Alloy Head etc weight savings

[Dave Bilyk]

Out of interest while I have the engine down, I got the bathroom scales out and weighed some bits and pieces.
....................Iron............. Al ...........saving
Heads... 2 x 26.4kg.. 2 x 13.5kg.. 2 x 12.9kg
Manifold.......18.6kg..........8.3kg.........10.3kg
Total...........71.4kg..........5.3kg..........36.1kg

Don't have the alloy timing case and water pump, but iron weights are;

Pump 5.2kg
Timing case 6.4kg
Total 11.6kg

can anyone fill in the alloy pump and timing case weights?
I would guess a total saving of around 5kg, say 40kg all told.
That's a hefty 3.3% saving / increase in power to weight even for a 1200kg car.

Dave

 

[Jim Rosenthal]

When I was looking for an engine for my Kirkham Cobra, the guys that built it made a point of advising aluminum heads- they said that even without more power (which aluminum heads generally will make, since you can specify a higher CR without detonation) the advantage of less weight and less weight higher in the chassis is well worth it.

They wouldn't let me use an aluminum bellhousing, though; they made me use a Lakewood scattershield, which weighs two or three times as much. At least it's down low. ..

 

[Ron Earp]

That's a hefty 3.3% saving / increase in power to weight even for a 1200kg car.

Dave

It is a lot more than a 3.3% weight savings. Cast iron covers and manifolds? Toss em or sell them on to a restoration enthusiast.

And, besides the weight, generally speaking if you're using a modern aluminum head you'll be getting a better flowing head which will result in more power. Win win.

 

[Brett James-McCall]

Dave,
I was always told that putting aluminium heads on meant you could run air-con and roughly keep the same weight as just having cast heads without air-con.

As for the timing cover, mine was ally to start with... and I have chopped the front off my water pump and plugged it. The pully and its housing weighs a lot in the total piece.

Here's an extract from Dave Champ's engine build from when he had his GTD:

As a final job for the day I decided to check the weight of the head and intake manifold versus the new ally ones. ​

<!--mstheme--><TABLE id=AutoNumber2 style="BORDER-COLLAPSE: collapse" borderColorDark=#000080 cellPadding=2 width="100%" borderColorLight=#000080 border=1><TBODY><TR><TD align=middle width="33%"><!--mstheme--> <!--mstheme--></TD><TD align=middle width="33%"><!--mstheme-->Heads<!--mstheme--></TD><TD align=middle width="19%"><!--mstheme-->Intake manifold<!--mstheme--></TD><TD align=middle width="49%"><!--mstheme-->TOTAL<!--mstheme--></TD></TR><TR><TD width="33%"><!--mstheme-->Old Ford steel units<!--mstheme--></TD><TD align=right width="33%"><!--mstheme-->50 + 50 =100 lbs<!--mstheme--></TD><TD align=right width="19%"><!--mstheme-->42 lbs<!--mstheme--></TD><TD align=right width="49%"><!--mstheme-->142 lbs<!--mstheme--></TD></TR><TR><TD width="33%"><!--mstheme-->New Edelbrock ally units<!--mstheme--></TD><TD align=right width="33%"><!--mstheme-->29 + 29 = 58 lbs<!--mstheme--></TD><TD align=right width="19%"><!--mstheme-->17 lbs<!--mstheme--></TD><TD align=right width="49%"><!--mstheme-->75 lbs<!--mstheme--></TD></TR></TBODY></TABLE><!--mstheme-->

So the total weight saving is 67 lbs, almost half the weight of the original items. If I had also fitted an aluminium water pump it probably would have been half.
This is a serious lot of weight off the top of the engine, above the centre of gravity of the car. It also represents about 30/1350 ths (2.2%) of the whole car's weight, which at 350 bhp is equivalent to an extra 8 bhp. Hardly astounding but useful. I can now add 30Kg of air-con equipment and keep the performance the same!<!--mstheme-->​

​

 

[Dave Bilyk]

Update, having received alloy Timing case from Mike Huddart.

....................Iron............. Al ...........saving
Heads... 2 x 26.4kg.. 2 x 13.5kg.. 2 x 12.9kg
Manifold.......18.6kg..........8.3kg.........10.3kg
Timing Case...6.4kg...........1.5kg..........4.9kg
Total...........71.4kg.........36.8kg........41kg


Dave

 

[PhillipM]

It also represents about 30/1350 ths (2.2%) of the whole car's weight, which at 350 bhp is equivalent to an extra 8 bhp.

<!--mstheme-->​

Even better as it's a percentage gain right from idle all the way to the redline so it'd probably have a similar effect to double that gain from other means.
And of course there's the handling benefits.

 

[Ron Earp]

Are you still using an iron pump?

 

[(C)arlos]

not to forget other savings

- brakes, Granda Calipers are quite heavy compared to Willwod
- NO knock on Wheels ( the adapters are heavy)
- no Glas rear window ( I have one and don't use it, way to heavy)
- no carpet
- no brake servos
- light tilton pedal box floor mounted
- paneling ( the GTD on my Jiig had a steel paneling :-( )
- rims, there are significant differences...the revolutions seem to be much lighter then image wheels having the same size....
- pullys
- seats...wau they are quite heavy. After looking into this I had mine made to my specs and they are less then 4kg each.
- etc

I looked into all of this and my tornado is (tanks half full) 950kg !


Ohhhh he ...forgot one think....the easiest way to save some pounds ... take a diet..


cheers
(C)arlos

 

[Brett James-McCall]

Ohhhh he ...forgot one think....the easiest way to save some pounds ... take a diet..

Drive naked? LOL

I think Dave is looking at stuff that he can do reasonably, but you could go as far if you are rebuilding your engine, look at an ally block as well.

If you go into handling, you could start to look at ancillary placement around the car ie moving fule pumps lower, moving battery and other stuff around to get a better balance/lower CoG.

I would do all of this of course IF I won the Euro lottery... instead I just want a car on the road :undecided:

 

[Dave Bilyk]

Ron, yes, still have the iron water pump, I have weighed it at 5.4kg, I expected the saving to be less than for thetiming case, so I have left it for later.

Carlos, now I see why you are skeleton.
Mines a DAX, so it will never be Tornado light, but
brakes, yes I have Wilwood and HiSpec
- NO knock on Wheels have standard hubs, but would only consider KO hubs, not adapters
- no Glas rear window - mine is plastic
- no carpet - I needed it to absorb the water on a wet run:laugh:
- no brake servos - ditched already
- light tilton pedal box floor mounted - Tilton top mounted is not that heavy.
- paneling ( the GTD on my Jiig had a steel paneling :-( ) - don't have any at all except GRP around the front compartment
- rims, there are significant differences...the revolutions seem to be much lighter then image wheels having the same size.... - I have 3 piece Image, they are quite light, its the tyres that make the difference.
- pullys - pressed steel
- seats...wau they are quite heavy. After looking into this I had mine made to my specs and they are less then 4kg each. I will weigh mine next time.

Brett, all good stuff to consider, but the lottery is mine, mine I tell you

Dave

 

[Bob Putnam]

Don't forget a lighter flywheel... Not only do you lose the basic weight, you also lose the rotating inertia.

 

[Dave Bilyk]

That's a good and interesting point Bob, and it applies to wheels and tyres to a lesser extent too. In the case my Renault transaxle I have a smaller Essex V6 flywheel for a 9-1/2" clutch compared with the larger standard flywheel for a 10-1/2" clutch, so get a head start.
Having drawn up my fwheel, it weighs 20.7lbf with an inertia of 414lbf.in^2 if anyone has weights or inertias for a standard 302 and a lightened one it would be interesting to compare.

Dave

 

[Brett James-McCall]

Dave,
As they refer to it in the cycling world, you need to start a Weight Weenies thread

Actually I might do that. It would be interesting to see what components people would choose if starting from scratch to acheive the lowest possible and what they would trade-off comfort over weight etc.

 

[Howard Jones]

I think you are going to need to consider a LS series V8. All Alum everything right from the start. AND by the time you buy the parts to build a all alum SBF you could have had it for a lot less money. I recently was looking at a crate LS6 I think. The 425ish HP version. It was 125 pounds less than the 425HP winsor FMS 302. Thats shipping weight. I am not sure about different crates or some such thing but it did make me wonder about how GM saved all that weight.

I would also wonder what a Audi V8 would weigh?

I also believe that a R21 with all the good upgrades will be about the lightest transaxle to support, lets say 400HP.

The real weight to be trimmed is in the body. My guess is a GTD body could be 200 pounds less...........but it wouldn't last long on the street if you kept to fiberglass and made it thin.

Once you get down to about 2000 pounds it gonna really cost big bucks to trim off the next 200. My guess on the 2000 -1800 200 pound cost would be 3-4 times more that the previous 200, 2200 -2000.

It could easily cost 3 times as much to build a 1800 pound GT40 as a 2600 pound car. Fun to think about however.

 

[(C)arlos]

Also replacing the copper waterpipes could be an option, but I have no idea how reliable the plastic tubes are ...Any experiences ?

 

[John S]

This is a very interesting topic. I would like my GTD40 to weigh around 1000 kilos or below and am wondering if this would be possible and where to start.
On top of that, the higher the weight the more important to get it down. The same goes for unsprung weight.
When the weather gets better I will try to get my car weighted and see how I can shed weight. Some of the things mentioned above will help me know where to look, but maybe some of you can share some more info on this subject.

John