318 hydraulic lifter preload.

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MOA

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A bit of a rant...........

Stock engine in my 72 Dart Swinger. It has 117k miles on it. Doing a top end rebuild. I ported out the heads using the info I gathered here (thanks for that), new cam and lifters ( high energy comp cam and lifters), new push rods. Using the original rocker arms and rocker arm shaft. This problem all started when I noticed one of the rockers was what seemed to me a bit too loose, then came the education about preload etc. I have a couple of lifters that have less than .006 preload, it may indeed be .000 preload. I've had so many people not know what the hell I'm talking about and say I'm making more of it than I should be.

From what I recall reading, the push rod preload should be between .030 -.060. Why do these people that have a lot of experience seem to not know anything about this?

I never intended to do a complete rebuild on this 318, money would be better spent rebuilding a 360. But since it's what I have and is numbers matching to the car, I felt it was at least worth refurbishing as long as I didn't have to do a complete rebuild. That being said........
Now that I've bough new pushrods that I didn't intend on buying, it looks like the only way to rule out the head not being assembled correctly is to buy new rocker arms as well. More money at an engine I wanted to keep the costs down on. (I'll bet this happens to a lot of people.)

I suspect the valve heights are not correct. One lifter/valve in question is #2 ex. If I lay a straight edge across the two valves next to it I get a .010 difference in height on #2 ex. It is shorter. Guy that rebuilt the head said that is not enough to worry about. The more I look into this the more I'm inclined to disagree.

.030 - .060, Is this the correct amount of preload?
 
How long have you ran the engine and did you soak the lifters or squirt oil into them before installation? They might need to run a bit to get pumped up. Hopefully you didn't flatten a cam lobe or two during break in.
 
Where do you read the engine has already run?

Lifter preload would be 'best' if the lifterplunger is about halfway its travel, with the lifter on the base of the lobe.

If lifter preload is not sufficient, you could install thinner headgaskets and/or mill the heads a bit more.

Stock engines came with steelshim headgaskets and during 99% of the rebuilds, thicker composite headgaskets are installed, lowering compression ratio.
 
.030-.060" is ideal if you are running to higher revs..... which I'd expect with the new cam. So that is what you should shoot for. If too small, then the valve on that cylinder/valve may not open fully; if too large, then the potential for pump-up and at high revs is increased. Possible variables:

1) The .010" shorter at that valve works out to about .006" at the lifter and pushrod side. So .010' per se is not awful. But, the valve heights as a group may not be all set right.
2) What head gasket do you have? As noted above, the originals were quite a bit thinner than the standard replacement head gaskets like the standard .051" Felpro's. So you likely have lost some preload there, as much as .020"-030". .039" Felpro 1008's would gain back .012" or a bit more over the .051" ones, plus a bit of compression to make it run better. 1008's run around $40 each.
3) Wear on the shafts and rockers. You need to inspect these for wear. Look at that short one and see if the inside of the rocker is worn. It may be a case of replacing only a few rockers.

It kinda sounds like you need to look at the parts you have (like the head gaskets) and then go through the process of assembling the valvetrain and doing some actual checks. With the intake off, you can actually see the preload. With the lifters fully down on a given cylinder (see the link below for procedure), look at the lifter piston and see how far it is below the retainer clip in the top of the lifter. That is the preload. It is quick and easy to check them all, by rotating the crank 90 degrees at a time, starting at TDC for #1 on the power stroke. If they show all very small to no preload by this quick visual check, then it is time to get some checking pushrods and go through the process (as in the same link below).

And, the way to see if the valves are set in the head properly is to measure the valve installed height directly, not by any of the indirect methods mentioned. So if you have serious doubts, take them back to the shop with the spec and ask them to measure them while you watch. If they won't, then throw the heads at them..... just kidding.... BTW, the valve tips being too high is more common than too low.

As for experienced people not knowing.... well if they are GM guys, many of those rockers have adjustable height rocker pivot balls so they never deal with it.

http://www.forabodiesonly.com/mopar/showthread.php?t=345989
 
This engine has not been started by me yet.

The heads are torqued with Felpro gaskets. I was under the impression that they are .040, my mistake if they are not. I am considering going with a thinner gasket, but, if the heads are not completely flat I could have sealing issues and they have not been machined. Any warp in the head or block will complicate things.

I have checked clearance at the retainer clip, that's the only reliable place to check preload as far as I know. And, it does not matter if the lifter has oil in it, in fact, I believe it is easier to check preload without oil in it. It's very easy to compress the piston in the lifter without oil, with oil, not so much.

I have a history of mashing the throttle, it will not be babied, what would be the point....
 
The only way you can accurately measure preload is the have the lifters dry, or at least bled of most of their oil. How can you possibly compress a column of oil inside a lifter to check preload? You cant! Anyways, here are some excellent instructions: [ame="http://static.summitracing.com/global/images/instructions/crn-99277-16%282%291.pdf"]http://static.summitracing.com/global/images/instructions/crn-99277-16%282%291.pdf[/ame]
 
My bad. I shouldn't have responded until the story unfolded. Details were sketchy at first and my original response was because of the unknown. I guess I've been lucky with cams and lifters. I always soaked hydraulics in a coffee can of oil and installed them in the block. Adjustable rockers got adjusted a half turn past zero lash on the base circle. Non adjustable's like our 318's got the rockers and shafts installed and the engine ran.
 
Thanks. Confirms I am checking for clearance in the right spot. I think I'm going to take the heads back off and have them checked, again. The thicker gasket is compounding the problem for sure. Thinner gasket, How much can I get away with? They have not been surfaced.
 
The 'thinner' depends on if the surfaces are reasonably flat (see the other on-going thread) and what your present CR is. With stock 318 pistons of that era, you'll don't have a lot of CR to start with so no real worries with CR for your case.

And agreed on the 'no oil in the lifter making it easy".

If your valve tip heights turn out to be low, then the seats need to be turned in deeper. But that may be a lot of work. Instead, I would consider getting the heads surfaced; it will help sealing and CR. Then if need be, I'd get a new set of pushrods after proper measurement. Can yours be returned?
 
Original pistons. I cleaned them up and installed new rings, and gap'd them.

I didn't feel the CR gain was worth the risk of the head not sealing. As per the other thread regarding sealing, that's something I want to avoid.
 
On a totally stock factory engine, .010" variance between valve stem heights is actually pretty good. I have seen a lot worse on original engines that were still in good shape.

However, when you start talking about performance cams you open up a whole nuther can of worms. It is always best to get the valve stem height dead right. Any machine shop that cannot, or that says "this is good enough" is not a machine shop at all, IMO.

With today's modern equipment available, there is ZERO excuse to have any variation at all on a valve job. Anything less is unacceptable.

All that said, IMO, on ANYTHING with a non adjustable valve train you are asking for trouble if you do not measure for proper pushrod length. You can complain, but in all honesty, stock rocker arms and custom length pushrods are really not very costly. Both can be had well under 200 dollars total.
 
Choosing to NOT surface the heads on a build is pretty much asking for trouble.
Most heads are warped because there's a cool mixture entering on one side and scorching hot exhaust exiting the other side.
 
This isn't a budget build but keeping cost down is important. This 318 is temporary until I can afford to build a 360. I was unable to find .010 longer push rods that I was sure would work so I bought stock length rods hoping it would take up the clearances I needed, it did not. I did find a few .030 over pushrods but not a full set. .030 should get all of the lifters in the mid range of spec.

It looks like there is no way around measuring each lifter preload and getting a custom set of push rods made.

As far as surfacing the heads go, that's why I didn't go with a thinner gasket, I am trying to keep costs down on this build. If it ends up being a mistake in the long run, well, I guess it will be another learning experience, ie: it cost me money. At this point, I would be ruining the head gaskets to take the heads off, too late. If the heads don't seal, I'll cuss myself later for it........as I'm doing an R&R.
 
If it hasn't bee run yet I'd pull the heads, have them milled .020", then reinstall them with the gaskets you have. Then you should be ok with the pushrod length you have assuming there's not a lot of lifter bore leakage from wear.

I'm with RRR on his assessment of the quality of work. But - at this point, it's a place-holder. Fix the problem, no need to redo everything. You need a flat head surface, and you need the effective length of the pushrods you have lengthened. Both are accomplished by milling the head. Go more than .020" and you might have intake fitment problems - so don't get carried away.
 
Thanks, appreciate the insight on this.
 
The shop that rebuilt the heads is a well known So. Cal. machine shop with 40 yrs in business. I'm not going to bad mouth them unless it's warranted, they are helping me out and I'm probably the PITA customer. :violent1:

I spoke to them and they are going to surface the head -.020, no charge. I didn't demand anything, they offered without me having to ask. I would have paid the surfacing charge and had no problem with it.

However, IMO, the valves are not where they should be. "But", I can only prove that by installing all new components or measuring them myself, which I do not have the tools to do so, and buying all new rockers and shaft is not what I want to do.

Plan of action is: Document all the clearances, get the heads checked and milled .020. Hopefully be able to use the new stock length push rods, ( 7.500). Re-check lifter pre load. At this point I should not have to do anything further with the valves/lifters. But if so, I do have 4 brand new push rods that are .030 longer 7.530, I couldn't source a full set of .030 over push rods. :???:

I'll post up the clearances when I get it documented.

What will be the compression ratio? Stock pistons, felpro gasket and -.020 milled head.
 
I'll see if I can put this in a format that's not too confusing.


#8 E. .026 I. .048 #7 E. .005 I. .035
#6 I. .024 E. .040 #5 I. .025 E. .013
#4 E. .017 I. .012 #3 E. .005 I. .016
#2 I. .026 E. <.006 #1 I. .023 E. .013

The <.006 could be binding on the retainer. The .005 is because there is very little resistance but it still grabs the wire.

I used a set of tip cleaners as feeler gauges because it's very difficult to get a feeler gauge in there. Bent the wire to fit in there with as little deflection as possible.
 
Crane cam: xe268H-10

Lift .477 .480

Dur @ .050 224 - 230
 
MOA said:
The shop that rebuilt the heads is a well known So. Cal. machine shop with 40 yrs in business. I'm not going to bad mouth them unless it's warranted, they are helping me out and I'm probably the PITA customer. :violent1:

I spoke to them and they are going to surface the head -.020, no charge. I didn't demand anything, they offered without me having to ask. I would have paid the surfacing charge and had no problem with it.
Click to expand...
Wow, that is a very good outcome. Glad it is working out, and my hat is off to the shop! Make sure you clean the bottom surfaces well when you get them back.

Good measurements too. You might want to get 3 new rockers on those 3 low measurements to see if that will tighten them up. And check the rocker shafts at those positions to see if they are worn a lot.

Computed static CR will end up around 7.5 if you have the pistons with the 4 valve reliefs (10 cc's total relief volume), and around 8.2 with flat topped pistons. That assumes starting with 68 cc combustion chambers, than a .020" head mill, and using .051" Felpro head gaskets. Yeah, 318 SCR's are looow....
 
After removing the heads and inspecting the bores again, I'm not satisfied with the bores. Ridge reamer cut to low into the cylinder and is in the area where the rings travel. It will not seal and I'll have to pull this back out to fix it. So, I'm doing a complete rebuild and that's not what I wanted to do. Heads are at the shop being checked over and having .010 taken off. KB pistons on order,. 028 head gasket on order. I checked the block and its out no more than .0015. The upside, this build should last a good long time and make for a fun street rod and isn't going to cost me as much as building a 360. If I were building a 360 I would be throwing more money at it than the 318. Keeping in mind, I don't have a 360 sitting here, I do have the 318 sitting here.
 
If I may ask, which KB's? Sorry for the setback! But you'll get better compression out of it and that will be good low end torque on the street.
 
KB 167. Discouraging since I don't have the money to even take care of half the stuff. I'm going to take some time away from the project and see if my disposition improves.
 
Good piston choice in one way, IMHO. SCR should be about 9.2-9.3 with those head gaksets, typical 318 head volume of 68 cc unmilled, and those pistons. If the head volumes are more like 64 cc unmilled, like some of the earlier open chamber 318 heads, then your SCR will be up around 9.7, and you might want to nudge that back down to 9.4-9.5 with the .039" thick Felpro 1008's..... if you can return the .028" ones.

Now, be aware that the KB's are considerably lighter than the stock cast pistons, by around 100 grams for piston + pin. I don't have my notes handy to give the exact number. So a look at engine balance is in order; the bobwieght is going to change by >5%. I don't mean to be more discouraging so sorry for this tidbit of info; it's just better to know everything going in, IMHO.
 
What does bobweight mean? These are 675-2 heads. I'm not sure what the combustion chambers are.
 
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