I bought an A100 van last weekend, drove it home without checking the oil, and now it knocks... In spite of my moment of failure, I promise that I have a great mechanical aptitude and even rebuilt a mild LA318 over the winter. Assuming there are few surprises, how quickly do you think a rookie like myself can rebuild this motor once machining is done and parts are in hand?

Also, any advice for the build will be greatly appreciated.

Here's what I have:

A100 van
225 with single barrel carb
3 speed manual
if the fender tag is still correct, 3.91 gears
only water pump/fan and alternator on the v-belt

Here's what I want:

Highway economy with enough power to push that hippo down the interstate with the A/C on full blast.



The engine budget should be around $1000-1200. I know the rebuild kits at NAP are around $400. The machinist charged me around $400-500 for the work on my 318. I think I might get a similar bill for the slant 6 with some additional mill work.

There's also a porting artist (seriously) in the area that I like to visit. He's very talented and reasonably priced. Unless that level of work improves MPG, it's probably overkill for this particular project.

The motor may be coming out tomorrow/today (12May14). I'll assess things as it comes apart. As of now, I plan to square the deck, mill the head to 9:1-9.5:1 CR, then slap it back together with the rebuild kit. If nobody responds, then that is what will happen. If everything comes together in a timely fashion, then modifying the intake to accept the BBD left over from my 318 is very possible. I'm a machine tool student, so I can do all the cutting on a mill at school and have a welder do the grafting.

Thanks for reading my first post!

-Gene

Check this thread http://www.slantsix.org/forum/viewtopic.php?t=23314
Also check these for lots of other good info http://www.slantsix.org/forum/viewtopic.php?t=38446
http://www.slantsix.org/forum/viewtopic.php?t=38465

Dave

_________________
86 Miser 170,000+
2 1/4" exhaust
Holley 1920 #55
HEI MSD BLaster 2
17.8 mpg

Man was I up late! I'm friggin exhausted. Here are some things that I forgot to mention that may need to be considered:

This van was purchased with the intent of doing 3000+ miles of road tripping, starting in mid-June. So there is a bit of urgency with this rebuild.

The van doesn't have A/C and I'd like to install a Vintage Air or similar type system. Suggestions are welcome, but keep in mind that my engine is in a doghouse, not under a hood. I've already contacted Charrlie about his A/C compressor brackets via a different forum.

I plan to replace the mech fan with an electric fan. One from a 90-95 Ford Taurus 3.8l moves a lot of air. After some measuring, it looks like one will fit very well after some minor modifications to the shroud. I put one in my Jeep a couple years ago and have to say that it's a great fan.

The BBS carb that is currently on the engine probably needs to be rebuilt or replaced. Since the tag is missing and it can't be properly identified, the more likely scenario is to modify the single barrel intake to accept my spare BBD instead.

The rear gears... I'm not opposed to changing them if that will improve fuel efficiency, but that's foreign territory for me and I don't care to venture there until after summer. However, if 3.55 or 3.73 gears can significantly raise fuel efficiency and highway speed with the fresh and (hopefully) more powerful engine, then it's more likely to happen sooner. I just have a lot on the list already, so that's most likely a back burner project.

Your input is greatly appreciated and I look forward to your responses

-Gene

You want to build the engine and select all parts with a mind for low RPM torque, not high RPM horsepower. With that in mind, I recommend staying with stock size valves but getting a three or five angle valve job done and some porting if you can afford it. I would step up to the Erson RV-10 or RV-15 cam discussed elsewhere on the site (just search for RV-10 and RV-15) and have your engine builder build the motor to achieve an 8:1 DYNAMIC compression ratio.

If you have the time, some significant gains in economy and performance can be had by fine tuning the distributor advance curve. Anyserious engine build should also upgrade to HEI ignition. It is cheap and reliable and is pretty much the best street performance ignition you can put on your slant.

I would stick to a one barrel carb for several reasons. First, I would run a Holley 1920 Economaster. It is has probably the best MPG potential of any carb for the slant six. They are somewhat hard to find, but I would at least stay with a one barrel carb.

Second, you will have clearance issues with a two barrel carb air cleaner in the van. You won't be able to find a stock-style closed air cleaner that will fit the two barrel and clear the doghouse. This is important because vans in general (and A100s in particular) are notorious for having hot engine compartments. One of the best things you can do to improve fuel economy and performance is rig up a cold air induction system so the motor draws cooler air from in front of the grill rather than hot air from the top of the engine compartment. In a van you really want to stay with a closed element air cleaner and try to have a cold air induction system.

3.91 gears would be great in a van used for in town driving, but if you are using the van for road trips and are up to it, I would definitely change the gears to 3.5 or even 3.2. I think if you do a torque-based build 3.2 gears would be a good compromise btween acceleration and cruising RPM.

If fuel economy is the primary goal, you may want to consider swaping to a four speed transmission (one with overdrive). I don;t do manual transmissions, so somebody else can inform you on the details of this swap.

The A100 was never offered with AC from the factory due to space concerns. You will have a hard time adapting a condenser to the front of the van and a hard time finding a spot for a compressor in the engine compartment. New high-efficiencyu condensers might fit, and you could probably work with Charlie S to find the smallest compressor that would fit and then use your fabrication skills to create some mounting brackets. I do wish you luck since I love AC. You may want to hop over to www.vannin.com and ask some of the guys over there who have A100s and are more familiar with them if hey have any suggestions.

Also, don't forget to make sure your brakes are in good working order if you hop up the motor.

Lastly, just remember you are driving one of the most un-aerodynamic vehicles on the road. To improve fuel economy keep your speed down. 55-60 is about as fast as you should go.

Keep us posted of your adventures, and pictures are always appreciated.

Be sure to calculate and "set" the DCR, as noted above.
No "corner cutting" on the bottom end... reground crank & reconditioned con. rods are a "must".

Pay close attention to the oil pump's drive gear... many of today's replacement oil pumps, have gears that are soft and quickly fail.

Get some highway gears into your Van (or an OD trans) before taking a long trip. 3.23 minimum or 2.94 if you really want MPG.
Run the ratio to RPM "numbers" using your rear tire size.
DD

What Doc said. However, if you switch to an overdrive transmission I suggest keeping the 3.9 rear axle gears. If you keep the three speed transmision, then I suggest switching the rear gears to 3.2. I have driven big heavy vans with 2.7, 3.2, and 3.5 rear axle gear ratios. 3.2 is about as low (numerically) a ratio as I would do in a van. 3.5 is nice with a three speed, but can lug the motor if the transmission is an overdrive.

That's the kind of info I wanted!

I spent last night and this morning tearing down the engine. Is it weird that I think disassembling that motor was fun as hell? The worst of it was the #6 rod bearing. The regular tired engine ailments of timing chain stretch and carbon buildup were present. I also found an alarming amount of non-metallic grit in block. It looked like oily walnut shells for media blasting. Disintegrated gasket, perhaps?

One thing that I was truly happy to see was inside the distributor: Pertronix! My Duster had points for a week after I bought it. It was my first time messing with a points system and I said "eff that!" Already having electronic ignition is awesome to me, since I would have bought it anyway. There's also an aftermarket coil: a fireball-something. Both of these are welcome sights.

Everything was dropped off at the machine shop this afternoon. He took some quick measurements on the #6 rod and crank: rod is good, crank should be alright. The bores looked good and will probably just get honed. Everything else looks like typical engine wear.

Squaring of the deck and milling of the head are on the ticket, as well as 3 angle valve job, hardened seats, rod recon, and a whole lot of cleaning. I neglected to cc the head before I left my garage, so he'll be doing that and milling the head accordingly.

I've considered dynamic compression ratio in my calculations. I'd read somewhere that 7.7 DCR was the highest one can go before mid-grade fuel is required, so that was going to be my target. Does anybody know the specs for the cam that comes in the NAP kit? "Stock style" is the only description. How does the RV10 and "stock style" cams compare performance-wise?

I think getting A/C to work is just a matter of configuration. I'm a little familiar with how the components work, but I need to read further into the specifics so I can make good decisions. There's a guy in New Zealand with an A100 truck that has a Vintage Air system installed, though it's a much smaller cabin to cool and probably has smaller components. As of now, I think the condenser is the limiting factor. VA has a decent selection of condensers in various dimensions. Maybe I should quit being lazy and just call them.

Brakes are definitely on the list. The van has a dual circuit master cylinder installed. It's getting replaced since the pedal only moves halfway and one of the reservoirs show no activity. I think the front and back lines were swapped, too.

As far as trans and gearing, the current setup will suffice for now. There's already so much on my plate at the moment and feel a bit inundated. I'll just install a radio to help pass the time while we creep down the interstate.

Thanks again everyone!

too bad while you tore it down, you didn't take your deck height measurements before pulling the rods and crank out of the block, without it you'll be hard pressed to get an idea of how much to mill off the deck and mill off the head to get the SCR/DCR you are desiring. Machine shops aren't used to our engine and if the guy applies the typical V-8 mentality, he can easily over shoot the CR when milling the head (most don't believe that we have a deck height of -0.175 on the average basis either and complain that they had to remove a generous scrape to get the CR requested).

Depending on how you choose your components you can run regular on a much higher compression ratio engine depending on cam, timing curve, and drivetrain component choices.
It is just that, it replaces your current stock cam, and will provide no performance upgrade with your engine...RV10 provides a little more duration and a little more lift and will add some power and low end torque to the equation. Some porting will help the engine breathe better as well.

Deck height is -0.125 on #1, and -0.135 on #6. I used a non-trashed bearing on #6.