Fuel injection rebuild

[Simmy]

Fetched the new Jtubes and exhaust after having it all fabbed up. Really chuffed they came out so well... But that's mostly thanks to Riaan who did all the hard work.

[Tony Z]

that engine deserves a better header than that - that glasspack silencer is going to hold things back. What size is it? You probably need 38mm branches and a 50mm pipe

[Simmy]

Thats precisely what it is - checked again this morning on the branches and main (but, if you will excuse the ignorance, exhause pipes are measured on OD, not ID? I would assume the Americans are to blame for that?)
When we last spoke, I think we called it fair for this engine. If/when I do go with forced induction, I will have to revisit the exhaustsystem anyway, but I believe this is good for ~100HP at present.

But truth be told... the glasspack is LOUD. I am hoping that I feel differently about it as a weekend drive, because it got a little much as a daily.

[Tony Z]

yip, OD...
Dont be scared to change the glasspack for a normal "offset" freeflow style muffler. I've done it before and it has free'd up some power as well as made things quieter

[Simmy]

I certainly will, but for now it will get a bit of a polish so that I can use it for the run-in period on the carb. Once I change over to the FI, then I will reassess how I feel about the thing... it still has value in scaring a few unwitting bystanders.

[Simmy]

The disassembly has started, so cleaning and prepping parts as I go.

I couldn't bring myself to sticking the exhaust back on in its current state, so I gave it some elbow grease and coated the steel flanges in high heat paint. I know it won't stay this way for long...



Polished the valve covers so that oil will hopefully run off better, for better cooling. You can also see the Matt black coating, again for better heat transfer.



Looking again at the cylinder heads, I think I will just bite he bullet and do the ceramic coating. I doubt it is going to make a noticeable difference now, but I am counting it as insurance for later. I don't think I want to do the pistons, since I feel the lack of heat transfer will keep them from expanding correctly. They are high quality forgings, so I believe they will tolerate more than most.

[Tony Z]

making progress...

matt black helps, but paint is an insulator. On steel it works as it transfers heat better than rust, but on aly I am not so sure.

Ceramic coating definitely brings temps down. I do it often. Even just doing the valves makes a nice difference. It gets expensive quickly...

[retrovan]

Totally agree with Tony

The more a aircooled engine is modified, the more help it needs to cool.

Sand blasted ally is the best as you have increased the surface area by near double, do not polish it,

Matt black or sandpaper finish is better the smooth black paint on steel.

The more ceramic coating you can do internally the better.

Heat killed my 1st modified engine, then I studied the topic,

and now understand how critical cooling and controlled running in of a modified engine is.

Have assisted my 1915 cc motor with max cooling during the running in period, and monitored the rev's as well as oil temp.

Now I have an engine I can tow with without issues.

Good luck with your build , you doing a great job.

Herman

[Simmy]

Thanks guys, I really do appreciate the feedback. Not having a lot of experience with this means I am working on theory and speculation a lot of the time.

I have been on and off on the ceramic - most people say its not worth it, but the theory of an oil/aircooled engine says it really should. That said I am not making this an all-out performance dragster, so the ceramic is to prevent heat transfer to the heads, and avoid some detonation. I will call PowerKote later to see what they can offer.

matt black helps, but paint is an insulator. On steel it works as it transfers heat better than rust, but on aly I am not so sure.

I completely agree, but I did my heat transfer calculation with and without paint and I believe it still makes beyond 0.5mm of paint (it was a rough calculation, and i seem to have lost it somewhere along the line). This is less than half of that, so the emissivity benefit far outweighs the conductive resistance of the paint.

The more a aircooled engine is modified, the more help it needs to cool.

Sand blasted ally is the best as you have increased the surface area by near double, do not polish it,

Matt black or sandpaper finish is better the smooth black paint on steel.

The more ceramic coating you can do internally the better.

Heat killed my 1st modified engine, then I studied the topic,

and now understand how critical cooling and controlled running in of a modified engine is.

Have assisted my 1915 cc motor with max cooling during the running in period, and monitored the rev's as well as oil temp.

I have tried to go through Bob Hoovers Sermons, and he stresses this all the time, so I buy into what you are both saying.
The polish on the inside of the covers is to avoid oil "clinging" to a rough surface. This it my working argument: The thin oil layer that sits there also acts as a form of insulator, and blocks heat transfer. The thinner it is, the less resistance it offers, which means you can get more benefit from the convective heat transfer that occurs. (If anyone is interested, read up on boundary layers and heat transfer)

[Haans]

Simmy,....this thread can be the base of a thesis for a Phd,.........unless you've already got one !!!!

You are flying way above me!!

Now when are you starting this beast ?

Haans

[Tony Z]

Barely touching the surface here...

[Simmy]

Appreciate it Haans! Just trying to do this right... I did a bit of engineering in a past life, so tying to keep that side of my brain working the way it should.

And Tony is right... There is even more to learn, but I would like to think the surface has been sufficiently scuffed for this level of build. Strokers and the other hi-po engines out there add even more variables to the mix.

[Simmy]

And whilst you lot are all here... It's been bothering me that I havent really taken care of the gearbox. I am thinking a Kaefer brace would be a good place to start to avoid wheel hop? Can these be installed after the engine is in?

Just trying to plan some of the next moves.

[Tony Z]

Kaefer cup brace is a good investment.
The one from CSP - the instructions say to install the brace with the engine in and the body removed... I've done one with the engine out and the body on and had to redo it as it hit the exhaust when I installed the engine. I am now making my own one for my 1302 which is also body on, engine out.
I would hate to install one of these with the engine in.
You can buy the premade kits, but they are not as sturdy as the CSP kit. Those can probably be installed with the engine installed already as there isnt welding and mocking up required. But they dont triangulate properly and can flex

You need to seriously consider a camber compensator, they improve handling tremendously.

I would say you should also consider HD or urethane engine mounts and a nosecone mount and a bellhousing strap.

Do it now before you go turbo, that way its done already. All you need to do is break the gbox once and you'll wish you had done the work initially.

[Wentzel]

I made my own brace and made the gearbox mount stronger. Using old style flat gearbox mounts and a diy gearbox nose support.

If you dont abuse it you should be fine with these additions for a while.

Haven't done the camber compensator yet because of ground clearance.

My std gearbox lived with this for years but I don't do burnouts or drop the clutch etc.