The 4" Bore Thread

[Zach Gomulka]

Looks like the last topic I posted was a victim of the forum crash, so here we go again...


All this talk about 4" bore motors has got mine and a lot of other heads spinning, and I want some answers!

Do you have to use an aluminium case? What modifications are needed?
Are they truely streetable/highway-able? Not just good for a weekend plaything! I'm talking much more than just around town...
What heads can be used? Hopefully something with more than 6 thick fins...
Can a normal fanshroud and cylinder tins be fitted? I hate those Porsche look-a-likes...
Where do you get pistons & cylinders? Are the pistons only available in one pin height? Slipper skirts? Cylinders in one length?

Who has a 4" bore motor out there? Please share your experiences!

[Jon]

Do you have to use an aluminium case? What modifications are needed?

Not if you know somone that can weld a stock case.

What heads can be used? Hopefully something with more than 6 thick fins...

JPM' ms230 has 4" as a option...   9 machined (thin) fins...

[Jesus]

i was told of a 4inchbore website but can't find it?

Thanks Alex

[Zach Gomulka]

i was told of a 4inchbore website but can't find it?

Thanks Alex

http://4inbore.com/

[71CALRIPPER]

Cant wait for mine 

[Roman]

The easiest way is just call CB and ask for a blank head stud case. They usually  have a bunch on stock.
It is clearanced for stroke, but has stock bore and no head stud holes.

-When you recieve it, just pull out the dip stick tube, weld some on #3 cylinder behind the dip stick.

-Next step is to fill the oil passage between the #3 and #4. Bore it smooth and make a rod in a lathe and fill the hole with it.
It needs some kind of fixation for the rod. Use your welder, loctite or your imagination, whatever works best for you...

-Next step is to bore the holes for the case savers and installl them. I used Würth Time sert.

-Next step is to bore the holes for the cylinders.

The case is done!

I have AA cylinders that works alright in an N/A config, but I wouldn't use them with a turbo.
I have custom CP pistons of my own design. It is the third set now and it gets better every time, even though they weren't bad the first time. My own design is a lot lighter than a 94 mm Mahle, but yet rated for 350 hp/9000 rpm.
Chevy etc pistons might work, but they aren't that good for a VW as they have the wrong pin size etc.
Ford pistons have the valve reliefs on the wrong place.
There is two options for heads as far as I know: JPM and modified Angle flow.
JPM needs no modification, but on the other hand it is more expensive.
The JPM head has more cooling fins if you want to run on the street.

It is possible to use a mag case, with steel plates etc, but it is a LOT of work. You can also modify a Water boxer  case, but it is a lot of work too.

Pitcures below:
Top: Welded case, machined flat
Second: Milling for case savers
Third: milling for cylinder holes. One to go!
Fourth: Done! 94 mm case to the left.

 

[ugly duckling]

here is one of my six stud cases zach . i had a nice little parigrf about my experiance but got kicked off becase im a slow typer so i will try later after dinner.JD .

[ugly duckling]

are they werthy of true street diving. yes sir. i will put my reputation on the line with out any doubts and say they are very very worthey. i would think that you and many others would already know this. they are worthey on even the crap gas you get at the pump. zach my original engine 3066cc i used the weaker case and crank (LOW DECK CASE AND 92 MM NON 411 MAIN CRANK) .after i toar the engine down for inspection i notice a hair line crack in it i wonder why  ::)i new it was weak but hey somebodys got to try it right. so then i put a 411 90mm. still using the weaker low deck case. did i ever put 5000 miles on it like you ask? more i would say . but since the engine was in the infant state i couldent keep my hands off the thing so i would tear it down from time to time to see how things  were wearing ( R D) and parts always looked great so it was back together. now that we have the better cases RASID DECK  now the true relibility begins (THICKER). i drove my car in 100+heat  in bumper to bumper traffic hiway freeway you name it. it was done .race and street worthy by far. i would not hesitate to even put another low deck 101 engine together for my self or a customer knowing what i have learend how to keep them alive .build one you wont be sorry that you did . UD .     

[John Rayburn]

.

[ugly duckling]

thanks for that Jhon boy.

[ugly duckling]

steve dalton another guy that has the experience on the subject. he had a few speed bumps that he had to drive over but as far as i know his old blue is a relible STRONG  runner and is drivin often . and another big bore fanatic is the one and only don pauter he has many street big bore miles under his belt. truly respectilble. and we cant forget rockey jennings. so yes there are many. UD .

[Steve D.]

Yup, I had a few hoops I had to jump through, but only because I tried a funky crank setup that took a little different approach to figure out.  As for the 4" bore part of the equation, it's been nothing but smooth sailing.  Only an 86 stroke here, but loads of HP and TQ all down low on the tach.  I actually had a friend in a reputable car club drive my car a few weeks ago and when he got into his fantastic running 94mm car at the end of the night "It felt like it was broken."  I haven't put as many miles on the car as Jeff has, but I'm catching up quickly 

To back up the legitimacy of Jeff's big block motors, I was driving next to him as he drove the car to Irwindale, and when he went on the 100+ degree 60+ mile Vegas drive, and the motor actually ran cooler than a few of the 90.5 and 94 bore cars that made the same drive- food for thought.

Just remember, it wasn't long ago that people were saying the same things about 94 bore...

[Lids]

What sort of cost is required to buy the basics; case, heads, barrel and pistons?

What length rod is needed?

Thinking about 82 x 103.

Does the crank need to be flanged?

[ugly duckling]

lids. 82 crank just your reg por lenght or vw lenght 22 mm pin. no the crank does not need a flange unless you want to do it .steve and i have had great sucsess with reg dowel crank 11/32 dowel mate no wedge. drag race with slicks in 2000 lb bettels. UD . 

[louisb]

My next engine. But I got to wear out the set of heads UD made for me first. 

--louis

[Lids]

Thanks Jeff, what about a rough idea on component costs.

[SlingShot]

Not long ago I purchased a set of vintage 100mm Empi Birals. They were originally designed for the 914/T IV Engine. I was contemplating building a type 1 engine with these, but I'm not sure if they will work because the cylinders are 3/8-1/2in   shorter
than a type 1 cylinder. I think the added deck to the Alum case could make it all work out, what do you guys think??

Sorry for the mild Hijack Zach

[Zach Gomulka]

Just remember, it wasn't long ago that people were saying the same things about 94 bore...

I was thinking the same thing. 94's came out in the late 70's I believe, but it wasn't until many years later where they finally got "street cred" Hopefully we can look back on 4" bore motors the same way someday

[cassa]

Easiest way out is tu use the waserboxer case with JPM heads no welding needed. has T4 registerbore/depth.
And is VW quality.

[ugly duckling]

yes the wasser boxer case is vw quailty i agree with you there. but is limited on stroke yes it has trhe studs in the location already if you can find one that you can remove the old head studs with out breakedge WATER DAMEDGE then cutting off the water jacket milling down. then the crank and bearing combontion. when it all comes down to it its just as much work to convert if not more headake than the autolina. just my two bits .UD . 

[ugly duckling]

here is a low deck that i finished today. its for sale or i will build it for my own personal use or will sell the engine when done complete or long block state. it is limited on comp i have run  as much as 10.2 comp with no problems.this one has the new gusset system on it for that extra muscle.makes a bitchen street case for the lower comp pump gas guy . UD . 

[Zach Gomulka]

I wanna see some of you SoCal guys drive your 4" motors to Vegas, Phoenix, Sacto, ect....

[Steve D.]

What does it matter?  How many people actually drove their 94 bore motors to Vegas, Phoenix, Sacto, etc...?

I did Vegas four times and Sacto once with my old 94 bore motor, Phoenix never because I don't like Arizona.  Point is, it will come around and it probably won't be too far off- I guess 250hp on California pump gas at low rpm through IDA's driving non-stop for an hour and a half through 100+ degree heat and stop and go traffic isn't enough reason for people to start building...

[karl h]

i did two bigbore wasserboxer engines, one 96 bore one 101.6 bore. removing the headstuds can be a pain, just like jeff said. dont forget you have to bush the lifterbores for type 1 lifters (has hydraulic type4 stock) AND: you cant run a sump. it does have more oil capacity stock, but not enough i think
dont forget it has a factory sandseal, so not every pulley will fit
i did fir stock sheetmetal, but it has to be modified extensively, the case is much wider
oh yes: it has a stock oilfilter that cant be used with a merged header without mods, no just hooking up the full flow
 i just bought two pentroofcases, seems like less work
do i have to weld at the no 2 cylinder spigot? didnt have to on the wasser case. and is the oil routing roman talked about different than with the wasser case?

[58vw]

i think jeff already did vegas from orange county....then won real street.....then drove home......

[58vw]

nice pic karl

[richie]

I wanna see some of you SoCal guys drive your 4" motors to Vegas, Phoenix, Sacto, ect....

Zach

Jeff drove his to vegas and back under the strict Real street rules with the rest of the guys,filling up with pump gas along with everyone else,running it hard at the track then driving home again,thats good enough for me,I have 2 pairs of angle flows sitting here waiting for Jeff to get some time to work on them

cheers richie,uk

[cassa]

yes the wasser boxer case is vw quailty i agree with you there. but is limited on stroke yes it has trhe studs in the location already if you can find one that you can remove the old head studs with out breakedge WATER DAMEDGE then cutting off the water jacket milling down. then the crank and bearing combontion. when it all comes down to it its just as much work to convert if not more headake than the autolina. just my two bits .UD . 

I run a 86mm VW rod crank in my WBX-oxy case almost NO clearance needed. Only on the bumps under the studs.
Headstuds can be difficult, but I have not had any big problems, and its easier to remove when the waterjacket is removed.

Waterjackets is a Angle grinder job. and kind of fun!  
No need to mill it down, I leave a edge for strength.

The Crank and bearing combo is the benefit!  run the 76,4 crank with 4" and you have a 2,5L blast.
or use 1mm oversized +1mm trust bearings on the main and wbx on the others for new T-1 cranks.

The reason I like it, is that it is dooable for common people to convert these. No need for big machining equipment. and ok 2,1 wbx engines are kind of cheap. Then one can use the case and crank++.  For the money one save, buy some GOOD heads.

The oil capacity is like 4 liters, IIRC. what is a T1 with normal deep sump?

Its not trouble free, but not that hard to manage. Only machining I have needed is the honing of the lifter bores.

my 2 cents

[BeetleBug]

The oil capacity is like 4 liters, IIRC. what is a T1 with normal deep sump?

Just to answer your question; 4,5 - 5,5 liters.

[Jeff68]

All right, now I feel like I'm in the dark ages with my 2110 :-(  This is great information.  Thanks Zach for starting this post and Jeff D. for taking the initiative to put it on the street and R & D it and put this out there.  Thanks for all who shared their experiences with doing this.  Too bad the economy isn't doing so well or I'd bet there would be many ready to try and do this, I know I would.  Maybe I'll take my motor apart (only 150 miles on it) sell the mag case, pistons and cyl's heads etc and go 4 inch.......This is cool stuff. Jeff R