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Posted by: groot May 2 2020, 01:15 PM

So, finally getting around to building a "beater" engine to develop my race car project (been idle too long). The idea is to build a reliable, decent engine that's not crazy expensive to sort out my car, then put in the expensive engine when the chassis is ready. I will only use race fuel with this engine.

Basic specs are:

• 96mm JE pistons
• AA Biral cylinders
• 80mm crank, chevy
• 5.4" Chevy rods
• 2.0L heads (Hoffman prepped) 51.3 cc
• 163/86B cam

So, to get ~0.040" deck height, I'll need 0.210" barrels shims (checked this today), but that puts me at a calculated CR of 10.7:1

Now, the question... should I source 0.220" or larger shims to drop the CR at the expense of deck height? A shim of 0.220" will drop the CR to 10.4:1, but raises the deck height to 0.050"

Thoughts?

Posted by: stownsen914 May 9 2020, 02:25 PM

Is 10.7 to 1 to high for a type 4 running on 110 octane? I’d have thought you’d be OK.

Is this a 150-160 hp engine, or more than that? I’ll be building a similar engine for a vintage racecar (though 1.8L in my case), so am interested to follow this thread.

Posted by: wndsrfr May 10 2020, 06:56 AM

I've got the same build... have to dig a bit to come up with my numbers but I'm on pump gas so just a tad over 10:1.
Jake or Len said not to be too concerned about calculated CR as the cam overlap drops the dynamic CR a lot....like below 9:1 iirc.
Give Len a call.... I'm betting that you're way safe on 110 leaded.
Oil sump needs to be deep. ..pretty sure I have a SCAT deep one here that I'm not going to use...lmk if you want it.

Posted by: stownsen914 May 10 2020, 08:53 AM

Just realized that you're talking about a 2316 displacement. I'd assumed smaller to make a race class. Wasn't noting the details apparently. So prob more like 200 hp.

Posted by: HAM Inc May 11 2020, 05:28 PM

Hey Kevin, I just saw this post. Hope you're doing well. Good to see you surface.

Are you going to hit the track with the 914 when racing starts back? Is Ford Motorsports letting you go do your own racing for while?

Since you're running race fuel I'd stay with the 1mm deck and 10.7:1.

Posted by: 914werke May 11 2020, 07:15 PM

Following

Posted by: groot May 14 2020, 09:50 AM

Hey, Len. Thanks... I should put together my oiling system plan and run it by you, too... It's a bit simplistic, but pretty far off of the stock system.

GT program is over, so, I've got some time to do other things now..... got a kart for my daughter, too.

Posted by: Charles Freeborn May 14 2020, 10:16 AM

Also very interested in this project. In reading through Len's website he recommends against rocker box venting (which my engine has) going to revisit that all. I've also got 2 coolers and an accusump, so not sure how that all figures into the equation(s).

Posted by: groot May 14 2020, 11:35 AM

So, I've taken steps to seal the case, entirely... dry sumps should be sealed case, but I've never seen a type 4 with a sealed case... I know my scavenge stage is not big enough to generate much vacuum, but, I'm going to hook up a MAP sensor to see if it does anything... and, I'll have to watch the valve cover gaskets.

I run an external pressure regulator, so no need for any case pressure regulation/relief.

I found a nifty adapter that allows this setup:

Posted by: HAM Inc May 15 2020, 06:59 PM

Hey Kevin, glad to hear you get to concentrate on your own racing again. Pretty wild your girl is old enough for a kart now. Time does fly.

The case prep looks good. I don't see any reason that won't work. Are you still using the pump I modified for you?

We experimented with zero crankcase venting on the last engine, which had two scavenge stages totaling 60mm's. I hooked up a vacuum gage on the dyno and we were pulling really good vacuum, upwards of 5"+ IIRC. Plenty enough to help make power and run zero venting, but every time we got to around 7K RPM's it would suddenly billow huge amounts of oil smoke out the exhaust. It was still pulling vacuum. I think it was due to severe ring flutter. I have always wondered if gas ported pistons would have solved the problem.

I went back to the -12 chimney vent routed to the top of the sump tank with a vent line from the tank to a catch can and the smoking went away.

Posted by: groot May 16 2020, 06:56 AM

Crazy stuff... about that sealed case.... Interesting, for sure.

Yes, I still have that pump. I've also modified a CB and I'll run them back to back on this engine, to isolate the pressure issue on the race engine, before I open it up to sort it out.

Posted by: HAM Inc May 16 2020, 07:43 AM

I'll be interested to learn how that works.

Which ever pump you end up with you'll still want to run a tuna can sump extension for more complete scavenging. Some baffling in the sump area to decrease sump volume is helpful, too. It also helps minimize windage.

Posted by: groot May 17 2020, 10:12 AM

Sump extension: check
Windage tray: check (see attached) I've got 2 stock ones and this modified one.

Aside from the windage tray, are you talking about additional bits to reduce the sump volume? Clever. We did some work on that for a recent project... it can yield benefits... we had to test the crap out of it to make sure it was durable and proven before we ran it.

This particular engine is about reliability with decent power, not SCCA-optimized performance (it's not legal for SCCA) to sort the car out and then figure out where to go next with the car.


Attached image(s)

Posted by: HAM Inc May 17 2020, 11:18 AM

Yeah, I'm talking about reducing the sump volume. I did it with epoxied aluminum panels. I tried to post some pics but got frustrated trying to generate url's for them.

I posted some pics last year on a thread of my epoxied case and pick up mods. A search should find it.

Kevin if you e-mail me I'll send you a bunch of pics.
info@hamheads.com

Posted by: groot May 17 2020, 01:25 PM

Use the "file attachment" under all the emojis for pics.

I can imagine what you did... probably some ramps directing the oil back the sump. Great idea!!

Posted by: HAM Inc May 17 2020, 02:49 PM

The case with the pickup tube in it was still a work in progress when the photo was taken. Still had panels yet to glue in place.

The pickup shot shows the way I removed the goofy M8 stud that runs down the stock tube. I also cut off the bottleneck with the o-ring that fits in the case and replaced with a fitted sleeve that seals to the case with Durco.
Inside the black circle you can see one of the two M6 bolt that secures the pickup in place from the outside of the case.

In the photo that shows the rest of the panels epoxied in place you can see that I blocked off the passage between the crank&cam gears tower and the sump. I did this to keep oil from sloshing out of the sump and into the tower during braking. Inside the black circle is the drain opening from the tower.

The other case half was easy to panel up as there was no pickup to work around. I blocked off all of the sump area on it.

I did two engines with this approach and both worked great.

Posted by: groot May 24 2020, 09:50 AM

I have some rocker options. Which would you recommend?

2 different rockers and 2 difference swivel foot options.

Posted by: HAM Inc May 24 2020, 05:31 PM

Definitely the 911 swivels (the ones in the top photos).

Stay away from the others. They have a nasty reputation.

Posted by: groot May 26 2020, 05:55 AM

Roger, thanks.