streetwize

iTrader: (12)

i have a steel hood on my 86 gxl. i have an aluminum hood that i want to switch out with. my question is do i need to replace the hood latch??? how are they different?

thanks for taking the time to help me with my question..

jackhild59

iTrader: (7)

Yes, they are different. IIRC the issue is corrosion -with the aluminum hood latch being suited (and insulated electrically?) for the aluminum hood.

Will the steel latch work? Probably. Should you use the proper latch? Yes, if you can get it.

ATRON3000

hood latch is the same from what I know but S4 &5 rads are a little different so there are interchangeability isuues.

clokker

iTrader: (2)

The only difference between the two latches is the spring tension...the aluminum version being weaker.
There is no special electrical insulation or anything else, just the spring.
They will interchange easily.

streetwize

iTrader: (12)

thats what i had figured... i dont think i would like to slam the aluminum hood to make the steel hood latch hold in place. with the aluminum hood latch less presure and force?

clokker

iTrader: (2)

In theory yes.
Can't say I can tell much difference between the two though.

Gringo Grande

iTrader: (97)

Clokker, feel free to correct me if I'm wrong, but on cars with the aluminum hoods it wasn't just the front latch, it was the side arms (whatever you call them) that were made out of aluminum or whatever as well. Basically if I recall correctly, the problem is theoretically with an aluminum hood + steel latches you get some kind of rust or oxidation or something.

Have I ever seen or had this happen to me or anyone I know? Nope. Would it take a while? I'm guessing so...but the arms and latches were different for a reason between the steel/aluminum hoods I'm 99.9% certain (at least the material they were made out of). =)

Rob XX 7

iTrader: (8)

you have to slam the alum. hood to close it regardless if your car came with it or not

clokker

iTrader: (2)

Since you offered...you're wrong.
At least about the hood latch.
I've pulled two aluminum hoods and latches from the junkyard and the latches are made from steel and are identical to the steel hood latches.
If someone hadn't mentioned that the springs were different, I'd never have known there was a difference.

I have an alloy hood on my car now but tried various latches until I found the one that fit/closed the best.
No idea whether it's the "correct" version or not...as I said before, I couldn't tell the diff between them.

It's certainly possible that Mazda took some sort of corrosion precaution with the alloy hood but I'm pretty sure that the latch wasn't it.

Pele

iTrader: (28)

A steel hood latch also has a round counter weight on the safety catch. This is absent on the Aluminum version.

Regarding the aluminum/steel corrosion theory... They will corrode, but think of this:

What are your rotor housings made of?
What are your side plates made of?
What are your tension bolts made of?
Ditto with your transmission housing and internals... Differential front and rear case parts... Ball joints and front control arms... Ummm. Any other examples?

The combination isn't that bad. A worse combination is Brass and Steel. Avoid brass radiators for that reason.

Then again, how many of these cars have had brass radiators in them with not problem?


Honestly, don't worry about corrosion. The road salt in the snow is the worst... You're in California, so you don't have to worry about any corrosion.

Give a good shot of White Lithium grease to your steel hood latch and enjoy your aluminum hood.
If it's lubed right, you set the hood down gently and press just above the latch to lock it down.

If I have to slam a hood, I open up a can of lube.

Gringo Grande

iTrader: (97)

Hi Clokker, you will have to forgive me but two trips to the junkyard doesn't seem to be the best way to provide empirical proof!

If you take a look at the parts fiche manual, both the 86-88 have DISTINCT latches for particular models as do the 89-92. There are 4 distinct hood latches that were sent with the cars:

FB01-56-620E: Steel Hood w/o Burglar Alarm
FB02-56-620F: Steel Hood w/ Burglar Alarm
FB13-56-620C: Aluminum w/o Burglar Alarm
FB15-56-620F: Aluminum w/ Burglar Alarm

On the 86-88 the hinges were the same regardless of the car. On the 89-92 there was a difference of the hinges based on whether the hood was aluminum or steel.

Hinge Steel Left: FB01-52-420E
Hinge Aluminum Left: FB13-52-420E
Hinge Steel Right: FB01-52-410E
Hinge Aluminum Right FB13-52-410E

This due to the oxidation issues and I believe the two different metals creating rust issues when you mix the two. A proper hood swap will involve swapping in the correct front latch + the correct hinges to be safe. I genuinely believe the experience and information you have provided in this post is incorrect.

Rob XX 7

iTrader: (8)

corrosion issues? come on guys let it go, hundreds of you have put alum hoods on cars that did not come with them, no ones hood is corroding like its in the dead sea.

What about the bolts, do they all use the same bolts? The bolts are still steel.

papiogxl

iTrader: (6)

The reason for the insulation is because without it, current could flow between the steel hinges and the aluminum hood. With only the latch uninsulated, current will not flow throught the hood, thus no corrosion.

Page 14-13 of the S4 FSM:

Caution
a) Do not replace steel hoods with aluminum hoods without replacing the hood hinges, as aluminum hoods need electrically insulated hinges to prevent electrolytic corrosion
b) Two types of hood locks are used; one for aluminum hoods and one for steel hoods. The strengths of the locks are different due to the weight of the hoods. Use only the proper lock for the respective hood.

Gringo Grande

iTrader: (97)

Hi Rob XX 7 -

I understand and appreciate your point. This may seem to be some sort of intarweb pissing contest but it is not. I hope, however, that my explanation makes sense to you...

When I first found RX7 Club I spent 6 months reading/searching before signing up. This saved me a LOT of bashing for asking questions for the 1,325,590th time. That being said, this site is probably the premier resource for RX7 information. While it may seem silly, I think we all have a duty to try and post as much correct information as we can.

My personal opinion of Clokker is I've read many very good posts by him in the past and will no doubt do so again in the future. However, in this instance, I was fairly certain he was incorrect.

All I care about, no matter how irrelevant it seems, is that the RIGHT information be published for someone else to see in the future. I mean from your post count, think of all the incorrect, stupid, and/or dangerous posts you have seen in your time here because someone was parroting some bad information by someone else.

Sometimes there are two different answers or methods of looking at information but, without proof, just saying, it is right "because" isn't a good answer and we do our fellow RX7 lovers a grave disservice by disseminating said incorrect information. =)

</soapbox>

Rob XX 7

iTrader: (8)

I appreciate your information and the time anyone spends to put that information out.

With all this hinge and latch talk it was starting to almost sound like a scare tactic thats all.


I went from a alum to a steel, back to alum. on my vert, a steel hood is by far the best LOOKING hood of them, the glue on the alum hoods can start to fail, and when they fail the hood will not be flimsy but rather the glue has shrunk and caused what looks like hail damage. I cured this on my hood with a combo of releasing the glue and having a PDR guy go at the hood.

The latch would not release the hood, you would have to hold the release and pull the hood open, I used a small piece of foam to hold the release.

But going the other way you will have latches that are stronger, hinges that are stronger as well. I guess if they are different material I dont know if that will really make for that much of a difference?

clokker

iTrader: (2)

If you'll reread my posts I believe you'll find the information within is entirely correct.
I already noted the difference in the springs.
We have not talked about the hinges previous to your last post and I'll be happy to concede that there is a difference- but I'll bet it's nothing more than some sort of isolation gasket.

Back to the hood latches...
The only difference between the latches with and without and burglar alarm is a minor allowance for the intrusion switch...these latches interchange functionally.

The only difference between the aluminum and steel hood latches is the retaining spring and the slight safety catch difference noted by Pele...there is absolutely no difference material/design-wise between the two. There is nothing about the alloy hood latch that would make it less conductive or better isolated.

I'd be willing to bet that you couldn't tell the two apart were they placed side by side and in practice, they both will work with an alloy bonnet.

I appreciate your desire to keep our info pure and correct and by all means, the recommendation to swap the latch and hinges along with the bonnet is definitely the proper way to go- although it'd be a cold day in hell before I'd pull my fenders to swap the hinges out- but you simply cannot say that the correct hinge has anything to do with electrolytic corrosion resistance because it absolutely does not.


Hug?

jackhild59

iTrader: (7)

Drop mine about 3-4 inches and it latches tight. Probably from the extra weight of the 6 coats of paint I sprayed trying to get my car to shine like Rob's.

No, wait, that can't be it. I wet sanded most of that paint back off.

Never mind.

jjwalker

I have a steel hood on my vert which came with an aluminum hood originally. The spring tension on the latch for an aluminum hood will not fully pop the steel hood. When you pop it, you have to dig your fingers into the edges to get it up as it doesnt pop up at all. It just unlatches, and you pry it up with your fingers.

freemanrx7

Correct! I had a silver aluminum hood on my 7 that came with a steel hood. The corrosion happened fast. There is a reason Mazda does the R&D.

misterstyx69

iTrader: (142)

..sort of In reverse though JJ..
ya.the Steel hood weighing in at 56 pounds will sort of Kill any Springing action provided by the "former" aluminum hood hatch to Pop it up so you can put your fingers under it.
But Most Guys are Into Putting the aluminum hood on,Instead of Steel.So The Hood Now will not Close...slammin the hood now is the Option,OR getting the Right hood latch with the Proper Spring is Better.
NOTE: this Should be NOT be taken Lightly.As the New LIGHTER hood could Open up/POP open while you are DRIVING and cause Damage..I saw some pics.,It scared the crap out of me.

Rob XX 7

iTrader: (8)

both of my cars with alum. hoods you have to slam them, they dont close that easy, and they are both from the factory with alum hoods.

daviddeep

iTrader: (4)

Can you elaborate on the extent and type of corrosion you saw on your car? Do you have any photos? Was it rust on the metal hinges or pitting/damage to the aluminum hood? I'm curious because I'd like to swap from a steel to an aluminum hood and want to be sure to do it correctly when I do.

I've read for years about the danger of using an aluminum hood with hinges meant for a steel hood, but you see little confirmation from anyone who experienced actual corrosion. I think this would be valuable info.

Rob XX 7

iTrader: (8)

a simple shim would solve the problem, you have to remove the fenders to get the hinges out so I dont think alot of people will be doing that.

A thin plstic shim would solve the issue and not effect hood alighment.

A dab of teflon gel on the bolts if your really concerned as well.

Pele

iTrader: (28)

Either that or a shim and a bushing where the bolt goes through the hinge.

Rob XX 7

iTrader: (8)

now im curious if someone can look up if the bolts are different?