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Aluminum Head
- Thread starter Money_Pit
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BUNDYRUM
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Hello Money Pit, welcome to the best forum around. Theoretically you should get more power from an aluminum cylinder head because generally they can take a higher compression ratio, (higher compression means bigger bang so as to speak). The problem with this is that it is difficult to find gas with a high enough octane rating to exploit the benefit of the high compression so what happens is you end up retarding the ignition timing to compensate for the gas which means you lose power. The biggest benefit is that aluminum dissipates heat better and that means less problems with the engine running hot, providing everything else is up to scratch. Regards, BUNDYRUM.
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Hi MP,
I think it depends on what you expect from the engine. I can only speak from experience about the Denis Welch aluminum head. I have reservations about some of the other supplier's offerings.
https://www.bighealey.co.uk/
The DWR head is a very high quality collection of parts. Ports & valve sizes are optimized & flow tested. Very high quality valves, valve guides, hardened valve seats, valve stem seals, springs & retainers, combustion chambers matched & head fully assembled. Internal sections of the casting are reinforced where needed for maximum strength & coolant flow is optimized.
I think that combined with the later BJ7 - BJ8 cam & a set of headers, this head would provide a very noticeable increase in power, reliability. If your engine was built after about Oct. 1962, it likely already has the improved cam. Cooler head temperatures which would help cope with the already relatively high (9:1) compression ratio on your engine. Whether it is worth the $4,500 or so would be your judgement call. If you subtracted the costs of porting, replacing valves, guides, etc. on your iron head, the cost difference would be quite a bit less.
If you are not after the extra power, it would likely be a waste of money.
D
I think it depends on what you expect from the engine. I can only speak from experience about the Denis Welch aluminum head. I have reservations about some of the other supplier's offerings.
https://www.bighealey.co.uk/
The DWR head is a very high quality collection of parts. Ports & valve sizes are optimized & flow tested. Very high quality valves, valve guides, hardened valve seats, valve stem seals, springs & retainers, combustion chambers matched & head fully assembled. Internal sections of the casting are reinforced where needed for maximum strength & coolant flow is optimized.
I think that combined with the later BJ7 - BJ8 cam & a set of headers, this head would provide a very noticeable increase in power, reliability. If your engine was built after about Oct. 1962, it likely already has the improved cam. Cooler head temperatures which would help cope with the already relatively high (9:1) compression ratio on your engine. Whether it is worth the $4,500 or so would be your judgement call. If you subtracted the costs of porting, replacing valves, guides, etc. on your iron head, the cost difference would be quite a bit less.
If you are not after the extra power, it would likely be a waste of money.
D
tahoe healey
Yoda
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Why don't you get the electrolitic corrosion. Is it the gasket that serves as a barrior?
MotorHead67
Jedi Hopeful
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I don't doubt the benefits of an aluminum head but I wonder:
If half the $4,500 was spent on porting, polishing, valves etc. on a cast iron head, would it perform as well and be a better mate to a cast iron block because they're of the same material and heat and cool at the same rate?
If half the $4,500 was spent on porting, polishing, valves etc. on a cast iron head, would it perform as well and be a better mate to a cast iron block because they're of the same material and heat and cool at the same rate?
Skip & Lynne
Jedi Warrior
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I have one thing to say, run it hot one time and see what happens to the aluminum head, blown head gasket and warped head. NUFF CED
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TH,
That's why you use a coolant which has effective corrosion inhibitors & change it frequently. Note that factory recommendations are very fussy about what coolant is used in aluminum & part aluminum engines.
MH,
Unless the person doing the porting has a flow bench & uses it, the result is likely to be quite a bit less than optimum. Things are not at all as they would seem when it comes to ports, valves, & gas flow. If you do find someone who actually gets positive results, the cost to do 12 ports & their valves/seats is likely to cost a whole bunch. Really effective porting is hard to do without experience & a flow bench.
Many engines use aluminum heads on iron blocks. Only a few of the poorly designed heads have had problems. They really do heat & cool at pretty much the same rate as the large mass of coolant in them prevents quick temperature changes.
I replaced an iron head that had huge ports, valves, & looked impressive, with the DWR head & experienced an immediate large torque & horsepower increase. The DWR head had much smaller ports but they were much more effective as the shapes & directions are really designed instead of just indiscriminently enlarged. I have found on a number of engines that partially filling selected areas & reshaping the intake ports made a remarkable improvement. It's the little things that count.
D
That's why you use a coolant which has effective corrosion inhibitors & change it frequently. Note that factory recommendations are very fussy about what coolant is used in aluminum & part aluminum engines.
MH,
Unless the person doing the porting has a flow bench & uses it, the result is likely to be quite a bit less than optimum. Things are not at all as they would seem when it comes to ports, valves, & gas flow. If you do find someone who actually gets positive results, the cost to do 12 ports & their valves/seats is likely to cost a whole bunch. Really effective porting is hard to do without experience & a flow bench.
Many engines use aluminum heads on iron blocks. Only a few of the poorly designed heads have had problems. They really do heat & cool at pretty much the same rate as the large mass of coolant in them prevents quick temperature changes.
I replaced an iron head that had huge ports, valves, & looked impressive, with the DWR head & experienced an immediate large torque & horsepower increase. The DWR head had much smaller ports but they were much more effective as the shapes & directions are really designed instead of just indiscriminently enlarged. I have found on a number of engines that partially filling selected areas & reshaping the intake ports made a remarkable improvement. It's the little things that count.
D
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[ QUOTE ]
I have one thing to say, run it hot one time and see what happens to the aluminum head, blown head gasket and warped head. NUFF CED
[/ QUOTE ]
Hi Skip,
It depends a lot on the head design. Besides, why run it hot? It's so easy to keep a cooling system working correctly. I don't even know anyone who has had the problem. Even on air cooled engines.
Aw, you guys do what ever you want! There are opinions both ways.
D
I have one thing to say, run it hot one time and see what happens to the aluminum head, blown head gasket and warped head. NUFF CED
[/ QUOTE ]
Hi Skip,
It depends a lot on the head design. Besides, why run it hot? It's so easy to keep a cooling system working correctly. I don't even know anyone who has had the problem. Even on air cooled engines.
Aw, you guys do what ever you want! There are opinions both ways.
D
Thanks Dave
Unfortunately mine is an early BJ7 (June of 62) so I'll have to go with a build up and BJ8 grind on the existing cam or perhaps look at the DWR1 cam which is slightly hotter with a 268 degree duration. I think the later with the aluminum head would be a nice combo followed up with a header.
Your thoughts?
DT
Unfortunately mine is an early BJ7 (June of 62) so I'll have to go with a build up and BJ8 grind on the existing cam or perhaps look at the DWR1 cam which is slightly hotter with a 268 degree duration. I think the later with the aluminum head would be a nice combo followed up with a header.
Your thoughts?
DT
Skip & Lynne
Jedi Warrior
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Hi Dave it`s a simple explanation, 3 teenaged daughters. One when she saw the temp gauge in the red hurried 18 miles home for me to check it. That was in a Honda Prelude, blown head gasket and warped head. The other was smarter she drove to school and then called me. To late again this was an Isuzu Trooper.It seems to me that cast iron blocks and aluminum heads have vastly different thermal expansion coefficients God bless them they are all out of college, married and have kids of their own but for 6 or 8 years my sanity took a beating. Skip
Oh yea they are all 3 BLONDES
Oh yea they are all 3 BLONDES
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Hi Skip,
Hopefully, folks driving rebuilt Healeys are more sensible.
I understand, long time ago one of my daughters had way too much to drink, drove or tried to drive on a long winding dirt road. Ran off the road several times. Totally mashed the front of the car including the radiator, drove 25 miles until the car refused to run any more & called her boy friend for help. He called me, we got the car home. Whole bunch of body repair. New radiator, got the engine started, it ran like nothing had happened. It had an iron head of course.
Another daughter, in same condition, drove another car over a parking lot divider & knocked off the pan plug. drove it 20 miles home & said the "oil" light was on. Got the pan welded, new oil, started it & no problems. Both cars were 2 liter Pintos. Pretty tough engines. The "kids" are in their fortys now. Their husbands have to do the repairs - thank heaven.
D
Hopefully, folks driving rebuilt Healeys are more sensible.
I understand, long time ago one of my daughters had way too much to drink, drove or tried to drive on a long winding dirt road. Ran off the road several times. Totally mashed the front of the car including the radiator, drove 25 miles until the car refused to run any more & called her boy friend for help. He called me, we got the car home. Whole bunch of body repair. New radiator, got the engine started, it ran like nothing had happened. It had an iron head of course.
Another daughter, in same condition, drove another car over a parking lot divider & knocked off the pan plug. drove it 20 miles home & said the "oil" light was on. Got the pan welded, new oil, started it & no problems. Both cars were 2 liter Pintos. Pretty tough engines. The "kids" are in their fortys now. Their husbands have to do the repairs - thank heaven.
D
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[ QUOTE ]
Thanks Dave
Unfortunately mine is an early BJ7 (June of 62) so I'll have to go with a build up and BJ8 grind on the existing cam or perhaps look at the DWR1 cam which is slightly hotter with a 268 degree duration. I think the later with the aluminum head would be a nice combo followed up with a header.
Your thoughts?
DT
[/ QUOTE ]
If you can afford it, you won't regret it. Great combination. Consider using the HD8 BJ8 carbs also.
D
Thanks Dave
Unfortunately mine is an early BJ7 (June of 62) so I'll have to go with a build up and BJ8 grind on the existing cam or perhaps look at the DWR1 cam which is slightly hotter with a 268 degree duration. I think the later with the aluminum head would be a nice combo followed up with a header.
Your thoughts?
DT
[/ QUOTE ]
If you can afford it, you won't regret it. Great combination. Consider using the HD8 BJ8 carbs also.
D
Skip & Lynne
Jedi Warrior
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AAAAAAAAHHHHHHHH YES a kindred spirit. They say suffering builds character. Where were you when I needed an understanding shoulder to cry on. LOL Skip
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I'm not sure it's over yet. Got some teenage grandkids. At least they don't live with us. Yet! Hoping for a break.
D
D
B
BUNDYRUM
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According to the book Advanced Engine Design by Heinz Heisler published by SAE aluminum dissipates heat almost 3.5 times better than cast iron. Even allowing for the fact that the construction of the aluminum head will be somewhat thicker in places than the cast iron one it still is 2.5 times better. I would have to say that the DWR head sounds the best proposition because as Dave says it takes a very experience person with a flow bench to get it right. Anyone with that kind of experience probably won't want to spend his time on a Healey head as there are bigger fish to fry out there. I'm sure that even the DWR head can be improved upon but nobody wants to spend the time or doesn't have the flow bench either. As far as the cam is concerned don't waste your time on the BJ8 grind, if you're going to this effort then get something a bit better as it probably won't cost all that much more if anything. What is wrong with getting a cam ground by someone in the US ? there seems to be plenty of people who do it. The header is a good idea even though DW's are only made from regular mild steel as he doesn't believe in stainless. You could always get it ceramic coated and then it should last longer, perform better and even look alright too. Regards, BUNDYRUM.
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BUNDYRUM
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Hello zblu, what brand are your s/s extractors? Can't imagine old Holden cams being designed from Healey ones especially as how old Holdens came out in 1948 (Holden was part of GM even then). Come to think of it the origin of the Healey engine came out in 1948, hadn't thought of that before. As someone said about side exhausts it's the muffler that controls the sound, and also the size of the pipe. Regards, BUNDYRUM.