TheSamba.com :: View topic - Building a 1905 motor 82stroke 86 bore anyone tried it ?

Fri Jul 20, 2012 2:37 am

Hi guys greetings from South Africa

i'd like to know if anybody has built
a motor like this before as i have some spare parts i can build it with
all i need is an engine for torq not for racing
i am using std sleeves bored to 86mm with a piston that's
comp.hight is shorter
a wbx 82mm crank H beam con rods
heads original vw heads still need to be reworked
anybody got some more info and or advice will be apreciated

Fri Jul 20, 2012 2:57 am

Be interesting to see what people say.

I think that stroker cyls are longer (so you don't have to shim so much).

Also you normally use longer rods to help with the rod/stroke ratio. Can't remember the magic number but I saw it posted elsewhere. I think it's 1.5 (rod length / stroke)

Maybe the funky pistons will help though..

Why not have the case bored for bigger cyls? I see you're in SA, dunno what it's like there. I have to farm parts to other states as there isn't a machine shop here that knows v.w beetles. I couldn't imagine being somewhere that far.. There many beetle machine shops there?

Good luck!

Fri Jul 20, 2012 3:22 am

HI
the way my calculations go with the pistons i want to use
i won't need shims the piston will stop 1mm under the sleeve
the rod ratio i think will only have a big effect if i was building
an engine that will rev over 5000rpm
as my car is geared now with the engine i have in it
1600 110engle cam
36dell's
ported std heads
it doesn't have nice torq low down
as my tyres are big and it brings the ratio down alot
the engine suffers to overtake ect.

i would have liked to go for bigger sleeves but with the exange rate
a sleeve kit is way above my price range

Fri Jul 20, 2012 7:57 am

ekacpuc wrote: Be interesting to see what people say.

I think that stroker cyls are longer (so you don't have to shim so much).

Also you normally use longer rods to help with the rod/stroke ratio. Can't remember the magic number but I saw it posted elsewhere. I think it's 1.5 (rod length / stroke)

Maybe the funky pistons will help though..

Why not have the case bored for bigger cyls? I see you're in SA, dunno what it's like there. I have to farm parts to other states as there isn't a machine shop here that knows v.w beetles. I couldn't imagine being somewhere that far.. There many beetle machine shops there?

Good luck!

The difference between a p/c set for 69mm stroke and a stroker set is the piston pin height; the barrels are the same length (except for 94's; they're about 1.5 or 2mm's longer). A build with a stroker p/c set, 82mm crank and stock length rods will come out very close to stock motor width. Rod ratio for a 1600 is 1.99; most motors built today use shorter rods for a much lower ratio (I believe some Honda motors have rod ratios in the 1.5's). A lower rod ratio makes the motor pull harder at lower rpms; VW used shorter rods in their type 4 motors to help move their heavy buses (1.85) and also in rabbit motors (1.69), again to allow a small motor to move a relatively heavy car.

Getting back to your motor; an 82 mm crank with 5.4" rods gives a 1.68 ratio. This is part of the reason stroker motors seem so unreal in the torque they produce; the cylinder fills more efficiently at lower rpms.. You can even use a Porsche length rod (1mm shorter) for even more pull. Some people complain that short rod ratios cause more piston/cylinder wear, and this is true when pistons have their skirts cut off (so they look like hockey pucks) to clear a longer crank. The trick is to clearance the skirt only where it comes in contact with the crank, leaving most of it for support so the rings don't cock in the barrel; far more work but necessary if the motor is to live a long life. Don't balance the pistons until after the mock up is done.

Hope this helps. Al

Fri Jul 20, 2012 12:13 pm

The pistons i am using has a pin height 8.6mm shorter than
std 85.5mm pistons
so the std length con rod is what i want to be using
but the motor won't be any wider than a std 1600 motor
not that it would matter as it is going into a Baja bug
and also speed is not an issue i want the motor to start
pulling from as low rpms as possible
i am also not sure what cam would work with this stroke x bore combo
that is why i would like to know if there are others that have built a
motor like this

Fri Jul 20, 2012 1:10 pm

What carburetion? What will be done to the heads- valve size, porting?

Fri Jul 20, 2012 2:31 pm

Welll, you did´nt exactly use a torque cam for the engine size there either, did you.

About 6 years ago I had a customer who had a lot of parts sitting, and wanted to build a good bus engine for his early bay. So I built him a 88 x 82 mm. Close enough. With exactly a W110 cam, stock "race rods" from Rimco, ported stock heads, 9 - 1 CR, Dual 40 Dells, 009 w. electronic module, stock heater boxes and a 1 3/8" header with a 2" free flow muffler
I did´nt like it. It had a dreadfull dip in the torque curve between 3200 and 3700 rpm. Then it sort of caught wind again and had its second peak at about 4400 rpm and had max hp at 5200 rpm. (114 hp @ 5200 and 164 Nm max @ 2900) The peak torque wasnt anything to write home about either.
I tried moving the cam around a bit, nothing good came out of that. Tried a 1½" header with 1½" J tubes. Got a little more even torque above 3100, bit still a great reduction in torque from 2900 to 3300, which was quite noticeable in the bus. In a beetle you wouldnt feel it that much.

From what I have tried, my personal opinion is that the 86-88 mm bore has outlived itself at 78 mm stroke.

The engine in the particular bus was taken out, and I built him one of my 1955 bus engines instead. Those produce better hp numbers, more overall torque and more peak torque and a much "cleaner" curve. The APB is also about 2,5 higher.

Fri Jul 20, 2012 3:50 pm

Torben, what are the specs on your 1955 bus engines?

Sat Jul 21, 2012 12:56 am

Alstrup wrote: Welll, you did´nt exactly use a torque cam for the engine size there either, did you.

About 6 years ago I had a customer who had a lot of parts sitting, and wanted to build a good bus engine for his early bay. So I built him a 88 x 82 mm. Close enough. With exactly a W110 cam, stock "race rods" from Rimco, ported stock heads, 9 - 1 CR, Dual 40 Dells, 009 w. electronic module, stock heater boxes and a 1 3/8" header with a 2" free flow muffler
I did´nt like it. It had a dreadfull dip in the torque curve between 3200 and 3700 rpm. Then it sort of caught wind again and had its second peak at about 4400 rpm and had max hp at 5200 rpm. (114 hp @ 5200 and 164 Nm max @ 2900) The peak torque wasnt anything to write home about either.
I tried moving the cam around a bit, nothing good came out of that. Tried a 1½" header with 1½" J tubes. Got a little more even torque above 3100, bit still a great reduction in torque from 2900 to 3300, which was quite noticeable in the bus. In a beetle you wouldnt feel it that much.

From what I have tried, my personal opinion is that the 86-88 mm bore has outlived itself at 78 mm stroke.

The engine in the particular bus was taken out, and I built him one of my 1955 bus engines instead. Those produce better hp numbers, more overall torque and more peak torque and a much "cleaner" curve. The APB is also about 2,5 higher.

I would not think a particular bore the stroke ratio would be the cause of a TQ dip on a TQ curve :?

Dont you think its would be more a head flow/cam/carb transition event?

Sat Jul 21, 2012 1:53 am

Krusher, that may be so. But the "funny" part is that I have built several 85,5 & 88 x 76 mm engines and one 88 x 78 with stock valved heads. Almost no matter which type of engine we want to have, mild or wild, that drop doesnt appear. Not the ones I have built anyway. (Well, maybe a little, but not the 15 Nm drop we saw with the 88 x 82 engine) My "medium" 1745 typically pulls about 105 hp and 155 Nm max. with more than 140 Nm available from 2500 -5200 rpm.
So theoreticly a 88 x 82 should do about the same, only maybe begin a little earlier, but something happens that I can not explain. Maybe someone else can.

T

Sat Jul 21, 2012 2:50 am

Quote: What carburetion? What will be done to the heads- valve size, porting?
i will go with the twin 36DRLA's i have, port heads with 40 x 35 valves

@ALstrup
do u mean the cam for the 1600 is not right for torq ?
i bought the engine with that cam maybe i should change it
and see what happens , any sugestions on a cam ? :)

that is a strange drop in torq do u think it only has to do with the long
stroke or a combination of variables working together ?

Sat Jul 21, 2012 3:54 am

Slakker.
A 1600 with a W110 cam can make torque, but "too high" up in the rpms to be usable for you, when you run big tyres etc.
One of the best cams around for lower end torque (that I have tried) is the CB 2280 and the CB 2239 I use the 2280 along with detailed heads and f.i. 36 dells in 1600 engines that need to pull torque from low rpm. At 8,5 CR mine usually pulls max torque around 2800, but pull hard already from 1500. and flattens out at about 5000 rpm. 130 Nm available from 1800ish to 4300ish rpm is about normal. They pull 80 hp easy on the dyno I use. Your engine may pull 90, but that´s no fun if it delivers in the wrong rpm range.

Wrt the behaviur of the small bore long stroke type 1 engine, I dont know. It may be the combo. But I - think - it has something to do with the type 1 cylinder head, because other engines have about the same bore/stroke relation with good results. But a larger bore shorter stroke or same bore less stroke engine doesnt seem to do it, at least not to the same extend. I have never seen it so violent as in that combo.

T

Sat Jul 21, 2012 4:06 am

74thing.
My 1955 bus engine is built around a Web 218 camshaft. V1 has detailed stock heads and heat exhangers and pulls 112 - 114 hp and 165-170 Nm torque. Its all over by 5300.
V2. has detailed 041 or 043 heads, 1½" exh. and pulls 122-125 hp and 170-175 Nm torque. Pulls hard from 2000 to about 5700. Both pull 1 ton trailers without problems if needed. Both typically make about 28 - 29 mpg @ 55 mph highway cruise in splitbusses. Bay´s are typically about 25 - 26 mpg.
T

Sat Jul 21, 2012 8:34 am

Torben,

What compression ratios do you shoot for in the v1 and v2 engines and what kind of valve springs do you use for each type of head?

Thanks

Sat Jul 21, 2012 3:12 pm

Hi Slakker

That's the 1600 engine you bought from me right? If so it has a W100 grind cam, I know it says W110 on the invoice but trust me it's a W100 profile.

Is the engine still running good heres the link to it http://www.thesamba.com/vw/forum/viewtopic.php?t=360458&postdays=0&postorder=asc&start=0

BTW I plan on building a 86mm bore x 76.4mm stroke engine using rebored 85.5mm barrels and a WBX crank

Sat Jul 21, 2012 3:26 pm

I do not think it is a good idea to stroke a WBX crank past 82mm, the oil holes get too close to the edge!

Sat Jul 21, 2012 3:45 pm

@Edmund
yip that's the engine , runs very well but with the big tyres not enough torq
in the lower rev range

Sun Jul 22, 2012 2:20 am

Slakker lives in a city which is at an altitude of more than 6000 feet. Thinner air there is said to result in a loss of power and torque of around 17%.

Sun Jul 22, 2012 2:25 am

I did a 78.8 with 87mm jugs. ran great.fk8 with 11.5 1 cr, then lowered it to 10.5 after a year of street driven, didnt realy notice much change.

Sun Jul 22, 2012 8:16 am

all this talk and its reminding me of south africa, eastgate the mall years ago in johanesburg and times in nelpsruit at promenade hotel :P

sorry out of topic!