HEAD BOLTS RESTRICTING OIL TO HEADS

[oldtimmc]

Hey all, I'm having trouble with my 447 fe stroker. Lost a pushrod after only about five hours of run time. I think it was a combination of wrong pushrod length and not enough oil getting to rockers. Rockers were PRW Pq. Twelve of the sixteen got chewed on by the cups. The lash adjusters are not even centered in the rockers themselves. You can see it with the naked eye. I'm switching to T&D street set up and ball ball pushrods. The oil issue seems to be only on the passenger side. After removing the rocker assembly on both sides and the distributor I put a drill to the oil pump. Good flow on the drivers side none on the passenger side. I removed the head bolt that corresponds to the oil passage for the rocker stand and lo and behold good flow from both the head bolt hole and rocker stand stud hole, tightened the head bolt back to just 60 ft/lbs and the flow dropped off significantly, less than the drivers side. I am going to talk this over with my engine builder to see what the problem may be. Gasket interference? Hunk of $#@! in the oil passage? Oh yeah, one more question, am I in for a blown head gasket down the road since I took out and put back in one head bolt?

[jayb]

I had that problem once, when I used ARP head studs with Edelbrock heads.  On one side of the engine, the head stud (which is a little thicker in diameter than the stock head bolts) was right up against the side of the hole in the head, and completely blocked off the oil transfer slot machined in the deck of the head, keeping oil from getting to that side of the engine.  I ended up chamfering the bottom of the head bolt hole so that it extended out a little from the original hole, and then the oil could get around to the other side of the stud, where there was clearance between the stud and the hole in the head, and everything worked fine.  You might have a similar situation with your head bolt.

I found this on my engine prior to any damage, because I always pre-oil with the valve covers off, to make sure the valvetrain is getting oil.  Always a good idea to do that.  As far as the head gasket goes, I wouldn't worry about; I'd torque the bolt/nut to the original specs and I'm sure it will be OK.

Also, the lash adjusters are not supposed to be centered; they go towards the outboard side of the port, to bias the pushrod a little ways away from the port.  Gives more clearance for the pushrod in the intake manifold hole.  You should have 8 rockers with adjusters biased to the left, and 8 rockers with adjusters biased to the right.  One of each for each cylinder.  The sets of 8 should be the same; if the adjusters are offset by different amounts, then you really did get a junk set of rockers.

Hope that helps - Jay

[Barry_R]

I've run into that here once or twice.  The head bolt closing off the feed.  Figured it was just a stack up of tolerances as Jay noted.  I ended up just turning the OD of the bolt down a few thou on the lathe - maybe .010 - and its been working fine for several years now in a local race car.

To reiterate what was already said - we pre-oil every engine with the valve covers off.  You just "find things" often enough to make it worth the added effort.  Over the years we've seen the aforementioned head bolts blocking oil, head gaskets blocking oil, rocker studs blocking oil (half the shaft oils - other half dry), and individual rockers that had no oil feed drillings & no oil.  Some engines oil right away, while others seem to take several minutes. 

You should see around 70-80 pounds of oil pressure "on the drill".  Much less and you have something goin' on.  If you have nominal or no pressure its a good change that a galley plug is missing - listen carefully and you'll hear it gurgling when you stop the rotation for a second.  The most common ones to miss are behind the cam sprocket and/or at the end of the lifter galley.  Look inside the distributor hole or through the fuel pump opening while spinning the drill and you'll see the "waterfall"....

[Qikbbstang]

 Read Jay's statement   "You should have 8 rockers with adjusters biased to the left, and 8 rockers with adjusters biased to the right." and   "then you really did get a junk set of rockers."
           I'm astonished I've got sets of Dove, Harland Sharp and FoMoCo Adj/NonAdj rockers and never noticed any offset in any of them-did I miss it?...... I've seen the "obviously offset rockers" because you can easilly see the large offset at the adjuster and granted think they're a great idea because it allows a little bit more port size. But I calling ALL non offset rockers "junk"?   Heck I loved Blair's using production FoMoCo Non-Adj on his hyd-roller motors.
           Another thing the FoMoCo rockers look to actually be forged steel because they have a wide parting line, yet I've seen broken adj-FoMoCo and Isky/Crane iron rockers. To me forgings would bend like hell long before before cracking so I guess they must be cast with what looks like a forged parting line?.................

[jayb]

Comp Cams rockers are from Dove, BB, and they definitely have the offset.  Looks like you missed it    Pretty sure Harlan Sharps are the same way, but I don't have a set here to look at.

What I was referring to by "junk" rockers was if the 8 that are supposed to be offset to the left have different amounts of offset; that would indicate that they were drilled inconsistently. 

[oldtimmc]

Thanks a bunch guys for the input. The oil pressure with the drill was up to just about 80 lbs. By the time I stopped the drill and looked at the gauge on the dash it was about 75 and falling. When I mentioned that the adjusters on the rockers weren't centered it was left to right front to back just all over. To me it just looks like $#@^y construction on PRW's part. As far as pre-oiling I was told to just pull the coil wire crank till you see some pressure and let her rip.

[Cyclone03]

No dont just crank away , your are PRE OILING it to fill all the oil passages so the bearings are not dry on start. Pull the distributor and spin the oil pump shaft COUNTER CLOCKWISE most use a drill , I use a speed handle and 1/4" deep socket taped to an extension.

[Posi67]

You didn't say what heads you are using but the factory heads have a larger size bolt hole through them on the 2 that oil the heads. Aftermarket heads appear to be all drilled the same size and yes, the bolt or stud can restrict flow. ARP bolts are shanked down which can help but the studs are not. If you have an aftermarket head (especially Dove) check to see if the heli coil for the rocker stud isn't blocking the oil feed hole. Sounds like you have other issues with damage to the rockers from the pushrod cups as well. Other ideas as mentioned are also worth checking.

[oldtimmc]

Heads are edelbrock performer RPM. The restriction is only when the head bolt is in. I pumped oil with the drill and oil flowed freely out of the head bolt hole and the oiling hole in the chamfer for the rocker stand. The PRW rocker stand is drilled larger than the stud that holds it the issue is down at the junction of the head and block with the oil trying to get around the head bolt to the short galley that leads to the rocker stand. As soon as you start to thread the head bolt in is when the oil to the rocker stand starts to become compromised and only gets worse the tighter the bolt. Initially when I spun the pump there was no oil at all coming out of the rocker stand orifice, only after the head bolt was removed did the oil flow freely from both holes and like I said as soon as the head bolt was back in only a thread or two the flow started to slow. It still oozed out of the head bolt hole with the bolt loose but the tighter the bolt the worse the flow out of the rocker stand orifice. Barry_r has it right the head bolt will have to be skinnied up a few thou.

[Lenz]

Shows the difference in head bolts?  I'm running the same heads with factory bolts and no issues, fired up the oil pump once I had the valve train together with a 1/2" drill and had good flow across all rockers.  Strange deal but a few thou can make a big difference.  Once you cut the clearance all should be well.

[Joe-JDC]

I would check the block/head dowels for proper engagement.  If the dowel is shoved up into the head, then it will move around under compression.  That is a possibility.  Joe-JDC

[fe66comet]

I was considering that same issue when I decided to go to through pushrod oiling. It seemed the most effective way around a potential oiling issue. I have had upper end oiling issues before and solved them by drilling the ports larger but a higher volume pump and tighter clearances on the valve train was necessary to maintain decent oil pressure. A simple solution for me would be drill the offending hole slightly larger.