Stupid, stupid SP1300 ideas

[Marc]

You'd need to have the case machined for the larger-diameter WBX #1 bearing and to accept the thrust shims and front seal (or there's a thinner seal that'll work without machining, Chicago Rawhide # 29513).
The WBX crank is a stouter piece than the stock Type I but it's still subject to flexing at high RPM - you'd gain the potential for 1000 RPM or so more, nowhere near the 9000 pipe-dream.

[petew]

Can I just clarify though, what you're telling me is the counterweights don't actually stop the flex completely. They just limit the flex some. So getting up near 9k is always touch and go. Right?

[FJCamper]

Hi Petew,

Correct. The counterweights lessen crank flex. The big Type 1 case problem is we only have three main crank support areas, not four as most of the iron block inline 4 cyl engines have. That's why a 16 valve Cosworth Ford 4-banger can run 9k.

We have four support bearings, but #4, right there at the crank nose where the crank pulley attaches, isn't much support, so all the stresses go to the #2 center main.

Do keep in mind we VW guys are turning revs today the Porsche factory could only wish for the 4-cam type 547 engine. Our road race Ghia ia redlined at 7k.

FJC

[Piledriver]

The extra mass in the WBX crank webs does the same job as the counterweights, the harmonic is gone.

The problem is you then need a T4 conversion flywheel and thrust/main bearing setup for a T4 or WBX machined into the case. has been done, but there goes the cheap and cheerful part of the project.
Plus you might as well build a 1914 or 2110 at that point, depending on which WBX crank you have.

A stock crank with welded counterweights properly done is a decent piece, and still sanely priced last I looked.

[petew]

Well, here's a funny little curiosity for you all. The SP1300 in the shed has this number...
F1127617 = 1966-70 1300. 180mm clutch, single relief, etc.

The 1600 in my oval window has this numbers...
F1914362 = 1966-70' 1300. 200mm clutch, dual relief case with large oil galleries.

Weird huh? My engine builder (Hans Klaack) was mystified when he looked up the number but found all the late model stuff.

BTW, how did Oetinger get away with build TSV1300s that rev out to 8k out of 36hp motors? Is that all in the crank and DP heads?

[Marc]

Not at all weird, you just need to take into consideration that many reference books are USA-centric and don't acknowledge numbers found in other parts of the world. The international information is in pretty short supply here and many folks are completely unaware of non-US numbers.

In the US, the 1300 was offered only in 1966 and all had "F0" cases. In `67 we got only the 1500 with an "HO" case. In `68 VW made a new version of the 1500 to meet ever-tightening US emissions regulations; those got a different case ("H5" in Bugs and "B5" in Buses) that was made from a less-dense alloy to facilitate better heat transfer through the case since higher operating temperatures were anticipated. H5/B5 are horrid and worthless for any kind of performance use - they were having problems when just a few years old as stock engines with cracking/warping & pulled studs.
The US has always received a single engine choice; in other countries where there are more options, the ones no longer offered here continued in production, using their original number series. In 1967, after 1300SP #F0999999, they went to "F1"; by 1970 those numbers ran out and "F2" began. Similarly, when they ran out of numbers in the HO (1500SP) series in 1968 they started using "H1". F1, F2, and H1 numbers never made it to our shores, only F0 (1966 only), H0 (1967 only), and H5 (1968 & 1969). The sole offering here in 1970 was the "B6" 1600SP.

The letter denotes the displacement and general configuration (i.e. singleport or dualport) but doesn't, in and of itself, define the engine any further. The H5/B5 series are unique in that they weren't offered worldwide and have that shitty alloy. Your F1127617 would've been built in 1967 with a case identical to the F0 or H0. Your F1914362 was produced in 1970 AS A 1300SP (that's what "F" means) but most likely has a case comparable to the "B6" used for the 1600SP in 1970, first one with large oil passages and dual pressure control valves. If it is in fact a 1600 now, that's because someone rebuilt it that way (and it would be of interest to know if they used 15/1600 heads or just flycut the 33x30mm 1300 heads to fit). 1200 & 1300cc engines came equipped with 180mm clutches, and 1500 & 1600 got the 200mm - so we know that's not the flywheel that it left the factory with.

Occasionally you will encounter a "factory exchange" engine that was built to a different configuration than what the recycled case was originally, for example here an "F" or "H" case was used to build a 1200 ("D") using the late 1200 cylinders with the 90mm O.D. lower spigots - the original number was completely milled away, leaving a cartouche where the new one can be stamped in. https://www.thesamba.com/vw/archives/in ... engine.jpg

...how did Oetinger get away with build TSV1300s that rev out to 8k out of 36hp motors? Is that all in the crank and DP heads?

Pretty much. The valvetrain was never intended for use much above ~4500RPM so it needs some upgrading to be reliable, and of course the cam itself needs to be more radical.

[petew]

Maybe I just need to port the SP heads to oblivion and move the pushrod holes...

https://www.youtube.com/watch?v=aijyLKCvbU8

[Marc]

The most radical SP intake work ever done didn't flow as much as a stock DP out of the box, so good luck with that.

[petew]

Yeah, I should sell it off and find a later dp1300. Then we can talk silly ideas about that instead.

[Marc]

Best use for a small-passage 1300 is either stone-stock or flycut the heads to accept 1600 cylinders to make an awesome little "driver" motor. CC the heads and set deckheights to stay below 8:1 with a stock cam (that'll still require mid-grade gas, for the cheap stuff keep it under ~7.7:1). Will run with a 28PICT/28PICT-1 or early 30PICT-1 but a `67-up 30PICT-1 with power fuel system would be better.
Wouldn't recommend keeping the 180mm clutch, though, unless you drive like Grannie. There are "Porsche" and "Bus" 180s that can handle a 1600 but a stock 200mm is at least as good with a lighter pedal/less wear on the linkage.

[petew]

I've also got a late bus 1600.

[Marc]

I've also got a late bus 1600.

Check the cast-in letters/numbers on the sides of the sump. You may have an AS21 alloy case with provision for mechanical fuel pump (something never available in the USA)...also, the intake manifold heatriser pipe is probably larger in diameter than usual...after a brief experiment with dual heatriser pipes in `74, the US market went to L-Jet FI (NO preheat) while the carbureted 1600DPs in Europe went to a single, larger pipe - in the Buses, anyway.

[farmer]

Light rods and light pistons will keep you in the grey zone a good deal above 5500.
Say 500 gram rods and minus 60 gram off of the pistons, 12½ lbs flywheel and a 3½lbs achiever or power pulley along with a meticulous balance job will extend the grey zone to about 6500.

[petew]

A couple of you have mentioned the "harmonic" that causes flex. Can someone explain this please?

[Piledriver]

A std T1 crank/rod/piston setup will start to "whip" in the middle due to a vibration harmonic at right around 5500 RPM.
The easiest solution is add mass to the crank, changing the frequency of the harmonic, and effectively eliminating the issue.

To fix/prevent this, VW added mass to the crank webs on the T4s, and on the WBX.
Welded on counterweights do exactly the same thing.

A boxer crank doesn't need counterweights, but the stock T1 crank needs more mass to not beat the case to death.
Welded on counterweights work.