Flat tappet failures
Team Owner
Joined: Mar 2002
Posts: 44,644
Likes: 1,827
From: Huntsville AL
I'm assuming you are trying to type "due to rebuilt lifters". I have never in all my years heard of or purchased a "rebuilt lifter", I can also say that when buying a new lifter no one ever asked for a core or charged me a core charge on a lifter.
Team Owner
Joined: Mar 2002
Posts: 44,644
Likes: 1,827
From: Huntsville AL
Yes using GM drawings. I'm sure you're also aware that GM doesn't really make anything in the way of automotive parts but their pretty good at assembly.
Sealed Power also makes (or did) the same lifter using GM drawings at a lower cost point.
Sealed Power also makes (or did) the same lifter using GM drawings at a lower cost point.
Last edited by Mr D.; Aug 13, 2021 at 01:43 PM.
Team Owner
Joined: Mar 2002
Posts: 44,644
Likes: 1,827
From: Huntsville AL
Sealed Power is a good source for parts but for some reason nobody has anything in stock. Not sure if this is a COVID thing or no longer manufactured.
Another part that will make your head hurt is stock OEM rocker arms. Non-Guided OEM rockers are no longer sourced by anybody.
Team Owner
Joined: Mar 2002
Posts: 44,644
Likes: 1,827
From: Huntsville AL
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Team Owner
Joined: Mar 2002
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From: Huntsville AL
If you can find them a lot of the Mercruiser Marine engine parts are the same as the GM engine parts and the water guys tend to be a lot cheaper that the cars guys. One example is some of the drive pulleys and rockers.
Is my vette stock?? HAHA
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use high ZDDP zinc and phosphate oil during break in and for the life of your cam. I run Mobil1 15W50. I get it at Walmart for $23 bucks a gallon and my current big block takes 2 gallons. I have never had any issues with solid flat tappets at all. Used 5 different ones in 5 yeaars just going bigger and bigger.....Did eat a roller solid lifter....that was bad. Dont buy any rebuilt roller lifters either
Pro
Joined: Nov 2017
Posts: 587
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From: Belgium
Wiped cam lobes are caused by the lifter not rotating, and/or not enough convex on the lifter heel, or improper heat treating. In the late 70's through 1984 or so....wiped small block lobes were pretty common. If you had a 305 G-Body car....it was a question of when.
One of our builders here will only use vintage OEM NOS lifters for flat tappet builds......while I think this is extreme, it gives him an extra piece of insurance to break one in. There was some real **** out there for a while...late 2000's to around 2011.....but a few other manufacturers stepped in. The problems are not nearly as bad now but extra attention to detail and precautions are necessary......
Cam failure is more often than not improper break in and/or assembly.
Here is what I do:
1) Make SURE as all lifters are being installed, that you use oil only on them, and that they spin freely in the bores with your fingers. I cannot stress enough how important this is. The lifters need to spin.....if they have any trouble doing that, thy will not last 3 minutes.
2) Use ONLY Moly paste on the cam lobes....liberally. Somebody should sue Comp Cams for including the red bullshit assembly lube in their kits......on a 100 degree day here in Texas, that **** will drip off the cam within three-four hours.......Moly paste is an excellent buffer in acquainting the two surfaces (lifter and lobe), and washes off harmlessly into 5-6 quarts of oil. Put it on the lobes only...NOT on the lifters!
3) Do NOT soak or "pump up" lifters like your buddies Dads Uncle who was a racer says to do......this is WRONG. A lifter full of oil will hold valves open and make the engine hard to start initially.
4) Know where your timing is. I can put an engine on #1, stab the distributor, mark the rotor position, #1 terminal on the cap position and turn slightly counter clockwise to achieve 10-15 degrees of initial timing. Lock it down and that is set! It WILL start in this position.....knowing where #1 TDC is, is the key......blow your thumb or the engine is on #1 already after a fresh build because you lashed the valves correctly and turned it another 90 degrees to #1 when you were finished.
5) On my personal stuff.........I use mechanical pumps exclusively, on my 72' I have a known good spare pump on the shelf that I installed for the first start of my 406. I KNOW this pump works....I KNOW the fuel is getting to the pump from the supply line as it will via gravity.........which leads me to.....
6) ......the carb.....fill the bowls with a squirt bottle if it is a mechanical pump......if the bowls are full, your ignition is hot, and distributor is in time.....it WILL fire......when you hear it, have a digital timing light on the cowl to record RPM and turn the stop to get 2500 RPM.
7) This is something that after 100+ cam break ins that will just **** you off.......MAKE SURE your rad hoses are tight! You know how many break-ins I have witnessed where the guys coolant hose blew off before the stat could open? At least half a dozen over the years.......and they were not my prep, customer or buddy install.....of course you have to shut down and address it. This may or may not be a problem for the cam but why take a chance.....double check your ****.
8) My friends always **** when the engine fires instantly after I prep it......why wouldn't it? All bases are covered. Being off 180 degrees because your buddies Uncles Stepmom had a son who put the T-Chain in Dot to Dot because "that's how the racers do it!" is one of THE most common things I hear.........probably heard it 50 times......
9) I do not recommend consuming alcohol during any portion of the above instructions!!!! Crack the first beer when it starts! You have 25 minutes to stand around and look stupid, plenty of time to suck down 3 or 4!
Jebby
One of our builders here will only use vintage OEM NOS lifters for flat tappet builds......while I think this is extreme, it gives him an extra piece of insurance to break one in. There was some real **** out there for a while...late 2000's to around 2011.....but a few other manufacturers stepped in. The problems are not nearly as bad now but extra attention to detail and precautions are necessary......
Cam failure is more often than not improper break in and/or assembly.
Here is what I do:
1) Make SURE as all lifters are being installed, that you use oil only on them, and that they spin freely in the bores with your fingers. I cannot stress enough how important this is. The lifters need to spin.....if they have any trouble doing that, thy will not last 3 minutes.
2) Use ONLY Moly paste on the cam lobes....liberally. Somebody should sue Comp Cams for including the red bullshit assembly lube in their kits......on a 100 degree day here in Texas, that **** will drip off the cam within three-four hours.......Moly paste is an excellent buffer in acquainting the two surfaces (lifter and lobe), and washes off harmlessly into 5-6 quarts of oil. Put it on the lobes only...NOT on the lifters!
3) Do NOT soak or "pump up" lifters like your buddies Dads Uncle who was a racer says to do......this is WRONG. A lifter full of oil will hold valves open and make the engine hard to start initially.
4) Know where your timing is. I can put an engine on #1, stab the distributor, mark the rotor position, #1 terminal on the cap position and turn slightly counter clockwise to achieve 10-15 degrees of initial timing. Lock it down and that is set! It WILL start in this position.....knowing where #1 TDC is, is the key......blow your thumb or the engine is on #1 already after a fresh build because you lashed the valves correctly and turned it another 90 degrees to #1 when you were finished.
5) On my personal stuff.........I use mechanical pumps exclusively, on my 72' I have a known good spare pump on the shelf that I installed for the first start of my 406. I KNOW this pump works....I KNOW the fuel is getting to the pump from the supply line as it will via gravity.........which leads me to.....
6) ......the carb.....fill the bowls with a squirt bottle if it is a mechanical pump......if the bowls are full, your ignition is hot, and distributor is in time.....it WILL fire......when you hear it, have a digital timing light on the cowl to record RPM and turn the stop to get 2500 RPM.
7) This is something that after 100+ cam break ins that will just **** you off.......MAKE SURE your rad hoses are tight! You know how many break-ins I have witnessed where the guys coolant hose blew off before the stat could open? At least half a dozen over the years.......and they were not my prep, customer or buddy install.....of course you have to shut down and address it. This may or may not be a problem for the cam but why take a chance.....double check your ****.
8) My friends always **** when the engine fires instantly after I prep it......why wouldn't it? All bases are covered. Being off 180 degrees because your buddies Uncles Stepmom had a son who put the T-Chain in Dot to Dot because "that's how the racers do it!" is one of THE most common things I hear.........probably heard it 50 times......
9) I do not recommend consuming alcohol during any portion of the above instructions!!!! Crack the first beer when it starts! You have 25 minutes to stand around and look stupid, plenty of time to suck down 3 or 4!
Jebby
Do you also do this when new rings have been fitted?
Tia
Thread Starter
Le Mans Master
Joined: Oct 2010
Posts: 6,930
Likes: 845
From: melbourne florida
2023 C3 of the Year Finalist - Modified
http://www.youtube.com/watch?v=Cn1nZFYt6Nw&t=1s
7t9.....when paste it in, delete the "s" in https......make it http. Works everytime.
Jebby
7t9.....when paste it in, delete the "s" in https......make it http. Works everytime.
Jebby
Pro
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Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Yes....when new rings are fitted as well......then when the cam is broke in, go run the hell out of it......
I spent a year at World Products back in 04'......they broke in three to four engines a day........30 minute cam run in (most all were Flat Tappet) and three WOT pulls......ship it.
Jebby
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
I gotta ask, Why even use a flat tappet cam? Is it the cost of roller conversion? For originality? Some other reasons?
Given that OEM's left flat tappet decades ago and since the quality has diminished, why take the chance? It seems the penalty for a wiped flat tappet is lots of time, work and money. And the potential is there, maybe even more so than ever before given lack of quality control and oil formulation changes.
Given that OEM's left flat tappet decades ago and since the quality has diminished, why take the chance? It seems the penalty for a wiped flat tappet is lots of time, work and money. And the potential is there, maybe even more so than ever before given lack of quality control and oil formulation changes.
Last edited by REELAV8R; Aug 16, 2021 at 12:17 PM.
Thread Starter
Le Mans Master
Joined: Oct 2010
Posts: 6,930
Likes: 845
From: melbourne florida
2023 C3 of the Year Finalist - Modified
Believe me hydraulic roller cams have issues too.. if someone installs a flat tappet cam correctly it isn't that big a crap shoot. Also on a budget build the diffence between a flat tappet and roller make a stroker crank affordable.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
To me it is strictly dollars and cents. When I built my 406, it was roller cam and GM heads, or Flat Tappet and Dart heads......guess which one I picked.
Roller is a $600+ upgrade, no matter how you slice it......
I told myself down the road I would put a roller in it when the funds are there......but the damn thing runs too good to touch it!
Jebby
Roller is a $600+ upgrade, no matter how you slice it......
I told myself down the road I would put a roller in it when the funds are there......but the damn thing runs too good to touch it!
Jebby
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
I remember when I rebuild my L-48 several of the lifters came out missing the convex surface on the face of the lifter, they were flat or even slightly concave. Lobe failure was a guarantee in the future. This was @ 61,000 miles on the stock cam, lifters and valve springs.
That pretty much solidified my decision to go with roller cam.
That pretty much solidified my decision to go with roller cam.