<< Previous Topic | Next Topic >>Return to Index  

How long will my custom grind cam last???

January 31 2004 at 5:01 PM
No score for this post
Paul Lovett  (Login Paul_Lovett)
Posters
from IP address 12.171.33.91

 
It's in the motor and I'm gonna run it regardless, but I was thinking about it today.

It's a solid flat tappet with fairly aggressive ramps. It has 270/276 degrees @0.020", 240/246 @0.050", and 152/155 @ 0.200". Compared to a typical solid grind like a Compcams Magnum it is quite aggressive.

A Magnum 270 solid has about the same advertised duration, 270 degrees @0.015", but only 224 @0.050", and 135 @0.200". A Magnum 282 has a little more advertised duration, 282 @ 0.015", but only 237 @0.050", and 142 @ 0.200".

To get about the same duration @ 0.200" as my cam, you have to go with a Magnum 294 which has 294 degrees @ 0.015, 248 degrees @ 0.050", and 153 @ 0.200".

What I want to know is, is my cam so aggressive it will have a significantly shorter life than a typical street cam?

The Magnum cams are not very aggressive. For intstance they work fine on the smaller GM 0.842" lifter, so maybe they are not a good comparison.

Also, my motor has Crower "dumbbell" solid lifters with the "Cool face" oil holes that put oil directly on the cam/lifter interface. It also has the hydraulic lifter oil passaged left unplugged. I know, I've read Steve Christ's book, too. "if you run solid lifters in a hydraulic block you'll have low oil pressure and the motor won't last, yada yada yada...."

As far as I can tell it just ain't so. I talked to close to a dozen cam manufacturers and every single one said that it wasn't true. I even managed to get Jim Kuntz on the phone. Real nice guy buy the way, taking the time to talk to some punk like me who wasn't even buying anything from him. He said it's an old wive's tale, too. I ran my 428 like that for 2000 miles and everything in it looked fine on disassembly, except for the cracked cylinder wall.

Anyway, sorry to get off subject. Just wondering what to expect from my new cam. Is the life gonna be significantly shorter than with a cam having less aggressive lobes? Thanks for any and all opinions.

Paul


 
Scoring disabled. You must be logged in to score posts.Respond to this message   
AuthorReply

P
(Premier Login FEfinaticP)
Posters
66.89.75.42

Rubbing and "hammering" on that cam

No score for this post
February 2 2004, 2:40 PM 

The cam will be experiencing a "metal to metal" forced contact every time it rubs across the lifter. There may also be a "hammering" action where the metal cam may actually have a "plastic" tendency.

You can take a big sheet of 1/2" float glass and tilt it up on it's edge. After a while the bottom will measure more than 1/2". I'm not sure about the hammering action on a cam, and whether it's enough to cause any deformity, but here's what I would do.

I would go for the oil product best known for minimal wear, and I'd be sure I didn't get "any" rubbing action out of the cam. From where I sit, Amsoil Series 2000 Racing oil has the absolute BEST anti wear specs in the business. I know of no product at any price that can beat it. Here is a link to the 20W50 I've used in my 928 Porsche. http://www.amsoil.com/products/tro.html

Here is what I'm talking about regarding the wear spec.






They have a 0W30 on the market, but I would also look at the 20W50, especially in a big block where the tolerances might be larger than some of these small imported mills.

regards, P


 
Scoring disabled. You must be logged in to score posts.Respond to this message   

P
(Premier Login FEfinaticP)
Posters
66.89.75.42

While you're at it, may as well get the gear lube too

No score for this post
February 2 2004, 2:58 PM 



Look at the spec for this stuff. It works. It works very well too.

I used it in a 944 transaxle (I have two 944s and one 928, all with transaxles) and it made a fantastic change in the ease of shifting, and it also took away a lot of the noise I was experiencing in the tranny that has 165,000 miles on it. The other transaxle I tried it in needed a rebuild due to a badly worn $400 bearing, and guess what? (A mechanic didn't come in the can, sob!) On that tranny it didn't do me much good. I am, however, now after the rebuild, going to drain the Swepco, and pump in some of this stuff. You'll note the reduce friction and increased milage claim too, which should equate to some speed on the track too.

P

 
Scoring disabled. You must be logged in to score posts.Respond to this message   

P
(Premier Login FEfinaticP)
Posters
66.89.75.42

Transaxle photos

No score for this post
February 2 2004, 3:08 PM 

In case you want to see my transaxle rebuild project, take a look at this link http://members3.boardhost.com/928s4vr/msg/35534.html

A 928 transaxle costs $13,000 new, and around $2500 to $3000 exchange "IF" you don't have major problems with it. You'll note the entire rear suspension has to come out of the car in order to remove the transaxle. Therefore, using the "best lube available" is in order. Same goes for the motor.

Right now I'm running Mobil-1 15W50 in my marine 427s, and as you can see from the prev chart I posted, it doesn't stack up too well against Amsoil. It is, however, far superior to just about anything else, and for the dollar, it's a very good product. I think Red Line makes a fine product too.

Personally, I think Amsoil makes a heck of a product. Porsche, by the way, is now actually "recommending" Mobil-1 as their preferred oil.

P

 
Scoring disabled. You must be logged in to score posts.Respond to this message   
Paul Lovett
(Login Paul_Lovett)
Posters
208.188.193.40

That's a good notion, Kimosabe!

No score for this post
February 2 2004, 6:50 PM 

Seriously, that's a geat idea. I used synthetic in my last motor, but it wasn't Amsoil. A 0W30 would make me a little nervous. A 20W50 would be fine. I wouldn't mind a 10W40 either if Amsoil carries it. I'll check their site.

I'm definitely a believer when it comes to using quality oil. I don't think non-synthetic can do the same job even if the oil change intervals are short and religiously done. Amen, Brother!

How long in your opinion should I wait to let the motor break in before switching to Amsoil? My cam is already broken in as I installed it in my last motor right before I took it apart. The rings and bearings in the new motor are all fresh, though.

Paul

 
Scoring disabled. You must be logged in to score posts.Respond to this message   

P
(Premier Login FEfinaticP)
Posters
66.89.75.42

Your break in period.....

No score for this post
February 3 2004, 8:14 AM 

.....you're going to have to get comfy with the break-in of the rings, etc. based on how the car runs and how it fares with a compression leakdown, etc. One thing about the synthetic products, you get what you pay for, and the film strength of an engineered space-age product sure beats what they pump out of the dirt.

I made the switch to synthetic in my twin 427 marine setup a few years ago and the motors seem to love it. I don't run them particularly hard, but I appreciate the cold flow characteristics and additional protection I get on start-up, and I also REALLY feel better about the added protection I have in the event I do want to show the boys how those big dogs can bark. There's nothing like seeing six of your best friends on the aft deck (aft deck is an open 15' x 12' on this express cruiser) all holding a beer, some with cigars, all grinning, looking back at all that white water those big motors are churning with 24" props and 2.5:1 gear reduction, and hearing the howl from those big copper pipes. When the time comes to do the deed, I know I have one of the best synthetic oils on the market (Mobil-1 15W50 in this instance) in the motors, and I just put the hammer down and run em at 4,000 rpm for a while. On a marine application in a 20,000 pound cruiser, that's pretty awesome because I can approach speeds of 32 to 34-mph even with six guys on board. I may switch to Amsoil next season, as I do think they make a better product.

regards, P



 
Scoring disabled. You must be logged in to score posts.Respond to this message   

Pippin
(Login TorinoBP88)
Posters
209.204.172.254

Have you already started the engine?

No score for this post
February 4 2004, 12:56 PM 

Have you already started the engine? I have herd that the first few starts on a high lift cam are the MOST critical to never let the engine below 2500 PRM and not above 4000 RPM to get a nice work hardened surface formed on the lobes and lifters.

Pippin
User Name: TorinoBP88
1868 Torino GT Fstbk

 
Scoring disabled. You must be logged in to score posts.Respond to this message   
Paul Lovett
(Login Paul_Lovett)
Posters
208.188.212.85

The motor has not been started yet, but the cam is already...

No score for this post
February 4 2004, 7:38 PM 

broken in. I put the cam in my last motor, broke it in, and ran maybe a couple hundred miles. By that time I had figured out something was wrong with my motor and it was going to have to come apart. It had a cracked cylinder. Since then I have got a new block, but I am reusing my cam and lifters.

What I was worrying about with this cam is not the break in, but it wearing out fast because the cam lobes are pretty steep and I have a fair amount of spring pressure for a flat tappet cam.

Paul

 
Scoring disabled. You must be logged in to score posts.Respond to this message   

Pippin
(Login TorinoBP88)
Posters
209.204.172.254

Well there is the basics of good oil

No score for this post
February 9 2004, 9:00 AM 

I do not know where to get Amsoil in my area, but i have read it is the BOMB of good oil, and that is would be best for keeping your engine alive. Short of that, I know that Mobile 1 and other such synthetics are really great! I like 15/50. But keep the oil clean or you are defeting the purpose. I think I saw some one talking about oils elsewhere on the Forum.

Also, do not idle in traffic if you can help it. Extended slow speed (like over rev)is hard on the cam.

Furthermore, make sure you are using a GOOD oil filter that both filters down to SMALL partilcles as well as FILTERS ALL of the oil at engine start up. Many engines bypass the filter either when it is too dirty or when the oil is thick and cold. When you start your engine, the oil pump takes the dirtiest oil, may bypass the filter and send dirty oil to the engine.

What about a stainless steel cartrage filter that is cleanable, that would both allow you to look at the particles in the engine, and they usually do not bypass. I know they are pricey, but really nice.

One more thing do you have roller or roller tip rockers, or stock ones?




Pippin
User Name: TorinoBP88
1868 Torino GT Fstbk

 
Scoring disabled. You must be logged in to score posts.Respond to this message   
Paul Lovett
(Login Paul_Lovett)
Posters
208.188.193.221

Too true. Higher idle speed can be a good thing.

No score for this post
February 12 2004, 4:40 PM 

I'll probably set it a little a higher along with using good synthetic oil. Maybe 900-1000 rpm.

Probably use a Mobil 1 filter. My machinist warned me away from Fram's in particular.

I do have roller rockers. They are Harland Sharp's. They have the roller tip, but not needle bearings on the shaft. They just have a bronze bushing on the shaft. They have worked fine so far.

Thanks for the advice,

Paul

 
Scoring disabled. You must be logged in to score posts.Respond to this message   
 
  << Previous Topic | Next Topic >>Return to Index  
Find more forums on CarsCreate your own forum at Network54
 Copyright © 1999-2018 Network54. All rights reserved.   Terms of Use   Privacy Statement