130lbs cranking pressure ????

Posted By: Wedgeman

130lbs cranking pressure ???? - 06/19/11 02:15 PM

HI guys...
Just finished bolting on my new set up....

Indy 360-1 heads milled to 55 cc
4 in stroker crank
10.8 cr

installes a Lunati mec cam , int valve cl at 55* ABDC
259/267* dur @ .050
Only have 130 cranking pressure , wallace says I should have 190......

130 even on all cylinder. I haven't started the engine yet,

Does it make any sense at all ????

Dan

Posted By: Crizila

Re: 130lbs cranking pressure ???? - 06/19/11 02:33 PM

Well, at least you got the same problem in every hole. It's a pretty hefty duration & late intake valve closing, but you are still low IMO. What was the starter cranking speed? Should have been around 500rpm. Did you miscalculated the CR? How far are the pistons down in the hole? Dished pistons? Valve lash set correctly? You might want to run it in a bit and then recheck it. Don't know why you would want to check cranking compression on an engine with no run-in time on it?? - even though I don't think it will come up 60 psi.

Posted By: Wedgeman

Re: 130lbs cranking pressure ???? - 06/19/11 02:41 PM

The base of the engine and rotating assy are the same as last yesr...

I double checked the calculations with the new cam specs and results should be there..

I only changed the cam and heads in the equation

Last year was a 250/250* dur cam with valve closing 71* ABDC

Posted By: Dodgem

Re: 130lbs cranking pressure ???? - 06/19/11 02:46 PM

It's new pistons and rings and never been run. valve lash is correct? You degreed the cam to 105.5??

Posted By: Wedgeman

Re: 130lbs cranking pressure ???? - 06/19/11 02:52 PM

same piston and ring as last fall....

Posted By: MR_P_BODY

Re: 130lbs cranking pressure ???? - 06/19/11 02:58 PM

Quote:

same piston and ring as last fall....

What did you degree the cam in at... sounds like its retarted

Posted By: Wedgeman

Re: 130lbs cranking pressure ???? - 06/19/11 03:04 PM

I just aligned the dots on the timing gear....

Could I loose 60 lbs if htey were misaligned ?

Dan

Posted By: DemonDust

Re: 130lbs cranking pressure ???? - 06/19/11 03:23 PM

Quote:

I just aligned the dots on the timing gear....

Could I loose 60 lbs if htey were misaligned ?

Dan

Never go by the dots unless you are installing a stock cam, even then you could be off a bit. I treat them as a reference point only. I got money that your cam is way off. It needs to be degreed...

All you need is a degree wheel, coat hanger/tig rod, and a $20 gauge from harbor freight and you can get it done

Posted By: MR_P_BODY

Re: 130lbs cranking pressure ???? - 06/19/11 03:34 PM

Quote:

I just aligned the dots on the timing gear....

Could I loose 60 lbs if htey were misaligned ?

Dan

Off hand I would say that is your problem... needs
to be degreed in

Posted By: Leon441

Re: 130lbs cranking pressure ???? - 06/19/11 03:38 PM

Your cam is retarded.

Once you degree it you will probably find it needs to be advance 4-6 degrees.

Leon

Posted By: Bob_Coomer

Re: 130lbs cranking pressure ???? - 06/19/11 05:01 PM

You cant always go by those calculators. What kind of formula are they using to figure this? There is diff types of compression for sure. Even if you advance the cam its not going to be 190 PSI.. It might gain 10 lbs...maybe..
Your over thinking it.. just run it see how it goes.

Posted By: HotRodDave

Re: 130lbs cranking pressure ???? - 06/19/11 05:04 PM

I still don't think you are ever gonna get 190 PSI with that cam and that compression, mabey get close if you advance it a bunch but 10.5 and a cam that big ain't gonna do 190. I do agree it is low but not 60 lbs low. Should always degree it in and you need to re check piston to valve clearance AFTER degreeing it correctly.

Posted By: Oyvind Mopar

Re: 130lbs cranking pressure ???? - 06/19/11 05:53 PM

Did you remember to open the throttle when testing!??
My

Posted By: BSB67

Re: 130lbs cranking pressure ???? - 06/19/11 06:32 PM

What was last years cranking compression?

Did you actually measure the intake closing point?

Is that the closing point at 0.050" or actual seat closing?

Cranking cyl pressure won't build until the valve actually closes.

Did you do the test with the engine hot? Lash will loosen (alum.head) closing the intake sooner raising the pressure. Thats probably only 5 psi.

Posted By: Wedgeman

Re: 130lbs cranking pressure ???? - 06/19/11 06:54 PM

Huge mistake !

Cam gear was off one tooth ! got pressure back to 160, lunati suggests .014 lash........

setting it at .017 gives me 10 more psi

I wonder why they are so small compared to a comp cam where lash is in the .020 neighboorhood...

Dan

Posted By: Cab_Burge

Re: 130lbs cranking pressure ???? - 06/20/11 01:34 AM

Quote:

Huge mistake !

Cam gear was off one tooth ! got pressure back to 160, lunati suggests .014 lash........

setting it at .017 gives me 10 more psi

I wonder why they are so small compared to a comp cam where lash is in the .020 neighboorhood...

Dan

Way to go

It always pay to check out the cause of all problems, especially when in doubt

Posted By: HotRodDave

Re: 130lbs cranking pressure ???? - 06/20/11 04:55 AM

Quote:

Huge mistake !

Cam gear was off one tooth ! got pressure back to 160, lunati suggests .014 lash........

setting it at .017 gives me 10 more psi

I wonder why they are so small compared to a comp cam where lash is in the .020 neighboorhood...

Dan

Just different lash ramps desighned into the cam.

You should still degree the cam

Posted By: viperblue72

Re: 130lbs cranking pressure ???? - 06/20/11 06:54 PM

160 sounds just about right with 10.8 and that large of a cam. 190 is not likely gonna happen.

Posted By: 7e5dartsport

Re: 130lbs cranking pressure ???? - 06/21/11 04:03 AM

hi dan! i live in st-jean, which is close to ste-sophie. if you have any problems centerlining your cam, just call me: 450-349-0167. it wont cost a cent . i have the offset keys, degree wheel and piston stop as well. p.s. je parle francais. by the way, i really like your combo! serge

Posted By: 440Jim

Re: 130lbs cranking pressure ???? - 06/21/11 03:08 PM

Quote:

Cam gear was off one tooth ! got pressure back to 160

Good catch. It would have ran like a dog with 14 degree (1 tooth) error.

One tip. With aluminum heads and a cast iron block, I like to set the cold valve lash 0.004-0.005" tight, so that when hot it will be closer to the cam manufacturer's hot spec. Then check it hot for final setting.

Posted By: Leon441

Re: 130lbs cranking pressure ???? - 06/21/11 10:03 PM

OK wich way were you off? Was the cam retarded?

I have went behind people who installed a camshaft advanced. And add insult to injury did it on a stock suspension car running street tires. Car would just blow the tires off. Then it would not MPH on the big end at all when it did hook. One guy wanted to run nitrous so I checked cranking compression. Small roller high compression small block. The thing had 270 PSI. Rediculous. So I retarded the cam and got it down closer to 200 psi, which turned out to be degreed where the manufacturer suggested to begin with. We drove it a little before spraying. The guy debated about not spraying it at all because the car actually hooked and ran on the big end.

In a nutshell cam timing affects cranking compression. Some cams more than others.

Leon

Posted By: Wedgeman

Re: 130lbs cranking pressure ???? - 06/21/11 11:10 PM

Thanks....

Do you know how much they expand when hot ? .004 ?

Dan

Posted By: moparmanjames

Re: 130lbs cranking pressure ???? - 06/22/11 01:10 AM

Quote:

Quote:

same piston and ring as last fall....

What did you degree the cam in at... sounds like its retarted

Posted By: HotRodDave

Re: 130lbs cranking pressure ???? - 06/22/11 06:19 PM

Quote:

Quote:

Quote:

same piston and ring as last fall....

What did you degree the cam in at... sounds like its retarted

Why does every one keep calling his cam names?

Posted By: Wedgeman

Re: 130lbs cranking pressure ???? - 06/23/11 02:44 AM

loll !

Thanks guys..

Dan