3400DOHC: GM did good. What can we do better?

Aaron · Post by **Aaron** » Tue Oct 25, 2005 11:52 pm

Neither of us honestly know enough to argue this. It is purely experienced opinion for now.

But by you and me trying different things, and seeing what works and doesn't, we get a good idea of how to PROPERLY fix it in the future. I'm not denying that smoothing out drainback will fix it, I'm just saying that I'm trying something different. Neither of us knows if either solution will work. Maybe I will still spin bearings. Maybe you will screw up the cams. Who knows?

Hopefully both work, then we can get a great idea of how to properly fix it.

If I had the time/money to do it truly right, I would smooth out the drainbacks. But I would also do 360 bearings, and definately do a high capacity pan.

The Dark Side of Will · Wed Oct 26, 2005 12:05 am

Series8217 wrote: How would you know how much restriction of oil to the heads is safe? There are a lot of surfaces up there to be oiled.. I realize an adjustable oil pressure regulator could be added but its not like you'd want to rev the thing and then turn it down until the lifters just start tapping then add a bit of pressure.

First of all, remember that at low flow a restrictor orifice isn't necessarily much of a restriction. It only becomes a large restriction at high flow (high RPM).

So basically, I think you have a good starting point... find the orifice size that gives you lifter tick at idle... increase the orifice size (area) a small amount (10% maybe) to avoid lifter tick.

The top end oiling needs are not nearly as critical as the bottom end oiling needs. The cam bearings and lobe faces/lifter faces don't have anywhere close to the force on them that the main and rod bearings do.
Lifters are lubricated with spray from the cam journals, as well as from around the tops of the friction surfaces via the gallery that feeds the lifters, drippage from the inside of the cam cover, etc...

Mach10 · Post by **Mach10** » Wed Oct 26, 2005 1:19 am

Guess I should show off my []D [] []v[] []D [] []\[] engine bay, now that I have pretty much everything the way I want it :thumbleft:

Series8217 · Post by **Series8217** » Wed Oct 26, 2005 3:45 am

Mach10 wrote:Guess I should show off my []D [] []v[] []D [] []\[] engine bay, now that I have pretty much everything the way I want it :thumbleft:

Good looking motor, but what a mess! Hahaha

Did you loop the hoses on your power steering pump? I hope you gutted it. Others have experienced problems with the looped hoses. I can't remember what happens though.

The Dark Side of Will wrote:
Series8217 wrote: How would you know how much restriction of oil to the heads is safe? There are a lot of surfaces up there to be oiled.. I realize an adjustable oil pressure regulator could be added but its not like you'd want to rev the thing and then turn it down until the lifters just start tapping then add a bit of pressure.
First of all, remember that at low flow a restrictor orifice isn't necessarily much of a restriction. It only becomes a large restriction at high flow (high RPM).

So basically, I think you have a good starting point... find the orifice size that gives you lifter tick at idle... increase the orifice size (area) a small amount (10% maybe) to avoid lifter tick.

The top end oiling needs are not nearly as critical as the bottom end oiling needs. The cam bearings and lobe faces/lifter faces don't have anywhere close to the force on them that the main and rod bearings do.
Lifters are lubricated with spray from the cam journals, as well as from around the tops of the friction surfaces via the gallery that feeds the lifters, drippage from the inside of the cam cover, etc...

Ahhh, I was thinking that lifter oil pressure needs would increase as RPMs go up, but that isn't the case now is it? So as long as there is enough at idle there is plenty while revving.
I'm going to look into doing this. That head oiling cover plate will very very simple to machine.
Not that any of this is necessary for my stock redline motor..

crzyone · Post by **crzyone** » Wed Oct 26, 2005 4:54 am

A non gutted looped ps pump actually draws about 10hp at high rpm, or so I've heard. About the only real problem. My hoses were looped, and I didn't gut the ps pump, no ill effects but it probibly did sap some hp.

Mach10 · Post by **Mach10** » Wed Oct 26, 2005 8:09 am

PS pump has been gutted.

As for hose and wire routing, I have to think about it for a while, in terms of how exactly I want to bundle it together. In the meantime, I get to test for leaks and bad connections BEFORE I make it almost totally inaccessible

p8ntman442 · Post by **p8ntman442** » Wed Oct 26, 2005 8:17 am

is that the intake I powdercoated? or did you paint that?

Mach10 · Post by **Mach10** » Wed Oct 26, 2005 9:02 am

It's a high-temp ceramic-based paint engine (or so the can says).

It's quick, it's dirty, and it doesn't seem to flake off at the first hint of oil. Plus it lets me "test-drive" the color (or something like it) before I have the motor rebuilt (and the uppers subsequently powder-coated or else properly stripped and painted/cured).

I was thoroughly impressed with the results; even consistent coverage, no sagging, and the stuff seems almost as tough as powdercoating for scratch and chemical resistance. Oil, Gas, brake cleaner, brake fluid... Nothing seems to touch it.

I'm sure it'll start flaking off in a few months... But by then the motor will be coming back out anyway

Kohburn · Post by **Kohburn** » Wed Oct 26, 2005 10:23 am

Mach10 wrote:It's a high-temp ceramic-based paint engine (or so the can says).

It's quick, it's dirty, and it doesn't seem to flake off at the first hint of oil. Plus it lets me "test-drive" the color (or something like it) before I have the motor rebuilt (and the uppers subsequently powder-coated or else properly stripped and painted/cured).

I was thoroughly impressed with the results; even consistent coverage, no sagging, and the stuff seems almost as tough as powdercoating for scratch and chemical resistance. Oil, Gas, brake cleaner, brake fluid... Nothing seems to touch it.

I'm sure it'll start flaking off in a few months... But by then the motor will be coming back out anyway

I have discovered it to be not extremely resistant to brake cleaner/carb cleaner

p8ntman442 · Post by **p8ntman442** » Wed Oct 26, 2005 12:28 pm

cant remember who bought this, its the one I thought was yours.

Kohburn · Post by **Kohburn** » Wed Oct 26, 2005 12:40 pm

what temperature do you bake it at and for how long? the aluminum epoxy I'm making my new intake out of wants to be heat treated for 1-2 hours at 250* for best results after curing..

Mach10 · Post by **Mach10** » Wed Oct 26, 2005 12:42 pm

Kohburn wrote: I have discovered it to be not extremely resistant to brake cleaner/carb cleaner

Time will tell. So far, though, it's held up fine to both. Not seeing any mottling or transfer as yet.

Again, I have no illusions as to it's longevity, but I prepped the plenum fairly well, so it should give me a couple of months

Kohburn · Post by **Kohburn** » Wed Oct 26, 2005 12:44 pm

Mach10 wrote:
Kohburn wrote: I have discovered it to be not extremely resistant to brake cleaner/carb cleaner
Time will tell. So far, though, it's held up fine to both. Not seeing any mottling or transfer as yet.

Again, I have no illusions as to it's longevity, but I prepped the plenum fairly well, so it should give me a couple of months

mines been on almost a year - only a few spots have really started to degrade on the front valve cover.. probably was a bit dirty..

main problem is the color seems to fade and get darker over time.. so i'll probably go with more of a real paint next time.

Series8217 · Post by **Series8217** » Wed Oct 26, 2005 1:18 pm

I've always used rustoleum on car parts. Worked great on my wheels, worked great on my motor:

I did use a dremel to grind off the mold parting lines. I also sanded the top until it was nearly smooth and then applied thick coats of primer until I had enough to fill in the rough texture and sand flat. In my opinion, painted rough cast aluminum looks worse than it bare.

Note that the Rustoleum paint is NOT resistant to brake fluid and cleaner, but you shouldn't be spraying that around your intake anyway! It seems to hold up find to throttle body cleaner and starting fluid. Chip resistance is moderate; it seems to be fairly flexible.

Kohburn · Post by **Kohburn** » Wed Oct 26, 2005 1:21 pm

the extra prep time to make it smooth really makes a difference

Aaron · Post by **Aaron** » Wed Oct 26, 2005 3:14 pm

Tell me about it that plenum looks great Series!

Out of all the pics of your motor--that one looks best.

p8ntman442 · Post by **p8ntman442** » Wed Oct 26, 2005 4:12 pm

Kohburn wrote:what temperature do you bake it at and for how long? the aluminum epoxy I'm making my new intake out of wants to be heat treated for 1-2 hours at 250* for best results after curing..

depending on the coating, there are different times and temps.

400*f for 35-40 minuts is typical for the regular colors, low temp clears need less. I would not bake anything in your kitchen oven or in a gas oven, use a electric one, they can be found anywhere for free, even if you use it and throw it away, the fumes will ruin your kitchen oven.

Kohburn · Post by **Kohburn** » Wed Oct 26, 2005 6:36 pm

well I was mostly asking - as in if you were to do the work :thumbleft: