I'm going to be building a new motor for my FB this summer (13B) - Are there any significant disadvantages to using used rotor housings (in good condition) as opposed to new? What should I look for to determine the condition of a housing?

 

When determining the condition of the rotor housings...look for flaking of the chrome around the edges of the housing and around the edges of the exhaust port. This is the main thing to look for when you are deciding whether or not to use the old housings. If the chrome looks to be still in good condition (when cleaned up of course) then there is no reason to go out and spend $$$ on new housings.

 

There is no way you're going to get the compression numbers out of a used housing as you will out of brand new ones. But from what i've read from kevin landers, is that differences aren't really that significant. IIRC he gets around 115psi on most of his used rotor housings, which is plenty for a daily driven vehicle.

 

mine isnt going to be a daily driver, how much hp do you think it would change? ill be running S5 rotors

 

There is no substitute for new housings.

 

I say used are just as good as new! I re-use them all the time, nothing
wrong with that! Unless the housings have gouges. flakes or chips
there good to go! Now used housings wont last as long (as miles),
but for performance there just fine!

JP

 

no, used are not as good as new. But they are adequate.

so no, there is a substitute, but if you can, then do replace them.

it all comes down to your budget, you get what you pay for.

 

i have heard 1/8 in. limit on flaking.

 

^ meaning how much flaking is on the edges of the rotor housing right?

well thats probably right, but i would say even that is a little bit much. I doubt compression numbers would be very good with that much flaking, and its only going to get worse once its gone that far. But there are lots of used housings out there with no flaking, i would say those are the only other options to using new housings.

Now right there im being hypocritical because i had very small amounts of flaking in my rebuild, but it was much less than 1/8 of an inch. Again it had to do with me being freaking broke

 

on the engine i just pulled apart...there was about 1/4 flaking on either side! luckily for me i had pulled apart an engine prior to that one and the housings were in prime shape

 

new housings are running in the $700 range X 2 (Last time I checked, the pre-86 12-A and 13-B housing were almost out of production). For that price, I would rather get a J-spec motor say from Robert. At least this way, I know that majority of the parts inside are still re-useable. Also, re-sell the used low compression rotors and find some 89+ n/a rotos.

 

If your housings are in pretty good condition, you could get them cermet coated and fixed. JHB Engineering will coat your housings with a ceramic/carbide coating, fill in pits and flaked areas and send them back good as new

The advantage to this is that the new coating is more durable that the original chrome, it's patch-able if you throw an apex seal, and I've heard it's got a smaller co-efficient of friction (I think that's how you say it...?).

Worth looking into if you have the money. I want to do that with my motor eventually.

Jon

 

does this JHB engineering place have a website, i couldnt seem to find it on google