Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
Calder
New Member
New Member
Posts: 3
Joined: Thu Jan 12, 2023 3:34 pm
Location: Central Texas

Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by Calder »

Howdy, first post here. About a year ago I bought a car (online) from a guy who had bought it at auction a couple years earlier, said he put a couple thousand miles on it, running pump gas and 104 boost. It was advertised as 2.3 Ford, I could see side draft Webers and a big header so I assumed it had some interesting period parts on it.

What I didn't expect was a full-on Esslinger motor circa 1990. Luckily the car came with the original builders, very detailed notebook which indicate it has the following...

'89-ish turbo block, decked and align-bored
stroker crank, now ~2.65L
5.7" rods
~12.75:1 compression
Esslinger aluminum head, #295
Dual DCO50 weber side drafts
Esslinger #2232.5 cam, solid roller (269@.050", .620 lift, 108 lobe separation)
400lb valve springs
Header w/1.75" primaries and 3" collector w/SuperTrap muffler
Electromotive HPV-1 ignition set to 8*initial, rising to 31* at 3K to redline

The motor is in a 1990 Rotus Seven which was raced on the east coast through most of the 90's, weights ~1600-lbs.

Since I received the car I've only driven it around the block in second gear, backed it into the garage and set about refreshing the important stuff and figuring out what I bought. Which it a bit more than I bargained for.

This spec motor is a couple notches higher than anything I've worked on before so I'm in line for a spot at a race prep shop to help me assess the motor and find out where things stand mechanically.

I'm still exploring what to do with the car, originally thinking sunday drive in the country and some autoX. Now I'm exploring vintage racing, NASA time trials, track day car, something more suitable for the motor.

Based on my lap around the block the motor sounds fairly healthy, had good oil pressure, and wasn't making any ugly noises aside from a mis-fire which I think was due to a plug wire resting on the header.

So far I've checked or done the following...
-Oil change, ~5.25qt Valvoline 20-50R with Wix 51515R filter, only drained about 3.5q
-new plugs, wires
-new timing belt/pulleys/front engine seals - Esslinger Kevlar round tooth
-valve clearances - in or very close to spec
-cheap bore-scope camera shows nothing bad in the cylinders, that I can see
-~140psi on all cylinders

Questions...
How should I approach assessing the motor, aside from disassembling and measuring?

Is there anything in particular to this combination of parts I should keep an eye on?

Is there a snowballs chance this motor could be streetable?

What would be the best approach to de-tuning it a bit, new pistons and cam?

Esslinger suggested using 110 octane, or E85... would a octane booster with 93 octane pump gas be a viable substitute for race fuel? Maybe just during assessment?

<scratching head>

Thanks
You do not have the required permissions to view the files attached to this post.
Tuner
Guru
Guru
Posts: 3184
Joined: Sun Apr 01, 2007 5:26 am
Location:

Re: Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by Tuner »

Esslinger suggested using 110 octane, or E85... would a octane booster with 93 octane pump gas be a viable substitute for race fuel? Maybe just during assessment?
NO! no pump gas. 100LL Avgas would be my choice. You can add octane booster containing MMT, 1 OZ per 5 Gal.
KnightEngines
Guru
Guru
Posts: 2682
Joined: Fri Jan 09, 2009 8:51 pm
Location: Australia

Re: Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by KnightEngines »

E85 will tame it a lot, and make more TQ into the bargain.
The webers can be tuned to run on it no problem.

Do a leakdown test, compression test, check lash, buy an on car spring pressure tester & log spring pressures as a baseline.
Check spring pressure & lash every 2nd race meet or 500 street miles.

When it's due for a freshen (20% leak down or so, or if the valve lash starts growing or the springs loose 15lb seat pressure) you can get the cam reground to a more streetable profile & replace Titanium valves with steel.
n2omike
Guru
Guru
Posts: 1067
Joined: Sat Sep 02, 2006 10:56 pm
Location: West Virginia

Re: Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by n2omike »

KnightEngines wrote: Thu Jan 12, 2023 5:32 pm E85 will tame it a lot, and make more TQ into the bargain.
The webers can be tuned to run on it no problem.
Just tuning Webers to run properly on gasoline can be a PROBLEM. lol
Tuning a set that is calibrated for gasoline to run on E85 would probably give me Turrets! :mrgreen:

This is a SERIOUS 2.3... I don't see it being anywhere near practical for the street. You can probably get GOOD money for it, as there are no aftermarket heads currently available for these engines, and that one has a lot of high end parts. 0.680" lift on a 2.3 Ford??? Dang... Not sure what I'd do in your shoes! Maintaining an engine like that isn't an easy task. It's designed for high rpm power, not lots of miles of street use. A lot of it depends on how aggressive the cam and valve train are.
KnightEngines
Guru
Guru
Posts: 2682
Joined: Fri Jan 09, 2009 8:51 pm
Location: Australia

Re: Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by KnightEngines »

n2omike wrote: Thu Jan 12, 2023 6:29 pm
KnightEngines wrote: Thu Jan 12, 2023 5:32 pm E85 will tame it a lot, and make more TQ into the bargain.
The webers can be tuned to run on it no problem.
Just tuning Webers to run properly on gasoline can be a PROBLEM. lol
Tuning a set that is calibrated for gasoline to run on E85 would probably give me Turrets! :mrgreen:

This is a SERIOUS 2.3... I don't see it being anywhere near practical for the street. You can probably get GOOD money for it, as there are no aftermarket heads currently available for these engines, and that one has a lot of high end parts. 0.680" lift on a 2.3 Ford??? Dang... Not sure what I'd do in your shoes! Maintaining an engine like that isn't an easy task. It's designed for high rpm power, not lots of miles of street use. A lot of it depends on how aggressive the cam and valve train are.
It's not hard to tune for E85, personally I got NFI, but quite a few customers run webers with E85.
1972ho
Guru
Guru
Posts: 1299
Joined: Thu Nov 21, 2013 12:52 am
Location:

Re: Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by 1972ho »

You wouldn’t want to sell it I would be interested in it.
Calder
New Member
New Member
Posts: 3
Joined: Thu Jan 12, 2023 3:34 pm
Location: Central Texas

Re: Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by Calder »

I appreciate the info folks! I'm not ready to sell it, yet. I was always intrigued by the work Esslinger did back then and to have a chance to run one is too good to pass up. The car came with a ton of period spare parts too, so I have to try... I just don't want to destroy it doing something stupid.

I haven't touched the carbs yet, the previous owner said they were ultrasonic cleaned by a race shop some time before the sale, the fuelsafe tank was serviced then also. I'm not scared of trying to tune the carbs for E85 or to do frequent maintenance so long as the fun:effort/cost ratio is OK.

I did do a leakdown test and all cylinders had practically no leakage, though the cylinders seemed wet or oily and it probably has Total Seal rings. I think the cylinders were wet because when I was driving it off the trailer I kept killing the motor trying to engage the clutch in reverse, had to restart a half dozen times, or more, then just putted around the block. The clutch acted like a light switch, later I found a nasty grey gelatin in the fluid reservoir. :!:

I haven't had much luck finding high octane fuel around here, but COTA is 15 miles away, so there has to be something. I'm definitely interested in learning more about E85 as there seem to be some solid benefits and there's a gas station near home. I assume the fuel cell, pump and regulator will need replacing, probably the braided fuel hoses too since these are 30 years old...and aside from that and a bunch of bigger jets what more would I need? & what's NFI?

I've considering switching to FI of some sort to enable different fuel maps for race gas or E85, possibly use the webers for the throttle plates and weld injector bungs onto the manifold, and most of that system could be used on a 2.5 Duratec or ?? later on...
Fusion Works
Member
Member
Posts: 177
Joined: Tue Jun 09, 2015 10:24 am
Location: Huntsville, AL
Contact:

Re: Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by Fusion Works »

Neat project. Lose that motor and and the car probably weighs 400lbs. Those engines are not light at all.

E85 is a solid choice, but its Octane isn't all that high.. Cranking compression is pretty low though, so that cam is rowdy. Gonna need to keep an eye on those valve springs. I might test them to see where they sit.

Webers are good carbs, but they will not be happy to have E85 sitting in them. E85 is great for power, but it hates sitting. Its bad enough in a closed system like a Fuel injection, but in vented float bowls it can get ugly fast if the system isn't flushed on a regular basis. One option would be to just run it on race fuel. You should be able to buy a drum of 110-112 fuel for $500-600. Look for a local Rocket or other "lower priced" race fuels. Still have to be careful with the open float bowls. This is a race motor, not a street motor and it will require a lot more maintenance than a street motor even if you are "lightly" running it.
KnightEngines
Guru
Guru
Posts: 2682
Joined: Fri Jan 09, 2009 8:51 pm
Location: Australia

Re: Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by KnightEngines »

I get customers on E85 to run methanol fuel stabiliser & seal the fuel tank if it's gonna sit for a while.
If it's gonna sit for a decent length of time I tell them to set up a 2 way tap on the pickup from the tank with another pickup line that can be dropped into a fuel can & run some pump fuel through the whole system before shut down.
Runs pig rich, but clears the E85 out for storage.
Calder
New Member
New Member
Posts: 3
Joined: Thu Jan 12, 2023 3:34 pm
Location: Central Texas

Re: Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by Calder »

I appreciate the info! Sounds like E85 may be a good option, but it will come with its own set of 'issues'. I ran into an old acquaintance who has 1000% more experience than me with engine tuning, he offered to help with assessing the motor, once I find some proper 'hi-test' fuel.

Dropping another motor in the car won't be as simple as I'd hoped as there is maybe 3/4" clearance below the hood and the oil pan is the only thing below the frame rails, ~2". From what I've found the Duratec 2.5 is several inches taller.

My friend suggested a Cometic 'Head Saver' shim as an easy way to lower the C/R a little, any thoughts on the merits of that route?

What's the issue with the valve springs and seat pressure? I learned the triple springs (~405#/130#) I have are no longer available from Esslinger, assuming I get into the motor, reduce the C/R, regrind the cam (or find another)... How do I know what rate the springs should be? Is that a function of the target max RPM. What would be the downside to using a spring that was 10 or 20% 'weaker'?

Many thanks!
xxdabroxx
Member
Member
Posts: 98
Joined: Wed Jul 22, 2020 10:38 am
Location: Central CA

Re: Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by xxdabroxx »

I've been running E-85 for the last year in my SBC powered Olds. >13.5:1 compression, aluminum heads and a custom carb. So far it's been great, car seems to like about 39* of timing best but I've settled in on 38* (doesn't really apply to your engine, but throwing it out there).

I just drained the fuel system a couple weeks ago while I make some changes to the car over winter. The car gets run throughout the year about every week or two, at least to warm it up. It's sat for at least the last month without starting and the carb was basically spotless minus one scratch through the anodizing on a metering block. Ethanol doesn't like raw aluminum.

To run E85 you definitely want a compatible fuel system, pump, lines, filter, regulator, etc. You'll need to upsize your pump accordingly too. I'm running a fuel cell with no foam, teflon braided lines, compatible pump, filter, regulator, and carb. Overall the fuel has been an awesome race fuel alternative, our buddies at the track pay $20/gal for race fuel, I buy mine at the pump for <$5 even with the fuel price spike the last year. I'd definitely say I've saved the cost of upgrading the fuel system in the first race season. It is a cold blooded fuel though, as winter rolled in the car got tough to start but it's doable.

This video has some footage of my carb after a year on ethanol about the mid point if I remember.

https://www.youtube.com/watch?v=o_qyvCuZVR4

Let me know if you have any other questions about ethanol, I'm new at it but have a little experience.
fabr
Expert
Expert
Posts: 584
Joined: Sun Jul 21, 2019 8:35 pm
Location:

Re: Accidentally bought an Esslinger 2.3 sohc race motor...yikes!

Post by fabr »

There is sooooo much overblown info about ethanol it is laughable . Follow just a few rules about storing it and there are zero issues using it. I've been running it for about 8 years now with no issues with corrosion at all. Basically all that needs done whenever the car will sit a day or more (especially true in humid environments) is to cap the tank vent/s and bowl vents. Yes all of fuel system needs to be ethanol friendly. As to raw aluminum not tolerating ethanol it is mostly a non issue unless you do not follow the rule of capping vents and/or store the fuel in plastic jugs sitting on a concrete floor. In other words handle the ethanol properly and it is a great fuel with no drawback other than the hard starting in cool(45 or so) weather. I do not use pump ethanol however since you have no control over the water content that may well cause corrosion issues . I buy and use anhydrous e98 by the drum ,blend it to e85. I do that because anhydrous ethanol is as water free as is commercially available and that cannot be said for pump ethanol. I buy 2 55 gal drums at a time that yields approx 120 gallons e85 and with shipping and new poly drums I have approx $5 a gallon cost. Beats the hell out of race fuel and the engine will love it.It would love it even more with a bit MORE compression. Ethanol loves compression even though the octane number will be a bit lower than race gas the natural cooling and knock resistance makes it comparable to higher octane race fuel. Don't be afraid to follow the rules and use it with confidence.
Post Reply