NEW(er) heads vs OLD heads

[bob in CT]

Depends upon how you read it. Looks to me like all Cubs below that number have the old head. All tractors above that number have the new one.

That page I linked was from 1970, five years before Eng SN 312390 was made.

You are missing the point Raymond. Eng-1 is stating sn 312390 as a break point for CUBS, not Lo-Boys! It does not state that the head is NOT used in Lo-boys below that number. I concluded from ENG-1 that all 154's used the newer head and that Cubs did not begin using the newer head until the "New" International Cub in 1975.

[RaymondDurban]

Ok Bob, I was just going by and confused what you said here...

... the later heads are very rare items on Cubs starting at ENGINE number 312390 including Numbered Series Lo-Boys.

[BullDAWG]

ok nube question but what is a "TC-37F" ????

Sorry, it's the parts manual. Here's a link: http://www.cleancomputes.com/Cub/Cub%20 ... index.html

TY thought it was something like that, I look in Rudi's all the time http://www.cleancomputes.com/Cub/index.html
I'm like a kid on Christmas day going through all the manuals n implements lists in there, but never got to that 1 yet

[bob in CT]

Ok Bob, I was just going by and confused what you said here...

... the later heads are very rare items on Cubs starting at ENGINE number 312390 including Numbered Series Lo-Boys.

Yeah, I was watching a basketball game at the time. I was going to say they are rare- but that is only true for Cubs since they were on all Lo-Boys. Above that number they were on all the engines, below that number they were split. I can't figure out why there was an overlap. Same pop-up pistons, carb and exhaust manifold. Why 2 heads?

[Clark Thompson]

If you do some measuring in the combution chamber you will find measurable difference in CC's and a slight difference in shape to allow for piston clearence when using POP up / High domed pistons.

[RaymondDurban]

As Bob mentioned before in this thread, the pop-up pistons were in use in the F-Cubs since '68 with standard heads with no clearance issues. If what you say is true, that the "newer heads" have extra material removed, then the compression would be reduced, resulting in lower HP.

[BullDAWG]

As Bob mentioned before in this thread, the pop-up pistons were in use in the F-Cubs since '68 with standard heads with no clearance issues. If what you say is true, that the "newer heads" have extra material removed, then the compression would be reduced, resulting in lower HP.

Not if the total cc of combustion chamber is same or even smaller on newer heads... example is look @ chevy heads with 64 cc chambers, the old pop up pistons that worked on the double hump heads (old 60's style racing heads) won't fit in new vortec heads even though both have 64cc chambers, but the new vortec chamber is heart shaped while the old style is wedge/kidney shaped... and to some a 76 cc head looks the same as a 64cc unless you know to look @ where the spark plug is and to notice the amount of metal in the chamber ( larger cc's have less metal around the plug so it looks like it pokes out a little, while the closed chamber has more metal around the plug area n plug looks like its sunk in a little...

[bob in CT]

As Bob mentioned before in this thread, the pop-up pistons were in use in the F-Cubs since '68 with standard heads with no clearance issues. If what you say is true, that the "newer heads" have extra material removed, then the compression would be reduced, resulting in lower HP.

Not if the total cc of combustion chamber is same or even smaller on newer heads... example is look @ chevy heads with 64 cc chambers, the old pop up pistons that worked on the double hump heads (old 60's style racing heads) won't fit in new vortec heads even though both have 64cc chambers, but the new vortec chamber is heart shaped while the old style is wedge/kidney shaped... and to some a 76 cc head looks the same as a 64cc unless you know to look @ where the spark plug is and to notice the amount of metal in the chamber ( larger cc's have less metal around the plug so it looks like it pokes out a little, while the closed chamber has more metal around the plug area n plug looks like its sunk in a little...

Raymond's reply was to this specific comment:

If you do some measuring in the combution chamber you will find measurable difference in CC's

and not Chevy heads. I guess I need to do a quickie cc job on those 2 heads.

[BullDAWG]

yes please, I know that the compression went from 6.5:1 to 7.5:1 compression ratio but wasn't sure if its all in the piston change or if its also from the combustion chambers being different cc's....

[bob in CT]

yes please, I know that the compression went from 6.5:1 to 7.5:1 compression ratio but wasn't sure if its all in the piston change or if its also from the combustion chambers being different cc's....

When did the compression change? Do you have that documented somewhere?

[BullDAWG]

When did the compression change? Do you have that documented somewhere?

Not sure read it on page 19 of " Farmall Cub & Cub Cadet " by Kenneth Updike (publisher MBI)

and I quote " In the late 1960s, IH changed these to cast-aluminum domed-top pistons. These pistons helped the C-60 engine jump from 10 horsepower to 15 horsepower and eventually to 18 horsepower. When the C-60 engine was outfitted with aluminum-domed pistons, the engine compression ratio soared from 6.5:1 to 7.5:1."

Now I'm guessing it was in 1968, the year I believe they switched to the pop-up aluminum pistons....

[bob in CT]

I did see information that the 154 was 7.5-1. In these late years, IH was not as diligent in keeping up with some documentation and I would rather see information coming from the source if possible. That was the reason I asked. If the Cub compression ratio changed in 1968, then it is only the pistons because the head did not change until 1975 on the Cub.

[Clark Thompson]

it wasnt only the dome top pistons that slightly upped the HP it was with the combinations of pistons, cam and carburation. I dont beleive it went to 15 engine HP though. Maybe on the numbered series loboys measured at the PTO. I am currently building a hopped up C-60. It is bored .060. Has a new after market head that is somewhat different than any IH head with much less CC's. Plus I had .040 shave off the head to gain another 3 CC's less in each combustion chamber. Im using aluminum flat top pistons with total seal rings.. The intake and exhaust ports are bored and poilished along zeneth carb and the manifold to go with it. Maybe by spring Ill have time to get it fired up.

[Boss Hog]

RPMs are a key factor in higher HP rating

[bob in CT]

Cam didn't change from 1955-on so you can rule that out.
Carb didn't change in 1968, so you can rule that out.
Carb, manifold, head, and RPM changed in 1975.

Talking Cubs only- not the Numbered Series.

Right now is a good time to stop repeating bad information about how a cam change increased horsepower. Show me a part number.