Awesome Start Up - Help With Fine Tune?

[78 granada]

Well we finally got the 78 Granada fired up and it sounds awesome! So if you can help me out, I have a lifter knock which is not unusual. I have RAU adjustable rockers and hydraulic lifters. Knock is coming from the front and those cylinders SEEM to be adjusted tighter if you go by the remaining threads (dimensionally) on the rockers. I have an instinct to actually loosen the noisy ones but that seems wrong. Can a hydraulic lifter that is too tight knock? Seems like it would be quiet but crack the valve open.

Next question is this: I have a Redline regulator for my Weber carb. Supposedly 3.5 psi max. I have it cranked down all the way and still have less than 3. Gauge is 'new' and it runs great at least in the driveway! Does a stock again 'new' mechanical pump only put out 3 or less psi?

Boy this thing sounds great. Had a good break in for the cam with good rpm until everything was up to temp. Hope that knocking didn't hurt the break in!

What do you all say? I know you've been there.....

 

[bubba22349]

Well we finally got the 78 Granada fired up and it sounds awesome! So if you can help me out, I have a lifter knock which is not unusual. I have RAU adjustable rockers and hydraulic lifters. Knock is coming from the front and those cylinders SEEM to be adjusted tighter if you go by the remaining threads (dimensionally) on the rockers. I have an instinct to actually loosen the noisy ones but that seems wrong. Can a hydraulic lifter that is too tight knock? Seems like it would be quiet but crack the valve open.

Next question is this: I have a Redline regulator for my Weber carb. Supposedly 3.5 psi max. I have it cranked down all the way and still have less than 3. Gauge is 'new' and it runs great at least in the driveway! Does a stock again 'new' mechanical pump only put out 3 or less psi?

Boy this thing sounds great. Had a good break in for the cam with good rpm until everything was up to temp. Hope that knocking didn't hurt the break in!

What do you all say? I know you've been there.....

Usually lifters will tick or click if they are loose. If it's knocking your instinct might be correct if the rocker adjustment is sugnifcatly tighter (i.e. Less thread adjustment showing) on those front lifters and the lifters Pistons may be bottomed out were there is no movement. This could even be holding those valves open slightly and causing them to slam or pound the valves against the valve seats. For sure try loosening them up some to see if it helps getting rid the f the knocking noise.

Usally the stock fuel pumps when new or rebuilt put out in the range of 5 to 6.5 PSI. Good luck

 

[powerband]

If in doubt about the rocker adjustment it's worth going through it one more time. . After initial start some reciprocating part may have some tolerances worn in a little... did you rev it up when testing the fuel pump, it puts out higher PSI as the RPM's increase.

have fun

 

[78 granada]

Much appreciated! I didn't notice pressure differences due to revs. Oddly the psi never went high, just low but we were at about 2K rpm and all seemed well! I would like to go back (and probably will) and set the lash again but man, when you have those things oiled up it gets real hard to 'FEEL' where the lash comes out. Do you literally just try and spin the rod and when it stops go a half or quarter turn? Or does it matter if you can push the rod down on the plunger? Dont you want that out of it before you take the additional quarter turn or so?

 

[bubba22349]

Much appreciated! I didn't notice pressure differences due to revs. Oddly the psi never went high, just low but we were at about 2K rpm and all seemed well! I would like to go back (and probably will) and set the lash again but man, when you have those things oiled up it gets real hard to 'FEEL' where the lash comes out. Do you literally just try and spin the rod and when it stops go a half or quarter turn? Or does it matter if you can push the rod down on the plunger? Dont you want that out of it before you take the additional quarter turn or so?

Many people have trouble feeling that point where the lash is at zero (light drag) it can take some time and experience to develop the feel nessiary, so it's very easy to over tighten them. There is another way that always works though it can be a little messy, that is setting with the valve cover off with the engine warmed up good set them running at idle. An old valve cover with a slot cut out of the top can help with the mess part. Back the adjustment off one at a time till they start to click real good then adjust them until they just stop (that's your point of zero lash) add a 1/4 turn and move to the next. Good luck

 

[78 granada]

So Bubba, if the lifter is pumped down so you can compress it, and you take the lash out but can still push the rod down that's far enough - just a quarter turn or so after that?
when I adjusted these it was all over the place so I repeated the thread dimensions from a couple that I thought felt pretty good. If you really go until you can't turn the rod there is quite a load on it! this part always confused me.

 

[bubba22349]

So Bubba, if the lifter is pumped down so you can compress it, and you take the lash out but can still push the rod down that's far enough - just a quarter turn or so after that?
when I adjusted these it was all over the place so I repeated the thread dimensions from a couple that I thought felt pretty good. If you really go until you can't turn the rod there is quite a load on it! this part always confused me.

78 Granada If you are doing it like thats the problem you don't want to be pushing down in anyway on the rocker / push Rod ect. this is why it's so hard to feel when it's right. The drag is very slight and yes it is still going to allow you to push the rocker, push Rod, and the piston in the lifter down even further after its correctly set oil under pressure fills that void. Using your two fingers to only turn the push Rod in a circle or back and forth, there should be absolutely no downward pressure put on the push Rod by your fingers or by the socket wrench your using to tighten the adjusting screw. Make sure the engine is turned to the correct position for the Rocker you are adjusting (cam is on the heel or low point) Then when you start to feel a slight drag that would be zero lash then turn it another 1/4 turn. If you get a lot of drag or your rocker adjustment threads are way different then you went to far. Good luck

 

[78 granada]

Cant wait to get out there and start over. Just might have gone too far the first time. thanks for hanging in there with me on this one!!

 

[bubba22349]

You can do it!

 

[B RON CO]

Hi, I like to set hydraulic lifters on a running engine. I will start up front and work my way back, or if there are any ticking valves go after those to quiet everything down. Mainly go slowly, loosening until it clicks, and tightening each lifter to give the engine time to adapt to each adjustment. If you think those couple of rockers are too tight go ahead and loosen them with the engine off until the rocker just floats on the valve, than start it up and finish the job. Some of my reasons for doing this on a running and warm engine are if you over tighten a rocker the engine will lose vacuum and shake like crazy ( this may have happened to you ) and you don't have to worry about being on the base circle of the cam. A running engine will tell you what it likes. Some guys will look at a vacuum gauge and tighten the rocker until the gauge starts to flutter, and then back off the rocker until the vacuum stabilizes. I find myself going after each rocker first to get it in the ballpark, and once again to fine tune each one. It is difficult to get one perfect if too many others are out of adjustment. Good luck

 

[78 granada]

It actually ran great! I was wondering if I can keep the wrench on the adjuster with it rocking to adjust it in motion so I didn't try it. The gorilla in the room is that I may have a sticking lifter - sure don't want to pull the head!!! Today will tell. Onward we go!
This is an edit update. I started over with the lifter adjustment and they are a lot closer now. Still a little noisy but I had them way too tight! Now that my RAU adjusters are backed off I will bet you I only have three or so threads engaged in the arms. They seem to lock up OK with the jam nut but man, there is a LOT of remaining thread in the adjusters that I would like to use. Anyone know if there is a slightly shorter set of pushrods for this 250 that still has the correct size cup end?

 

[bubba22349]

one thing to remember is that the lifter preload on these engines is around .050 to .070 of inch this is a very small amount adjustment after the point of Zero lash. As an example 1/16 of an inch is .0625. Good luck

 

[78 granada]

without a doubt I was over adjusted! Now most of the lifters are making some noise but the heavier knock I had previously has subsided so I think going back to square one was the thing to do. I am half a turn after no lash and it sounds like I need to go more. Good point on the narrow preload window Bubba and thank you for that! I am guessing that I should add another 1/4 turn but I think a full turn from zero lash would start to be at the .050. If anyone is reading this take it from me; DO NOT pre lube the lifters before adjustment!! I am actually thinking about putting a new set of dry lifters on this cam (the one that was really loud has me worried that it may be defective or I ruined it) and if I can find a set of pushrods that are shorted,with the same dimension cup end I am going to swap those too. I only have a couple threads of the adjuster into the rocker at 1/2 turn. Feel free to speak up anyone - I am fishing a little bit here! Bubba, can't thank you enough for the solid advice!!

 

[B RON CO]

Hi, glad you are getting your lash under control. Better too loose than too tight. I soak new lifters in motor oil before I install them, and put assembly lube on the bottom. We use to use white grease before there was assembly lube. Good luck

 

[78 granada]

I actually submerged them and pumped them to fill up with oil. A carry over practice from building motors that have no adjustment - a no brainer. Anyway some sort of pumped up and some sort of didn't. I have a feeling I have one that just won't pump. Anyway there seemed to be too much variation in the feel when I was adjusting them. Didn't mean to give the impression I would install them totally dry!!! thanks for catching that.

 

[78 granada]

I actually submerged them and pumped them to fill up with oil. A carry over practice from building motors that have no adjustment - a no brainer. Anyway some sort of pumped up and some sort of didn't. I have a feeling I have one that just won't pump. Anyway there seemed to be too much variation in the feel when I was adjusting them. Didn't mean to give the impression I would install them totally dry!!! thanks for catching that.