Steve's Ride

[simplyconnected]

'Pressure' is defined as, resistance to flow. I'll use the garden hose example becuse it applies. When the hose is unrestricted, pressure is very little but flow is at max. Put your thumb over the end, and pressure rises but flow slows proportionally.

There are different ways to restrict oil flow. I like using aluminum heads and I tap the oil hole in the second stand with 1/4'-20 threads. Some guys use a brass carb jet because it has a head. I use a set screw but I let shallow threads stop the depth.

FE engines run at idle with FIVE PSI oil pressure. To me, that's too low. I want to see 20-psi or more at idle and 45+PSI at running speeds. In order to get these results, a HIGH VOLUMN oil pump needs to be installed with restrictions in the heads. It's the classic 'thumb over the hose' affect. Rather than running all the flow unrestricted through the rocker shafts, they simply don't need that much oil so I restrict it. As a result, oil pressure at idle speed raises.

Oil pressure comes at a cost. The oil pump driveshaft and distributor gear deliver more hp than the stock setup. The pressure relief valve also dumps more oil back into the pan at high rpms because proper pressure is attained and 100% flow is not needed. Were's the benefit? At low rpms when extra demand is put on the main bearings. The crank always needs to be floating and suspended in oil pressure. 5-psi ain't gunna make it.

A double-row true roller timing chain needs to power the roller cam, distributor, and oil pump. These are only available for 1963 (and later years).

BTW, what distributor gear did you get for your new Comp cam? - Dave

[Yadkin]

The cam gear appears to be machined in.

What size hole to drill into the set screw?

My new Jeep with the Chrysler Pentastar engine has a dual pressure pump. At start up it runs 80 psi, at low speed warm-up it runs 40, and under load it runs 80 again. It takes 5W-30 non-synthetic oil and the computer monitors the engine load over time and tells you when to change the oil up to an 8000 mile interval.

[simplyconnected]

...BTW, what distributor gear did you get for your new Comp cam? - Dave

This gear isn't part of the cam.

[YellowRose]

Steve's Ride

Steve, please downsize your pix to 800x600 at the max and re-post them. Otherwise, the webmaster is liable to take them down..... 800x600 is the maximum size allowed for posting on this Forum...

[Yadkin]

I'm not sure why it matters, as they are just links. But here goes:

[YellowRose]

Steve's Ride

It matters because there are long standing limitations on the size of the pictures that are allowed to be uploaded to this Forum. That limit is 800x600 for a .jpeg file, and 800x1200 for a .jpg file. There is also a file size limit too. For a .jpeg or .jpg file it is 146.5kb. If you go to Manage Attachments below, you will find those file limits for each type of file that can be uploaded. Another reason why it matters is if you upload a file that is larger than 800x600 it causes one to have to slide back and forth to see the whole picture and read the text. A file size of 800x600 does not cause that.

[simplyconnected]

Steve, these picture limits were set by Alexander. Text limits for each page follow the widest picture. I'm sure that back then many more people had 4:3 screens. Some still do. As a courtesy to them, we abide by Alexander's simple request. Folks with 16 X 9 screens never see a problem (or a difference) but folks with older systems (around the world) must scroll back and forth to read the text for the whole page.

Your cam gear pics are nice. When you bought the cam, what distributor gear did they tell you to use for your particular cam choice? You may not know this, but if you use the wrong distributor gear it won't last long.

Here is a distributor gear:

Call Comp Cams at 800-999-0853. Ask if you can use your stock distributor gear for your new cam. You may end up spending an extra fifty bucks to satisfy your cam gear. - Dave

[Yadkin]

I told them I had a bone-stock '64 TBird 390 motor. If it doesn't fit my stock gear, I'll have to change something then.

[simplyconnected]

This is not a matter of 'fit' but a compatibility issue.
Call them.

[Yadkin]

Yeah they said I nee a bronze gear or composite.

[Yadkin]

The rocker set came in today.

[Yadkin]

I'm working on my piston selection now. Here's my calculations.



My machinist measured the deck clearance for the existing pistons at 0.18. I guessed a 0.041 gasket thickness and 1 cc piston dish and crevice volumes, then used the advertised engine dimensions and found the advertised compression ratio of 10.1 to 1.

He cc'd the heads and found them actually to be 76cc, and with that and the measured cylinder wear my existing ratio was about 9.9.

He's suggesting that we shoot for a compression ratio of between 9.5 to 9.75. So depending on how much clean-up needs to be done of the deck or head mating surfaces, that will determine the chosen piston and gasket.

I figured out a useful rule of thumb for this engine: Every 1 cc of added unswept volume reduces the compression ratio by about 0.1. Every .005 mill reduction or reduced gasket thickness does the exact opposite.

[simplyconnected]

Steve, I'm real happy to see you're getting into the reality of a good engine overhaul. It's not a simple thing you slap together.

I'm going to suggest you stick with a compression ratio around 9:1 for many reasons. Yeah, 10:1 offers more punch but it also requires higher octane gas. Detroit filling stations only sell 10% gasohol and I wouldn't be surprised if they kick that up to 15% very soon. So, they have NO regard for classic car needs. Lower compression engines last longer between rebuilds because they don't stress the rings, rods or bearings as much.

Did you pick a ring yet? I suggest you use moly rings. Most new cars are built with them (and hyper eutectic alloy pistons). If this build was intended for a race application, I would suggest forged pistons. In the absence of a supercharger or turbocharger, hyper eutectic will work just fine and they are not expensive.

You are headed in the right direction. Congrats on using the roller cam. Now you can use regular oil with no special additives.

I'm confused about the distributor gear because I've never heard of a 'composite'. - Dave

[Yadkin]

Originally I was leaving this up to my mechanic/ body guy (Brad) but he's been having health problems and my project with him has been put on the back burner as he's had to cut back to mostly working his day job only. Since then I've taken over all of the chrome work and the engine build. It's worked out well for me since the colder months here are typically slow for me employment-wise.

I think "composite" means an aluminum-bronze alloy of some sort. I purchased a Mallory #29430 which is bronze. The stock distributor is very cool with the FoMoCo logo so I'm going to rebuild it with a Pertronix module. I'd like to clean up the housing (maybe soda blast?) and then paint it with a clear coat. After it cures I'll use a scotch brite pad on it to dull the finish back to a natural look.

I'm curious as to why you think I should stay at 9.0 compression ratio. My machinist (Kevin) thinks I need to go with 9.5 to 9.75 with the cam that I have chosen. (Valve lift is 0.529, duration at .05 218 224 intake-exhaust.) I understand that I'll need premium fuel, but that was what the engine was originally designed for with a higher 10.1 ratio.

I understand the desire for a hypereutectic piston because of the wear properties (16% silicon) but I've searched through all the brands that Summit Racing carries (they seem to have a near complete selection) as well as four our five other online catalogs and Keith Black is the only one that I found that is remotely applicable. That's the last piston on my table. With a .04 gasket the compression ratio is only 8.5 and with the thinner .02 gasket, only about 8.9. Kevin would have to mill down 0.04 with the thin gasket to achieve 9.5.

The third section of my table is the Sealed Power forged piston. This uses a 4032 alloy which is 11% silicon. With the thin gasket it will give me 9.5 without milling. Kevin may need to mill to get completely flat surfaces anyway, but the block and heads are in great shape so he may not have to do much to it.

I found several forged pistons with the low silicon 2618 alloy that give high compression but I'm building a street engine so won't consider them. I want this engine to run 250k miles before I rebuild it again.

[Yadkin]

I was wrong. Composite is a high-tech material, in this case carbon fiber. Pricey!

http://www.summitracing.com/parts/HRS-94402/