High compression head ????
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Topic author - Posts: 164
- Joined: Sat Mar 09, 2019 5:12 am
- First Name: Mike
- Last Name: Sleep
- * REQUIRED* Type and Year of Model Ts owned: I have 26 & 24 coupe, 25 pickup, and 26 Fordson.
- Location: Kansas
- MTFCA Number: 31639
- MTFCI Number: 31639
High compression head ????
I’m helping a guy get a car running after 15 years. It starts and runs smooth. It has this after market head. I am assuming it is a higher compression. I think it is a “Giant” brand. When doing a compression test what PSI reading should I get? Thanks
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- First Name: Scott
- Last Name: Conger
- * REQUIRED* Type and Year of Model Ts owned: '13, '15, '19, '23
- Location: Clark, WY
- Board Member Since: 2005
Re: High compression head ????
Assuming it is a 5.5:1 head, somewhere under 5.5 x 14.7... so something in the range of 72-75PSI would be quite good
another source puts it at only 4.3:1, which would be something under 4.3 x 14.7, or around 58PSI
hopefully someone who has cc'd one will chime in
another source puts it at only 4.3:1, which would be something under 4.3 x 14.7, or around 58PSI
hopefully someone who has cc'd one will chime in
Scott Conger
Tyranny under the guise of law is still Tyranny
NH Full Flow Float Valves
Obsolete carburetor parts manufactured
Tyranny under the guise of law is still Tyranny
NH Full Flow Float Valves
Obsolete carburetor parts manufactured
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- First Name: Eric
- Last Name: Dysart
- * REQUIRED* Type and Year of Model Ts owned: 1914 Touring, 1916 Touring, 1927 Runabout
- Location: PNW
Re: High compression head ????
According to the Tulsa Club technical page on head design, the Haibe, Giant Power, and Simmons Super Power heads are similar in combustion chamber design and volume. Measured at 255 cc, the resulting compression ratio on an un-milled example would be 4.3:1. http://mtfctulsa.com/Tech/head_design.htm
Keep crankin’
Eric
Keep crankin’
Eric
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- First Name: Mark
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- Location: Portland Or
- MTFCA Number: 52564
- Board Member Since: 1999
Re: High compression head ????
Not all era replacement head were higher compression, some were just better designs that allowed better firing and combustion.
I know the voices aren't real but damn they have some good ideas!
1925 Cut down pickup
1920 Dodge touring
1948 Ford F2 pickup
1925 Cut down pickup
1920 Dodge touring
1948 Ford F2 pickup
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- First Name: Les
- Last Name: Von Nordheim
- Location: Fallbrook, CA
Re: High compression head ????
I have been running a Giant power head on my 13 touring and have been happy on performance. Do not consider it a High compression head.....just a head with better design. The head is cast iron, larger coolant capacity and does not eat out like aluminum heads. Better squish design compared to stock high or low head. The Z and Puris aluminum head have smaller combustion chambers, improved design and provide more compression =better performance. JMHO
Les
Les
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Topic author - Posts: 164
- Joined: Sat Mar 09, 2019 5:12 am
- First Name: Mike
- Last Name: Sleep
- * REQUIRED* Type and Year of Model Ts owned: I have 26 & 24 coupe, 25 pickup, and 26 Fordson.
- Location: Kansas
- MTFCA Number: 31639
- MTFCI Number: 31639
Re: High compression head ????
THANKS for all the info. Going to try to give the old car a test drive this weekend. Been sitting for a few decades.
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Re: High compression head ????
I have a Giant Power Head. Before fitting it I measured it and calculated 5.1:1 compression ratio.
It does have the 'squish' areas above the pistons.
It makes a significant improvement to performance.
On most of those hills where in High with the stock '26 head you gradually slow down from 30 to about 22, it holds 30 or close.
Before the Giant, I tried an aluminium head with a higher CR (above 6:1 I think). Not a 'Z' or a Prus, but well made with steel washers counterbored into the top for the bolts. No identifying marks. This also performed well, but I felt it was a bit too much and that something would break sooner or later.
Giant = Goldilocks for me.
It does have the 'squish' areas above the pistons.
It makes a significant improvement to performance.
On most of those hills where in High with the stock '26 head you gradually slow down from 30 to about 22, it holds 30 or close.
Before the Giant, I tried an aluminium head with a higher CR (above 6:1 I think). Not a 'Z' or a Prus, but well made with steel washers counterbored into the top for the bolts. No identifying marks. This also performed well, but I felt it was a bit too much and that something would break sooner or later.
Giant = Goldilocks for me.