Pushrod tips?

RammaR · 10-10-2010, 07:33 PM

I replaced the heads on my '96 4.0 OHV last February and had a real problem getting it to run. (some of you might remember this thread:http://www.explorerforum.com/forums/...d.php?t=268590)

Turned out that if I torqued the rocker arm assembly down to 46 ft-lbs per the haynes manual, the intake valves were hanging open and it was backfiring through the intake. I backed of the pedestal torque so that I could spin the pushrods between my fingers when they were at TDC and that got her running.

The heads were a "new" (not remanufactured) aftermarket casting. It still doesn't run perfect and maybe a tad bit warm, so I'm thinking the pushrod length may be a little off still. Plus I don't know that I like leaving the rocker arm bolts at ~25 ft-lbs to get rods to remain spin-able.

I thought about going with the deltacam's package, but the new pushrods would be even longer than my current rods after their 190k miles of wear.

Any tips on how to measure what the ideal pushrod length should be? Or maybe just shim up the rocker arm pedestals a little?

Thanks.

imp · 10-10-2010, 08:33 PM

When you replaced the heads, it is possible the head gaskets you used were thinner than the old ones by an amount just enough to prevent the valves from seating fully. Did you measure thickness?

If that's the case, check with Ford; shorter pushrods are available for many engines having no adjustment means. I seem to recall 0.010", 0.020" shorter were often available.

Just a thought..... imp

RammaR · 10-11-2010, 09:37 PM

New gaskets were part of the fel-pro kit from Orielly. Good thought, but I doubt that's it and I really don't want to pull the heads again unless it is an absolute must.

imp · 10-12-2010, 02:42 PM

Quote:

Originally Posted by RammaR

New gaskets were part of the fel-pro kit from Orielly. Good thought, but I doubt that's it and I really don't want to pull the heads again unless it is an absolute must.

Understood. In the "stack-up" of parts involved in removing/replacing heads, ONLY the gasket's thickness represent a variable which can affect valve closure, IF: valves and valve seats were NOT ground (grinding seats valves deeper into head, DECREASING pushrod/lifter clearance); head gasket surface was NOT machined in any way; or, replacement heads had machining differences from OEM specification.

It only takes a little bit, if valve seating was near borderline to begin with, to prevent a valve or two (or more) from seating properly. I have seen a 0.010" thickness difference in gaskets cause this. Please be aware, that depending on gasket construction, some gaskets will COMPRESS MORE under load than others, even if the starting, unloaded thickness, is the same.

Just another thought. Not trying to be nit-picky. imp

*ahodges* · 10-12-2010, 02:51 PM

I believe the original push rod length is 5.5 inches exactly

10-10-2010, 07:33 PM	#1
RammaR Wannabe Elite Explorer Franklin, TN '96 XLT 4x4 Join Date: Aug 2001 Posts: 199 Vehicle Specs (Original Poster)	Pushrod tips? I replaced the heads on my '96 4.0 OHV last February and had a real problem getting it to run. (some of you might remember this thread:http://www.explorerforum.com/forums/...d.php?t=268590) Turned out that if I torqued the rocker arm assembly down to 46 ft-lbs per the haynes manual, the intake valves were hanging open and it was backfiring through the intake. I backed of the pedestal torque so that I could spin the pushrods between my fingers when they were at TDC and that got her running. The heads were a "new" (not remanufactured) aftermarket casting. It still doesn't run perfect and maybe a tad bit warm, so I'm thinking the pushrod length may be a little off still. Plus I don't know that I like leaving the rocker arm bolts at ~25 ft-lbs to get rods to remain spin-able. I thought about going with the deltacam's package, but the new pushrods would be even longer than my current rods after their 190k miles of wear. Any tips on how to measure what the ideal pushrod length should be? Or maybe just shim up the rocker arm pedestals a little? Thanks.

10-12-2010, 02:51 PM	#5
ahodges Elite Explorer Oregon,OH 1996 XLT - 347 V8 Join Date: Aug 2009 Posts: 871 Vehicle Specs	I believe the original push rod length is 5.5 inches exactly __________________ 1996 Explorer XLT Supercharged 347 w/ BW4406 Build Thread, 8000K HID Headlights and Fog Lights, Custom electric fans with painless controller, Stainless running boards, etc... 1999 Ranger XLT manual 2WD 3.0L (DD). Window visors, 35% front tint & 20% stock rear tint, 6000K HIDs, 96 explorer rims.. mostly stock 1997 Mountaineer (Swapped 4x4 4.0 OHV from my 96 Explorer) (Sold)

10-10-2010, 08:33 PM	#2
imp Wannabe Elite Explorer Missouri Ozarks 2004 XLT Join Date: Nov 2009 Posts: 1,184 Vehicle Specs	When you replaced the heads, it is possible the head gaskets you used were thinner than the old ones by an amount just enough to prevent the valves from seating fully. Did you measure thickness? If that's the case, check with Ford; shorter pushrods are available for many engines having no adjustment means. I seem to recall 0.010", 0.020" shorter were often available. Just a thought..... imp

10-11-2010, 09:37 PM	#3
RammaR Wannabe Elite Explorer Franklin, TN '96 XLT 4x4 Join Date: Aug 2001 Posts: 199 Vehicle Specs (Original Poster)	New gaskets were part of the fel-pro kit from Orielly. Good thought, but I doubt that's it and I really don't want to pull the heads again unless it is an absolute must.