Author Topic: Question for Stangman.  (Read 2879 times)

0 Members and 1 Guest are viewing this topic.

plovett

  • Guest
Question for Stangman.
« on: January 05, 2019, 02:32:47 PM »
Hey Stangman,

I hope you don't mind another question about your current engine?  The reason I am asking is it seems like a really good combination.  I really like it.  Most internet posters don't have any idea what they're engine really does, you do, and your combo seems very streetable to boot.  Soooo...… my question is about your cam.

You have a Compcams 280TL/288XTX solid flat tappet cam with a 112 LSA installed on a 108 ICL.  Those are fairly aggressive lobes, not crazy, but more aggressive than old school type lobes.

Question 1)  I think you have a center oiler 427 block?  I think a center oiler block does not have pressurized oiling to the lifters unless it has the passage drilled out.  My question is, does your block have the unmodified oiling system?

The reason I am asking is I am curious if that fairly aggressive camshaft works fine that way, without "extra" oiling?

Question 2)  Is there anything special about your camshaft or lifters?  Nitriding?  Tool Steel?   Etc?

Question 3) What valve spring pressures are you running?  And are the retainers just normal steel types?

Thanks so much for any information,

paulie

plovett

  • Guest
Re: Question for Stangman.
« Reply #1 on: February 23, 2019, 12:04:08 AM »
Just a bump. 

paulie

Stangman

  • Hero Member
  • *****
  • Posts: 1683
    • View Profile
Re: Question for Stangman.
« Reply #2 on: February 23, 2019, 01:32:50 AM »
No problem Plovett. The cam I got through Barry but what you are describing seems to be the one.
Yes my motor is a 63 centeroiler that doesn’t have any special oil mods besides what all the big three do to all there engines. The springs that I have on there are the ones that come with the out of the box survival heads and I think they are good for 600 lift and I’m at 620. Although the motor sounds good it really is fairly mild to drive around on the street. The cam had nothing done to it as far as Nitriding, I did the normal break in with Brad Penn
30w as a matter of fact the temp started to rise slowly to about 210 and I shut it off after about 15 minutes and put a fan in front of it for the next 10 to 15 minutes. I’m using the dumbbell lifters everyone says they are heavy but I feel comfortable with them. As a matter of fact I bought an extra set of of Brent when he had those sets for sale to have in case I ever do a cam change. It idles at 850-900 in gear even with the 2x4s. Might raise it a little just for the extra oil splash on the cam. Not sure what you mean by an aggressive lobe the cam is a few sizes smaller than the last one I had in there. I used to have the smallest voodoo drag race solid cam from  Lunati. I hope this helps you.

plovett

  • Guest
Re: Question for Stangman.
« Reply #3 on: February 23, 2019, 02:01:17 AM »
Thanks, Stangman.  That helps.  By aggressive lobes I mean how steep the cam lobe is, how fast it opens and shuts the valves. 

paulie

My427stang

  • Hero Member
  • *****
  • Posts: 3918
    • View Profile
Re: Question for Stangman.
« Reply #4 on: February 23, 2019, 09:42:34 AM »
I just looked at those lobes and have a couple of questions for Stangman too

If you are 280/288@.020, 250/254@.050 112 LSA on 108, at a lash point of .020 you'd have 64 degrees of overlap.  Fun with math....

1 - What are you actually lashing at? Those .020 numbers are valid for a .035 lash at the valve with a 1.76 rocker, but my guess is that you are much tighter, especially with one of the lobes being a tight lash design.  I am asking because tighter lash would essentially make advertised duration and therefor overlap slightly greater

2 - Have you measured idle vacuum?  I ask because although I have a solid plan for the 461CJ cam, I haven't bought it yet and it's similar overlap and although there are a ton of other variables, I'd love to hear idle vacuum numbers for a 64-66 overlap cam with your kind of intake centerline
---------------------------------
Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

Stangman

  • Hero Member
  • *****
  • Posts: 1683
    • View Profile
Re: Question for Stangman.
« Reply #5 on: February 23, 2019, 10:24:05 AM »
I haven’t actually had a vacuum gauge on it. As far as the lash on the card it is 18 intake and 20 exhaust. I haven’t done a hot valve adjust is a long time so I cold adjust 12 intake and 14 exhaust. I assume 6 thousandths growth from the cast block aluminum heads. If anyone has better advice I’m open to it. Now I know it says 112 on a 108 but I seem to remember 107 for some reason. I don’t have a list of all the clearance and all the technical stuff never got that but I seem to remember on one of the sheets I got with some readings on it cam installed at 107. It’s been 3 years now so I would have to go find it. I will be out for the day I will answer you guys later

plovett

  • Guest
Re: Question for Stangman.
« Reply #6 on: February 23, 2019, 11:56:42 AM »
I assume 6 thousandths growth from the cast block aluminum heads.

I use 7 thousandths on my aluminum head iron block engine, but I don't know if that is more accurate than 6.  That is just what I have found from checking lash cold and hot.  I set my cold lash at 10 or 11 thousandths to hit a target of 18 thousandths hot. And that is splitting hairs anyway. 

Stangman

  • Hero Member
  • *****
  • Posts: 1683
    • View Profile
Re: Question for Stangman.
« Reply #7 on: February 23, 2019, 06:17:35 PM »
So My427Stang are you saying because the lobes are aggressive and why would you thing the lash should be at .35, that the duration might be more because of the tighter lash. And why would only one side be a tight lash design. I know a little bit about cams but some of this stuff your saying is new lingo to me unless your just saying something in a different way. I do know tightening up the lash obviously makes the valve open a little sooner but I guess it also closes a little sooner. I don’t understand the whole it should be a 0.35 lash.

My427stang

  • Hero Member
  • *****
  • Posts: 3918
    • View Profile
Re: Question for Stangman.
« Reply #8 on: February 23, 2019, 07:29:40 PM »
So My427Stang are you saying because the lobes are aggressive and why would you thing the lash should be at .35, that the duration might be more because of the tighter lash. And why would only one side be a tight lash design. I know a little bit about cams but some of this stuff your saying is new lingo to me unless your just saying something in a different way. I do know tightening up the lash obviously makes the valve open a little sooner but I guess it also closes a little sooner. I don’t understand the whole it should be a 0.35 lash.

Not saying it should be .035, not at all, but the .020 tappet rise equals about .035 at the valve due to rocker ratio.  So yes if lashed less than that .035 would have the engine see more duration than indicated. Btw tight lash opens sooner and closes later so it gains on both ends
« Last Edit: February 23, 2019, 07:33:12 PM by My427stang »
---------------------------------
Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

Stangman

  • Hero Member
  • *****
  • Posts: 1683
    • View Profile
Re: Question for Stangman.
« Reply #9 on: February 23, 2019, 08:23:35 PM »
Ok right. I get it.

plovett

  • Guest
Re: Question for Stangman.
« Reply #10 on: February 24, 2019, 07:58:20 PM »
Is the lash on cam cards always for lash at the lifter?

My427stang

  • Hero Member
  • *****
  • Posts: 3918
    • View Profile
Re: Question for Stangman.
« Reply #11 on: February 24, 2019, 11:28:10 PM »
Usually it’s at the valve with the specified rocker ratio. However, Bullet does ID theirs at the lifter and in the lobe catalog and tells you to calculate with your rockers. Ironically on the cam card when you get the custom cam they do it for you

The odd thing is that when you compare solids you have to look at adv duration rating. Most are at .020 but some are at lash value, like Erson, which means it may have a different .020 value if comparing to a comp or other cam
---------------------------------
Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch