I need to purchase a cam for my 1969 L89 427/435 engine.
I’ve decided to not use a solid lifter flat tappet cam due to all the failures documented on many different car forums and failures seen with friends builds.
This leaves me with most likely a hydraulic roller.
I have a hydraulic roller in my other corvette, a 1969 L71 (427/435) and love the way it sounds.
However, it is more aggressive than the factory original and it requires a spacer for the valve covers which look hokey.
Looking for some suggestions for a factory equivalent only in a hydraulic roller. I realize I’ll lose the characteristic sound that a solid lifter car makes but the truth is I can’t afford to go backwards in the case of flattening the cam. I just don’t want to risk having a failure.

 

Here is a short 15 sec video of the roller cam in my black 69 427

 

Flat Tappet failures are 100% a direct result of improper installation and break-in. There were some bad lifters going around a few years back but that seems to have gone away.
You have a solid cam.....bonus for you as you can use a solid lifter with the EDM hole in the foot to leak oil right on the cam lobe.
I have a procedure for breaking in flat tappet cams and the only real thing that is different on a Big Block is the inner valve springs will need to be removed during break-in......

If you are hell bent on a hydraulic roller then you need to figure out the valve/spring/retainer/pushrod setup.......you have to run valve cover spacers due to the fact that you have Full Roller Rockers.....that is the only reason you would need this.
You can go to a Comp Magnum Roller Tip rocker with a short Poly-Loc and that would be a fine setup for the street.......
You will need a pro to figure out the spring, then once you have the spring number....everything else works around it like the Locater/Cup, Valve seals, Valve length.....etc.......pushrod length is important as the stock sizes are no longer correct.

If this were my car.....I would put the bleeding lifter flat tappet in it......the other setup will run you $2000+ by the time you are done and you need a pro to figure it out.....also, you most likely are not getting out of it without removing the heads.....

Jebby

 

Jebby, thanks for replying
You say improper install and break in are 100% cause of failure. Yet if you go over to the Yenko forum, there are guys that have been building and restoring these solid lifter cars for 25-30 years with no problem and now in the last few years they are seeing failures.
Rick Nelson, the premier LS6 Chevelle restorer, said he never had a failure in 25 years, now almost all of his startups have failed.
I also keep hearing a wide range of reasons for failure.

My question to you is what are these lifters with an EDM hole? Who makes them and where do you get them?
Who would you buy from in todays world?
My criteria is I want a cam with close to the same specs as a factory L89/L71 had. If I go roller, I want it to fit under the factory BB valve covers.

 

A couple of threads from the Yenko forum and YT on cam failure.


https://www.yenko.net/forum/showthre...04#post1634904

https://www.yenko.net/forum/showthread.php?t=177064

 

Howard Camshaft Rockwell checks their camshaft and lifters. They also parkerized the camshaft. Check the website for the details on their warranty.

 

Comp offers the lifter with the hole.......and it works.....
Roller cam has nothing to do with the height of the valve covers....the pushrod height and whether or not you run a large aluminum roller rocker does.....also the height the poly-loc plays into it some.......you see, once you get to about .660 lift or so....the retainer will crash into the guide on a stock head.....so you have to run a taller installed height, which requires longer valves and longer pushrods...now everything is higher and will not clear the valve covers.......there are plenty of hydraulic roller cams that have sub-.600 lifts.....so no real issue here.....just make sure you are aware of the lift and the rocker arms......

I have a problem with claims of the Yenko and LS6 resto guys......mostly about the timeline.......if they had no problem with break-ins I call BS because this all started in 2005......when the Zinc was quietly pulled from the oils and none of the cam manufacturers gave two ***** about telling anyone.......so saying they had no failures I have trouble believing because I worked for a big engine shop at that time and there were nothing but failures......so right after we figured out what was going on, the one manufacturer of Flat Tappet lifters in the US decided to not make any for unknown reasons......so the market was flooded with offshore lifters that were not convex at the bottom and they ALL failed.......since then a couple of American manufactures got back in the game and the quality is back as far as I can see.....

I use mostly Howard's cams and lifters......but the same manufacturer of their flat tappet lifters makes them for Enginetech too which is an Engine shop supplier......I have used these now for over 10 years and used Comp before that and never had one lifter failure even after 2006.......BUT....I came up with a procedure I use to fire the engine and break them in......I have a flat tappet in my own 406 and broke in four of them last year in four different small blocks......not a problem......

I do not and will not listen to anyone about flat tappet cams especially those who just sit there and slam the whole deal without knowing WTF they are talking about......if LS6 guy is losing every cam he installs....he is doing something wrong, from not checking his parts prior to install the actual install to the break-in procedure.......a lot of these forums are Echo-Chambers of solid BS......and there is no better way to act like you know something than bashing stuff that everyone is on the bandwagon bashing......a guy who does $100k restores is GOING to figure out the problem and solve it......a quick way to do it is to use OEM GM lifters for instance....which are out there if you look. I know a builder who does just that. But who is going to disqualify the Yenko or LS6 guy? No one that has no clue....that's for sure.....

I recently bought some Summit brand lifters and measure them as well as checked the foot with my straight edge.....no issues...and they are identical to the Howards and Enginetech parts I have on the shelf too......they are going in my Camaro.

You do not have to listen to me either.......but just know that if you go roller....you are in for a lot of changes, and a BIG cash outlay of parts...plus finding someone knowledgeable to setup 50 year old Winters heads with Hydraulic roller springs, seals...etc.....there are several ways to skin that cat......

If you brought that L89 to me I would have zero issue putting you into a solid flat tappet using the EDM lifter and my break-in procedure......and you could do it for about $500 in parts.....and zero need to change the spring package.

These are just my thoughts......I use and run flat tappets and you can too. Oh....I am 52 years old and have been building engines since I was 13 years old.....mentored by two Pro-Stock builders and a Super Stock builder.....Yenko and LS6 mean about squat to me. I don't even do this for a living anymore LOL.

There is a member here....ChrisHewitt....that has a thread about his conversion to Hydraulic Roller on his 69' L-71......and I was giving some pointers.....somewhere in 2019 I think......great thread with a lot of info on his experience.....
He went roller, headers and a mod to the Magnaflow mufflers on an otherwise bone stock car and it made a huge difference....

Jebby

 

Thanks Jebby
I know very little about camshaft selection, hence my post on here.
I do have a Howard’s cam in my black car I posted the video of.




I guess I’ll research a bit more on the EDM lifter.
Ive tried several different search query’s and can’t find that particular thread but I’ll keep looking.
Appreciate all the info!

Joe

 

That cam is only .600 lift.....and 230ish @ .050......not radical at all in a 427ci engine......this cam isn't keeping you from using valve cover spacers....your valvetrain gear up top is....

Jebby

 

Found it on my home computer....

https://www.corvetteforum.com/forums...dations-2.html

Jebby

 

Thanks Jebby!
Unreal, I looked thru the whole member ship for a Chris Hewitt. Then searched using key words. Clearly I’m as bad at computer stuff as I am at searching for a camshaft ha ha

 

Yeah....it was a bitch to find....had to use a workaround....search function is sick right now with the flu...lol

Jebby

 

I'll back up everything Jebby has stated above. Absolutely correct.

Lars

 

Tuna, yes very happy with my cam. If I had to do it again I’d probably go a little more aggressive and use the one Jebby selected. 😀. Maybe a cam swap in my future, or more likely and second engine, pull the original for safe keeping.

I have day dreams about my second engine: more cam, aluminum heads, 7000 rpm. Then I can spin it and not worry. 😀

 

Lars,
are you agreeing with the use of EDM lifters and a solid lifter cam?

Looks like Comp is out of the EDM lifters…….

 

How fun would that be? Now I am daydreaming.....LOL......
L-71's to me are the Zenith of the musclecar era......L-88 is hitting the lotto......the experience of either on the street is polarizing to even the experienced.......ton-o-fun....

Jebby

 

Just for kicks I took the cam specs from all the major cam house catalogues (Comp, Crane, Lunati, Isky, Crower, Howards, Edelbrock, Trickflow, GM) for high rpm (6500) Chevy 427s and put them in a spreadsheet and averaged them out:

intake @ .050: .239
exhaust @ .050: .243
intake lift: .592
exhaust lift: .601
LSA: 111

So that might be my next cam. My current cam is 230/230, 570/570 with 112 LSA . Specs seem pretty tame by comparison, but it performs really well. 14 inches at 750 rpm and pulls hard to 6000+. 1st gear useless, 2nd gear spins, finally hooks in 3rd. I have an M21 with 4.11s.

 

Your "average" cam is not far off from what I spec'd back then....lol....

Jebby

 

Jebby indeed: .244/244, .612/612, 110. I noticed it’s a single pattern. Do modern heads (AFR, etc.) not need more exhaust lift and duration like the original heads?

 

I also have the Winters heads on my LS6 tribute build.

Originally built and dyno'd with a solid roller, 270/278* adv, 230/238* @.050", and 250/550# valve springs that it required. 485HP/550TQ @ 5600/3400. 15" vac @ 850. 110LC

Then talked with a lot of people about how fragile the aluminum is on these old 074 heads, They will snap rocker studs off with strong valve springs. Saw some broken ones. Make sure you use the special long rocker studs.

I was "probably" OK at that spring level, but I still did not want to risk it. I wanted something a little milder that was easier on the valvetrain. Less maintenance and less likely to break.

So decided to change to a hydraulic roller profile, which has less aggressive ramps than the solid roller, and let us use hydraulic roller level springs. 190/430# Beehives even. PAC 1255X.
The new cam has almost exactly the same .050" dur, but longer on adv* b/c it has less steep ramps.
It was a custom Bullet cam, 290/299 adv, 232/242@.050", .600" lift, 112LC There is 58* between adv & .050" dur, vs 40* on the old solid roller.
Should have slightly more overlap (71 vs 55*) and slightly less vac at idle. Target is 12-13"
Running it with tight lash solid rollers, so that should tame 3* duration out of the H.R. profile, and wind up with 67* overlap.

We even managed to get the stainless roller rockers to fit under the stock height valve covers, but it was really tight. It required the short 3/8" high poly locks, and a careful geometry check.

The extra adv duration will definately kill off some of that 550#TQ , oh well, too bad. am more concerned that it doesn't break.
If I went a little too conservative on valve spring, let's call it a safety margin, or "insurance".