Head swap

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Coolmopar

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Swapped heads on a 73 dodge dart 318 went from stock heads to a set of 302 castings with 1.88 stainless valves. Engine runs great but now has a lot of lifter clatter and it didn't have it with the stock heads. Any suggestions on why?
 
What did your preload look like when you tightened the rocker shafts? Perhaps the 302 heads rocker supports are a different height?
 
the 302s didnt come with the 1.88's and valve steam hights are now off, to correct need to measure for push rods and order correct length, or add adjustable rockers...
 
Yep, run #1 up to compression stroke at TDC on the harmonic balancer.

Now check the preload on the intake and exhaust valves on that cylinder. You probably can spin the pushrods with 2 fingers.

Check the rocker arm for end play at this point, if there is looseness there between rocker and valve stem then you need longer that stock push rods. There should be a slight preload there on a correctly set up engine, zero valve lash.

If you are lucky enough to find one of the same Stainless Steel valves, measure that length as compared to the stock valve length, that should show you the difference right there.

Or look up the valve specs online and compare them for length. Resellers on ebay usually have all of the valve specs listed.

Stock 302 heads with stock valves bolt right on the LA 318 engines with the stock LA Pushrods, no problem, no clatter.
 
Also - just spit balling- the thickness of head gaskets will add to distance. Fel-Pro blues are .040” thick and factory steels were like 1/2 that. Just the 0.020” is not a lot but adds to the distance. Add that to longer or shorter heights (dependent) and you get noise. Jmho.
 
Ok, thanks guys. I will check it when I get home. I didn't think of the valve stems being a different height. I used .040 thick head gaskets.
 
The engine also has a 454 lift cam that I installed about 3 years ago. The 302 heads were ported and opened up for the bigger 1.88 valves. Really runs strong just makes a lot of clatter and it didn't make noise before. Everybody was saying the 302's bolt right on and go. Didn't think of the valves being longer.
 
Coolmopar said:
The engine also has a 454 lift cam that I installed about 3 years ago. The 302 heads were ported and opened up for the bigger 1.88 valves. Really runs strong just makes a lot of clatter and it didn't make noise before. Everybody was saying the 302's bolt right on and go. Didn't think of the valves being longer.
Click to expand...

Actually your new valves are probably shorter, hence the clattering not taking up the slack.

Or the new valves are sitting up a lot higher (at the seats) from the larger seats not being cut as deep as the factory seats. Making the valves appear shorter.
 
Coolmopar said:
Swapped heads on a 73 dodge dart 318 went from stock heads to a set of 302 castings with 1.88 stainless valves. Engine runs great but now has a lot of lifter clatter and it didn't have it with the stock heads. Any suggestions on why?
Click to expand...

2 things. Head gasket thickness and I think your valves could be set lower in the 302 heads...that means the rockers tilt down more to meet the valve and the pushrod needs to grow to take up the slack on the other end of the 'teeter totter'.
What valve stem height are the 302 heads compared to the old heads...also what head gasket?
 
Cam and head change with different valves. You need to do a push rod length check. Even with adjustable rockers you can have the wrong length push rods.
 
That makes sense. Head gaskets are .040 compressed thickness. Machine shop says valves are installed to stock spring height so you can use your factory valve train.
 
Coolmopar said:
That makes sense. Head gaskets are .040 compressed thickness. Machine shop says valves are installed to stock spring height so you can use your factory valve train.
Click to expand...
Spring height can be adjusted without changing the stem valve height.
Just get an adjustable length checker and figure it out.
Use the average.
 
You guys were right. I rotated it to number one top dead center on the compression stroke pulled the valve cover and I could spin both push rods easily with two fingers. Can't move them up and down but I can spin them. Question is now what length pushrod do I need? Stock push rod length is 7.500 I'm learning on the fly.
 
Yes stock 318 pushrod length is 7.5

Here is a simple test you can do to see if your stainless steel valve stems are sitting .030 to .050 ths too low.

Paint stick measuring 1 1/8" wide standing up off of valve cover gasket surface on the heads, your valve tips should be flush with the top edge of the sick to work with your stock push rods.

This picture is off stock 302 heads:
20200827_084517.jpg


Have been measuring stock 318 / 360 valves for total length, they both come in at 5".

You badically have 360 valves in your 318 heads.

Think the main issue is your new valve seats were not machined as deep as the stock seats, coming up short on the valve stem tips.

Believe your new stainless valves are stock length from what I am gathering here.

My best guess right now you are at zero lash with no preload with your current setup.

Guessing you need to add .030 to .050 ths to the stock length of 7.5 push rod.

7.5 + .030 = 7.530
or 7.5 + .050 = 7.550 new push rod length.

Best to measure for new push rods though.
 
Coolmopar said:
You guys were right. I rotated it to number one top dead center on the compression stroke pulled the valve cover and I could spin both push rods easily with two fingers. Can't move them up and down but I can spin them. Question is now what length pushrod do I need? Stock push rod length is 7.500 I'm learning on the fly.
Click to expand...
Swore I left a reply....

The proper way to measure is with a pushrod length checking tool. Just as the engine sits now, (as you described above) you would insert the checking pushrod and twist the pushrod to make it longer until you depress the lifters plunger. This amount is generally ether up to the end user or via the instructions by the lifter manufacturer or cam manufacturer.

Considering what you described, if I didn’t have the measuring tool but have zero up and down movement, I’d add .050 or round up to the next measurement for a off the shelf pushrod for a Hyd. lifter. As long as the plunger is depressed at a minimum of .020, I’d feel good about it.
 
the base circle of that cam has been lowered to give you lift so you need a longer pushrod, the gasket has added to that too. Id get adjustable rockers. This is gonna happen again with a bigger cam in the future with custom rods. looking back to my first post of the 302 peds being a different size, that was an ill thought out snap judgement. Sorry 'bout that but the preload was the ultimate concern.
 
Thanks for your help guys. I was looking at that exact size push rod online last night. 7.550 I think you are right it is just sitting on top of lifter and not depressing it at all. No up and down play just looks like exact size without depressing it at all. Hopefully I didn't ruin my lifters by running it like that? It ran surprisingly good, just noisy.
 
I would not run the engine anymore. The plunger is smashing the retaining clip. Very bad.
as long as you get that plunger depressed at least .020, your good. You may want more of a depressing. That’s up to you. Comp cams has adjustable pushrods like MoPar used to sell. They adjust exactly like a pushrod measuring tool. Once you get the length needed, tighten them up and call it a day.
 
what 454 lift cam
new or regrind?
phista hypothised you may have a reduced base circle
regrind for sure
neet trick with that paint stick for a quick check
learn something new all the time
 
I'm not running it anymore. Hopefully I didn't already damage them. It's a crane cam i installed 3 year's ago. It was new then. Just swapped to different heads this time. Same cam that I already had in it. 454 lift
 
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