View original topic: H case query Page: 1, 2  Next
wedgie Wed May 02, 2012 3:34 am

I've got an HO case with an 1835 thin wall p/c combo, SP. Yes I know, not ideal, but it runs okay and I can't afford better right now. I recently acquired a dead motor, serial number starts with just an H rather than HO or H5, which seems to indicate that it was made before the HO case. My question is, are the H cases as prone to problems as the HO and H5 cases? I'm also wondering if there would be much gain in performance if I swapped my SP heads for DPs. Everything internal apart from the p/c kit is stock and I'm running a Holley Weber. Once again, not ideal but in these straitened times one must make do!! Any input greatly appreciated, thanks.

mark tucker Wed May 02, 2012 8:21 am

I think "yes" will do it for all of it .but somebody will say Im rong again so dont take my word for it, waite for 8 more responces & devide the sum by9 to get the answer.hey where's RC???

wedgie Wed May 02, 2012 12:54 pm

Further reading on the H case situation leads me to the conclusion that the issue arose as a result of VW upping the ccs/HP of the 1300 (and therefore the heat generated) without upping the cooling capacity, thereby causing stud failures as a result of thermal expansion etc etc. VW countered this by increasing the cooling with the doghouse shroud, and by changing to 8mm studs. I'm wondering, as I've already got case savers in my 1835, and the cooling is pretty good (exposed engine in a buggy, doghouse shroud) maybe I can continue getting away with it? Should I consider changing to 8 mm studs - I could do this at the same time I pull the motor to put on the twin port heads.

craigman Wed May 02, 2012 6:55 pm

Don't waste your time on ANY of the "H" cases..

veedubcrazy Wed May 02, 2012 7:07 pm

I have an "H"case in my '67 and it runs fine. But I wanted a correct block for that year. It did have case-savers put in though. Cheap insurance. It runs fine with no problems...

wedgie Fri May 04, 2012 7:56 pm

Okay, I've started pulling apart the dead engine I've acquired, and so far it's in surprisingly good nick. At some stage in its past life it's been converted to a 1600, and case savers have been installed presumably at the same time. I'm wondering if I was to put 8 mm studs in, would that plus the doghouse cooling effectively leave me with a post 72 case, without the dual relief of course...What I'm curious about is - did the alloy composition get changed in response to the problems with the H cases, or were the problems solved just by the 8 mm studs with savers plus the doghouse?

DarthWeber Fri May 04, 2012 8:55 pm

VW improved the alloy of later model cases, the AS21 cases used for FI engines were the best. The internal oil galleys on your H case are small compared to the later model cases, this was another big improvement too.

The thing to consider is this, in a case as old as the ones you have, it has been heat cycled countless times. Assuming the engines were never overheated or run hot for a long time or over-reved, even then, the case material would be weakened by the sheer hours and hours of use. The AS41 magnesium alloy used in older cases is not a strong alloy by any means and has limited life even when used under ideal conditions. VW did not design these cases as rebuildable items.

I would urge you to choose a better case for a performance build.

HRVW Fri May 04, 2012 9:51 pm

:idea: 1968-9 engine cases were of a softer metal and the studs pulled leading VW to INVENT the case saver.

When building engines we in the trade would just install the case savers in all the blocks that came our way...still have many left over in my parts inventory...8mm and 10mm.

clonebug Sat May 05, 2012 7:12 am

Here is one weak spot in a "H" case engine.

It leaked a little bit of oil and I thought it was the flywheel seal.

Notice it only has less than a inch before the crack hits the oil gallery plug.

Once that happens it would be toast.

This is a pretty common problem with this series case.

wedgie Sat May 05, 2012 6:49 pm

Ye gods. I'm starting to think that I might just have to sell a kidney and get a case I can trust.

DarthWeber Sat May 05, 2012 8:19 pm

wedgie wrote: Ye gods. I'm starting to think that I might just have to sell a kidney and get a case I can trust.
Now yer thinkin'!! :twisted:

Dangermouse Sun May 06, 2012 1:11 am

You dont say what the engine no. of the case is but consider also that you're in NZ and not the US; there are differences in 'H' cases throughout the world and not all of them have the same poor rep as the US H cases. It depends also on which market you're in. My (NZ) 'H' case (H1259065) is dual relief with 10mm passages with deep studded #3 and 8mm oil pump studs and so was a grand candidate for a rebuild, which I duly did. It's been troublefree. So while the H cases are rubbished in the US, that doesn't always apply elsewhere so check it closely before you decide not to use it purely because  it has a H stamped on it...

The advice I was given was that - The "evil" H cases are the `68/`69 H5 Type I (and their B5 bus-motor brethren, as well as the contemporary Type III cases). H0 (1967 1500 Type I and II) were not cast from the same cottage-cheese alloy, nor were any `70-up cases. The US-market engines had to meet tighter emissions specs which meant higher operating temperatures, and the less-dense alloy was employed in order to improve heat transfer through the case - turned out to be a very bad idea, the softer alloy was much more prone to cracking/warping and pulled head studs. For `70, the oiling system was improved, allowing the use of the stronger AS41 alloy.
In the US market there were no H1 cases. The last `67 case here was something like H0874199, then the H5 came in. But in other countries the H0 series continued until they ran out of numbers in mid`68 and went on from H1000000. My H1259065 is of late`69 vintage (non-US, obviously); the large oil passages and dual-relief setup indicate that it's comparable to the B6 1600SP sold in the US in 1970.

mark tucker Sun May 06, 2012 9:21 am

how far was the split case bored??10mm or 8mm? I have some of the early cases and all have a perfect line bore.was that due to low ho? better material?better bearings? better fuel?better cranks?old farts driving them?I plan on opening up the oil gallys,adding case savers,& sticken a big old stroker crank in one of them. one already had the bergerman shroud of turin cars on it .so sweet.and never ran hot a single day.(the shroud did have some major mods)

wedgie Tue May 08, 2012 1:40 am

The case I'm currently using in H0024946, the spare is H1168296. The HO case has 10 mm studs, with case savers. No idea how far it was bored. Given what Dangermouse says, maybe I should stick with the HO, possibly opening up the oil galleries. I at least know its history since 1983 - from then till 2004 it sat unused, and since then has only done about 3,000 ks.

Many thanks for the input.

wedgie Fri May 18, 2012 3:19 pm

Okay then, I've got a plan. I'm going to pull both engines apart, check the state of each case and pick the best one to rebuild. As I'm financially strapped, I'm going to try and get the best out of what I've got by upgrading cam etc. Here's what I have in mind.

Pick best case, machine for full flow, case savers etc
Engle 110 cam (possibly with straight cut gears - if I can figure out whether they would be of real benefit)
Standard crank and rods
Twin port heads with 1.25 rockers
Re-use existing 1835 p/c set, with better cooling from doghouse shroud
34 PICT carb or Holley 5210 progressive

I'd be really grateful for comments/suggestions on the above, please. Does anyone have any idea on the likely hp output I could expect?

Matthew Fri May 18, 2012 6:43 pm

Straight-cut gears are of no benefit to the engine you are planning. The are only useful on engines running super high valve spring pressures. Your combo is probably good for 80hp at the crank.

wedgie Fri May 18, 2012 8:20 pm

Fair enough. I'd been reading somewhere about how straight cut gears eliminate end pressure on the cam bearing, but I can't really believe it would be a major factor in what I'm doing.

Re 80 hp at crank - what could I do with what I've got planned to get a bit more hp?

Matthew Sat May 19, 2012 4:51 am

You would need dual carburetors and cylinder head work to get more power. Also a counterweighted crank so it will last at the rpm it will turn to get that power. 80hp was with the progressive carb btw. Less with the 34 pict.

wedgie Sat May 19, 2012 12:59 pm

Okay, thanks for that. I presume you're meaning bigger valves, porting etc?

Matthew Sat May 19, 2012 1:28 pm

Ported stock valve heads with a competition valve job would be all you really need to break 100 hp with dual 40idf webers.

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