TheSamba.com :: View topic - 87mm big bore kit, does it matter what engine I use?

Mon Nov 11, 2013 9:21 am

Hi guys, I just bought a 87mm big bore kit here in Iceland, it includes pistons, cylenders and rings, the seller told me that it would stroke a 1600 motor to a 1641. My question is, can I use this on a 1300 motor, 1300 crank and case?
please, any info would help me

Mon Nov 11, 2013 9:30 am

you can use on a 1300 also, BUT the 1300 heads have to be bored out to the 1500/1600 size. The case is the same size, and all use the same crank/rods.

Mon Nov 11, 2013 9:38 am

I do have head from a 1600DP can I use them?
is there anything else that I can do to increase the power, higer compression another camshaft and valves maybe? do you have a recipe for a nice 1641 motor?

Mon Nov 11, 2013 9:41 am

More power... sure, go bigger.

How much more power can you afford?

Changing the camshaft requires the case to be split and is a full rebuild.

Mon Nov 11, 2013 9:41 am

Yes, you can install the 87s and the 1600cc DP heads for a nice upgrade in power. The top 2 center head studs are shorter on DP engines, you'll have to use washers or better yet, the proper head studs, for those 4.

What carb(s) and exhaust?

Mon Nov 11, 2013 9:42 am

hehe yes I know I can go bigger ;) but I want more power from 1641, can anyone tell me how much power I would gain from a plain 87mm add on? just the big bore kit and heads?

Mon Nov 11, 2013 9:46 am

If you can add the 1600DP heads along with a set of dual carbs it will add a lot more.

Mon Nov 11, 2013 10:13 am

can you tell me how many hp I could make out of it?

Mon Nov 11, 2013 10:51 am

:) There is not too much difference from 85.5 to 87 mm.

Your engine would still be able to use the same heads and carb w/o going the expense of DP heads, three piece intake manifold and a 34-3 carb.

I'm concluding you wish a increase in power while not going the expense route.

I have in the past rebuilt many 1641cc engines for the bug and T2 vans.

Going to a richer main jet and maybe adding a set of 125.1 ratios will have a slight satisfying increase of power....not a ground shaking power but noticeable under normal driving conditions w/o the engine straining and your foot to the floor etc.

The 1300cc engine was a one yr thing in the US while it could still be used in other countries later on.

As mentioned the heads would have to be opened for the cyls other then that everything else would be used.

I drove the same kind of engine in a 71 Bus from LA Calif to Mexico City, Acapulco and back up north along the Pacific coast to Calif avg 20 mpg the whole trip and had plenty of power when needed.

VW mechanic (retired in Baja)

Mon Nov 11, 2013 11:00 am

but the OP doesn't have 85.5s, he has a 1300. And he already bought a set of 87s. He's asking if they can work together, and if so, how.

Mon Nov 11, 2013 11:21 am

ice-beetle wrote: can you tell me how many hp I could make out of it?
The difference between a 1300 SP (50 hp SAE gross/40 hp DIN or SAE net) and a 1600 DP (60 hp SAE gross/48 hp SAE net) was 10 hp SAE gross, 8 hp SAE net/DIN. A 1641 DP with otherwise stock components won't make much more hp than a 1600 DP, I'm guessing around 50 hp SAE net/DIN, so maybe a 10 hp SAE net increase from a 1300 SP, assuming you have a 34 PICT-3 for the 1641 DP.

Mon Nov 11, 2013 12:45 pm

:) The last time I saw a 1300 engine it had 77mm pistons.

Granted, I gave a 85.5 to 87 as a small increase comparison but reality he has a original? 1300 thus the 87 would be a sizable increase in power for him.

As to the actual HP number it would be inconsquensual at this point and mute unless put on a Dyno. Number is just that a number.

He has limited himself with a SP engine and talking duals etc is way over his head and ability (with all respect).

What I gave was a workable solution and possible low costs.

His 1300 heads have small valves and the 30-1 carb would need the 127.5 or 130 main jets but still workable and added fine tuning.

His engine still has the early 69mm Bull Nose crank unless it was changed in the past......time does strange things and weird results.

Mon Nov 11, 2013 5:32 pm

yes the heads and cylinders will help, a small cam will also help,as can 1.25 rockers. you realy need to step up to more carb when going up in cc and power. you realy need to make sure the entire engine is ready for the "new life"

Mon Nov 11, 2013 9:36 pm

Recipe that I have done=

87x69 **balanced etc.
Port work on those dp heads helps!
Single hi-rev springs.
Engle 100
dual Weber 40 Idf w/stock 28mm vents
1 3/8" Bugpack header w/quiet pack
lightened 8 dowel flywheel
doghouse German cooling

*this engine has good power and good mileage. I have also done a thick wall 88x69 with very similar parts, but with larger different heads and a Fat boy muffler, with J pipes. Made my bus haul ass around town...as well as be able to comfortably go 80mph on the highway. Pretty affordable engine that won't leave you single...and that you can build yourself.

Tue Nov 12, 2013 5:31 am

The 1300 is 77mm stock. I still have stored a 1300 that came wits 83, vw oo9 and a 2bbl carb,was in a 57 bug. W ith this modest cyl increase and add ons it got around very well, going dp & 87's would be more and would make 4 a decent driver, extra carb increase gives as much a boost.

Tue Nov 12, 2013 11:29 am

thanks for the answers guys, hehe over my head? no not really, I have built engines, mostly small block ford and some gti's,, I have put together beetle engines, this was just some wondering, I have 3 sets of 1600dp heads so that won´t be an issue, I like the idea with 2 webbers, better camshaft and bigger valves, thanks alot :D

Tue Nov 12, 2013 3:30 pm

:) Ok, sorry but the question about HP from a original 1300cc with 77mm pistons to 87mm sounded like a newbee and not from an experienced builder. My answer would have been different.

Now if you had asked about going 40 over on a small block...different story.

Tue Nov 12, 2013 11:56 pm

hahaha true ;)
but I really do thank you for the help :)

Wed Nov 13, 2013 10:03 am

If you're buying intake manifolds and carburetor mounts for the dual port anyhow, getting dual Kadrons will help a lot.

The issue many of us have with 87mm pistons is heat. You, being in Iceland, most likely will not have quite so much of an issue with that. Keep the air shrouds, get a dual port doghouse and oil cooler if you can. Your #3 exhaust valve will thank you.

Sat Apr 10, 2021 2:55 am

hi

if i may ask would the 87mm 1641cc liner kit fit on a normal 1600cc engine ...

just to remove the old ones and place these

Rish