To stroke or not to stroke, that's my question....

gleason · Post by **gleason** » Sun Apr 06, 2003 8:52 pm

Well we're building a new engine for the vert and this is what we are using so far.
new alum. case with savers,drilled tapped, etc,
stock reconditioned balanced rods
90.5 Mahle p/c
Lightweight lifters
Engle 110 cam
dual 36 dells
lightened flywheel
40x35.5 heads p&p w/hd single springs and s.s. valves
heater boxes

I know, but I need the heat in Wisconsin in a vert.
header w/hide out muffler
034 svda dizzy
stock rockers/shafts
and that's all I can think of now. I have to make a decision on what crank to use. I was looking at a Scat 69mm CCW 8 dowled but found out that for about $150 more, we can build a 74mm stroker. I guess that makes it a 2???. Is the performance gain of a stroker worth the extra money? Do you see any flaw or weak links on this engine? It isn't a daily driver as I only put on about 5k a year. I drive a lot around town but would like to run it on the highway a little more. I know the 1776 would be fine for this, but $150 isn't alot more to spend. With the driving I do, this should last my lifetime.

Do you think it would be worth it? Thanks all.

JordanK · Post by **JordanK** » Sun Apr 06, 2003 9:30 pm

I hear you on the heater box thing...
I would suggest that you rethink the use of the scat crank either way-They dont' have the greatest rep. and i've heard a number of complaints about them. CB Performance has a new forged 69mm crank for $169...hard to beat that. You might want to check it out. I would say go ahead and stroke it, but you're getting near the limit carb wise if you do that. You would need to run some bigger vents in the 36's to let it breath very well, but it's doable. I say go for it. (of course, it's not my money I'm spending.

)

gleason · Post by **gleason** » Mon Apr 07, 2003 8:49 am

So what's everyone else think about a Scat or not? I have to make a decision in the very near future and I value all responses.

danimal · Post by **danimal** » Mon Apr 07, 2003 9:28 am

gleason, when you increase the valve size, you typically must increase the exhaust pipe diameter to match, or the engine could run hotter and be difficult to tune... so if you want stock heater boxes, you should run stock valve sizes... just p/p the heads for better flow.

the money you save on the heads can be put towards a stroker crank

i personally would never buy a stock stroke aftermarket crank... the factory vw cranks are better, you just need to get 'em counterweighted... if you are lucky, you'll have a core crank that's in great shape.

dan
oceanstreetvideo.com

Post by **Marc** » Mon Apr 07, 2003 9:29 am

I'd go with a DPR or Demello (DMS) modified stock crank instead, whether 69 or 74/76 stroke.
About the only downside to the stroker is that you'll need barrel spacers, both to compensate for the direct reduction in deckheight and the increase in compression ratio afforded by the larger displacement; for example, if your heads yielded 8.18:1 on a 1775, you'd need .126" in barrel spacers for a 1904 or .176" for a 1955 to maintain the same C.R. - even if you enlarged the chambers you'd still need ~.100-.140" in spacers to maintain the same deckheight that the 1775 would have. This shouldn't be enough of an increase in engine width to cause any real fitment problems.
The stock heater boxes are a real problem with bigvalve heads even for a 1775, and making the engine bigger is only going to exacerbate it. Have you looked into the Kymco oversized boxes?

gleason · Post by **gleason** » Mon Apr 07, 2003 10:45 am

I haven't looked any larger boxes yet, and what I'm thinking of doing is running J-pipes for now until I decide what type of boxes to use. I guess it's not that big a deal to take the J-pipes off later this summer and slip some boxes on. I just thought that I'd do it once and get running sooner. I don't know what size the J-pipes are that I have on now, but I'm assuming they are the same size as my header, as I have them slipped into the header.

If I stick to the stock size valves and have a p&p job done to them, and run standard boxes, how much if any will my performance suffer? I guess that with the changes made with the p/c, good p&p on good stock heads, 40 drla dells, 110 cam, lightened lifters & flywheel, I should have a pretty decent running engine. This would give me a little more performance and the option to run stock heater boxes.

What kind of hp do you think this will put out? I don't want to stifle it too much, but I do want the best of both. More power and heat/driveability and something that will be durable.

RoWaMe · Post by **RoWaMe** » Mon Apr 07, 2003 11:15 am

Gleason, I think the biggest factor would be if you want to invest in that 1 1/2" exhaust system with heater boxes (Kymco's was mentioned above but there are other systems like Berg) that you'd NEED if you want heat and go with the 40x35 heads. If so, then do that and stroke it for 76 or 78- the larger valves will support the additional volume to get sucked into the combustion chamber. If you want to keep the stock heater boxes per Danimal's advice, then stick with the stock-valve heads, and go no more than a 74mm crank. I have a 1641 with home-ported stock-valve heads (per CLF tech info and "How to Hotrod VW engines" book), Engle 110 cam, 36 Dells, 7.5 CR and single mufler header. Strong highway runner with plenty of heat. In contrast, I built a mild 78x90.5 with stock-valve heads (winters in NY) with 40 Dell's and it was a pig- did not want to rev past 5500. But this was my first stroker engine and I surely did something "wrong". I think the performance woul'dve been better with a smaller stroke with those stock-valve heads.

danimal · Post by **danimal** » Mon Apr 07, 2003 1:34 pm

rowame, the max rpm point at which your motor could have developed it's peak power rpm was as follows: 2200 x cfm@10"(~99 cfm x .632=~63) = 138600 / cid of one cylinder(78x90.5=122c.i. /4=30.5) = 4544 rpm's.

now plug in the numbers for your 1641, and watch what happens to the peak power rpm point... it takes a big jump... people should always run a headflow vs. displacement calculation for any motor that they want to build, then pick the camshaft accordingly.

so there might not have been anything wrong with that n.y. winter motor... in fact, you were probably over-revving it

gleason, using the 2007 example above:
.24 x cfm(~99)@25" x 4 = 95 h.p. at the most, if those 35x32 headflow numbers are correct... tweak your headflow to see how much power gets lost or gained.

the heads are always where the power gets made... everything else in an engine revolves around attempting to get the max flow thru the ports.

note that the .24 and 2200 numbers used above are for street engine efficiency... use .2721 and 2000 for race engine efficencies.

dan
oceanstreetvideo.com

Guest · Post by **Guest** » Mon Apr 07, 2003 3:50 pm

Hey RoWaMe

Did you make it to the VW show in Etown on sunday. Couldn't make it there with my 68 Ghia Vert,. had other obligations just couldn;t get out of. How was the field of ghias that showed up. I was at the October show last year and won 1st in the modified ghia class.

Guest · Post by **Guest** » Mon Apr 07, 2003 3:59 pm

[quote="Anonymous"]Hey RoWaMe

Did you make it to the VW show in Etown on sunday. Couldn't make it there with my 68 Ghia Vert,. had other obligations just couldn;t get out of. How was the field of ghias that showed up. I was at the October show last year and won 1st in the modified ghia class. This is 68ghiamann I can't reply if I sign in with my user name

Guest · Post by **Guest** » Mon Apr 07, 2003 5:02 pm

Gleason:

I built that stroker recently-1904 (90.5 x 74) and I am running it with the dual Dell 36's a Web 119, 40 x 37 dual spring valves and a 1 5/8" merged header with Fat Boy.

I haven't finished breaking it in yet, so I cannot really speak to the high rpm's, but down low it moves and runs really nicely.

By the way, crank came from DPR along with one of his lightened flywheels and stroker clearanced rods. Good guy and reasonable prices.

I too wanted heat, but had to give it up for the larger valved heads. Good excuse to build a stocker for this winter.

Good luck,
Rick

Empified · Post by **Empified** » Tue Apr 08, 2003 10:03 pm

The 1904 is a great combination. With the 36 dells you'll be pretty maxed out as far as how big you can go. You'll really notice the difference on inclines and passing other cars with a stroker versus stock crank as you'll have alot more tork. If you must have heat then look at the gene berg heater boxes or you could use an external oil cooler which you should have anyway with a box and fan that blows the heat into the cabin. Good luck. Empified..............

RoWaMe · Post by **RoWaMe** » Wed Apr 09, 2003 7:42 am

Danimal: very interesting results on your flow calculations! My 2-liter winter engine did indeed run out of breath above 5G. Was running an Engle V-26 cam, Berg 1.4 rockers and dual valve springs. I'm planning to use the case and heads again but this time with an Engle 110 (maybe even just an 100??), 8:0 CR, 1.1 rockers, HD single springs and Kadrons. Since I'll use a 78mm cast crank, the Kads will help keep the revs down below the critical 5500. My 1641 felt much livelier above 4G than the 2-liter, and would pull to about 5500!

68ghiaman, yes I was at Englishtown, NJ Sunday. Was CCCold and breezy but at least clear skies and no snow like it did last year! Many good finds in the swap meet! Ghia turnout was low; there was a very nicely done '68 Ghia cabrio, refrigerator white with grey tweed interior, stock 4 1/2" chromies, 165 tires and stock engine. Bumpers were nice but the towel bars were a little misaligned. Engine compartment sheetmetal around the engine was squeaky-clean, which is quite rare these days. Also a nice medium blue '67 ghia coupe, original unrestored condition but with fresh repaint and unfortunate messy engine compartment. Maybe only 1-2 more Ghias that I did not look at this time.
Are you planning to drive up to the CVA Dust-Off in NE CT April 27?

mschilling · Post by **mschilling** » Wed Apr 09, 2003 8:44 am

I vote for the stroker. The extra $150 isn't much and the extra stroke won't hurt at all. I built a 90.5x74 and it worked out fine without spacers, and using B pistons giving a low 7:1cr. Berg claims their ported stock valved heads outflow the competitions big-valve heads (out of the box) and you can use your stock (cast alum) heaterboxes. I have a set on my 1776 and they're beautiful heads.

JordanK · Post by **JordanK** » Wed Apr 09, 2003 5:59 pm

mschilling-

Just curious, what did you pay for the berg ported heads? Do you feel that theyr'e better than, say, out of the box 40x35.5 044's?