1950 and 1951 valves

[billfish]

Could some one tell me the difference between a 1950 and a 1951 intake/exhaust valve. Mac's lists the 1950 as 8BA-6505, $6.95 and the 1951 as 1BA-6505, $19.95. Do these two years use a different valve. They both look the same in the picture, straight stem and use the same guide-8BA-6510?

[Mike51Merc]

I think the '51s are self rotators with slight differences.

[flatjack9]

There is a small difference in the location of the valve keeper. I sure don't see why there would be that big of price difference. 51 went to a different retainer system with a shorter spring.

[tubman]

That's over $200 difference for a full set of valves! How much does it cost to install hard seats?

[billfish]

Van Pelt information says the 8ba valve is 4.49 inches long and the 1ba valve is 4.54 inches long. Other vender's prices are close between the two valves I think Mac's must be a mistake but they so no. Anyway I guess there not interchangeable.

[GOSFAST]

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Originally Posted by billfish

Van Pelt information says the 8ba valve is 4.49 inches long and the 1ba valve is 4.54 inches long. Other vender's prices are close between the two valves I think Mac's must be a mistake but they so no. Anyway I guess there not interchangeable.

Hi Bill, the 8BA valves, both early and late, are both 4.820" (nominal), the difference is in the keeper location. The later valve ('51/'53) has the groove down .200", the earlier one has it down .260". This is mentioned above and is correct.

I put a shot below of the later OEM (Manley #A711 replacement) on the left and one of ours we keep here. You can see the keeper locations.

Thanks, Gary in N.Y.

P.S. We use only the early Stainless valves on the right, not the Manley pictured. They should be in the $120.00 neighborhood for 16, slightly less maybe.

[billfish]

Attached are pictures of two valve train kits from mac's. one is for a 1950 at $226 and the other is for a 1951 at $395. They look the same but the valves are different as described in above post. I'm thinking the 1950 model would fit in my 1951 but would not have the rotating valve operation that the stock 1951 has. Am I kidding myself or are they interchangeable if the complete kit was installed?

[JSeery]

Originally Posted by billfish

Attached are pictures of two valve train kits from mac's. one is for a 1950 at $226 and the other is for a 1951 at $395. They look the same but the valves are different as described in above post. I'm thinking the 1950 model would fit in my 1951 but would not have the rotating valve operation that the stock 1951 has. Am I kidding myself or are they interchangeable if the complete kit was installed?

Sorry Billfish, these two photos don't just look alike, they are the same photo!

[Ross F-1]

Yep, the one on the right isn't the 1BA type. See below

The rotators aren't enough with no-lead gasohol, you really need hardened seats. Don't ask how I know...

[billfish]

Pictures above are correct-Mac's got lazy and used the same picture on there website. The question is can the two assembles shown above be interchanged between the 1950 and 1951 8ba engines. For some reason the 1950 complete valve train kit is $226 and the 1951 Kit is $395 at Mac's.

[40cpe]

Yes they are interchangeable if you use the complete set up of each one. I remember that there are two different height lifters but I don't know how that relates to these valve setups. someone will come along to straighten that out. If you use adjustable lifters, it is a moot point.

You don't HAVE to shop at Macs.

[aonemarine]

I would have to assume that the installed sping height is the same on both set ups.
But what is the correct installed height??

[Ol' Ron]

The early 8BA engines had asingle spring retainer. In mid 51 they switched to a two piece Valve rotator assy along with a different length valve and lifter. However, the blocks are the same and the valve assys are interchangeable. I prefer the rotators for a street engine.

[billfish]

I'm having no luck finding a listing for a solid lifter for the 1951 8ba. Are they available or are they all adjustable. Only thing I find is a 91a-6500 for up to 1948.

[JWL]

NO, the valves are not the same length for all years. Although the difference is usually easily handled with adjustable lifters.

[Walt Dupont--Me.]

The early lifters are 1.720 long, the later lifters are 1.750 long. I save all the 1.750 lifters, they come in handy when butt grinding valves with performance cams. Walt

[tubman]

Originally Posted by billfish

I'm having no luck finding a listing for a solid lifter for the 1951 8ba. Are they available or are they all adjustable. Only thing I find is a 91a-6500 for up to 1948.

I got an NOS set from Southside Obsolete earlier this winter ("Barnfind08" on here). They are new and the price was very reasonable.

[GOSFAST]

Here's a shot below of a few more valves for comparison, one is the OEM intake, then a Manley replacement, and the ones we stock here.

Thanks, Gary in N.Y.

P.S. The ones with the keys only .200" down may actually help in some situations where the spring pressure needs to be slightly lowered, but so far we haven't seen it here.

[billfish]

Thanks to everyone for your help and information, this site is incredible. I'll update when I get to this job. Right now I'm running pretty well with a couple of weak exhaust valves. Looking to keep cruising this Summer and get to this in the Fall.