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Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 01 Nov 2016 15:58
by sneax
haha - unfurtunaly the rules should realy be followed - they had sonme cars taking the head off after the race! :shock:

I just contacted one of the officia FIA judges to find out what is possible ... but after all i hear from you guys here - I hope I can use an L engine!

I just got an additional info about my "race engine" and that is that it used the same headers and intake!
that means it has one exhaust port for 2 and 3!
And that means it is NOT an L engine right?

thank you so much!
great forum!

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 01 Nov 2016 17:47
by Chickenman
I downloaded the Carrera Panameric Rule book. Going by your car # 190, it looks like you run " Sport Menor " class. Looking over the rules for that Class I don't think you can run an L-serie's Datsun engine in that car and in that class. I would triple check with the FIA on that. Are you planning on running a different class? A link to your class rules would help.

Regarding the engine in your particular car. J serie's is a pushrod OHV engine and is a copy of BMC B engine. I think it probably got a special dispensation because it was an exact copy of the BMC B engine and was produced by Nissan from the 1960's through the 1980's. Long after BMC had discontinued production. FIA is funny about things like that.

However, if you swap in a more Modern engine, you " MAY " limited to 1600cc...

This is the pertinent section for Sport Menor. Page 29;
Engine:In this category and in all cases, the use of a modern 4 cylinder engine of mass productionwith the same configuration as the original engine of that particular car (inline or boxer) with a maximum displacement of 1,600 c.c., 4 valves per
cylinder and double overhead cams (D.O.H.C.) is permitted.

Any limited production or prototype car of the era must keep its mechanical characteristics. However, an increment of 15% over its original 1954 displacement is permitted.

A maximum of 6" (15.24 cm.) of inline re-location of the engine from its original position is permitted.

The teams are free to use up to 2 carburetors with 2 barrels each.

No fuel injection systems are permitted.
The sentence in Red is rather confusing. If that allows a 2 valve per cylinder OHC engine with 15% displacement than the original, then an L-18 or L20B might be a legal swap. Check with the FIA.

If the FIA says that you are limited to 1600cc with a more modern motor swap. Then I would search for A Toyota Twin Cam motor ( 4A-GE ). Plentiful, reliable, lots of performance parts and make good HP. Pick up one from a bone yard. Swap in dual Webers and a header and enjoy. ... 6-valve.29

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 01 Nov 2016 18:13
by Chickenman
Rules for " Sport Menor " appear to allow any 5 speed transmission. That's another reason to go for a Toyota 4A-GE motor if you are limited to 1600cc with a Modern motor swap. 1980's -1990's Toyota Corolla GTS came with 4A-GE, RWD and a sweet little 5 speed. Get the motor and tranny together. No silly adapter plates required. 115 to 140HP stock depending on generation ( 1st to 3rd Generation )

The Toyota motor will put out more power than a Nissan L-16 ( 8 valve SOHC ) . And it's lighter. You can also buy the Black Top 20-Valve 4A-GELU from Japan used. These are really strong engines and a favorite for Drifters because of the high power output. 160 to 165 HP stock. ( 4th and 5th Generation ) Injection would have to be switched to carbs though. Not a big deal. ... 4a-ge.html

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 01 Nov 2016 20:49
by datzenmike
L20Bs are 2 cm or 0.778" about 3/4" taller that the L16/18. Just get a lower air filter.

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 01 Nov 2016 22:07
by 510rob
Yes but how much taller is an [OHC L16] than a [not-OHC J18]?

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 02 Nov 2016 05:52
by Three B's Racing
Chickenman wrote:Definitely looks like a J series, which is a copy of BMC's B Engine. It's not an A serie's.

Not worth modifying IMHO. Very ancient push-rod design with limited performance and few parts available. An L serie's would be much better. A modified L20B should make 160+ crank hp easily with typical modifications such as twin Webers or Mikuni's, headers and a decent cam. L18 would be similar, but a bit less HP and torque. L18 is about 1" less in overall height than L20B.

If you are swapping engines something like a KA24DE or SR20DE ( Dual cam, 16 valve engines) may be better. The KA's go up to 2400 cc and the SR engines 2000cc.

Edit: Just noticed that you are limited to 2000cc' forget about the KA24DE. Too big. I'll leave the info for reference though.

KA24DE is a bit of a tall and bulky engine, but probably not more than the original BMC engines. SR20DE is very compact and lighter than a KA24DE or L serie's. You'd have to check dimensions for fitment. Tons of these engines in wrecking yards and dirt cheap. KA24DE easier to find than SR20DE.

KA24DE are Torque monsters and fairly low revving. KA24DE has more overall HP and Torque potential for modified Normally Aspirated engines ( No replacement for displacement ), but at the expense of more bulk and weight than SR20DE.

SR20DE are rev happy and best in a light car. If memory serves me correct the redline on the stock SR20DE was 8,000 or 8,500... from the factory. Please correct me if I'm wrong

Now if your Race 1800 engine does turn out to be an L-Series, that is probably going to increase your HP by a minimum of 50 percent right off the Bat, compared to the ancient J serie's. Take some pictures when it comes in and get more specs.
KA24de does have more hp than the SR20DE S13 @ 145hp. But you get ahold of the SR20DE S14 it's 165hp. Revs are limited to 7200 unless you retune for higher reving. I'm running a NA S14 with 10lb aluminum flywheel and Tomie Poncams and I'll tell yah what, it scoots. Ran a friends VG33 Celica and let him see my tail lights.

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 02 Nov 2016 08:25
by Chickenman
I think this whole discussion hinges on the proper interpretation of the rules, which to me looks like he is going to be limited to 1600 cc with any motor other than the J series. Which is frankly, a " Tractor " engine. That is what BMC originally designed it around.

Question to Site admin. Why do we not have page numbers on the posts? Makes referral back to earlier posts much easier.

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 02 Nov 2016 16:33
by sneax
Righty right ...
Great analysys :)
I think you guys are right ... it depends if the FIA officials will allow me to run a L engine! I have put together a few arguments like MGA had already in 54 a DOHC version of their engine ... and more!
I would love to run an original (looking) Datsun engine. But in the end it comes down to a numbers game if my car will be competative against the 356,s.
If I can barley squeeze 140hp out of an "tractor" J engine I might be better off and way cheaper and lighter as well with a Toyota 4a-ge or an other high powered 1600cc engine! (just read it has to be a 16V)
@chickenman or anyone:
you think i can get an 4age, and get 160hp + out of it with a carburator or two and no turbo? Do I have to tune it therefor much like crank pistons etc... or just plug and play or maybe a cam etc...? :)
Looking on ebay - 4age with a 5 speed are freaking cheap with under 2k$ including everything! wow ... that would leave me a lot of my budget for other stuff! :)
are some versions and years better then others? has to be a 16v!

thanks again!

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 02 Nov 2016 18:26
by SteveEdmonton
Sorry, I know the conversation has moved past this point already, but I'm wondering why a Datsun J-series engine of 1800cc displacement, which is a direct copy of the BMC B-series motor of 1800 cc displacement, was ever put into this MGA in the first place!

What was the advantage? Same basic design, same limitations-- but much harder to find parts.

All I can think of is that "somehow" the J-series was viewed in such a way that it enabled a previous owner to increase the car's displacement. MGA's were never more than 1600cc stock (the earlier ones were 1500). But even there, I can't think of any reason why a J-series of 1800cc would have been the "go-to" motor instead of an MGB motor, which is also 1800cc. The MGB motor has LOTS of go-fast parts that are readily available-- and also has a 5-main design in all but the very earliest models!

Maybe the J-series was simply "handy" at the time, and more readily available than the MGB motor? If the swap took place in Mexico, and J-series motors were relatively plentiful there, I suppose that might be it.

But anyway, from this line of thinking, why not consider using the MGB ("original") version of the J-series 1800cc motor-- instead of this mysterious "race" version of the J-series that's been mentioned a couple of times. MGB parts are easy to get, with all sorts of aftermarket bits to get them running very, very well indeed.

Of course they're still OHV, and cast iron, and very limited in their potential compared to any of the modern motors that everyone has naturally been suggesting to Guido. I get it! But if (BIG "if"!) we really want to consider all the options, maybe this is another one that at least merits a few moments' consideration.

(Full disclosure: I have an MGB-GT and, despite all of its numerous limitations, love it!) :D
74 MGB-GT B-series 1800cc.jpg
74 MGB-GT B-series 1800cc.jpg (150.81 KiB) Viewed 1716 times

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 02 Nov 2016 21:30
by Chickenman
The Panamerica rules are very strange. You really have to read them thoroughly and they do differ from class to class. The reason he can run a BMC B engine or the Datsun " Copy " is that you are allowed to increase the displacement of an original style engine ( BMC 1600 in MGA ) by 15%. That is 1840 cc. Thus the BMC B series engine is eligible. Since the Datsun J series engine is an exact copy of the BMC B engine it was probably allowed a special dispensation by the FIA. Similar to how BMC bought the licensing to the Buick 265 ci Aluminum V8 and rebadged it as a Rover engine. The engines are built to the same blueprints. Just rebadged. That's my thoughts any way...

As far as Options, that's up tho the original owner. his budget and what the FIA allows. It takes a pretty highly modified BMC B engine to reach 130 to 140hp. Stock rating was 94 HP. And it's a 60 year old design. A 4A-GE 16v makes 128 HP stock. A 4A-GE20v makes 160 to 165 hp stock. Both can be run on carburators and both can be easily modified to produce even more HP with a Cam swaps. Don't know if the FIA will allow the 20v versions though. The Formula Atlantic 4A-GE's 16V engines were running to 220 to 230 HP on Webers back in the early 80's. But those engines would not be suitable to run in Panamerica or any Rally car.

Toyota Atlantic 1992 Hasselgran. 232 BHP ... 0612ss.htm

From BMC B engine Wiki:
1.8 litre engines

The engine was enlarged again to 1.8 L (1798 cc) in 1962. Bore was 80.26 mm (3.160 in) and stroke was still 89 mm (3.5 in) , power is rated at 94bhp @ 5500rpm. The engine at first had a three-bearing crankshaft with a five-bearing version appearing in 1964

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 02 Nov 2016 21:41
by Chickenman
One thing of special note: What fuel Octane is available in the Panamerica? This can really have an effect on what engine you can run. Apparently you are limited to refueling at PEMEX stations only. What is the Maximum fuel octane at these stations?

Edit. Apparently the PEMEX Red is 92 AKI ( R&M/2 ) or 96 RON. Anything over 10 to 1 CR. I would be dumping in a good Octane booster.

A water separator for the fuel system may be a good idea as well. Some of the older PEMEX stations are known to have problems with water contamination.

Panamerica rules:
For all of the categories, it is obligatory that the all of the cars use the commercially available unleaded fuel ("Magna" – green / "Premium" – red) available at PEMEX service stations. The use of aviation fuel is prohibited. The penalty is disqualification from the event.

The use of fuel additives and octane boosters is permitted.

It is obligatory to refuel at the PEMEX service stations or at the official service areas along the route. When the car is being refueled the competitors must have a fire extinguisher on hand. It is strictly prohibited to refuel in any other location; the penalty will be disqualification from the stage.

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 02 Nov 2016 22:14
by Chickenman
SteveEdmonton wrote:(Full disclosure: I have an MGB-GT and, despite all of its numerous limitations, love it!)
Nice engine bay!!


Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 03 Nov 2016 06:44
by datzenmike
Depends on the gas. Most of ours is 10% alcohol, and alcohol will mix with gas and water. This mixture will just run through the carb normally and there is never a problem. If this is 'real' gas like the '70s, humidity can sweat in the tank and could form puddles. The pick up tube shouldn't suck these up but with hard cornering, bumps? maybe, and only when the tank is down to the last half gallon and sloshes. Find out more about the gas used.

Water doesn't mix with gas so 100cc of gas line anti freeze (methyl hydrate, about $3 a liter pain dept. WallMart) per fill up will mix with both and join them. This keeps the any water in suspension and both will be sucked through the carb and burned.

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 03 Nov 2016 07:08
by bertvorgon
Having had an arms length experience with a customer of my sponsor, who ran the Panamerica a few years ago, in his Corvette.....

Absolutely make sure you find and test a GOOD octane booster, BEFORE you go. He did not listen to us and ended up breaking the engine, after all that work and effort to get there! Not all octane booster is created equal, you want something that increases the octane by FULL POINTS...not fractions, so read the fine print and do some homework.

Tire choice.....he ran Toyo R888's and ended up destroying all the tires, Too soft for the aggressive nature of the roads, even went through the spares.

Re: MG-A with Datsun 1800 needs to get FAST!

Posted: 20 Apr 2017 15:34
by sneax
hello all
I am back! :D
back in Mexico city, back to the planing of the engine wap and therefore back the the forum.

I talked to a bunch of people and right now my choice of engine come down the L20B or the MGB.

Reasons are amongst others that those are available here without have to ship them from the states and I decided against the modern engine for more torque and usability. so it has to be only 2 Valves per cylinder... no 16 valvers!

I could get my hands on two L20B for a decent price. the main question is now > will I fit that under the hood????

Can you guys give me some numbers please?

How tall is the L20B ...with a super flat but wide race oil pan? from pan to head cover? or will the bellhouse the lowest spot anyway?

And additional question... will the webers have to be mounted just next to the head or can I get them a bit lower or maybe in an slight angle?

For the L20B I will have to modify the crossmember anyways and I am checking if I am allowed to modify the hood!

thank you
greetings from mexico city