Ive see all kinds of different valve stem seals for a street hemi. Deep down I have my doubts it will change anything , But decided to do them while I have it opened up

Some say valve guide machining is required, yet some say not, but show what appears to be the same exact style of seal. AKA called a Positive Lock seal .. ( and it appears thats the style on the car now ???????)

Ive found what looks like a normal umbrella seal . yet others say this type will not work with dual springs

Silver Seal # 65120 silicone seals worked great on mine.

This is on your Satellite? What are you doing with double springs?

yes, on the Satellite.

I had a long conversation today with the man who built the engine back in the early 90s

We've come to the conclusion its ring seal he remembers early on it had a fuel pump issue the owner put on it and seriously flooded it , and he feels it washed the rings out of it.

I bought it knowing full on compression was a little high for a street car. Knowing I would want to do a piston swap at some point. to make it a little more pump gas friendly

SO,,,,,,,, plan is put it back together for now and save some pennies up for a piston change maybe next year or so

As for the valve springs. No idea , but thought all Hemis had double springs ??????

If I read the parts book accurately, single spring with dampener.

There is not one answer to your question. You need to know the inside diameter of the inner valve spring and outside diameter of the top of the valve guide. Measure with a dial caliper. Once you have these dimensions, Give me a call and I look in our supply of seals. I use the super blue seals, they work best. They let in enough oil to lube but not enough to burn. They will probably outlast your car.

Hemi Cylinder head guy since 1984, I've tried them all.
Best regards!

Outer spring with surge damper and inner spring without. They were dual spring according to service manual.

As stated it really depends on how the heads were modified if they were. I used FP SS 72522 valve guide seals on my 66 heads, but I had new bronze valve guides installed. 2.2/2.5L seals.

Thanks for the replies all.
Like I said I talked to the gent who built it.
We came to the conclusion pretty good odds its ring seal.
But he gave me some ideas and things to try ( heavier oil weight , with a zinc additive , change pcv valve etc etc )

I knew going in a piston change was in my future with the car and those plans havent changed in that respect. I just need to rebuild the piggy bank before I can cross that bridge .

Again, many thansk for all the replies.

But yes it has both inner and out springs AND a dampner between said springs .
I dont think my hand held spring compressor will do the springs anyway so cyl head removal would be required either way

While we’re here, would you use a different seal for the exhaust and intake since the exhaust is down in the oil more and intake is up top?
And should the intake spring get more oil splash then the exhaust because of how they set on the head?

Just an FYI to anybody reading this thread, 5.2 & 5.9 Magnum umbrella seals fit a Gen 2 Hemi as well. I'm running them on stock Iron heads with beehive springs.

I had my 1970 parts book handy and it list 3418491 as the Hemi valve spring. Looking at the picture in this eBay ad for allegedly NOS springs, 3418491 is a single spring with dampener.

3418491

If you trace this from 66 to 71, you will see changes made wrt to the heads. Mechanical to hydraulic and spring changes. But OPs car is 66.

You've piqued my interest once more. I'll drag out my '66 parts book and take a look tonight.

I also have to consider my car IS NOT oe stock either.

It has a comp cams kit in it. I do not know if said kit included and/or required updating to dual springs or not

Builder doesnt remember ( engine was built late 90s or very early 2000s time frame ) BUT he thinks the seals are from Comp Cams as well

here is the cam card if it helps / matters

PS, i plan to maybe pull it down further either next year or year after. Actual time frame will be determined by the end result when I get it back together this time with the changes Im making
But I will have the heads looked at then and make sure all is right

You are right on. 1966 parts book calls for 2780682 outers and 2780693 inners. What is even more interesting is I found this brochure that has the spring rates for both inner and outer springs and mentions that a surge damper was used also.

1966 Street Hemi Brochure

I love minutia. Good job!

The service manual is your friend to Just went through a lot of this building this

I thought I would update this,.

I just changed the oil in mine ( street hemi with approx 2500 miles on it.)
Went to a Rotella T straight 30 weight and added the Lucas oil ZDDP additive per recommendation of the man who built it. And So far ,,,,,,( knocks on wood ) ,,,,,, it has helped my oil consumption issue . I was going thru almost a qt of oil every 150 / 200 miles. Since the change Ive put almost 200 miles on it and its still on the full mark The only other thing I did was I welded a piece of sheet metal to block off one port in the valve cover that is under the PCV valve to help limit as little oil as possible getting under the valve and possibly being sucked in the intake. Also added an nos PCV valve as well
I did NOT change valve stem seals . After my talk with the builder we both decided it was 100% waste of time and money

PS, The engine builder and myself had a long talk and he highly recommended these changes ,,especially the oil recommendation. And in 100% honesty , Never in my wildest dreams would I have thought the changes I did would have made such a change

Now, I will add. Do I think it cured it ? , absolutely not. But it sure made a change for the better,,,,at least so far so good anyway

The PCV not baffled could suck a lot of oil. It is like a vacuum running all the time. One thing you could of done before the baffle being installed would be to install a catch can in the PCV hose to allow the droplets to drop into the container. After 50 miles you could of opened it to see what accumulated.

To be honest, I didnt think about a catch can. The baffle plate under the valve in the cover has some huge holes in it and I felt far to big especially the one along the upper side of the cover. So I welded in a small piece of sheet metal to cover about 90% of the upper hole( there were still 2 large lower holes )

Ok, hear me out as you guys are gonna think Ive lost my mind.

Drove the car to a local cruise nite last weekend. approx 90 miles round trip, some hiway some inter city driving . Car used just a tad under a qt of oil round trip.
Oil is now straight 30wt with a ZDDP additive

Drove it yesterday to Phoenix ( taking an extra qt of oil with me to top it off when needed. ) just a click over 350 miles ROUND TRIP .........

I ckd it about halfway back on the return trip , was maybe MAYBE a tad over 1/2 qt low. Ckd when I go home and its still less than a qt low. Shows right above the add mark.
Both times I verified it was right on the full mark when I left

WTH ????????