New 4a084 Build

[qahqn8]

Hi Everyone:
Thanks to Corky, who found this on Ebay, I am the proud new owner of a 4a084. I’ve been reading up in the manual and I think I understand most of the internal parts. My question is what parts are permanently removed. Correct me if I’m wrong but the following are removed (and please add any I missed):

- Shroud
- Governor (plate the hole)
- Flywheel/Fan Housing (to have access to driveshaft)


My other question is about the Solex carb conversion. I would stick with the stock carb like Papee suggested but I have a friend who does a ton of VW work. He offered to help install and tune a Solex. Are there any pictures of how people have mounted these on the intake? I’ve seen lots of posts about this but no pictures. In addition, what have others done to get the Solex properly jetted? As always thank you for the time and information.

- The new village idiot

[bgmcl60]

i left the bell housing and flywheel on and ordered a 12 volt starter for the engine. i called arrow props about an adaptor for the 1 3/4 shaft already mounted to the flywheel. flywheel and bellhousing is cast aluminum. couldn't weigh 20 lb. i haven't had mine running without flooding. i think the carb mod is the best investment.papee has a thread about the solex carb and intake mod with pictures.

[aerokirk]

Qahqn8,
I have posted pictures of my intake modification which you can see if you look at aerokirk's build. There are three pics on about page 6 (post #114). You can also see pics on one of Papee's posts. You basically cut off the flange end and use a hole saw to cut a circle out of the top center of the spider. You then use the core in the hole saw to plug the end you cut the flange off of and weld the flange onto the top of the spider. I mounted a Solex 34 which I found that I needed to install one size leaner idle jet and one size larger main jet. I think I also mentioned these things in my build post.

I also posted a video of the carb conversion somewhere on this site, possibly in the Videos thread

[yamahaulerG1]

I found that a 92 Saturn starter bolted to the shroud and lined up with the ring gear on one I had. But I felt that the stock flywheel might block some air from the prop and the fins actually direct the air towards motor away from the prop. But it still worked just fine till I could find something better. Also I ran a tuned 28mm solex it didn't turn anymore rpms then the stock carb but it had better throttle response.

[qahqn8]

Thanks for the information. Is there a benefit to leaving the flywheel and bell housing on? Aerokirk - thank you for the reference, its exactly what I was looking for. The spiders are cast aluminum correct? Sounds like the Solex gives you a bit more punch and maybe even a few more revs. Thanks again everyone. I've been posting like a fool and your patience and expertise are much appreciated.

- The new village idiot

[Corky]

Welcome to the 4A084 club !!!

No benefit to leaving the flywheel in our application other than giving a starter a place to bolt up and the ability to check the timing...But IMO the set-backs out weigh the gains...Which include added weight,and as pointed out the reverse airflow from the flywheel blocking and fighting the props airflow...

You'll be stripping all the shields,wiring harness, and even the original sending units eventually... I have a pic of the parts taken off{and on the table} in my build thread also...

The intake "joint" as Saturn Supply calls it is cast aluminum... And remember there's no dumb questions except the one's you should have ask ahead of time...

[Corky]

I found that a 92 Saturn starter bolted to the shroud and lined up with the ring gear on one I had. But I felt that the stock flywheel might block some air from the prop and the fins actually direct the air towards motor away from the prop. But it still worked just fine till I could find something better. Also I ran a tuned 28mm solex it didn't turn anymore rpms then the stock carb but it had better throttle response.

Good info on the starter that will surely help someone out if they're trying to use the factory bellhousing and flywheel...

[Corky]

i left the bell housing and flywheel on and ordered a 12 volt starter for the engine. i called arrow props about an adaptor for the 1 3/4 shaft already mounted to the flywheel. flywheel and bellhousing is cast aluminum. couldn't weigh 20 lb. i haven't had mine running without flooding. i think the carb mod is the best investment.papee has a thread about the solex carb and intake mod with pictures.

Papee has stated there's a common problem with the original carb's float sticking the quick cure is to tap on the carb to unstick the float...If that does'nt do the trick you may need to go deeper and look for dirt/debris holding the float open...

[qahqn8]

Corky - Thank you for the help and for finding that engine in OKC (Should be here today or tomorrow and I feel like a kid before Christmas). Your build posts have been unbelievably helpful too, I'm going to model my build off of yours with the exception of leaving the bow at 5'. I saw your post with all the parts taken off, I just wanted to make sure I got everything. Speaking of sending units... I was actually wondering if the fuel pump on these is capable of pulling fuel from an external tank like what you see on most of the builds, of if you needed something a little more powerful? Do you remove the governor?

One other thing... It is a secret that I closely guard... I suck with any kind of electrical work hahahaha. That being said the whole 24v to 12v thing has me scratching my head. I understand the problem but not how/where to install a rectifier. I see that many people put starters on these and I am assuming they are 24v starters since a 12v starter probably could not turn the motor over... so a rectifier must be installed between the 12v battery and the 24v starter? Is that right?

Once again thank you for any information.

[aerokirk]

[QUOTE=qahqn8;34592]Thanks for the information. Is there a benefit to leaving the flywheel and bell housing on? Aerokirk - thank you for the reference, its exactly what I was looking for. The spiders are cast aluminum correct? Sounds like the Solex gives you a bit more punch and maybe even a few more revs. Thanks again everyone. I've been posting like a fool and your patience and expertise are much appreciated.

- The new village idiot[/QUOTE

The best strategy is to convert the 24V system to 12V (including the starter). You shouldn't need an additional fuel pump to pump up to the engine as the stock pump works well if your tank is fairly close to ( usually right below or just forward of) the engine.

[qahqn8]

Just got the 4a084. Appears to be in really good shape. The oil is still clear and most of the red plastic caps are on so there's a chance this motor has never been turned over. It turns freely but not to easily, will measure compression tonight... Here is my list of daily questions:

1). Compression should be about 120 psi?
2). Someone scavenged the fuel pump off of this so I'm going to mount an external pump. I need a cover plate for existing hole were the original pump would have attached. Has anyone found something that works or will I have to fab one?
3). I read on another thread about using Bradd Penn 15W-40 break in oil... Were you happy with the results. I've heard mixed stuff about break in oil in general working on cars. What do you guys think?

As always thanks for the help and opinions.

[aerokirk]

My opinions to your questions:

1) Yes, it will probably get close to that pressure if you're using an automotive pressure gauge to test, however, being a Teledyne Continental engine, it is almost identical to an aircraft engine so I would use the pressure bleed down method to test it accurately. You will need a special two gauge tester for this which any A&P aircraft mechanic should have. You basically charge each cylinder with air to 80psi and the second gauge measures pressure leaks (rings, valves, etc). Values of 60 over 80 are considered good,

2) Not too sure on this but I'm going to guess that you'll end up making up your own plate ... 1/4" aluminum works well for this.

3) I would definitely recommend a straight mineral oil (break in oil) for at least the first 25 hours since again, this is basically a small aircraft engine.

JMO

[qahqn8]

Thanks Aerokirk. Appreciate the expertise

[Corky]

I'll add a few thoughts....Make sure the electric fuel pump has a working PSI in the range needed for the carb (solex or zenith}...It's not much...Around 3-5 PSI...You'll flood the engine if the pressure is more than that...So that means either the output is in that range or you may need an inline regulator if the pump's output is above the range...IMO the easy way {and least amount of problems} would be to simply bolt an 084 mechanical fuel pump back on there...

Here's another reason why I prefer the mechanical pump : I'm prone to overthinking all situations that could arise on the water...IF....If by some chance you would have an electrical problem on the water that electric fuel pump could need to rely on the battery...Whereas if you had the mechanical pump the engine is still self-sufficient and would run after the rope start...
No choice you make is the "wrong" one just throwing that out there...

Again, nice score on the engine it appears to be new...I wouldn't worry too much about a compression check considering the condition of the engine...If it were run the exhaust manifolds would show evidence of the run I think you'll be fine in assuming the best...

[qahqn8]

Hi Corky:

I started cleaning up the engine and looking at things that need to be taking care of before a test start. All in all its in good shape. The air filter box is dented pretty bad but thats getting pulled off anyway. One of the valve cover boxes has a crack in it so that needs replaced too. Everything else looks OK.

Good point on the mechanical vs. electric. I fabbed a cover plate and found an electric 5psi pump for $35 (haven't bought yet) but I also found replacement OEM pump on Saturn surplus for $75 (which seems steep). Does anybody on the website have a 4A084 fuel pump that they'd want to sell? I'd prefer to stay mechanical but I also don't feel like letting Saturn Surplus take me to the cleaners.

[yamahaulerG1]

I have used both not at the same time electric and mechanical fuel pumps both work fine I've had a mechanical pump go bad and it filled my crankcase with gas and electric pumps that have gone bad is an easy fix if you make long rides you can carry a spare they don't use much power either. Here is where I buy mine they ship very fast also. http://m.ebay.com/itm/NEW-GLOBAL-AUT...ON-KIT-GA8016S

[Bart]

i have one, i will send you my phone # in a message
never thought about selling one. but you can only set on so many things.

on another note, i thought i would test and see if it still worked. i just didnt think of where the outlet line was pointing. it went right up my nose, just glad i was using water and not gas. yep, it shoots out pretty far.

[qahqn8]

Hahahaha glad you're OK and thank you Bart. Got the PM, ill text you ASAP. Thanks again

[yamahaulerG1]

This is what makes this site great ppl helping each other out. I think I have some valve covers also pm me if you still need one. I have a few parts I don't need anymore be glad to get rid of I've been scraping some just to get it out of my way. And that link to the electric pump is less then $13 + free shipping it's hard to beat for anyone reading

[Corky]

I tried the link and it takes me to the ebay homepage.. For some reason I can't see the fuel pump...