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Username Post: Drill steam holes in a 235 Block??        (Topic#367410)
chevyivar 
Contributor
Posts: 163

Age: 41
Loc: Norway
Reg: 08-30-12
01-08-22 04:02 PM - Post#2834150    

Hi guys.
I have a 235 that im rebuilding, it came with a 261 head.
The head has the steam holes and the block doesn't..have been searching the web but nothing.
Would it be possible to drill the steam holes in the block using a head gasket as a template?

1939 Chevrolet Master Deluxe 85
1954 Chevrolet Bel Air Sport Coupe
1954 Chevrolet Bel Air Convertible


Edited by chevyivar on 01-08-22 04:05 PM. Reason for edit: No reason given.

 


GregH 
Contributor
Posts: 193
GregH
Reg: 01-25-04
01-09-22 02:03 PM - Post#2834229    
    In response to chevyivar

The 261 had siamesed cylinders that made the need for the steam holes. A 261 needs them and has to have them drilled if using a 235 head. A 235 block does not need them.



 
chevyivar 
Contributor
Posts: 163

Age: 41
Loc: Norway
Reg: 08-30-12
01-09-22 04:08 PM - Post#2834246    
    In response to GregH

Thanks Greg, i Didn't know that. Guess ill go for a 235 head gasket.

1939 Chevrolet Master Deluxe 85
1954 Chevrolet Bel Air Sport Coupe
1954 Chevrolet Bel Air Convertible


 
haysd 
Newbie
Posts: 4

Reg: 05-10-22
05-10-22 02:19 PM - Post#2840982    
    In response to chevyivar

Have 1956 truck 261 and a 848 head off a 235 motor. I want to bore the openings in the head to match the in the middle between the arrangements of chambers on the 261. Is the piece involved a similar size as he openings in the square? I likewise recollect an inquiry being pose about "point", there and point is as well??



 
Airlifter 
"7th Year" Gold Supporting Member
Posts: 860
Airlifter
Age: 76
Loc: Tazewell county, Virginia
Reg: 06-07-15
05-10-22 05:24 PM - Post#2840998    
    In response to haysd

I installed an 848 head but I didn't drill the steam holes. I have read that it is not necessary and I wasn't near a machine shop near my location. Engine running fine.

1951 styline deluxe sport coupe w/'60 261 engine & 54 powerglide


 
rrausch 
"17th Year" Silver Supporting Member
Posts: 14810
rrausch
Loc: L.A, Cal. & St. Louis...
Reg: 04-07-03
05-11-22 05:53 AM - Post#2841017    
    In response to Airlifter

The 261 engines came in 2-ton trucks that were often worked hard. Hauling heavy loads up and down hills, especially in summertime, created a lot of heat in the engine. The steam holes and the full-pressure oil system both helped dissipate heat. But for our uses, I have read drilling the holes in an 848 head are not needed. Is that true? I have not heard of any overheating disasters from guys running 261/848 engines without drilling the steam holes.

1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.




 
haysd 
Newbie
Posts: 4

Reg: 05-10-22
05-11-22 08:35 AM - Post#2841028    
    In response to rrausch

Is the bit used the same size as he holes in the block? I also remember a question being ask about "angle", so is there and angle??





 
rrausch 
"17th Year" Silver Supporting Member
Posts: 14810
rrausch
Loc: L.A, Cal. & St. Louis...
Reg: 04-07-03
05-12-22 04:37 AM - Post#2841086    
    In response to haysd

I had mine drilled at the machine shop. If I can get to it, I've got a 261 head out in a barn shed. I'll try to take a look at it today, and maybe take some photos of the angle of the steam holes.

1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.




 
chevyivar 
Contributor
Posts: 163

Age: 41
Loc: Norway
Reg: 08-30-12
05-13-22 12:20 AM - Post#2841126    
    In response to chevyivar

FYI.
I ended up not drilling holes in my 235 block. I installed the 261 head together with the 261 gasket. working temperature is normal and no leaks, Still breaking in the rings, So far so good.

1939 Chevrolet Master Deluxe 85
1954 Chevrolet Bel Air Sport Coupe
1954 Chevrolet Bel Air Convertible


 
rrausch 
"17th Year" Silver Supporting Member
Posts: 14810
rrausch
Loc: L.A, Cal. & St. Louis...
Reg: 04-07-03
05-13-22 10:28 AM - Post#2841146    
    In response to chevyivar

Glad you sorted it out.

Here is what I found:

This is a 1959, 261 head.
As can be seen, one steam hole is almost 90 degrees, while the other is slightly angled at 15-16 degrees from vertical.

Between cylinders 1&2



Between 3&4



Between 5&6




1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.




 


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