs:

1964 Bonneville convertible (3,985 lbs.) 400 engine block. 62 heads with some port work. This motor belonged to an old friend that passed away almost 30 years ago. He used to street race it in his 64 GP with nitrous so it absolutely needed a rebuild by the time it got to me. He did the cylinder head port work himself.

According to the receipts from my rebuild, the engine has L2262 .030 pistons and a Comp Cams 275 DEH Dual Energy HFT cam with Comp Cams High Energy 852-16 lifters. Do these pistons give me too high compression for street?

The 62 heads have ARP rocker studs, guide plates, 1.52 Comp Cams roller tip rockers and have had port work. Springs have 120 lbs seat pressure.

1966 Tripower, spec’d by Old Man Taylor. Mallory distributor, MSD box.
Exhaust is factory cast iron long branch headers and a pair of nice mufflers.

The transmission is a 700r4 rebuilt with B&M components and a B&M Holeshot 1900-2100 stall locking torque converter. 4.10 posi rear end. With about a 29” tall rear tire (255/70-15)

The car had tons of power early on, almost too much for my driving style, but, man, was that idle a sexy rumble. Recently it felt like it was gradually dropping in power and had trouble with detonation. (failing lifter cause the detonation? Or is it due to that high compression ratio and today’s gas?)

Thanks!

[Steve C.]

No matter what you decide to do, unless already done so I would suggest you check your current valve spring pressures. Tested with their retainers in place at their verified installed height.
Valve springs can lose pressure over time.

If the decision is made to upgrade to a hydraulic roller cam new valve springs will be in order, and with a presumed increase in their pressure used.


.

[Formulajones]

As Steve said I'd be curious on valve spring pressures too.
Since it was built 20 years ago can't necessarily blame it on faulty parts, a very slim chance anyway. Only 4000 miles tells me it sits a bunch so a lot of extended sitting cold starts comes to mind. Not that that's the problem but not the best thing for it either.

Probably the why isn't all that important to you now, just gotta cover your bases 2nd time around.

[b-man]

Big Pontiac cruiser.

I know I’ve recommended this cam a hundred times or more but for a mild street engine looking for longevity use a factory low-lift lazy lobe 9779068 cam. The more aggressive fast acting lobe aftermarket grinds are more likely to fail compared to the gentle factory grinds as you can understand.

Put the Mellings SPC-7 in it with the highest quality lifters and a new set of springs and drive on. You’re probably spending 95 percent of your time between 1000 and 3000 rpm, this cam will fill the bill. It’s not like the cars that came factory equipped with this cam were slow, they more than held their own on the streets.

[MrArt2u]

Thank you all for the quick responses.
Steve, the 120 lb spring pressure was written on the receipt by the head builder 20 years ago. I figured if it came down to pulling the motor to scrub oil passages, I would send the heads to a machine shop with new springs and have him confirm/set the new spring height and pressure.

Formulajones, I agree it's hard to blame faulty parts in a 20 year old build. I hadn't heard anything about faulty lifters back then like I do now. This car did sit, sometimes for years at a time. I had really screwed up the paint job on it back then and parked it until the pandemic when I pulled it out and repainted it and fell back in love with it.

b-man, That all makes sense. I will put the Melling SPC-7 on my list. Is there a known go-to highest quality lifter that you all use with this cam? I'm wild guessing a 10:1 CR with my 62 (72cc) heads and those L2262 pistons, does that combination work with that cam alright?

And do you all suggest pulling the motor to do a deep clean? Would you install new bearings or rings? I know I want to replace and update some gaskets and the rear seal as I was getting some drips from it.

[b-man]

Johnson Hylift lifters, I used the same ones along with a NOS 068 cam in my 421 HO build.

Tear it down and do rings and bearings for sure. There are a lot of metal shavings in there. You’re already sealing everything up again so it makes sense to break the glaze on the cylinders and install rings properly gapped and new bearings. This also gives you a chance to inspect your bearings for signs of detonation damage and adjust either the compression down a little by cutting a small dish in the pistons or upping your fuel octane.

You could also have someone competent rework the combustion chambers to add a few ccs of volume to drop the compression a little rather than play with the pistons which could get damaged during the process which likely includes pressing the pins to remove and reinstall them on the rods. Checking the combustion chamber volume at the very least will confirm your actual compression ratio, those #62 heads usually are somewhere in the neighborhood of 76 to 78ccs before resurfacing.

The 068 was used on plenty of 10:1+ compression engines from the factory, it has long seat to seat timing and is pretty friendly with 10:1 engines and especially ones with lower gears like you have.

[tom s]

check the filter first.Tom

[MarkS57]

Originally Posted by b-man

Big Pontiac cruiser.

I know I’ve recommended this cam a hundred times or more but for a mild street engine looking for longevity use a factory low-lift lazy lobe 9779068 cam. The more aggressive fast acting lobe aftermarket grinds are more likely to fail compared to the gentle factory grinds as you can understand.

Put the Mellings SPC-7 in it with the highest quality lifters and a new set of springs and drive on. You’re probably spending 95 percent of your time between 1000 and 3000 rpm, this cam will fill the bill. It’s not like the cars that came factory equipped with this cam were slow, they more than held their own on the streets.

Agree, originally, my 400 had this exact combination, 62 heads and 0.030 L2262's. The SPC-7 worked very well & was 93 octane pump gas friendly.

[steve25]

Odd’s are that since that motor had only 4K on it and no doubt was well maintained during those 4000 or so miles I would have to say it’s just a case of number 7 not braking in as well as all the others when the motor was run for those first critical 20 minutes.

With all that cast iron metal grit in the motor it should all come down so everything can be inspected and the oil galleys flush out and the crank oil passages need to be brushed and flushed out.

Hopefully your piston skirts are ok as well as the cylinder walls.

[Tim Corcoran]

I recently read an article in Hemmings Muscle Machines about using proper break in oil, especially for flat tappet cams. Most people know you should not use standard auto parts store oil for an engine with flat tappet lifters. For a flat tappet cam you need an oil that has a high ZDDP additive package to protect the cam and lifters not only during break in but throughout the life of the engine. There are a few different companies that offer this oil that has the high ZDDP levels to protect flat tappet cams. For those who may not know oil now days is formulated for fuel economy and catalytic converters, the higher ZDDP additive package significantly reduces the life of the catalytic converter which is another reason they took most of the ZDDP out of the oil. The modern engines have closer tolerances are are made to run on thinner oil. For my wife's Toyota RAV 4, Toyota says she must use 0-16w oil. All modern cars also run roller lifters and they don't have the extreme high pressure metal to metal contact of a flat tappet cam so it's ok to lower the ZDDP package. Now here is the detail that most people get wrong. For break in, especially for a flat tappet engine you need to us NON-DETERGENT break in oil. If you get the good oil with the extra ZDDP but it's not specifically non-detergent break in oil the detergents in the oil wash away the ZDDP at the most critical time during the first few minutes during cam and lifter break in. So make sure you use the right break in oil and also use a high ZDDP formulated oil for the life of the engine. You won't find this oil at Autozone, or O'Rileleys of NAPA, or Walmart either. Don't use diesel oil in your car as the type of ZDDP additives for a diesel engine is not the same additive. There are two basic types of ZDDP a fast acting and a slow acting, oil formulated for diesel engine uses the slow acting ZDDP and it doesn't provide the same level of protection for a gas engine with flat tappet cams. I'm no expert, this is coming from the article and personally I take it as good advice. While were talking about flat tappet cams most people know there is a specific break in procedure for flat tappet cams. The cam lobes and lifter face are not pressure oiled like the rest of the engine is and rely on splash oiling from the crankshaft. That is why you need to get the engine started right off no excessive cranking because the carb was not primed or the timing isn't right, and you don't let it idle during break in. You need to keep the RPM between 1500 and 2000 RPM for the first 20 minutes. if your engine is getting too hot or you need to make adjustments it's OK to shut if off and continue when everything is right. One more thing, valve spring pressure, if it's too high that's enough to destroy the ca/lifer during break in and it might not show up right away. Most failure is at break in and you might not know it until it continues to wear away to a point that it's really knocking on your door telling you something ain't right. Beware of running high lift long duration flat tappet cams, in most cases if your going that direction hyd roller may be a better choice. For mild performance cams like the 068 for example flat tappet may work fine. Butler Performance will build you a complete engine but they won't build an engine with a flat tappet cam. Hmmmm seems there is a message in there some place.

[MrArt2u]

It sounds like the 068 Melling SPC-7 cam with Johnson Hylift lifters is the way to go if I want to keep a hydraulic flat tappet cam. For valve springs, do I have to measure spring height before selecting?

So it looks like the block will be taking a trip to the machine shop, have them install new cam bearings and a quick cylinder wall hone for the new rings (if I'm lucky and the walls and skirts are not scored too deep) Anything else I should be considering?

Tim Corcoran, I hear what you're saying about the proper break in oil and the zddp. I intend to use the best available to me when I fire this up. I'm pretty sure I followed the best advice 20 years ago as well but that may have involved pouring in a bottle of "break in" treatment with standard detergent oil. I know a lot has changed for us in the last 20 years. I also hear what you're saying about Butler not building engines with a flat tappet. Part of me is scared of these flat tappet cams and wants to go roller but I have heard some negative things about them, some excessive valvetrain noise complaints, some catastrophic failures, and the cost is quite a bit more than the HFTs. This is my first lifter failure and I definitely do not want another!

[Schurkey]

If this was me, I'd pay the extra money for either a roller cam/lifters, or AT MINIMUM have the camshaft nitrided. Years ago, that was about a hundred bucks--about doubled the cost of the cam. I don't know what it costs now.

[moontower69]

Are CROWER 68404 springs good for a stock rebuild with 068 or 067?

Wanna avoid risk of failure and like you said Bman, most driving will be between 1000 and 3000 RPMs....

[hurryinhoosier62]

Originally Posted by Schurkey

If this was me, I'd pay the extra money for either a roller cam/lifters, or AT MINIMUM have the camshaft nitrided. Years ago, that was about a hundred bucks--about doubled the cost of the cam. I don't know what it costs now.

X 2. I wouldn’t use a flat tappet cam unless it was nitrided. I don’t know if it’s defective cam cores or lack of proper parkerizing that is causing the problems, but nitriding will take care of both,

[MrArt2u]

I'd read that a roller cam/lifter set up adds about $1,000 to the combination once you add up everything needed.
If I stick with the flat tappet, nitriding just the lifters at $50 a pop adds about $800 to a flat tappet cam set up. I don't know how much it costs to nitride a camshaft.

I'd love to hear from people that have actually done any of these, good, bad and ugly.

[grivera]

Make sure the FT lifters rotate easily in their bores

Regarding nitrading, have you read this thread?
http://forums.maxperformanceinc.com/...ight=Nitrading

[77 TRASHCAN]

Cliff had some sort of coating applied to a HFT cam, been a while back, hopefully he will respond.

[Formulajones]

I nitride all the flat tappets I've done here. On top of that I prefer a lifter with a direct lube option as well. This puts pressurized oil right on the face of the lobes so you aren't relying on just splash lube, especially in idle conditions.

Been doing this for years and is currently done on both of our daily drivers with over 100,000 miles between them to date. Still running perfectly.

As far as cost it starts getting spendy. Nitriding the cam used to be $100 just a few years ago but it's now double that. Lifters that lube the cam can be as much as $300-$400 or so. Ya get what ya pay for I guess. None of this stuff is cheap to do anymore. I won't do a flat tappet without these options but typically I do rollers on most builds and just bite the cost. I really don't worry about failures, that's honestly few and far between.

[P@blo]

Roller lifters have few and far between failures? I bet they are on par with the FT failures just lack the density in people running them.

These engines were designed to use a FT cam and that is a fact. Sure you can run roller but don't expect it to solve all your problems because it won't. Don't get me wrong though if I saw no roller failures i'd be running them.

What about the DLC coated FT lifters coming out? Could be a game changer.

[67Lemons]

The other issue with a roller set up is that it’s overkill for a stock type rebuild with a stock cam or a person wanting to do a simple cam swap to hot rod their old cruiser. The cost is prohibitive & it requires some head work for springs & studs then a new gear for the distributor plus a valley pan possibly, plus, plus, etc, that’s beyond what most folks will do for a weekend cam swap in the garage. Hopefully more manufacturers start utilizing DLC coated lifters so the guy who wants an 068 to upgrade from his 066 has a viable path for a small upgrade that will last & not break the bank.