Topic: 1978 Trans Am - 400/W72 rebuild question.

[Daniel78ta]

Hey chuckles...
Thanks for the link!  Looks like they tons of good stuff.... 
Lots of rods to choose from too. 

I appreciate the link.. 
Dan

[Daniel78ta]

Geno…
wanna school me on Hydraulic Flat Tappet cams VS. Hydraulic Roller cams.. and also flat tappet lifters vs. roller lifters?  Are the Rollers really worth the price difference?  From what i have been learning -  using a Roller Lifter & Roller Cam that the "break-in" is not as involved or serious!!  Less chance of something bad happening with the rollers upon break-in.. Plus, less friction which is always a plus!!

Its a big price $$$ difference between the two styles for sure!   But, is it really worth it for a performance street build - thats not driven very often?

Or should i just stick with the original plan using The Flat Tappet style?

thanks geno.. - your 2¢ is appreciated!
dan

[72blackbird]

Geno…
wanna school me on Hydraulic Flat Tappet cams VS. Hydraulic Roller cams.. and also flat tappet lifters vs. roller lifters?  Are the Rollers really worth the price difference?  From what i have been learning -  using a Roller Lifter & Roller Cam that the "break-in" is not as involved or serious!!  Less chance of something bad happening with the rollers upon break-in.. Plus, less friction which is always a plus!!

Its a big price $$$ difference between the two styles for sure!   But, is it really worth it for a performance street build - thats not driven very often?

Or should i just stick with the original plan using The Flat Tappet style?

thanks geno.. - your 2¢ is appreciated!
dan

Hi Dan,
A roller cam allows more the valves to open sooner and close later for a given lift and duration than a flat tappet cam, thus it fills the cylinders better and creates more power. The lobes of a roller cam are much steeper than the ramps of a flat tappet cam- the design of a roller lifter allows it to travel over the steeper lobe, something the crowned surface of a regular lifter cannot do. Hydraulic flat tappet (HFT) lifters also rely on the spin that is created by their crowned surface as the cam rotates- it's this spin, as well as chemical additives and metal treatment to the cam lobes that prevent the HFT lifter from eating into the surface of an HFT cam lobe during operation. Roller lifters have a roller at the end that contacts the lifter, therefore they don't need to spin and are prevented from doing so with retainer bars that tie pairs of roller lifters together. The retainers also have pivots at their ends to allow each roller lifter to travel up or down independently of the other lifter it's paired to.

Unlike the break-in period that is required for all HFT cams, roller cams can be installed, adjusted, and ran immediately- no break-in procedure is required. Hydraulic or solid roller cams also don't require constant application of anti-wear additives like zddp to keep the lifters from eating into the cam lobes- the lobes of a roller cam are hardened. The downside is of course the cost of a SR or HR cam over a HFT cam- $900-1200 for the specific roller cam, roller lifters, moly pushrods, and stiffer valve springs needed, vs. $300-400 for the HFT set up. The decision to run a roller cam over a HFT cam is yours- budget vs. a more efficient and more powerful cam is often the deciding factor. Many cannot afford or don't want to spend more for the better cam, so they go with the HFT. But all modern cam-in-block engines use roller cams, so the technology is proven.

Geno

[Daniel78ta]

Thanks Geno for the rundown on the Cams..
Its pretty clear that the Roller cam is a better choice in the long run!  More efficient and able to squeeze a little more power from the motor!

Does roller tip rockers work with a roller cam?  Or does a roller cam need the specific roller rockers? 

Also, would roller rockers fit under the stock W72 valve covers? 

thanks Geno.
dan

[72blackbird]

Hi Dan,
Roller cams can squeeze alot more power out of an engine, but like anything else the more aggressive the cam, the less vacuum you'll have at idle and the rougher your idle will be. Pick a roller cam that's works for your SCR, operating range, and desired powerband. The main advantage of milder roller cams is ease of maintenance- no zddp needs to be added to the oil and chance of a flattened cam lobe is almost eliminated.

Roller tip rockers work with a roller cam, but most builders who use a roller cam opt for the full roller rocker with a needle bearing fulcrum. Either will fit under stock valve covers if you use .25" thick valve cover gaskets.

Geno

[Daniel78ta]

Hey Geno..
Thank you for your help.. You have cleared up some questions I had.  The idea of roller cams is much more clear.
I'm going to look around at the different manufactures and what they have to offer..! 

Or.... You know that Crower 60241 I was thinking about... If I called Crower and asked for the 60241 as a roller cam, would I be able to get it?  Or would that be considered a custom grind? 

Now that I know the roller rockers will fit under my stock W72 covers - I just may consider a roller in my build!  Decisions, decisions, decisions - but, that's part of the fun right?!!! 

Thanks Geno..
Dan

[72blackbird]

Dan,
Crower does custom grinds, but to be honest I would get a bit more aggressive cam than a 60241 if I'm going to spend $400 for a cam. Ask your builder to recommend a roller cam he thinks will suit your needs.

Geno

[Daniel78ta]

Hi Geno..
You know for what I'm looking to achieve in my build - I'm going to stick with the flat tappet cam and my original plan..

But, i do appreciate your advise and schooling on the roller cams!  The big part of the Rollers that intrigues me is not having a real break in period!! Then on the other hand - if the motor is built correctly there should be no problems with the Flat Tappet! "I worry too much"

Got my Envoy paid off today… So I'm going to start buying parts next month.. I will probably contact you for size and or manufacture on some parts.

***thank you Geno***
it's good having guys like you on this forum!!
-dan

****By the way - got any photos of your Trans Am on here? id like to see it!! ****

[72blackbird]

Hi Dan,
A roller cam is nice, but I think an HFT cam will do the job for you just fine. As long as you add zddp to your oil, soak your lifters in oil right side up, coat all of the cam lobes with the moly lube supplied with the cam, properly set your lifter preload, and run your engine at 2000-2500 for 15-20 mins. at first fire your cam should break in okay. If your engine doesn't fire when you first turn the ignition on, adjust your distributor so it does.

Another important detail often overlooked by many is the valley pan- over the years it fills with debris, and will make a cam fail if it isn't thoroughly cleaned. Washing the valley pan in a parts washer isn't enough- I split them, grind them clean, repaint them inside and out, and them re-spot weld them.

Geno


My 72 Esprit is no TA, but she isn't stock either- lol

[Daniel78ta]

Geno…
your black bird looks mean!!!  I really like the front end on the old firebirds and old trans ams.! 
Always thought that front end really makes the cars look like some firebird/gto hybrid.  Sharp looking car Geno!

You know, i thought about just replacing that valley pan when the motor gets re-built!  Rockys book suggested an aftermarket!  But, taking it apart would work also - and i can get my hands dirty!!.. 

Well, here in a few weeks i can start purchasing the parts for my future rebuild.!  One or two parts here and there is the plan.  Id really like to have the motor done sometime this coming summer but, i might have to be patient cause its going to cost a lot.. Once i have all the parts (cam, pistons etc) purchased - then paying the 2 grand for the machine work won't be such a stretch..


**Got a recommendation for a double roller timing chain - that comes with the chain? Comp Cams?? Sealed Power??**

thanks
dan

[Daniel78ta]

Geno..
I was looking at this Comp Cams double chain....  Would this be a good one?

http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=7112&Category_Code=PontTiming

Thanks
Dan

[72blackbird]

Geno..
I was looking at this Comp Cams double chain....  Would this be a good one?

http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=7112&Category_Code=PontTiming

Thanks
Dan

Dan,
That timing chain is a bit overkill. A regular double roller timing chain is all you need- Check Summit for this roller timing chain.

http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=3112&Category_Code=PontTiming

Geno

[Daniel78ta]

Hi Geno..
Going to order up that timing chain you listed..!  thank you..

You know im really leaning towards the Crower 60241 cam.  But, i have not been able to find a sound clips or a video where a guy has used one.. I have found videos of the Comp EX262 in a 77 trans am.. I really like the lope and rumble this cam has at idle.. Will that Crower 60241 have some of that lope/rumble at idle?  Also will i be able to use the stock stall.. The auto, turbo 350 has a stock stall of 1800 in it.. 

Side by side number comparisons of the Crower 60241 & the Comp EX262 look really close.. Does that mean they will sound similar?

I have decided i want a little more lope and rumble than stock - but without getting carried away!!  

thanks Geno..
dan

[72blackbird]

The Comp XE 262H is a 110 LSA cam- that's what gives it a lopey idle. The Crower is a little smoother at idle, but has a wider power band- it's a 112 LSA cam. You can't go wrong with either choice on a low compression 400.

Geno

[Daniel78ta]

Hey Geno,
after much research and bugging the s#^* out of you..    
I have made a detailed parts list for my rebuild.  Part, Manufacturer, Price, Etc..  I have attached a PDF of the list of parts and machine work I'm planning on.. If you get a moment can you take a quick look at it and see if anything jumps out or is wrong?  Or if i have selected a sub-par part..

making a list like this is really helpful.. shows me just how much its going to cost etc..  She might just be pushing 350hp when done.!

thanks,
dan