1915 Build Advice Wanted

[clockworkbox]

I am going to build my first motor over 1600cc, I wanted to build a 1776 but the shop doing the work on my case convinced me I would be happier with a 1915 to pull these Pennsylvania hills. I have been collecting parts for a reliable 1776 but now I am shooting for a reliable 1915. My parts list is below, I have everything listed except for the heads and exhaust...
AS41 case opened to 94mm
94mm Mahle Forged Pistons
EMPI 69mm forged CW crank
CB Uni-Tech 5.4 rods
Eagle 2280 cam
Dual 40 Webers with 40 CSP manifolds
CB Maxi Pump 2 oil pump/filter
CB 1.1:1 rockers with solid shafts
123 Ignition distributor
EMPI GTV-2 40 x 35.5 heads 58cc chamber single springs
1.5” merged header
I have read every 1915 thread here and I'm not sure especially about the cam and my CR (I think I want 8.5). The case is at the shop and I also wonder if I need to have it decked. My remaining budget is limited...
I am not trying to build a dragster but any feedback about what I have/need is appreciated. Thanks
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'69 Beetle (pieces)
Learning the hard way is still learning...

[challomoner]

I have been informed by a very good authority that the csp 40mm manifolds make less power than the cb manifolds, luckily before I bought manifolds for my current build.

[clockworkbox]

[H2OSB]

Using the CB Performance engine calculator, and assuming a .040 deck height, I get you at 8.4:1 CR. I know that's not what you're asking about, but it's one more piece of the puzzle.

H2OSB
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[clockworkbox]

[Brian_e]

Sounds like you are headed down the right track, but you need to let us know how you plan to drive it, and if you want heater boxes or no?

What is your upper RPM limit you like to rev it to? You use the upper limit, and the displacement to determine the valve size, and the cam duration.

A 2280 in a 1915cc in a bug will be a bit low revving. More of a bus engine.

Keep the ports and valves small but efficient.

For a really fun 1915cc in a bug, I would use Tims ported 37x32 heads, and a web 163 w/1.3 rockers, and 9.0:1. Reliability will not be a problem if its built correctly.

If you want it a little more mild, do a web 218, and the same heads.

You won't be able to guess on your deck height, especially if the shop already skimmed the cylinder surfaces. Just mock it all up with the actually parts you will be using, and then adjust it from there. It is really the only way to get the deck dead nuts where it needs to be.

I always suggest a Vspeed muffler because they work so good. A standard out the back 1.5" merged header will be second. A sidewinder style LAST.

Brian
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[clockworkbox]

Not sure about the RPMs, want to be able to do 75-80 on the highway (we have hills) without killing the motor. Probably not over 5k I'd guess. I will look into Tim's heads. The Vspeed muffler with j tubes is on my list, maybe some 1.5" heater boxes down the road but also looking at the CSP Super Comp exhaust. Thanks!
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'69 Beetle (pieces)
Learning the hard way is still learning...

[67rustavenger]

[Alstrup]

Challomer is correct with the CSP/Redline manifolds, but in that performance window it is not a problem.
Cam, fine IMHO. A hair mild, but it can work well.
Case. YES! Get it decked so you can dial in your deck height. But also so the cylincders get a proper seating surface instead of that wimpy edge many shops leave you with. Deck it 1,4 mm. Then you arfe sure you have room to play with no matter the brand of cylinder kit.
Heads.... Well,,, how to put it... You need to get them rebuilt and ports´n chambers corrected before you even install them. They are horrible out of the box. I keep getting such heads in from engines which will not run properly. Some of them with only 1000-1500 miles on them. And its a total rebuild. On the positive side, the casting itself is OK, so once that is done the heads are fine.
CR. I agree, 8,5 is the sweet spot for that cam and medium grade fuel.
If you want to have a little more rpm band you can safely add 1,25 rockers to it. That will wake it up some when you wring its ear.
If that is the chioce the Super Comp in 38 mm (1½") is fine for a 1914. In fact ist is close to perfect. The super comp is good for a solid 130 hp and up to 145ish if you know what you are doing. But a fregular 1½" merge header will of course also be able to do the job well. There the muffler choice is the ticket to success.
A customer of mine built a 1914 around that cam. But we went a little ballistic on the heads. We started with a set of CNC Panchitos and flow optimised them yet another notch and went with Scat 1,25 rockers (1,32 IRL) 9-1 C R and a CSP Super Comp exhaust. That engine pulls almost like an old turbo diesel and delivers 110 hp @ 5000 rpm and 175 Nm torque. It runs very well and is very fuel efficient too.

But yeah, get those things fixed so they don´t bite you afterwards.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[nsracing]

STick a 74mm stroker crank in there and really make come alive.

T"he 1915cc is one lazy motor to me. The 2054cc on the other hand is a nice motor. Just the right size for brute force. And it stays cool.

[clockworkbox]

A pair of Tims stage 1 wipes out my budget but thats what they recommended with 1.3:1 rockers. I now have about $150 for a cam which means a W110 or something from CB, their build kit comes with a 2250 but I think that would be too agressive for what I am looking for. The 2280 is not recommended for dual springs. I'm really looking for a cam that wont beat my valve train up too badly and I would like to keep this motor driveable on the street. I do not plan on taking it on the drag strip. I will save for the exhaust and think Im going CSP super comp. Thanks for all the help so far. I think I just need to figure out my cam now.
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'69 Beetle (pieces)
Learning the hard way is still learning...

[Alstrup]

I do not know who to point you towards on the east coast, but how about getting those GTV heads you already have fixed? That will cost a pretty penny yes, but not what a new set of heads will set you back. If it has to be a CB cam I´d suggest a 2239 and 9-1 CR. And Scat or Engle sgl hd springs. If you need to send them anyway, maybe talk to Brothers in Ontario Ca. Or ask Tims if they will help you out. Both do nice work.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[clockworkbox]

I do not have the GTV heads yet, they were just suggested by the shop doing the case work. I think I am going with the Tims stage 1 heads, by the time I had the EMPI heads redone, it would probably be more than just getting the Tims heads.
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'69 Beetle (pieces)
Learning the hard way is still learning...

[nsracing]

I will be going close to Williamsport tomorrow to pick up a lawnmower.

Mock the engine and see what you got. No need to fret about stuff before that. The 1915cc will be straight forward - just like stock. The deck will have to be cut down on the case as the lip will get very small when bored for 94mm.

Gotta be careful too when boring to that 94mm size as if not centered can eat the inserts. I bore them very carefully and centered to where the original center was using a dial indicator.

Many shops use a taper center tool and that may be acceptable to many. But not me -

Mock the motor and see where you need trimmed or whatnot. Do the dynamic balance too while you are at it.

[Alstrup]

[croSSeduP]

If you are going to run stock heater boxes I'd recommend a set of Tim's (Performance Workshop) stock valve ported heads. They call the Super Stock.
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[clockworkbox]

Based on advice here I have the following build list now:

AS41 case opened to 94mm
94mm Mahle Forged Pistons
EMPI 69mm forged CW crank
CB Uni-Tech 5.4 rods
Web 218 cam
Dual 40 Webers with 40 CSP manifolds
CB Maxi Pump 2 oil pump/filter
CB 1.25:1 rockers with solid shafts
123 Ignition distributor
Tims stage 1 heads with dual springs 40x35.5
1.5” CSP super comp

What CR should I shoot for with this set up? 9.0? Thanks for all the help so far!
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'69 Beetle (pieces)
Learning the hard way is still learning...

[clockworkbox]

Going nuts trying to figure out how the cr can possibly work on this 1915…
I have ordered a set of Tims stage 1 heads which Greg tells me have 60cc chambers. As I understand it, I’m looking for about .05 deck height. When I punch the numbers into the CB engine calculator, this gives me a cr of 8 which is too low. If I have Greg cut the heads to give me 55cc, that gets me to 8.5cr but I think this may still be too low. I’m also unsure of how to get the deck height to .05, there is a chart here that says even with a 1.5mm decking of the case I would still be at .230… If I bump the crank up to a 74mm and drop the head cc to 55 I can hit 9cr but I don’t understand how you guys make a 69mm crank hit a reasonable deck height and cr. I’m selling off as much stuff as I can to fund this snowball. Can I run a 74mm crank without clearancing the case? Will the dual 40 Webers still be ok? Am I heading out of the engine reliability zone? There is a lot of conflicting information…
Here is where I’m getting the theoretical deck height projections from:
https://www.thesamba.com/vw/forum/viewtopic.php?t=612050&highlight=deck+height+projection
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'69 Beetle (pieces)
Learning the hard way is still learning...

[challomoner]

[Brian_e]

You have your parts chosen. Now you pick a compression ratio.
For a web 218, in a bug, I would go 9.0:1. If you live above 4000', I would go higher. The cost difference between high and low grade gas is minimal, so I would plan on running good gas.

Now you work backwards. No matter the engine displacement, it should always be built with a .040-.045" deck height. So start plugging stuff into your calculator. If its a 1915 and 9.0, you will need a 52cc chamber to go with your .045" deck height. If you use a 74mm crank, you will need a 56cc chamber. So you will need to tell Greg what CC you need YOUR heads to be. He can cut them to anything you want. You are not stuck with only 2 available chamber volumes.

If I were you, I would do the 74mm crank for a few reasons. The 40x35 heads are to big for a stock crank 1915 and a 218 cam. It will need to rev to high. If you bump it and build a 2054cc, you are getting much closer into the range where the 40x35 will start working good, and you will get a counter weighted crank, 8 dowels, etc. You will need to get a light flywheel which is already drilled for 8 dowels, and you will need some clearanced I-beam rods. The CB uni-tech rods are easy and decent. Make sure yo have A height pistons also.

If you want this thing to be sporty feeling, the web 163 is a better choice as well...especially if you bump it to a 2054cc.

There is no way of guessing your deck height. You will need to mock it all up and measure it with the parts you will be using. Plan on trimming the cylinder bases, or getting the case skim cut to make it right. That's just the way it is if you want to do it all 100% correct.

For other people reading this....DO NOT order your heads, or any other parts for that matter until you have the entire engine figured out. Mis-matched parts just make for bad combo's, more expense, and frustration down the road.

Brian
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