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Engine component weight reduction

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robcadle

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Going through new shipment of parts I got for my engine upgrade. All upgrade parts quoted are from Denis Welch.

Al head (with guides seats and valves, without rocker assy): 35.5 lbs
Stock iron head (same state as above) 84.9 lbs

Al flywheel 10.4 lbs
Stock flywheel: 28.2 lbs

Al backplate 7.7 lbs
Stock backplate 20.0 lbs

New starter: 9.5 lbs
Factory starter: 18.3 lbs

Alternator: 9.5 lbs
Generator: 21.4 lbs

Total weight savings: 100.2 lbs

This doesn’t include impact of tubular headers versus cast iron exhaust manifold, or triple Weber/manifolds versus twin SU’s (not sure which one weighs more).

Hopefully interesting info for others.

Rob
 
Sound like all good things. Don't forget to subtract the weight that is no longer in your wallet:greedy_dollars:
 
Are you using it on the track or road?

The weight in the flywheel helps the engine tick over, removing too much may affect that if you are using it on the road and could be a PITA. I would check with DW to see what they say. I have had some 6 to 8 lbs removed from my flywheel and all is fairly cosy.

:cheers:

Bob
 
just curious but what about the front plate? do they not make it in aluminum for a reason?
 
The front plate is significantly smaller and lighter than the rear. I’m guessing that is the reason they don’t offer an AL version of it, but I was still surprised they do not.
 
Bob Hughes said:
Are you using it on the track or road?

The weight in the flywheel helps the engine tick over, removing too much may affect that if you are using it on the road and could be a PITA. I would check with DW to see what they say. I have had some 6 to 8 lbs removed from my flywheel and all is fairly cosy.

:cheers:

Bob
Click to expand...

Ditto. My wife drove a 240z for years and at one point we installed a stock 280z motor with added aluminum flywheel. Bad idea. In order to keep from killing the engine, one had to give it a lot of gas and feed in the clutch. Of course the car had AC, which exacerbated the problem.

I'm a big fan of Tom's lightened flywheels in combo with easier BJ8 diaphragm clutch.
 
I don’t think 10 lbs will be a problem given the mass of the clutch assembly, the rotating inertia of the crank, and the engine’s inherent low end torque. There’s still a lot of inertia in there.
 
I have the same combo and more on my BT7. I machined all the pulleys and water pump out of aluminum. lightened the bottle lifters with bucket type and smiths brothers push rods.
10 -- 11 lbs on the flywheel works very well on the street. I reduced weight by 130 LBs. I had to lower the front suspension by 5/8 inch to return to level due to weight reduction that brought the front end ride height up
 
Thanks for that feedback. I’m worried about the ride height impact and thinking I’ll probably need to fit new springs. Did you use shorter springs to reduce ride height or use some other method?

Curious also what else you fitted for reduced weight.

I haven’t included the crank damper, aluminum sump, or AL water pump pulley. I think these are probably low impact on weight but I’ll see soon.

My primary objecting in the engine part selection was power and reliability increase but 100+ pounds weight reduction is very welcomed.
 
robcadle said:
Thanks for that feedback. I’m worried about the ride height impact and thinking I’ll probably need to fit new springs. Did you use shorter springs to reduce ride height or use some other method?

Curious also what else you fitted for reduced weight.

I haven’t included the crank damper, aluminum sump, or AL water pump pulley. I think these are probably low impact on weight but I’ll see soon.

My primary objecting in the engine part selection was power and reliability increase but 100+ pounds weight reduction is very welcomed.
Click to expand...
I’ve seen photos of spacers used to lower the spring bottom plate thereby lowering the height. Maybe someone will post the photo(s)?
 
Tom's Import Toys has the front end lowering kits at reasonable cost. Are there similar kits for lowering the rear?

Unfortunately my steep(ish) driveway doesn't allow for any lowering otherwise I'd be doing this.
 
I forgot to mention more weight savings can be had by pitching the steel backing plate to gear box and making one out of aluminum.
The arm to spring perch floor is 2 piece construction on Healeys.
By separating this 2 piece (A arm) to (spring floor) by removing the 4 bolts.. one by one and carefully fitting spacers of the appropriate thickness along with longer grade 8 bolts.
This keeps the spring rate the same but lowers the ride height. Toms Import Toys in Oregon sells them in a variety of thicknesses. Dan
 
Patrick67BJ8 said:
I’ve seen photos of spacers used to lower the spring bottom plate thereby lowering the height. Maybe someone will post the photo(s)?
Click to expand...
It’s really simple. Replace the bolts between the lower A-arms and spring pan with longer ones and insert cylindrical spacers between the arm and pan. I had the DW spacers in there, but it lowered the front end a bit too much for the aluminum sump. I replaced the spacers with (IIRC) 1/2” nuts. They slip over the bolts.
 
robcadle said:
Thanks for the tips on ride height adjusters. That will be an easy fix once the cars on the road.
Click to expand...

The easiest way to do this is get two long pieces of all-thread. Remove two diagonally opposite bolts from the spring pans and replace with the all thread. Secure the all-thread with suitable nuts on top of the pan and bottom of the wishbone. If you want to be extra-cautious bind the coil spring with a chain so it will remain compressed Remove the other two spring pan bolts. Slowly unwind the nuts on the all-thread until the spring is able to come free. With the spring out of the way, you can put your spacers between the pan and the wishbone using the all-thread ones first to bring up the wishbone and pan to the coil spring, then do up the other two.
 
robcadle said:
The front plate is significantly smaller and lighter than the rear. I’m guessing that is the reason they don’t offer an AL version of it, but I was still surprised they do not.
Click to expand...

They're available, you just need to broaden your search.
 
The front plate looks to be about 1/4" thick. I'm guessing it wouldn't be too hard to make one using the original as a pattern.

Am also guessing you could weigh the original, then figure out what the difference would be in aluminum for the same piece.

Couldn't tell from the examples I found on eBay whether the holes around the periphery were threaded or not.
 
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