Moparts

Clearances

Posted By: beepbeepdon

Clearances - 06/05/12 04:54 PM

Loose or tight?......Any opinions?

main bearing clearances .00275
rod bearing clearances .00250

Posted By: dartman366

Re: Clearances - 06/05/12 06:06 PM

race motor or street driver??

Posted By: beepbeepdon

Re: Clearances - 06/05/12 06:21 PM

Sorry about that....Race only...Stock steel crank.... 7.100 K1-Tech Billet 4340 H-Beam Rods

Posted By: dartman366

Re: Clearances - 06/05/12 06:27 PM

on my 408 Terry set the clearances at .0030-mains,,,.0028 on the eagle rod's, so you are pretty close in my opinion.

Posted By: beepbeepdon

Re: Clearances - 06/05/12 06:29 PM

Thank you for your input...I really appreciate it

Posted By: Cab_Burge

Re: Clearances - 06/05/12 06:48 PM

Quote:

Loose or tight?......Any opinions?

main bearing clearances .00275
rod bearing clearances .00250

That is tight in my opinion, tighter than I like to use in a race only motor

If you used a thin oil,5W20 or zero weight, you'll probally be fine with those clearances, make sure you have some heat in the oil before racing it though

I like to have between .003 to .004 on the mains and .003+ on the rods using the 2.200 rod journal size, bigger on the stock Mopar rod sizes, 2.375

I use 5W20 or 5W30 wt. oil only in all of my motors now, street or race only

Posted By: beepbeepdon

Re: Clearances - 06/05/12 07:02 PM

Thanks Cab...The reason I am asking is that Joe Gibbs recommended a 5W40 Synthetic (DT40) based on those clearances....I am not necessarliy second guessing them but just wanted to get various opinions......Long story short....I lost my cam (flat tappet/solid)last year and I feel it was due to a poor choice of oil ( on my part)....So after an expensive rebuild I DO NOT want to take any chances with oil selection again...Hence the choice of zinc "rich" Joe Gibbs oil.........Man I should have gone roller...DOH!!!!

Posted By: BB Dart 69

Re: Clearances - 06/05/12 07:48 PM

Quote:

Quote:

Loose or tight?......Any opinions?

main bearing clearances .00275
rod bearing clearances .00250

That is tight in my opinion, tighter than I like to use in a race only motor If you used a thin oil,5W20 or zero weight, you'll probally be fine with those clearances, make sure you have some heat in the oil before racing it though I like to have between .003 to .004 on the mains and .003+ on the rods using the 2.200 rod journal size, bigger on the stock Mopar rod sizes, 2.375 I use 5W20 or 5W30 wt. oil only in all of my motors now, street or race only

I use 30wt oil,

Posted By: MR_P_BODY

Re: Clearances - 06/05/12 09:20 PM

Quote:

Loose or tight?......Any opinions?

main bearing clearances .00275
rod bearing clearances .00250

That almost exactly what my 416 clearances are...
I normally run .003 and .003 ... I wouldnt worry
about it... if you run heavy oil you'll see high
pressures

Posted By: rickseeman

Re: Clearances - 06/05/12 10:19 PM

The book says .002 to .003 so your perfect. Is that a bad thing?

Posted By: beepbeepdon

Re: Clearances - 06/05/12 10:48 PM

Thanks Mr P_Body

Posted By: beepbeepdon

Re: Clearances - 06/05/12 10:49 PM

It is a good thing...nice to know I'm in the safe zone huh?
Thanks for the help

Posted By: Cab_Burge

Re: Clearances - 06/05/12 11:01 PM

Quote:

Quote:

Quote:

Loose or tight?......Any opinions?

main bearing clearances .00275
rod bearing clearances .00250

That is tight in my opinion, tighter than I like to use in a race only motor If you used a thin oil,5W20 or zero weight, you'll probally be fine with those clearances, make sure you have some heat in the oil before racing it though I like to have between .003 to .004 on the mains and .003+ on the rods using the 2.200 rod journal size, bigger on the stock Mopar rod sizes, 2.375 I use 5W20 or 5W30 wt. oil only in all of my motors now, street or race only

I use 30wt oil,

I'll share a little information on oil wieght based on past dyno testing, motor #1 with 30 WT oil saw a ten HP increase in the oil temps being 130 F versus raising them to 160 F

Motor # two and later saw no HP or Torque differences with both 5W20 WT and 5W30 WT between 90 F and 200 F

A ten HP change at the track can throw your dial off a bunch