1600 Stock engine

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Enginefreak~66
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1600 Stock engine

Post by Enginefreak~66 » Wed May 24, 2017 1:02 am

Hey all,
I am going to build a 1600 twin port for my 76 aussie bug and want it to last as long as possible and be fairly bulletproof.(and survive a few clutch dumps :wink:)
This what i am thinking so far:
Straight cut gears
Full flow oil pump and filter
empi pulley and sand seal
Standard heads
standard 34 pict carb and manifold system
Gt tuned exhaust
Norris cam and lifters - 352s
69mm cw crank-for a bit more balance. I am just wondering where to get the crank from - any suggestions will be appreciated.
Rev limiting rotor @ 5800 rpm
Cheers,
Lawson
4 valves are better than 2 :wink: :wink: :lol: :lol: :lol: 8) 8)

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Marc
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Re: 1600 Stock engine

Post by Marc » Thu May 25, 2017 2:45 pm

I doubt that combination will ever see 5800, it'll be all done by 4500 or so. Doesn't really warrant a CW crankshaft if you'll be keeping it below ~5000, but if you go ahead with one you'll want to lighten the flywheel a bit to compensate for the added inertia...not necessarily to the ubiquitous 12-lb weight, but perhaps ~15 lbs. The influx of Chinese new cranks has sort of pushed the old-school cranks that were made by welding counterweights to an original German forging off the market but they're still available from a few sources and would be my first choice, but for an engine this mild anything except a cast crank should be fine.

Note that as a rule any CW crank you buy is going to come drilled for 8 dowel pins, using the SPG pattern where one is slightly offset for indexing purposes. It's challenging to do a proper job of matching a flywheel to an already-8-dowelled crank (simply using an SPG drilling guide doesn't guarantee perfect alignment, the only way to be sure is to drill them both together and then ream to the correct interference fit) but again, your combo won't be putting severely high stresses on the junction so perfection's not really mandatory. Use an oversize washer under the gland nut and an undercut nut if you can find one (Berg used to sell the GB202 modified stock nut but nowadays only offers CrMo @ ~$50, overkill IMO for this build). A $16 Chinese one from AA Performance Products would be fine. They sell cranks too; I haven't used one of theirs but haven't heard any negative reports about them FWIW. Always check the clearance between the head of the gland nut and the center of the clutch disc since a thicker washer and/or a flywheel that's been resurfaced a lot both reduce that - once the disc wears it can contact the glandnut, preventing clean release.

With stock 1.1:1 rockers that cam should be fine with good stock springs (I'd put a .030" shim under each to stop them from chewing into the head). If you wanted to step up to 1.25 rockers some cheap HD singles would be wise IMO. For just about any engine that's expected to be thrashed upon, even a near-stock one, it's a good idea to go to a "solid" rockershaft setup to eliminate the liabilities of the stock wavy washers & springclips - I'd add that to your list. Stock pushrods and valve adjusting screws will do with the 1.1s (.387" lift); for the 1.25s you're at .440" and getting close to needing HD pushrods and swivelfoot adjusters...that may not be justifiable budget-wise for the small power gain offered.

Never been a fan of either the sand seal (other than for off-road use) or the filter-pump. The pump's better than having no filter at all, but typically they come with gears quite a bit longer than necessary resulting in oil pressure high enough to open the cooler bypass in normal driving - you may need to install a stiffer spring and/or run lighter oil than you would with an old-school legit fullflow setup based upon a stock sized pump. Also, be sure it's going to clear with your chosen exhaust system. It's cousin, the in-n-out pump, has fittings to connect hoses to a remotely-located filter...if you're willing to accept the potential liability of the added plumbing, IMO you should just go ahead and do a classic full-flow setup. There's also an aftermarket fitting which goes in place of the rear pressure control valve for the return line if you're leery of drilling & tapping the case for it - those work but eliminate the control valve so warmup can take a little longer (I wouldn't go that way in a cool-weather location).

You really don't need the straight-cut timing gears; even with HD single valve springs, just using cam bearings with double thrust shells would be enough to control the endthrust generated by stock gears. But they'll do no harm if you like the noise.

Another suggestion - again for an AA product...I swear I'm not on their payroll ;) would be to have the heads flycut to the 98mm size used for late 90.5 and 92mm cylinders and get a set of AA's "thickwall slip-in" 88mm pistons/cylinders. No machinework needed to the case and you get 1679cc, still within the limitations of the stock carburetor but enough bigger to feel the difference (can't really say that about slip-in 87s, and they have rather thin cylinderwalls).

Enginefreak~66
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Re: 1600 Stock engine

Post by Enginefreak~66 » Thu May 25, 2017 9:18 pm

Hey Marc,
Thanks for the reply,
I have decided against the full flow oil pump and am going to full flow the case, and will only use a 26mm pump
Are the cb welded cranks original with welded counterweights? -http://www.cbperformance.com/product-p/1110.htm
I don't mind the sound of straight cut gears. I will definitely be using double thrust cam bearings...
I think i will just stay stock 1600 size...
Any other recommendations?
Thanks heaps,
Lawson
4 valves are better than 2 :wink: :wink: :lol: :lol: :lol: 8) 8)

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Marc
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Re: 1600 Stock engine

Post by Marc » Thu May 25, 2017 11:09 pm

Based upon the description at CB's website they apparently are reground used cranks but that's about all the info available there. The one review posted isn't exactly glowing.

I get mine done at DPS - José does nice work and only uses German cores. Others have reported good things about Demello's welded-CW cranks. I'd expect either to be adequate for this project (and superior to what CB Perf is selling).

http://dprmachine.com/products/crankshafts-type-i/

https://www.thesamba.com/vw/classifieds ... ?id=696395
Last edited by Marc on Sat May 27, 2017 5:21 pm, edited 1 time in total.

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Re: 1600 Stock engine

Post by Marc » Thu May 25, 2017 11:10 pm

Duplicate post but this forum doesn't allow deletions :evil:

adlbeetle66
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Re: 1600 Stock engine

Post by adlbeetle66 » Tue Jun 06, 2017 10:09 pm

Hey Marc,
Wondering if port flow is torque or power and what the port velocity changes?
Cheers
Last edited by adlbeetle66 on Tue Jun 13, 2017 5:52 am, edited 1 time in total.

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Marc
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Re: 1600 Stock engine

Post by Marc » Tue Jun 06, 2017 11:43 pm

For a stockish 1600 with a 34PICT-3, port work isn't going to show much gain - you might be able to pick up a couple HP at >4500 RPM but it can only make it less responsive putting around town; I'd just open both the intake opening and the manifold to the diameter of a stock metal gasket and call it good. You can't get in too much trouble with a mild "mini-D" home port job though...IMO that'd be worth it if you think you may be switching to some small duals on this engine someday.

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Re: 1600 Stock engine

Post by Marc » Tue Jun 06, 2017 11:57 pm

For a stockish 1600 with a 34PICT-3, port work isn't going to show much gain - you might be able to pick up a couple HP at >4500 RPM but it can only make it less responsive putting around town; I'd just open both the intake opening and the manifold to the diameter of a stock metal gasket and call it good. You can't get in too much trouble with a mild "mini-D" home port job though...IMO that'd be worth it if you think you may be switching to some small duals on this engine someday.

Even in bone-stock form the intake tract of a 1600DP is a little too big for around-town driving - they make about 3HP more than a 1600SP at ~4400 but give up some driveability at the low end (the infamous "flat-spot" hesitation on acceleration is a direct result of the lower velocity).

adlbeetle66
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Re: 1600 Stock engine

Post by adlbeetle66 » Fri Jun 09, 2017 1:56 am

Hey Marc,
So a higher velocity port is for more torque or power?
Does port flow affect much (polish of ports) ?
Cheers
Last edited by adlbeetle66 on Tue Jun 13, 2017 5:53 am, edited 1 time in total.

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Marc
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Re: 1600 Stock engine

Post by Marc » Fri Jun 09, 2017 2:06 pm

There's no simple answer. The "conventional wisdom" is that a port with too large of a cross-sectional area (therefore lower velocity) will cause a loss of low-end power - to an extent that's true, but SO many other interracting factors exist.
One thing I've found to be true is that large ports tend to have poorer mixture distribution and will benefit more from the "squish" effect of tight piston deck heights which increases turbulence in the chamber. Smaller, higher-velocity ports will have more "swirl" of the incoming charge and suffer less from lack of quench area - making them more tolerant of hemi-cut chambers or big deck heights.

I suppose it'd be safe to say that if you're primarily interested in overall driveability and not peak power it'd be wise to avoid opening up the intake ports a lot.

http://garage.grumpysperformance.com/in ... -area.333/

Enginefreak~66
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Re: 1600 Stock engine

Post by Enginefreak~66 » Tue Jun 13, 2017 5:47 am

OK thanks for the advice.....
Hopefully build an engine soon...
Cheers,
Lawson
4 valves are better than 2 :wink: :wink: :lol: :lol: :lol: 8) 8)

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