Stock 340 Rebuild - Roller Cam?

[Yellow71Cuda]

Machine shop recommends a roller cam and lifters for my stock 340 rebuild.  Thoughts? 

[Cudakiller70]

Yes good advice! Oil type not as critical for wear. I recently bought a flat tappet cam and after reading about lobe wear and oil reformulation wish I went roller.
Just my  others here know way more about this than I.

[1 Wild R/T]

If you were building a 360 or a 408 absolutely grab a roller block & proceed..  Building a 340, there are many sound reasons to say yes but there are also reasons to think about it... 

Distributor gear compatibility Bronze? Composite? Expected lifespan?

Tie-bar type rollers don't like to idle or you get into roller shaft wear issues

Expensive

[Yellow71Cuda]

 

Thank you!  I'll have to ask the machine shop more questions.   

[1 Wild R/T]

I suggest you do some research before talking to them so you have a through understanding of the issues....

Oh, small blocks sometimes have issues with losing oil pressure because some rollers open a huge internal oil leak....   http://www.hotrod.com/articles/mopp-0908-small-block-roller-camshaft-install/

OK, after some reading, the oil pressure issue mostly relates to Comp roller lifters..

It looks like Morels get the most thumbs up...

Ok, looks like Lunati cams have a cast distributor gear so that problem has a work around...

So now you need to read about roller lifters & idling....

Ok, I did a search... Solid roller no extended idling....  IE five minutes is way to long...  Hydraulic roller, no problem....

So it comes down to price... But lose one flat tappet cam & suddenly the roller was cheap... 

[Yellow71Cuda]

I suggest you do some research before talking to them so you have a through understanding of the issues....

Oh, small blocks sometimes have issues with losing oil pressure because some rollers open a huge internal oil leak....   http://www.hotrod.com/articles/mopp-0908-small-block-roller-camshaft-install/

OK, after some reading, the oil pressure issue mostly relates to Comp roller lifters..

It looks like Morels get the most thumbs up...

Ok, looks like Lunati cams have a cast distributor gear so that problem has a work around...

So now you need to read about roller lifters & idling....

Ok, I did a search... Solid roller no extended idling....  IE five minutes is way to long...  Hydraulic roller, no problem....

So it comes down to price... But lose one flat tappet cam & suddenly the roller was cheap...

Thank You! 

[HP_Cuda]

Roller valve trains are good for longevity and high rpm use. Of course I'm talking about quality components.

Are you planning on spinning this motor up? Are you building something that would take advantage of that? Everything is a tradeoff.

Look at it this way, Cody just built a 340 recently and took it to a dyno shop and made some pretty decent HP with fairly stock components. Maybe drop Cody a line and ask him some questions cause you may be in alignment with him on engine build specifics.

[Cuda Cody]

I just build them to stock.  Really, a bit less then stock as I lower the compression to about 9.3 to 1 so they start easy and run good on today's crappy fuels.... and mine have a flat tappet cams.  Not saying it's the best way, just they way I have done it and it's worked good for me.

I get about 350 HP on a stock 340 six pack build.  Originally they were rated at 290.  The thing I really like about the engines I build is they START right up and run awesome!


[video]https://forum.e-bodies.org/gallerypics/videos/1_09_03_17_1_25_52.mp4[/video]

[Cuda Cody]

Here's how they start right up.  I use Mr. Six Pack cams too.

[video]https://forum.e-bodies.org/gallerypics/videos/1_01_04_17_12_12_06.mp4[/video]

[Chryco Psycho]

If you were building a 360 or a 408 absolutely grab a roller block & proceed..  Building a 340, there are many sound reasons to say yes but there are also reasons to think about it... 

Distributor gear compatibility Bronze? Composite? Expected lifespan?

Tie-bar type rollers don't like to idle or you get into roller shaft wear issues

Expensive

+ & - to everything , hyd rollers have a slight advantage in power but limited high HP as the lifter will collapse under heavy loads , solid rollers are amazing but you need special lifters with a small pin hole on the bottom to provide adequate oil to the roller on the street & any roller i expensive , Flat tappet generally are better but you need the right oil or the cam will fail  solid falt tappets can get close to roller performance but still require adustble rockers& heavy pushrods  , lots to consider !

[RUNCHARGER]

Hmm: If only the aftermarket roller stuff was good for 200,000 miles like OEM roller stuff is. I hate all the precautions that need to be taken with flat tappet cams but the stuff I build really has to be a roller setup these days. I think for a stock 340 (or even 440 for that matter) I would go to a hydraulic flat tappet and dot all the I`s on installation, break-in and maintenance.

[1 Wild R/T]

In a totally stock motor a flat tappet should be fine, just make sure to use the proper oil, break in procedures, set the engine up so it fires immediately you don't want to have to crank on it for 15-20 seconds or more as is so common with guys who haven't done allot engine work.... I've seen enough Gas Monkey/Overhaulin clowns who don't have a clue grind away at the starter... Not how should be done..... You want things right, it should light immediately... Then take the RPM's up to 2500 immediately , Check the timing with a dial back light, it should be around 34-36 degrees.... Let it run above 2000 RPM's for 30 minutes.... Don't let it idle, if it gets hot, springs a leak, whatever get off the throttle & shut it down... No idling... Once you fix your issue fire it up & right back to 2000+ RPM's... After 30 minutes let it idle.. Take it for a drive... Smoke the tires...Run it wide open some to really seat the rings.. Just try to keep the RPM's under 5000 for the first hundred miles or so....

[Shane Kelley]

I have built many motors. 340 happens to be one of my all time favorites. If its a street car I recommend a good hydraulic flat tappet cam. Crower makes some nice cam saver lifters that have a little groove that oils the cam. The factory relied on splash off the crank shaft. Be sure and run a good quality high Zinc oil. I run Lucas Hot Rod oil with high Zinc. I get it from Summit Racing. I also prefer to run adjustable rockers so I can adjust the valves perfectly. Sometimes cut heads or block can cause issues with the non adjustable ones.

For cam break in. I know everyone says you must run engine above 2000 rpm for 30 minutes. There is another way. Sand your lifter bottoms with 1000 grit sand paper until all the machine marks are gone. Then use a polishing rouge like you would for stainless steel  trim with a buff wheel. Polish the lifter bottoms until they look like chrome. Use a good cam assembly lube. I have probably built a dozen motors using  this method. To date I have yet to have any cam failures. I read this trick in a old GM racer manual. 

[jimynick]

I have built many motors. 340 happens to be one of my all time favorites. If its a street car I recommend a good hydraulic flat tappet cam. Crower makes some nice cam saver lifters that have a little groove that oils the cam. The factory relied on splash off the crank shaft. Be sure and run a good quality high Zinc oil. I run Lucas Hot Rod oil with high Zinc. I get it from Summit Racing. I also prefer to run adjustable rockers so I can adjust the valves perfectly. Sometimes cut heads or block can cause issues with the non adjustable ones.

For cam break in. I know everyone says you must run engine above 2000 rpm for 30 minutes. There is another way. Sand your lifter bottoms with 1000 grit sand paper until all the machine marks are gone. Then use a polishing rouge like you would for stainless steel  trim with a buff wheel. Polish the lifter bottoms until they look like chrome. Use a good cam assembly lube. I have probably built a dozen motors using  this method. To date I have yet to have any cam failures. I read this trick in a old GM racer manual. 

THANK YOU! I've been having second thoughts about the flat tappet cam and lifters I'd bought and this sounds quite do-able and something I'll do on my own build. 

[Chryco Psycho]

That is a cool tip , i have never tried doing that but I can see why it would work ,Thanks