What to do - my 1969 Beetle 1500 cc SP

[bibliomane74]

Yeah, I checked and rechecked the valve adjustments there a few times. It's officially something else...

[helowrench]

Well that sucks, but from the compression check with oul, it sounds like the head to me. Cracked valve or bad seat. I have had a cracked piston do this. Cracked above the top ring a chunk of the land was missing.

More than likely you are ok on pistons and cylinders. Only a teardown will tell for sure.

I still stick with my recommendation for a warmed over 1600dp using your original case if it checks good.

[bibliomane74]

Sounds like a plan. I will get started tearing down tomorrow and I will make sure to get back on and write up my first rebuild. If I'm going to do the 1600 DP using my original case - does that just involve changing out to DP heads? And that would fit the original 1500 SP case? I thought there was an issue with the studs or something.

[Marc]

My money's on major compression leaks and resulting erosion of the head and cylinder sealing surfaces. Once an engine's been driven very long with loose heads, merely tightening down the bottom four head nuts is closing the barn door after your horses have escaped. Loose heads make a characteristic noise, similar to that of a blown exhaust flange gasket but half-a-heartbeat sooner when the throttle's cracked open. It'll only be noticeable on a cold engine in the early stages, if caught by then retorquing may buy many more miles of use. Once the noise is present on a warm engine, major surgery is indicated.

...I still stick with my recommendation for a warmed over 1600dp using your original case if it checks good.

Even a "good" H5 case (one that passes the "daylight test" at the center main web, of which there are virtually no remaining examples) is barely adequate for service as a stock 1500SP, and then only after line-boring, thrust cutting, cam tunnel resizing, decking, and head stud insert installation. Even with all that money invested in machinework, it may still suffer pulled case studs upon assembly which require Helicoiling. If you do manage to get it assembled, it's still more likely to crack, or warp if overheated than any other VW case before or since. The oil pressure control system isn't designed to support a doghouse cooler, and the passages are barely adequate in size to feed a cross-drilled crank. A more appropriate use for the elusive "good" H5 would be as a 6.6:1 1300SP with a plain-bearing crank, and even then it'd be a step down from an (older) F0 or H0.

NO WAY IN HELL would I ever use an H5/B5 case for a bone-stock 7.4:1 1600DP, much less a "warmed-over" one - it's the kiss of death.

[bibliomane74]

I think I've read enough to make me quite nervous. I am relatively new - so even if I think the H5 is looking good when I get it torn down, I can't be confident. So, I need a 1600 DP case. I just have to find one on this side of the Mississippi for crying out loud. Tons in CA. I'll keep looking, though, because I really need it. Feel like I won't be able to rest until I get that part ironed out.

[helowrench]

And the slippery slope of build creep that culminates in a 2332 has begun.

[helowrench]

I would recommend finding a local machine shop for the vw world (they usually do harley stuff as well).
Most of the time they will have a case prepped and ready to go. I managed to pick one up for $250 that ha dbeen dropped off, worked, then the guy never came back.

[Stray Catalyst]

Buy a good case - you're not saving money if you make a 1600DP that runs for a few days before you pull out a stud. I've tried re-using cases without line boring and the like, and sometimes you get lucky... but the 1835 on my workbench is an AS41 case that came from Air Cooled Engineering, where Art Thraen properly line bored it. It's not cheap, but it's also not thousands of dollars.

If you're rebuilding an engine, there's no real reason to stick with 1600. 1776 is a good size with extra power, but not so strong that you're exceeding the limits of your case. If what you want is just a simple engine that'll carry you to highway speeds, buy a turn-key motor (craigslist often has them, sometimes with terminally rusty car included) and rebuild at your leisure with a new or re-machined case, while you can still drive the car.

[Chris V]

There are new 88mm P&L's that don't require case machining - but DO require head machining (thick at the top where cracking occurs)...From 1585cc's to 1679cc's and it's <$100 to have the heads opened-up.

We still have the pieces floating around the garage from an abandoned H5 I found on a jog a several years back...converted to DP - the pushrod tubes weren't even rusty yet...but a rod had ventilated the case.

[aussiebug]

The easiest rebuild it to convert you 1500sp into a 1600sp. The 1600 cylinders and pistons drop straight in (no case mods), and the modest increase in hp (about 4hp) will not kill the case if it's in good condition.

I have such a conversion (on an Euro/Australian H1 case which is apparently a slightly better case than the US H5 case), which has 400,000km on it with just the one rebuild (into a 1600).

I used the existing 1500 heads which results in a slightly higher compression ratio, so the engine prefers 93 RON octane rather than the stock 91 RON octane (87AKI in the USA). But the heads are completely original - no alterations apart from fitting new exhaust valves. Alternatively, you can use new/rebuilt 1600sp heads and use the normal 91RON/87AKI octane.

If you decide to look at this option, check the end play in the case, and also check the cylinder studs for any pulling out of the case - if even one stud has started to pull out of the threads, then ALL studs would need case savers (threaded collars) machined into the case, or scrap the case and get a later model engine. Also carefully check the 1500 case for cracking - most common around the No3 cylinder case hole, but can occur in other areas too.

[Marc]

We've heard about your wonderful H1 case, Rob, but it is SO remarkable that there's no way it could be remotely comparable to the "cottage-cheese-alloy" H5/B5 cases we got in the states. I believe I've mentioned before that I suspect it's a continuation of the H0 series - they made so many of those that they ran out of numbers for them and had to progress to H1 - which is not cursed with the metallurgy problems of the H5. The H5/B5 motors were VW's first attempt at meeting US emissions regulations and they were apprehensive that the operating temperatures would be too high, so they intentionally cast the cases from a less-dense alloy to facilitate better heat transfer through the bottom end. As it turned out, temperature turned out to not be an issue but they proceeded with the funky cases and didn't rectify the situation until the `70 model. When the L-Jet fuel-injection motors came along, which DO run hotter, they again changed the alloy but that time they got it right with AS21, which is actually stronger when hot than AS41, and addressed the issue by improving the efficiency of the cooling fan.

The best use of a (US) H5 case is to keep the rain off of potentially recyclable internals. Once it's apart, it's a good stud donor or doorstop. When broken into small pieces, it's exciting to set on fire.

[helowrench]

With magnesium and fire. Mo bigga mo betta.
Nothing like chemical enhancement and 45lb of magnesium on a bonfire.,
then the firefighters put it out.
and lit it again
That was fun.

[Stray Catalyst]

Case halves like that are fantastic on the bonfire! The last one I burned, you probably could have seen with the unaided eye from space. DO NOT try to put it out.

[Marc]

Not with water, anyway - that only makes it angry.
But you can snuff it with enough sand or cement mix, it's a good idea to have lots handy should you choose to try this...

[helowrench]

I had helicopter transmission cases. Weighed in at 45lbs.
We would donate them to the local fire depts who would use them for training.
Our one condition was that we could come and watch.