Watcha P-Pump cummins go Boom!

Sled-pulling, Drag results, Dyno results

Moderators: Greenleaf, KTA, BC847, Richie O

Re: Watcha P-Pump cummins go Boom!

Postby oldestof11 » Sat Jan 24, 2015 10:48 am

So much goes into blowing a head gasket. If I was to rate it:

Back pressure

But ask anyone on CF or Facebook, it is ALWAYS boost or back pressure.
93 D250~ Mismatch of cheap parts, trying to look fast going slow
User avatar
14mm rotor
Posts: 4147
Joined: Tue Apr 24, 2007 4:46 pm
Location: Northern Illinois

Re: Watcha P-Pump cummins go Boom!

Postby RCCUMMINS89 » Sat Jan 24, 2015 10:52 am

The injector itself has a tremendous amount of play in it as well.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 full line dealer, if you don't see it please ask.
14mm rotor
Posts: 4826
Joined: Mon Oct 03, 2011 4:19 pm
Location: Spirit Lake, ID

Re: Watcha P-Pump cummins go Boom!

Postby fatty » Sat Jan 24, 2015 10:56 am

Also beating on it before it warms up is a large cause IMO.

Couples months ago a, guy I know with a 6 leaker spent thousands on fixing his blown hg "the right way"/bulletproof it (which wasn't a cummins swap, so not sure what he was talking about). He tells me last weekend it's pushing water past the overflow again. He's one of those guys who gets in the truck and puts the pedal to the floor.
91.5 w250
14mm rotor
Posts: 798
Joined: Tue Nov 04, 2008 8:52 pm
Location: Washington

Re: Watcha P-Pump cummins go Boom!

Postby DMan1198 » Sat Jan 24, 2015 10:58 am

Yup that is a sure fire way to blow a head gasket
Ducati- professional nap taker, and thread derailer extraordinaire
Brownie: 80 dodge heavy half. Ghost cummins under the hood, and some sinister plans
The Roo Hunter: 93 w250, lifted, 2 whistle machines, and a bunch of other go fast goodies, uhh..... not there yet
Jaeger: 12 ram 3500. Lifted, exhausted, and fed an excessive quantity of air
The Huntress: 02 Jetta TDI. No muffler, egr, horsepower
14mm rotor
Posts: 2241
Joined: Sat Aug 10, 2013 6:26 am
Location: Slave Lake, Alberta

Re: Watcha P-Pump cummins go Boom!

Postby stillsmokin » Mon Mar 02, 2015 10:38 pm

I've seen where drive pressure on a Cummins gets so high that the deck of the block comes off the cylinder barrels. :yuck: I have been to a private diesel dyno in this country where there are holes in the walls and roof of the metal building from departed internal components of diesel engines. Good thing there was lots of beer to keep us warm since it was winter! In an ideal build the ratio of drive vs. boost should be 1:1 or less.

FWIW, a competition 12V is a whole different animal. It is usually entirely hard blocked to keep the cylinders from cracking from the increased cylinder pressures generated by high fuel delivery, 40-50 degrees timing, and massive air flow. Plain head studs won't hold the head down on the fire rings. Everything exposed to combustion is coated. It also has huge clearances to compensate for the heat and loose is fast, you've got about 5-7 minutes of run time before the oil temperature gets high. So you warm it up until it'll idle without puffing either into it (which is a project), shut if off until you're ready to go, or get out on the track and pull the trigger.
93 W350LE EXT CAB, dually, 5 speed
fuel screw!!!!
Posts: 224
Joined: Sun Jan 07, 2007 9:08 am
Location: Eastern Nebraska

Re: Watcha P-Pump cummins go Boom!

Postby shackwrrr » Thu Mar 05, 2015 3:42 pm

If you watch close when it blows, the separation is below the timing case top. I believe this is a case of the block being ripped in half by pure pressure.
1991 w250 RCLB
3 speed auto Non IC truck
fuel screw!!!!
Posts: 34
Joined: Mon Mar 02, 2015 5:47 am


Return to Competition

Who is online

Users browsing this forum: No registered users and 2 guests