Flat tappet cam install considered a risk?

[Jerryl]

The misalignment cant be easily corrected. If you take the precautions you will be good. Weak springs, EOS, and keep the rpm over 2k when breaking in.

Agree.
212/212 Flat tappet, 6K miles, no issues

Just curious, but how can the lifter bore be easily corrected? Also is the idea behind using weak springs to save the cam? Wouldn’t lifter bounce be a concern on a new cam and cause a wiped lobe?

See cam thread in sig

After struggling and thinking about this for a year as well , I came to some conclusions. While I am far from an expert, this is what I did:
1. Make sure you assemble correctly. This means getting the cam position right. Belief it or not, you CAN vary the lobe positions by 0.030 if you are not careful.
2. Use the correct assembly lube.
3. Bench bleed the lifters!
4. Make SURE your preload on ALL valves is correct. Verify geometry when you assemble as well and use valve springs with the correct (Low) seat pressure.
5. HAND Prime, prime, prime .......... prime again till you see oil out of ALL pushrods. (Prime till the cows come home :tongue: )
6. Make sure your engine starts right away .... first crank-up. IOW, check, and re-check everything!!
7. (I) Put 1/2 bottle of EOS in the filter before priming, the other halve in the engine with straight 30W oil.
8. Keep RPM at 2000 -2400 - 30 minutes (What I did)
9. Drain the oil, cut the filter, inspect, inspect, inspect.
10. Run EOS with any oil afterwards.

I would never use flat tappet cam over roller , I wiped out two of them killing two motors and they were 206/206 comp cam like yours , properly broken - in I should add , to spend the extra money for roller set up to make more power is not the right reason , flat cams will can make as much power ,BUT for piece of mind , cooler running motor , oil selection without looking for specific additives to stop lobes going south ETC ,ETC ... I would suggest you to go with roller !!!! tha's my 2 cents .

If I had the budget, I would have installed a full roller as well. Hands down, no questions asked!

While there are horrific and expensive nightmares posted about flat tappet cams, I now realize there are just as many (if not more) success stories. Most people who do plan on racing the motor, run flat tappet cams, so it is fair to say that the "majority" of average TR owners run a flat tappet cam.
The decision on a roller for the majority comes down to "Your budget".
JMHO

 

[84gnguy]

I have not had any recent or previous problems with hydraulic flat tappet cams from Crane (Summit brand) Lunati and Ultradyne (now Bullit)

EOS and straight 30 for the 20 minute break in always and no excessive spring pressures

 

[bodycount]

Agree.
212/212 Flat tappet, 6K miles, no issues




See cam thread in sig

After struggling and thinking about this for a year as well , I came to some conclusions. While I am far from an expert, this is what I did:
1. Make sure you assemble correctly. This means getting the cam position right. Belief it or not, you CAN vary the lobe positions by 0.030 if you are not careful.
2. Use the correct assembly lube.
3. Bench bleed the lifters!
4. Make SURE your preload on ALL valves is correct. Verify geometry when you assemble as well and use valve springs with the correct (Low) seat pressure.
5. HAND Prime, prime, prime .......... prime again till you see oil out of ALL pushrods. (Prime till the cows come home :tongue: )
6. Make sure your engine starts right away .... first crank-up. IOW, check, and re-check everything!!
7. (I) Put 1/2 bottle of EOS in the filter before priming, the other halve in the engine with straight 30W oil.
8. Keep RPM at 2000 -2400 - 30 minutes (What I did)
9. Drain the oil, cut the filter, inspect, inspect, inspect.
10. Run EOS with any oil afterwards.




If I had the budget, I would have installed a full roller as well. Hands down, no questions asked!

While there are horrific and expensive nightmares posted about flat tappet cams, I now realize there are just as many (if not more) success stories. Most people who do plan on racing the motor, run flat tappet cams, so it is fair to say that the "majority" of average TR owners run a flat tappet cam.
The decision on a roller for the majority comes down to "Your budget".
JMHO

Hmm, good read but no amount of shims will change the lifter bore.

 

[BLACKHAWK38]

THAT'S a big 10-4 on cryogenic treatment !!

Cryogenic treatment would be the way to go with a flat tappet cam.

I had REED CAMS do a 188°/188° .403 lift cam with Cryo treatment, they send out the cam BLANK to get treated and then cut the cam after it has been treated, I also had the valve springs chilled to

THE cam is in my turbo Riviera Convertible which is a heavier car than a GN, that is why they recomended the shorter duration profile for tons of off idle torque! , With a fresh 109N/A block rebuild, I chose TRW turbo pistons(.030 over>235 cu. in., rollmaster timing chain, TA33C turbocharger, ported champion irons, 1.65 roller tockers, and with one steel shim Head gasket, ARP head studs, new GM front cover with oil pump passages enlarged.

With a 2400 stall Converter the turbo spools fast and is fun to drive comming off a stop with almost instant Tons of torque !

Regards, Blackhawk 38

 

[Jerryl]

Hmm, good read but no amount of shims will change the lifter bore.

This is what I noticed.
Lifter bore postion is only a function of cam location, correct?
IN other words, if you pull the cam out, the lifter bore location changes in relation to the lobe.

Now, if you think about it, the cam bottoms out against the cam plug.
How accurate are these manufactured and "how far in" is that installed? See, you CAN in fact affect the relative lifter bore location.

 

[bison]

Just curious, but how can the lifter bore be easily corrected? Also is the idea behind using weak springs to save the cam? Wouldnt lifter bounce be a concern on a new cam and cause a wiped lobe?

I said it cant be easily corrected. You arent revving the engine to 5000+rpm during break in. 2000-3000 rpm is no problem and i have never experienced any bounce or cam failure related to break in when using weaker springs and EOS. Anyone who does not want to install weaker springs is just adding in one more risk factor to shorten cam life and cause an expensive rebuild. In this case you should go roller. I can easily change all the springs in 1.5 hrs. Not much time when you consider the BS and expense you would go through if you wiped lobe(s). I prefer rollers myself. Much less hassle once set up correctly but require stiffer springs which dont last as long either.

 

[Clark Porter]

If you're using dual valve springs, break in the cam using the outer springs only, if you don't happen to have a set of worn springs. Use a big fan to keep the engine temp. down.

 

[bison]

Use a big fan to keep the engine temp. down.

 

[mazdatech78]

I lost a comp 206-212 in 8 miles. It was broken in properly and the cam still ate #3e lifter. Its a crap shoot lately with some on the inferior parts that are on the market, i.e. Chinese lifters and what not. I wouldnt chance it, a little more now saves you a whole lot later. Im running comp roller and havent run into any issues yet. I just wish I spent the money the first time instead of taking out a perfectly good motor.

James

 

[Drewster]

Mazdatech78
did you use EOS or any additive when you did your break in?
Andrew

 

[mazdatech78]

No EOS, used 30wt dino oil and weak springs.

 

[SouthernCal GN]

No EOS, used 30wt dino oil and weak springs.

Oil today doesn't have the zinc content (anti-scuff/anti-wear compounds). Adding EOS or breaking in with diesel oils (Rotella, etc) adds that protection of the zinc into the mix.

 

[BlackBandit]

My experiance

New engine. Dino with EOS. 30 minute break-in varied rpms 2-3k, imediately changed the oil and inspected filter. More dino, more EOS. couple of low boost pulls (to seat rings) 50 miles, change oil/inspectfilter. More dino, more EOS. 100 miles later change oil/inspect filter. More dino, more Eos. Anyway, same after 500 more miles, same after 1000 more miles. Went to 2000 mile oil changes feeling very confident that I had dodged the cam bullet. Hadn't even thought about it for quite some time when the engine hit 8-9k miles and wiped a cam lobe. So now I'm building a new engine. Metal from the lobe wiped the mains, rods, and cam bearings. Also ate the crank up pretty good. Is a flat tappet worth the risk? Not for me. If I were to ever put one in another one of these engines I would probably never stop worrying about it. HTH james

Edit: FWIW I did not have a cryo'd cam. If I was going to run another flat tappet I'd definately try having it cryo'd.

 

[mazdatech78]

I dont think even if I ran EOS with the break in it would have helped. From what ive been told some 109 blocks have worse #3e lifter bore issues than others. That would explain why some guys have problems with flat-tappets and some swear by them and have no problems. Its all about what kind of risk you are willing to take. If you're a risk taker go for it, just dont be suprised if your rebuilding your engine in the near future.

James

 

[toofastforyou]

After indeed wiping some cam lobes in my GN, I decided to have a roller cam installed to end this problem once and for all...

Claude

 

[Drewster]

BlackBandit ....did you continue to use EOS or Rotella T or any other suplement with Zinc with ALL of your oil changes before the lobe wiped?

Anyone hear of a cryo'd cam wiping?
A

 

[Jeasen]

Diesel Oil

The zinc will also be removed form the diesel oil soon so don't think this will be your savior in the future. A flat tappet cam is old technology and the government of the USA has decided that there is no need to support old technology. Think about it, they would like to have your old car off the roads of the good old USA. If replacing a cam shaft or when doing a rebuild update to new technology, a roller cam.

 

[conn84gn]

Diesel oil will have Zinc they are only lowering it slightly.
The new Rotella has a different color container, White I believe
Many people don't like STP but it also has Zinc
Cheaper than EOS
I have 5000 miles on the cam

 

[Adrian87]

Do it once, do it right and get the roller. I wiped 2 cams in less than 10k miles, no drag racing, just street driving. Trust me. Save up a little more and get the roller.

 

[87GN_70GS]

the cam bottoms out against the cam plug.

Err...no...Actually it is the thrust bearing surface on the backside of the front of the cam that rides on the thrust bearing surface on the front of the block.

Valvoline Synth Oil Treatment (VSOT) and CD-2 SLOB (Street Legal Oil Booster) have zinc in them at .17% and .48% respectively. The best part is I bought SLOB at Big Lots for $1.