oil pressure and adjustable hydraulic valve adjustment

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bwhitejr

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When I first broke in the engine, my mechanic set the adj valves. It ran great and did not overheat. We discovered that the oil plug under the distributor was left out and caused low oil pressure. I have since installed the missing plug. My question is....Do the valves need to be reset, due to their being set with low oil pressure? I forgot to mention it now runs terrible and gets really warm +190.6.
Any insight would be greatly appreciated.
As part of my study of the issue. I found that the adjusters are 24 threads to the inch. That doesn't square with Compcams suggestion of 1/2 - 3/4 turn after zero lash. To achieve 0.030 to o
0.040 cushion.
 
Lay out how you figured this, and what is your rocker ratio?

1 T would be 1/24" which is .042

1/2 T would then be 1/2 that or .021"

X whatever your rocker ratio, 1.5? would be .03'd something

3/4 of .042 is about .032, X 1.5 rocker is .047
 
Wow didn't figure in the rocker ratio. Which is 1.5. Thanks for reminding me.
But do you think the valves need to be re-lashed because of the low pressure when they were set?
The pressure when they were set was about 12 lbs. Now it is 55 lbs.

Anyone have an opinion?
 
Yea, re-do them for sure. They probably were barely pumped up. And rag on the original guy who assembled the motor who left the plug out. Hope it did not see any mileage or use with the plug out as the bearings could be the worse for it.
 
Get the motor warmed up, back off each rocker one at a time til that valve ticks, then slowly tighten til the tick goes away and then 1/4 turn more. Good to do anyway once in a while, especially if you beat on the motor a lot, like at the drags. Adjusting them can't hurt if done right.
 
airgrabber said:
Get the motor warmed up, back off each rocker one at a time til that valve ticks, then slowly tighten til the tick goes away and then 1/4 turn more. Good to do anyway once in a while, especially if you beat on the motor a lot, like at the drags. Adjusting them can't hurt if done right.
Click to expand...

Dont mean to be a smart ***...but trying to adjust a rocker on small block mopar while it is running takes alot of talent...please film it for me...

as the adjuster is going to be moving...not like a small block chivy.......

I would leave them alone also.
 
SETTING VALVE LASH – DODGE 273 V-8

Here's the method I've been using for many years:

Rotate the motor in the direction of rotation until you have #1 cylinder at TDC of the compression stroke (both valves closed). Adjust clearance on intake valves 1,2,5,7 and exhaust valves 1,3,4,8.

Then rotate the motor, in the direction of rotation, 1 revolution
to TDC for # 6 cylinder and adjust intake valves 3,4,6,8 and exhaust valves 2,5,6,7.
 
You have a couple issues. First - the "getting hot". 190 isn't hot. If the cooling system can maintain it, regardess of load or weather - you're fine. If it creaps up and you can't bring it down - it's a problem, and can be result from too much friction - aka a bearing problem because the bearings get starved if that cam plug is left out. The lifters don't take much to get them pumped up - but I'd go through and reset the preload. IMO it should be measured if you don't know, then you can duplicate it down the road.
 
Yea it's a pain while its running, you can do it with the motor off but set the idle low enough and it's doable while running, especially with 273 style rockers and their interference fit adjusters. I've done it with both style adjusters.
 
Let me understand one thing is the oil pressure numbers you gave are at an idle 12 psi and now it's 55 psi if so 55 psi is way to high. Most oil pressure is checked at 2000 rpms. If you have 55 psi at an idle and the engine hits 5000 rpms and oil pressure increases you could have well over 100 psi that could be close to blowing the oil filter up and you losing all oil pressure. The rule of thumb I us is 10 psi per 1000 rpms that keeps you safe. As far a valve adjustment it doesn't hurt to recheck it just to be sure. I make sure the exhaust valve is open and adjust the intake valve once all the intakes are done do the same with the exhaust valves with the intake valve open yes it takes time but it your engine and if the valves are to tight it will never run right. And one other thing if the engine is staying between 190 and 210 you should be good with that I wouldn't worry until it get to 230 - 240 range then you have an over heating problem. Good Luck
 
Thanks to all who replied.
I have reset the valves. But I think I found the problem. While adjusting, when I got to the #6 exhaust I found the rocker arm floppy. The adjusting screw was tight,so it wasn't because it worked loose. I adjusted the screw, but it left no threads visible. The other adjusting screws have 3-4 threads showing.

Does this mean what I think it means?

What needs to be done at this point? How can I confirm my suspicion?
 
sounds like you wiped a cam lobe. low oil pressure to the cam bearings & rocker shafts will do that. also if you ran it for an extended period of time like this, chances are your cam bearings are jacked. (thus the engine running way hotter now than during breakin period)

mopar_LA_oiling_diagram_zps8b4098d7.jpg
 
Pull the intake off and look. If it's good you only have spent for the intake gasket set. If it's bad that will have to come off anyway.
 
If I did wipe a cam lobe. Does the engine need a complete tear down and rebuild. (i.e. new cam, rod and main bearings and de-glaze cylinders?
 
All depends on how much is rubber away, and where it went to. If it's just beginning to go then I'd say it's probably ok. If the lifter face is concave and/or the lobe is almost round now, tear it all down and prepare to clean it out - and don't forget the cam bearings.
 
bwhitejr said:
If I did wipe a cam lobe. Does the engine need a complete tear down and rebuild. (i.e. new cam, rod and main bearings and de-glaze cylinders?
Click to expand...

yes. not "complete" that makes it sound like more than it really is.

bearings are cheap, and if you do it now you are much safer. main and rod bearings are probably still ok. chances are they were getting enough lubrication, but could just be replaced at this point, that's up to you.

cam bearings will take some work to replace. cylinders & rings are probably fine & dont need to be touched. but like moper (dave) said you should pull the intake and inspect what you can.

however, if you continue running it, without digging deeper, then you could be in for a lot more work.
if you wiped a lobe that metal had to go some place...

what work you have now is not too bad... consider that some racers pull their engines down after every week of racing :D

right now the big thing to worry about is the cam bearings and whether the cam lobe is gone. it could just be a bad lifter on that one valve.
 
If the worst did happen, then clean, clean, clean all of the oil passages and block/head surfaces with flushes and with physical means (brushes) to get all the metal particles out. Hope it is not the cam but hey, it IS machinery....
 
Thanks for the suggestions. This weekend I will take the intake manifold off and see what I have. I hope it's not too bad. I would hate to have to pull the engine and transmission out of the car. My son and I built this car together and now he has graduated and moved off on his own. Wish me luck.
 
Saturday I out the valve covers back on and started the engine. It still has the problem on #6 exhaust which cause a miss, especially noticeable at idle. But overall the engine is running smoother. My guess is the valves were too tight after the oil pressure was boosted with the replacing the distributor oil plug. Could this be the case?

My machinist says to bring the engine to him and he will fix it for between $800 and $1450.
Does that sound reasonable?

thanks!
 
bwhitejr said:
Saturday I out the valve covers back on and started the engine. It still has the problem on #6 exhaust which cause a miss, especially noticeable at idle. But overall the engine is running smoother. My guess is the valves were too tight after the oil pressure was boosted with the replacing the distributor oil plug. Could this be the case?

My machinist says to bring the engine to him and he will fix it for between $800 and $1450.
Does that sound reasonable?

thanks!
Click to expand...

First off... WHO left the oil plug out? If it was your Mechanic/Engine Builder. He bought the problem. You should not have to pay him ****!
 
Any oil pressure related issue should go right back to the guy that assembled and left a condition that allowed for damage. That would be the plug left out... But - if the cam went bad due to some other reason - you turning it over too much before it running, messing with lifter preload, etc, then it's going to be hard to press him to take responsibility for it.
Personally if it were me, it wouldn't cost you a dime. A middle of the road I think would be him doing the labor for nothing and you paying his cost on replacement parts. If he's going to charge you more than parts I'd argue that.
 
bwhitejr said:
after the oil pressure was boosted with the replacing the distributor oil plug. Could this be the case?...............My machinist says ...........between $800 and $1450.
Click to expand...

Mad Dart said:
First off... WHO left the oil plug out? If it was your Mechanic/Engine Builder. He bought the problem. You should not have to pay him ****!
Click to expand...

moper said:
Any oil pressure related issue should go right back to the guy that assembled and left a condition that allowed for damage..
Click to expand...


wrjjol.jpg
 
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