Zinc plate case through bolts?

[tholyoak]

Having some parts plated and was wondering whether there are any potential negative impacts of having the case through bolts yellow or clear zinc plated?

Todd

[faapgar]

All day long.

[bkreigsr]

Fred, please expand.
'All day long' on the zinc plating or 'all day long' on the negative effects?

There is currently a 3.0 rebuild on the FS forum with zinc plating on the case bolts, and I'm wondering if this is a good thing or not.

Thanks, Bill K

[Harpo]

Zinc has minimal corrosion protection. If your going to have them electroplated to prevent them from rusting then have them done in either cad or zinc-nickel. If you get them electroplated please have them baked immediately after @ 400. Time in baking is dependent on the hardness of the bolts. Or go with stainless steel from ARP

[gomezoneill]

THIS: stainless steel from ARP

[proporsche]

how could the trough bolt get rusty?? What would be reason to zinc them design??you will never see them ..

Ivan

[AutoXer23]

Do you guys who do zinc plating have a place to send it out to or do you use local places?

[VFR750]

I believe the factory bolts were cadmium plated.

Based on my 30+ year old bolts, the only rusty regions were the exposed head and bare threads. I.e. cosmetic surface rust. Bare in mind they were also caked with oil leaking and dirt.

The working threads and under-head fillets were clean and unrusted. Which means the cad plating was still doing its job. So there was no need to replace the bolts.

If the body of the bolts are rusty, I would recommend replacing them. They have been compromised. Plating would only hide the damaged surface.

Reinstalled after cleaning. 18,000 and 5 years later no issues.

[Shaun @ Tru6]

Case through bolts were originally black zinc phosphate which has minimal corrosion protection. If you replate them they must be baked. Yellow cadmium has better corrosion protection than zinc and less hydrogen embrittlement.

I used to do them in black phosphate, first pics but do them with Cerakote now. Yellow cadmium is a good solution but Cerakote looks correct and will last longer.







Cerakote and yellow cadmium on the left

[Quicksilver]

Originally Posted by Shaun @ Tru6

Case through bolts were originally black zinc phosphate which has minimal corrosion protection. If you replate them they must be baked. Yellow cadmium has better corrosion protection than zinc and less hydrogen embrittlement.

I used to do them in black phosphate, first pics but do them with Cerakote now. Yellow cadmium is a good solution but Cerakote looks correct and will last longer.

. . .

How thick of a coating does Cerakote create? It should make the threads out of tolerance. What kind of machining/treatment do they require?

(Been looking at Cerakote for some other items and it looks bomb proof.)

[Shaun @ Tru6]

Applied correctly, Cerakote is only a little thicker than plating. Acorn nuts spin right on.

I have Cerakoted a lot of hardware, never an issue.

Just did a set of A-arms in Cerakote. These torsion bar adjusters are "loose" if anything.

I am strongly against powder coating and only use Cerakote.

[bkreigsr]

Shaun, not to get too far off track - but whats the up-charge for specifying Cerakote, if there is one ?

Bill K

[proporsche]

[QUOTE=Shaun @ Tru6;11171896]Case through bolts were originally black zinc phosphate which has minimal corrosion protection. If you replate them they must be baked. Yellow cadmium has better corrosion protection than zinc and less hydrogen embrittlement.

I used to do them in black phosphate, first pics but do them with Cerakote now. Yellow cadmium is a good solution but Cerakote looks correct and will last longer.

.................................................. .....................................
Would you explain to me ,i wonder ,how those through bolts can get rust on them if the are inside the engine case no oxygen only oil on them..thanx

Ivan

[Shaun @ Tru6]

Originally Posted by bkreigsr

Shaun, not to get too far off track - but whats the up-charge for specifying Cerakote, if there is one ?

Bill K

Bill, Cerakote and yellow cadmium are both $10 per bolt.

[proporsche]

so,is anybody here to tell me the reason to cover the trough bolts with zinc or anything???

Is it just to be pretty, i guess?

Ivan

[SoyRacer]

Originally Posted by proporsche

so,is anybody here to tell me the reason to cover the trough bolts with zinc or anything???

Is it just to be pretty, i guess?

Ivan

People do it for bling factor. The truth of the matter is that case bolts expand and contract which will allow some plating to flake. That flakes are truly dangerous as they can cause damage to bearing surfaces as well as clog oil passages. I just utilize through bolts raw and will sometimes have the acorn nuts and washers plated if the build calls for “bling”.

[proporsche]

yup that is kinda my point..there is absolute no reason to do that to the bolts-nobody will ever see them again unless the next mechanic will love it...;-) the rest is design i got that..

Ivan

[gled49]

+1 for Soy.