Motor for a bus

1fasbug · Post by **1fasbug** » Tue May 20, 2003 1:21 pm

I'm planning on building a new motor for my bus. This will be the first time I do a complete build and I want to take my time and do it right.

I already have a DMS crank 78
044 42x37 heads

What I plan on buying:

New alum case
90.5 b pistons
5.5 scat I beams
web cam 116 with web lifters on 112 or 114 lobe

I was hoping for some suggestions on carburation (Dellortos if I can find a good pair) and if 9 to 1 compression can be done on pump gas in a bus.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue May 20, 2003 3:15 pm

Aluminum case?????

1fasbug · Post by **1fasbug** » Tue May 20, 2003 4:17 pm

Jake
I was at least hoping for a bump and thump comment

I feel pretty comfortable with the new cases and they are now coming cnc machined for strokers and full flow. I'm more concerned about the size of the heads and the reliability of the motor with that high of compression in a bus.

Since you posted, Jake, I do have a question for you directly. In one post you commented that you have not built a motor in two years that was lower than 8 to 1. Could you share what CR your 1679cc bus and thing motors are set at? But the way if they made a stroker 88mm piston set that is what I would be running.

Thanks for your feedback.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue May 20, 2003 4:24 pm

I set up at 8:1 for bus engines, but thats according to cam and valve margins.

I like VW parts, VW did not use a sand cast aluminum case THAT WAS CHEAPER to make (and still is) for a reason.

The Aluminum cases are just like a chrome fan shroud to me! was given one by one of my suppliers last year. It has enough machinist dye all over it that it looks like its bleeding,(thats how many flaws I found in 30 minutes) I threw it outside in the rain, been there every since, its already exfoliating.

regis101 · Post by **regis101** » Tue May 20, 2003 5:27 pm

....looks like it's bleeding. Now that's funny

Eaallred · Post by **Eaallred** » Tue May 20, 2003 7:17 pm

Save some money and run stock rods.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue May 20, 2003 7:20 pm

I'm with Eric, especially on a Bus, that 5-5 rod will kill your powerband!

Post by **Marc** » Tue May 20, 2003 7:34 pm

MASSIVE TYPE IV wrote:I'm with Eric, especially on a Bus, that 5-5 rod will kill your powerband!

What, like the 42x37 valves won't? With normal tire sizes on each, an early 002 or red-gear bus box is geared 20-25% shorter than a Beetle, the tach'll never drop below 3000 on the highway anyway.
.100" difference in rod length will make a difference but it's only one factor and it's not as big of a deal in the real world as it seems on paper. If it makes the deckheight come out right without having to custom-make pistons or cut down barrels, I just don't see a problem.
What I want to know is, what's the exhaust system going to be on this puppy?

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue May 20, 2003 7:36 pm

1-3/4 Merged....LOL

I have had decent luck with bigger valves in a bus, just choke up on the cam a little and they broaden out power nicely.

1fasbug · Post by **1fasbug** » Tue May 20, 2003 9:49 pm

Close,
I have a merged 1 5/8 and I was planning on some type of turbo muffler(probably a-1).

I really appreciate the responses but I wish they were a little clearer. So the valves are too big? The rod ratio will not work properly? The exhaust is too big? If it would be easier you could just tell me what you would use.

I understand that some of you build motors for a living and your experience is not free. But building a motor myself is something I want to do, its not just to save money.

Thanks for taking the time and providing direction.

wellington · Post by **wellington** » Fri May 23, 2003 9:29 am

I don't see how the 5.5 rods will kill the power band. Yes shorter rods will increase piston speed, The rod ratio of 5.5 on a 78mm crank compared to a stock rod on a 69mm stroke is already lower.

Post by **Marc** » Fri May 23, 2003 9:54 am

1fasbug wrote:
I really appreciate the responses but I wish they were a little clearer. So the valves are too big? The rod ratio will not work properly? The exhaust is too big? If it would be easier you could just tell me what you would use.
...

But what fun would that be? Seriously, my first choice for a bus would be smaller valves & 88s but unless you find some NOS collecting dust or bend over for custom-mades I guess 90.5 is the next-best choice - and that opens up the valve size choices a bit. The valves aren't too big for that exhaust, just for stock heaterboxes (same goes for the displacement). I'm using 356 rods in my Beetle's 2017 because they're what I had around and will make it simple to get the 7.5:1 I'm after. I'll be running a GB308 (FK-7) and Sig Erson 1.5s on 42x37.5 044s with 44DCNFs and a Kymco 1½" heaterbox system - as this is a daily driver I'm not after ultimate performance, just an honest 100+HP and long life on cheap gas - it'll probably be the last engine I ever build for this car. I'd have no reservations about using a slightly longer rod though if that's what it took to yield the desired C.R.
Like wellington said, when you put it into perspective compared to the stock rod ratio of almost 1.99:1, the difference between 1.74, 1.76, or 1.79 just isn't worth fretting over - go with what you have or what fits.

1fasbug · Post by **1fasbug** » Mon Jun 02, 2003 4:42 pm

I just started ordering parts for the new motor. I was hoping to get some more feed back. The motor is going into a 1967 camper. I'm not really looking for hp but torque and reliability.

So the parts I ordered today:

Rimco prepped alum case opened for stroker and 90.5's. I had all the gallies tapped and it's full flowed.

Stock rods set up for stroker and I will have everything balanced.

I plan on doing some more ordering tomarrow and would like some feed back on these parts:

Web cam 111 Dur@50 272 and 476 lift on 114 lobe seperation

Weber 44's the kit from Cb with the linkage

What oil pump to run?

Thanks for any feed back.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Mon Jun 02, 2003 7:12 pm

A Web 111 is MURDER on lifter bores,a nd has high dynamic CR.

I seldom use them, they wear everything valve train related very prematurely. SUPER FAST RAMPS!

Guest · Post by **Guest** » Mon Jun 02, 2003 11:29 pm

Thanks for the advice on the cam. It did seem like a lot of lift with out ratio rockers.
Looking at the webcam site the 110 looks like it might be it ticket. I'm going to call them tomarrow and see what they have to say about it. Here is what the web site list: 435 lift 284 dur@50 and I'm hoping the 114 lobe seperation will give me a nice flat curve that comes on low. How much compression can I expect to bleed off from static with this cam?