The Stovebolt Site Forums The Shop Area Engine Shop Blue Flame or Thriftmaster?

I noticed some unusual wear on the side of my '55 3100 valve cover, and it looks like I may have a '55 "Blue Flame" engine. See picture here:

Blue Flame Logo

Were blue flame engines installed on manual transmissions? Was it an option? I have 3 on the tree, and I thought the engine was original. It is a '55 dated engine, but now I'm wondering if it was replaced with a passenger Blue Flame engine some time ago.

It's also possible that someone just applied a Blue Flame logo to the orginal Thriftmaster a long time ago. Aside from tearing apart the engine to check if it's got hydrolic lifters, is there any way to tell exactly which engine is installed?

Here are the casting numbers:

Block: 3837004 GM7, J215
Head: 3837161 GM1, J125

By the way, the serial number stamped on the block is 0877432 F255X.

From online documentation, the "X" in F255X indicates it is a 3100-3800 Thriftmaster 235 engine, leading me to beleive that the engine isn't a Blue Flame, and was just labeled as such a long time ago.

I'd still like to verify it though.

You don't really need to be "tearing apart the engine". Just pull the side cover to examine the lifters.Looking at the top of them will indicate hydraulic or solid.

As you most likely know, the Blue Flame engine was a car engine.

In some years (1954 and 1955, for example ), there were two versions of the Blue Flame 235. Yes, in 1955, a Blue Flame Six (235) could have been used on car that had a manual transmission.

In 1954 and 1955, a Blue Flame Six might have had mechanical lifters.

The "Blue Flame" name was used before there was a 235.

The X suffix in "F55X" shows up as a 1955 first series 1/2 ton truck Thriftmaster 235 with standard clutch.
That engine would not be drilled to supply oil to hydraulic lifters.

Same would be true for Chenzo's 0877432 F255X (or, for any 235 Thriftmaster/Loadmaster truck engine until 1958) - is that correct, Dave?

Yes Tim,
There is always an exception, like they ran out of truck engines near the of the day and grabbed a car engine, there should be no truck engine before 1958 that will be drilled for oil supply for hydraulic lifters.

.....couldn't someone have changed the valve cover?

One easy way to tell if it's passenger vs. truck is to see of the motor mount bosses along the side of the block are drilled and tapped. My 55 first series 261 has the bosses on the sides but not drilled out.

I would like to verify the mount drilling, I am not sure that it is always true.

I agree, that drilled mounting bosses is not the acid test, numbers are the only real way. But if you see a motor without drilled bosses it's only for a truck, drilled bosses could have been done by the factory or later.

Couldn't you just pull the valve cover to see? I would think the lifters would'nt have ajustment if it was hydrolic, abd it's only 2 nuts to take off. A lot easier than the side covers.

Thanks all for the replies and info.

Considering the block has the F255X stamping, I'm thinking the engine block is the original Thriftmaster, and not a Blue Flame passenger car engine. As Achipmunk mentioned, a previous owner probably just swapped out the valve cover for a Blue Flame cover.

When I removed the valve cover for inspection last week, I noticed the rockers are adjustable, indicating solid lifters are installed... or at least solid lifters are meant to be installed with that head. Here is a picture of the rockers under the valve cover.

http://i109.photobucket.com/albums/n77/vjsoto/1955%20Chevy%20Truck/IMG_2610.jpg

I also looked for rear mount tapped bosses and there were none.

So it looks like I got a good ole Thriftmaster.

Chenzo

The rockers are the same and adjustable with both solid and hydraulic lifters.

Oh... so I cant tell from the rockers, eh Dave?

Well, I suppose if the lifters are hydrolic, then they should compress and spring back, right? If they are solid lifters, they wont compress or spring back.

I'll save the dive into the side panel for a later day.

Chenzo

Your engine, being a truck engine, could only have solid lifters, unless someone drilled the block to supply oil for hydraulics.

I'm guessing it's entirely possible (but very unlikely) that someone installed hydraulic lifters into the engine and just adjusted the rockers to make the hydraulic lifters act like solid lifters... but that's pretty far fetched.

But hey... I've seen worse!

I'm gonna go out on a limb and say it's got solid lifters and I'm good to go.

Why would you put ajustable lifters on a hydrolic set up? What reason could there be?

Maybe you could tell me a Chev that does not have adjustable rockers.
It would mean making two styles of rockers, for both types, when adjustable works for both.
It is true that once set you never need to readjust.

How would you adjust your hydraulic lifters if they were not adjustable (this is not a trick question)?

hydraulic lifters - 235 - adjustment procedure is on page 6-12

F255x- the 2 stands for second series.

A lot of engines that were designed to run only hydraulic lifters, had the length of the push rod predetermined, so no adjustment was necessary.
This worked fine until you shaved the head or ground the cam, then special push rods could be needed.

Thanks,I missed the "2" in "F255X". That engine would not have center side mounts.

Dave,

I tried to subtly correct your F55X in a post above.

Just so people know (and, correct me if I am wrong) F255X is an indicator that the Flint-build ("F" prefix) truck 235 (designated but the "X" suffix) is a 2nd series truck (designated by the preface "2").

255 was not used for any 1955 car engine (right?).

Did all 1955 car engines use the low-mounted ("internal") water pump as was only used on "255" and later truck engines?

And, finally, 255 used on any 1955 Jobmaster 261 truck engines?

Cars did not have mid year model changes like trucks so all car 235s had the low mount water pump.

A second series 1955 261 would be 255N or 255Q

Sorry gentlmen, I stand corrected. Thanks for the edjucation. I thought because the lifters had a spring in them, they used another kind of rocker. Know that I read the shop manual I under stand. Always room for learning.