Pushrod problem on small block

[451Mopar]

I pulled the 360 apart yesterday, and the only cam lobe that was wiped out was the #3 Exhaust lube, but when I removed the pushrods, I noticed that several of them had rub marks on the sides where they go through the pushrod holes on the heads. I think this is in part that I am running 1.6:1 rocker arms. The Rocker arms are the Crane Gold aluminum, and the pushrods are also the recommended ones from Crane for this setup. I am also using stock heads.

Anyhow, I guess I will have to clearance the pushrod holes?

The only other dammage I noticed was the lower shell of the #4 Main bearing was worn to the copper. The other bearings (main and Rod) only had some minor scratches?
Ideas on why only one bearing was so bad?

I still need to check the oil pump and see if it's wasted. Engine had oil pressure, but with all the metal from the wiped cam in the oil, I had better check everything.

[BJSracing]

Yes you will probably have to clearance the pushrod holes. As far as the mains go that could be where the metal from the cam lobe went to. Als it could be a matter of the main journal bores or improperly torqued.

[darktone]

Do you have the right length push rod? Don't you have to see where the roller tip is riding on the valve stem when the lifter is fully extended and make sure the geometry is right?
Was the block align bored? Might have been a tight cap on #4?

[DartGT66]

In a moapr with fixed rockershaft height, there is not much you can do to the rocker arm geometry or pushrod length.

[72Challenger]

Of course there is. You can always order custom pushrods in any length you want. You can shim the shafts to raise them, or use lash caps on the valve tips to effectively lower them. And if you really want to get fussy, you can change valve stem length.

[451Mopar]

I'm not sure about the #4 main bearing, I think it just got alot of the metal from the cam. The main bearings were align honed, and I also plasti-gauged all the bearings and they all check out good. the crank turning torque with all the caps tightened was also really low, no tight spots at all.
Rember this is not a low mialage engine and I ran it knowing the cam was going out.

I need to clean the block, maybe some garbage partly plugged the oil passage to the bearing?

I just dissasembled the oil pump, and even though it was working, it is all scratched up and has alot of nicks in the rotor. I'll be replacing it too.

I think this wiped out cam lobe is going to cost me at least $500 in parts to re-ferbish the engine. Almost would have paid for a roller cam setup that shouldn't have this problem using the junk motor oil thats out there now.

As for the pushrods and rocker arms, I did shim the rocker shafts to get the correct geometry both with the roller tip over the valve stem, and with the pushrod adjusting nut. When I assembled the engine I was a bit concerned about the pushrod clearance problem, but when truning the engine by hand everything cleared. I'm sure at high RPM the pushrods may have deflected a small amount. There are maybe 3 pushrods that show no rubbing, and I think 10 or 11 show very minor rubbing (almost like a spot was polished on the pushrods), but at least one does show some pretty bad wear on the side of the pushrod. I think I will be able to see on the heads where the pushrods were rubbing so i can clearance the pushrod holes.

I also, just checked the valve springs and installed heights. The valve springs were supposed to be installed at 1.650", but were installed at 1.695". I think the difference in seat pressure is about 10-15 pounds? Closer to 105-110 pounds when it should have been 120 pounds seat pressure.

Right now I only have the heads and oil pump at my house, the rest of the parts are still at my friends where I dissasembled the engine.

I plan to take the engine down to the machine shop, have it cleaned and put new cam bearing in it.
I plan to install new piston rings since everything else will be new, and the rings are not very expensive, so I will see if the engine needs a light hone job.
I din't notice a ridge in the cylinder, just carbon buildup above the top ring.

[BJSracing]

I would check the clearances on the block and the mains and rods before you put this thing back together. It will save you alot of heart ache. Trust me I know. I have suffered the machine shop mess ups once already. It won't happen to me again.

[451Mopar]

Thanks, When I built the engine I checked all the clearances and everything was right in spec, but I just looked how long ago it was when I built the engine, and found that I actually built it around 1999-2000, so is been together a few more years than I thought.

I will double check everything again when I put the engine back together.

[451Mopar]

Well, I had to have the crank turned another 0.010".
On the pushrods, seven look fine, four show quite a bit of rubbing top and bottom of the pushrod hole, and five show slight rubbing.

I ran a 1/2" drill bit through the pushrod holes and three holes did have some restriction to the drill bit. I tried working the bit to make the hole oblong, and it may be ok, but I ordered up some larger drill bits (33/64, 17/32, 35/64, 9/16) to try and slightly enlarge the pushrod holes. Luckely I did not do much porting around the pushrod hole area inside the ports so it looks like I can go a bit larger without problems.

Anyone else have problems with the 1.6:1 ratio rockers?

I ordered up a new set of pushrods, so if anyone wants a slightly used set of pushrods let me know. I replaced the adjuster screws in the rockers so I have some used ones too.

[BJSracing]

Did you ever have the block decked or the heads shaved? If so you may have to shim the rocker shafts to get the geometry back right. I know that it was metioned before but it is something that you need to take a second look at. Who's pushrods did you use? Also what lifters.

[451Mopar]

I think part of the problem is both the block and heads have been decked.
The real issue is the Small block 59-degree tappet angle that makes it so the pushrod moves in a arching motion and not straight up-down.
The Pushrods and rocker arms are Crane Cams, the Cam and Lifters are Hughes Engines. I believ I used a 0.030" shim under the rocker shaft so the rockers roller tip was centered over the valve, and when the lifter pre-load was set to 0.040" there was two threads showing on the ball end of the adjuster to rocker body, which I was told should be correct?

[dave571]

Originally Posted by 451Mopar

Anyone else have problems with the 1.6:1 ratio rockers?

.

Yes.

I had a similiar issue with a guy's 406 stroker (360 .020" over with a 4" crank) It would eat pushrods. Pulled it apart, and checked all clearances. Everything was good except that 3 of them had rub marks

1.6 crane golds, on top of E heads.

Enlarged the holes, fixed.

A friend of mine is more into SB's than me, and at the time he told me it was something he had delt with as well.

[345Dart]

Originally Posted by dave571

Yes.

I had a similiar issue with a guy's 406 stroker (360 .020" over with a 4" crank) It would eat pushrods. Pulled it apart, and checked all clearances. Everything was good except that 3 of them had rub marks

1.6 crane golds, on top of E heads.

Enlarged the holes, fixed.

A friend of mine is more into SB's than me, and at the time he told me it was something he had delt with as well.

And is STILL dealing with it in the new magnum aluminum heads mating up to a non-roller lifter and hydraulic cam. The 1.6 rocker is the problem with the LA heads .

Be carefull oversize drilling as you are taking metal out all around. I use a die grinder as it is only part of the hole closest to the shaft that you need more clearance.