Spitfire head

[DonaldSmith]

Dpollo said that the Spitfire head would lower the compression ratio, and stated some bore and stroke dimensions.  I guess I don't understand. 

Don't the pistons rise to be level with the top of the block, regardless of bore and stroke? 

I can see different heads having different combustion chamber volumes.   I could see a problem with a head cast for a small bore,  but used with a large bore.  The pistons might kiss the head at the edges of the combustion chambers.     

  

[Brad47]

Thank you I’ll try 

[55 Fargo]

17 minutes ago, DonaldSmith said:

Dpollo said that the Spitfire head would lower the compression ratio, and stated some bore and stroke dimensions.  I guess I don't understand. 

Don't the pistons rise to be level with the top of the block, regardless of bore and stroke? 

I can see different heads having different combustion chamber volumes.   I could see a problem with a head cast for a small bore,  but used with a large bore.  The pistons might kiss the head at the edges of the combustion chambers.     

  

Well what does bore and stroke do????

In a 250 or a 265 the cylinder volume is larger, correct?

Now lets use the 250 4 1/2 inch stroke 3 7/16 bore.

A 218 has a 4 1/8 stroke and 3 3/8 bore.

So now if you placed the smaller chamber 218 head on a 250 it increases the compresssion accordingly. 

Place the larger 250 on a 218 and theoretically you lower compression accordingly.

My illustration is a bit vague but it gets to the point.

Perhaps Dpollo can elaborate on this in more detail....

[Brad47]

It would be nice if it could work but it’s a little out side my realm of expertise.

[Don Coatney]

I used a dial indicator to measure valve lift with my reground cam to insure I had ample valve to head clearance with the shaved head I installed.

[greg g]

Don, what was your total lift on the regrind?  I believe stock was on the order of  .0375 to .0395, so trying to find out how much higher the regrind was over stack.

[Don Coatney]

33 minutes ago, greg g said:

Don, what was your total lift on the regrind?  I believe stock was on the order of  .0375 to .0395, so trying to find out how much higher the regrind was over stack.

Advertised at .410" lift minus the .015" lash for an actual of .395". I do not know the factory lift.

[greg g]

I was told .375 by George.  .020 doesn't seem like a lot of difference.  Even at the full .410 it doesn't sound like it would make a lot of difference.  Was there a big change in duration?

[55 Fargo]

13 minutes ago, Don Coatney said:

Advertised at .410" lift minus the .015" lash for an actual of .395". I do not know the factory lift.

Its  a .395 lift and a 242 duration a common mild cam.

Stock is .375 lift.

That cam should spin up to 4500 rpm though.

There certainly are more agressive but as they rise so does being less street tame.

Not a real hiperf cam grind but a little more pop than stock..

[55 Fargo]

2 minutes ago, greg g said:

I was told .375 by George.  .020 doesn't seem like a lot of difference.  Even at the full .410 it doesn't sound like it would make a lot of difference.  Was there a big change in duration?

.410 is a big difference Greg specing from .375.

Now .435 gets wild...

[55 Fargo]

2 hours ago, Don Coatney said:

I used a dial indicator to measure valve lift with my reground cam to insure I had ample valve to head clearance with the shaved head I installed.

This is a rough guide line and does not specifically include a Canadian 218.

[55 Fargo]

Okay fooling around in the shop for a few minutes this afternoon. I actually ran my ATV and snow blade down the driveway a few times, had a about an inch of snow....LOL 

So I pulled the head off my Industrial 265 engine, here are some pics, thew chambers are huge and quite deep, I do think this head might have been cleaned up in the last rebuild.

This engine is not bad, and if it did not have a tiny bit of cyl ridge and a rust spot on cyl 6 I would fire it up and possibly use it as is.

This head will not be getting used, I am looking specifically for a late 1950s big truck 250 or 265 head if possible.

This engine is supposed to have 7:1 compression ratio, as per 1960s spec for Massey combines, now if this is true, not sure why it can't be milled to accomplish 8 or even 8.5:1 compression, but have been advised its not a good head to use and milling will not improve it.

This head on a 218 or a 228 would no doubt drop the compression drastically.

If I milled it, it most likely could stand to .100

 

 

[Brent B3B]

Recycling the thread title.... ?

can someone tell me why three of my head bolts are threaded inside the head of the bolts?

I am guessing this is a transplant motor in a truck I have......just curious 

 

 

[Dodgeb4ya]

They are threaded to mount engine parts and ground cables to the cylinder head area of the engines in both cars and trucks.

The tread size is 3/8" X 24 TPI

On some of the trucks.... 1-1/2 ton on up two are used to mount the top bracket of the oil filter housing to the drivers rear side of the head.

Chrysler straight eights use them to mount the air cleaner bracket on 1946-48 Cars.

The head is a 1946-54 Chrysler car head... could be a valuable 265 engine?

Edited August 7, 2019 by Dodgeb4ya

[40desoto]

1 hour ago, Brent B3B said:

Recycling the thread title.... ?

can someone tell me why three of my head bolts are threaded inside the head of the bolts?

I am guessing this is a transplant motor in a truck I have......just curious 

 

 

On my 1954 265 engine those threaded bolts are to mount the throttle linkage assembly on top

[greg g]

Most stock heads measure 2 inches thick at the head bolt flat to the bottom edge of the head where it meets the block.  A micrometer measurement should indicate whether the head has been milled earlier in it's life.  When I first my 56 230 engine, I have .040 taken from the head and .010 from the block.  My machinest calculated compression went from 7 to 1 to 8.5 to1.  A healthy increase.  So measure your head and any you might think of buying to establish if they have been messed with.  My opinion is the increase in CR really wakes up these engines some one has suggested that .090 is the limit without needing to mess with valve clearence unless you have a highlift cam installed.

[Don Coatney]

My Spitfire head measured 1.930". I do not know if it had ever been shaved.

 

 

 

[chrysler1941]

10 hours ago, Brent B3B said:

Recycling the thread title.... ?

can someone tell me why three of my head bolts are threaded inside the head of the bolts?

I am guessing this is a transplant motor in a truck I have......just curious 

 

 

On my 1941 Spitfire, threaded bolts are for throttle bracket, Vacuum tube to carb, clips,  and air cleaner bracket 

Edited August 7, 2019 by chrysler1941

[Plymouthy Adams]

this has been answered twice now......they are for mounting various engine control brackets and often also found up front in the vicinity of the thermostat housing as a battery ground point.  In all seriousness, I would look at replacing that heavily corroded one pictured...

Edited August 7, 2019 by Plymouthy Adams

[Matt Wilson]

I'll answer it a third time.  On my '49 Power Wagon, these bolts were used for attaching the horn.

[Brent B3B]

13 hours ago, Don Coatney said:

My Spitfire head measured 1.930". I do not know if it had ever been shaved.

 

 

 

I’m right with you Don, measured 1.925”

sadly though I think only the head was changed for “ the cool factor”.... Thinking i only have a 236 in this truck. 

Thanks everyone for the info.

[greg g]

I used them to facilitate the building of my dual carb throttle linkage, and for fastening my battery ground strap not yet attached in this pic but you can see the threaded head near the thermostat opening.

[chrysler1941]

1 minute ago, greg g said:

I used them to facilitate the building of my dual carb throttle linkage, and for fastening my battery ground strap not yet attached in this pic but you can see the threaded head near the thermostat opening.

My opinion threads are too few for serious ground connection.

[greg g]

Been working fine for over45000 miles.

[kencombs]

2 hours ago, chrysler1941 said:

My opinion threads are too few for serious ground connection.

But, the real connection is between the flat cable end/bolt/washer/bolt sandwich.  Not just the threads.