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Post by Zed on Jul 16, 2017 10:24:31 GMT
and this my friends is why I didn't bother spending big bucks on my air cooled and went Subaru. If you are ever in Hampshire and want to take a look let me know. You just need a builder who isn't obsessed with HP bit is obsessed with long lasting, cool running, torquey engines. I got lucky if you count several days engine chatting as luck. It's not rocket science, but how many who know what HP their builder is heading for (to attract customers)? Everyone! How many know what the torque numbers will be? Or for that matter what the standard torque figures are? Virtually nobody. I've been reading on the net lately, all the advice is cocked towards HP. People with hyper expensive 2.8l monsters have less torque than I do - they traded it in for more top end HP and heat. The only sensible bus related info comes from Jake Raby, who generally comes over as a know it all twat to my reading. He won't build a road bus engine over 8:1 CR. He does say why, just "because I said so". Twattish delivery, but correct advice I reckon.
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Post by Deleted on Jul 16, 2017 10:28:21 GMT
and this my friends is why I didn't bother spending big bucks on my air cooled and went Subaru. If you are ever in Hampshire and want to take a look let me know. You just need a builder who isn't obsessed with HP bit is obsessed with long lasting, cool running, torquey engines. I got lucky if you count several days engine chatting as luck. It's not rocket science, but how many who know what HP their builder is heading for (to attract customers)? Everyone! How many know what the torque numbers will be? Or for that matter what the standard torque figures are? Virtually nobody. I've been reading on the net lately, all the advice is cocked towards HP. People with hyper expensive 2.8l monsters have less torque than I do - they traded it in for more top end HP and heat. The only sensible bus related info comes from Jake Raby, who generally comes over as a know it all twat to my reading. He won't build a road bus engine over 8:1 CR. He does say why, just "because I said so". Twattish delivery, but correct advice I reckon. I think we agree that the difficult bit is finding someone to build decent ' properly spec'd' engines. If I thought I could of I would have.
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Post by razzyh on Jul 16, 2017 17:33:45 GMT
Oil pressure delay could be air in the sender extension as detailed above - I get same every time I remove sender from it's stalk and some air gets in. I can't see it would still be running if it really had no oil pressure for 10-20 seconds every time you started it. I'm not sure it's air in the sender. The engine sounds well rattley at start up. I'll do a vid.
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Post by Zed on Jul 16, 2017 17:43:52 GMT
Hydraulic lifters?
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Post by razzyh on Jul 16, 2017 18:40:35 GMT
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Post by paulcalf on Jul 16, 2017 19:27:31 GMT
@zed do you remember (about 2 years ago) asking me to find out my compression ratio from my engine builder. I posted what my builder said about compression ratio and temps, various people chipped in their 2p's worth and also said Gene berg was 20 years out of date! So I also included links to what John Maher said in his performance guide. Link thelatebay.com/index.php?threads/which-engine-spec-to-rebuild-to.52108/page-2Your question and this old thread may be very relevant!
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Post by Zed on Jul 16, 2017 19:54:29 GMT
Ray should read all that up to and including the bit where Paul W poo-poo's low CR as old thinking. I've learned now though Paul, thanks initially to meeting you and your cool running engine.
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Post by paulcalf on Jul 16, 2017 20:01:42 GMT
I'll post the key bits of info on compression ratio for those that don't want to look at the other thread: zed said: ↑ And I'd love to know what your CR is. Maybe I went a bit mad and that's my extra heat. @zed I asked my engine builder about my compression ratio, mentioned yours was 9:1 and heat etc. I've posted his reply as it may be useful for others as well ---------- Forwarded message ---------- From: Harry Harpics<harryharpics@btconnect.com> Date: 3 June 2015 at 14:58 Subject: Re: Compression Ratio - NOT URGENT To: Paul Hi, that high compression will be his problem. Tell him to Google Gene Bergs findings on compression versus fuel octane rating, it was done many years back, but he was and his findings still make him the “main man” for all things air-cooled VW. I rarely go over 7.9 – 1 as this allows the use of normal 95 octane unleaded. For 9.1 he will need over 100 octane fuel.Regards Paul holmsen, Jun 3, 2015: Gene Bergs info on this is 20 years old. And he made engines to last for 200k miles. zedders, Jun 3, 2015: Halfway then - 8.5:1 ? Or maybe I'll leave it, I've almost decided I'll keep this one as a thrasher and build a big sensible "touring" engine as well. Paul Weeding, Jun 3, 2015: You can run street engines at a higher comp than that...As Holmsen says, that data is over 20yo and fuel composition has changed a lot... Normal unleaded is now 10% ethanol, and that will lower the running temperature of the engine... It'll almost be like running water injection on a turbo engine.... paulcalf, Jun 4, 2015: @zed paul Weeding holmsen I'm not technical at all, i was asked to find out the CR of my engine so asked the engine builder who knows his s h i t . He doesn't go over 7.9:1. - I passed on his comments as I thought it would be helpful.John Maher Racing has produced a Guide to performance engines he has lots of info on compression ratio unleaded fuel etc. It says he doesn't recommend going much over 8.0:1. @zed have a read of the JMR CD I sent you, it has loads of info that may be helpful when building your next engine. I'll post a few JMR bits below about compression ratio and unleaded fuel
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Post by paulcalf on Jul 16, 2017 20:03:55 GMT
paulcalf, Jun 4, 2015: I hope JMR don't mind me posting this, his £12 CD is well worth it for people thnking of modifying their engine, COMPRESSION RATIO The most common cause of engine failure (apart from incorrect assembly or poor parts quality) is using too high a compression ratio. Most people don't even know what compression ratio their engine is running.
The other main consideration is the octane rating of the fuel. If your cylinder heads have the appropriate seats and valves for unleaded fuel, you have to be certain that the octane rating of the fuel you use can support the compression ratio of the engine. All my street engines can run on unleaded fuel. The higher the octane rating of the fuel, the more resistant it is to detonation. The higher the compression ratio, the greater the heat level generated in the combustion chamber. If this heat level gets to a critical point, it will ignite the incoming air/fuel mixture before the spark plug ignites. The explosion will try to push the piston back down the cylinder while it's still on it's way up. This is an extremely efficient way of destroying parts. It's commonly referred to as 'detonation' Many factors will determine what the C.R. of a particular engine should be set at. For starters, an air cooled engine will usually have a lower compression ratio than it's water cooled counterpart. Combustion chamber temperatures in an air cooled engine are higher than those in a water cooled engine, so attempting to run a C.R. of 10:1 on a mildly tuned street engine because your friend's factory Ford does, is not a good idea. Higher C.R.s can only be run if a fuel with a suitably higher octane rating is available. In all out drag race engines, C.R.s of up to 15:1 are used but they are run on super high octane racing fuels (114 to 117 octane) and are only run for a couple of minutes at a time; while they are on full throttle, under load for a matter of seconds. When building a stock engine, I set the C.R. at 7:1. This takes a little more work, but gives the customer an engine that runs cooler and will last longer.Engines using modified heads, performance cams, improved carburetion etc. breathe better than stock and will help the heads to run cooler. Depending on the specification, a modified street engine can safely run a higher C.R. than stock but I certainly don't recommend going much higher than 8.0:1 for an engine that is intended for daily use.If you’re tempted to run high C.R. to get that extra bit of horsepower, the life and reliability of the engine will be shortened. Engine temperatures will soar, the heads will crack and the cylinders will distort, creating case pressure and oil leaks. Some people will fit external oil coolers to make them feel more comfortable about the oil temperature, but they're not addressing the root of the problem: excessive combustion chamber temperature. C.R. could be reduced by increasing the deck height with cylinder spacers (the way most other people do it, if they bother to check!) but I prefer to keep the deck height on a street engine as close as possible to 0.060".Running extra deck height will reduce the C.R. (put some figures in to the equation and find out) but will not give as efficient a burn in the combustion chamber as a close deck height / dished piston combination. As the piston approaches TDC, it compresses the air/fuel mixture. The flat top of the piston comes within 0.060" of the flat area of the combustion chamber (even closer when things have warmed up and expanded), referred to as the 'squish area'. This forces the air/fuel mixture into the combustion area of the head. With a dished piston you still have the flat area around the perimeter of the piston to force the mixture towards the centre of the combustion chamber. In an engine where the C.R. has been lowered by merely running extra deck height, pockets of unburnt air/fuel mixture can remain on the outskirts of the piston, resulting in less force on the piston crown, therefore lees power at the flywheel. On larger capacity engines, it isn't possible to achieve the desired C.R. by dishing the pistons alone (about 0.070" is as deep as you can go without any sacrifice in reliability). E.g. a 2007cc engine (78mm crank, 90.5mm pistons), with 0.060" deck, 51cc heads and a 0.070" x 70mm dish in the piston will have a C.R of 8.5:1. To extract maximum performance, deck must remain at 0.060". If we want to lower the C.R. to 8.0:1, we need more volume in the combustion chamber. Great care must be taken not to remove material from areas that will affect the flow performance of the head. If the chambers are modified to give a volume of 56ccs, this will give a C.R. of 8.0:1. On an engine equipped with 40mm x 35.5mm valves, Engle 120 cam and a pair of 44mm or 45 mm carbs, this C.R. will give excellent performance, with no detonation or cooling problems. Providing the components are of good quality and the correct assembly techniques have been followed, there is no reason why a combination like this shouldn't last 80 to 100,000 miles.
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Post by paulcalf on Jul 16, 2017 20:19:36 GMT
Ray should read all that up to and including the bit where Paul W poo-poo's low CR as old thinking. I've learned now though Paul, thanks initially to meeting you and your cool running engine. I've messaged Ray and hope the info will be of use. My engine still drives well (touch wood), but i've had a few issues since the 'air filter stud breaking off and entering the engine' problem got sorted out.
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Post by paulcalf on Jul 16, 2017 20:32:14 GMT
I just need to find another engine over the next few months. Or go scooby which is a consideration. I know of an 1800 short block engine coming up for sale at a good price soon (not through VW circles, but through an engineer) Hoping to get more info later this week, it is apparently in v good condition Tempted to buy it myself for a spare, but no cash and i'm type1 engine and 1800's are type 4 i think? I'll let you know more, but it may be a good option for you
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Post by Zed on Jul 16, 2017 20:33:33 GMT
@zed do you remember (about 2 years ago)... I remember it very well as after Laurie's gutless plodder and my high revving heat limited efforts I was just getting to grips with what made a good engine. It's not easy when you're up against seemingly everyone apart from a handful of older engine builders. Most of them as it turns out will have done vw apprenticeships and also modded grass track beetle engined racers. They'll have tried everything you could think of, from all sizes up to 10:1 compression, to sharpening fins, cutting heads in half, tiny strokes with shortened pistons, different valve sizes, cams, styles and amounts of head porting, chamber shaping, squish. Anything to rev higher, anything to produce torque and on and on. They've done it all and have so much more than theory behind them.
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Post by paulcalf on Jul 16, 2017 21:00:40 GMT
@zed do you remember (about 2 years ago)... I remember it very well as after Laurie's gutless plodder and my high revving heat limited efforts I was just getting to grips with what made a good engine. It's not easy when you're up against seemingly everyone apart from a handful of older engine builders. Most of them as it turns out will have done vw apprenticeships and also modded grass track beetle engined racers. They'll have tried everything you could think of, from all sizes up to 10:1 compression, to sharpening fins, cutting heads in half, tiny strokes with shortened pistons, different valve sizes, cams, styles and amounts of head porting, chamber shaping, squish. Anything to rev higher, anything to produce torque and on and on. They've done it all and have so much more than theory behind them. I love the old VW wizards I take my bus to an old school vw mechanic in Bradford who has been working on them for at least 40 years. I've been using him on and off for 20 years. My current engine was built by Paul Miller (Harry Harpics) in Essex who has been doing it for 20+ years. I've experienced two of his engines and both have driven really well. I just wish i knew an old school VW dude based closer to me!
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Post by Zed on Jul 16, 2017 21:13:07 GMT
What I think I've learned. A cheap Type-4 2L based bus engine spec. As big capacity as possible within budget - 104mm pistons £500. Stroking is not necessary, it lowers the power band which is low enough already and it's expensive - a new crank for starters and you might want to get it balanced too. Standard cam or very mild cam - again the power band is in the right place already. Pushing it up the revs makes driving less relaxing. Reuse oil pump after inspecting. Reuse followers (refaced). Reuse pushrods and rockers. New bearings and gasket set £150. Case and head machining for barrels under £200. £850 so far. Very little really? Just as well. After capacity it's head work for the win, new valves and guides, reshaping and match porting, major reshaping of the valve seats - Rob cut a whole fin off mine. This is where most of the time was spent and why upping the capacity by an extra 25% increased the torque by 225% (80 to 180ft/lbs). It can't be anything else as the rest is stock. If you can find someone who really knows how to do this headwork it's worth whatever they charge IMO. 8:1 CR!!! Fat carbs. Reuse stock exhaust and heat exchangers. So there you have it. As long as your 2l is in good nick, £850 of parts and machining would get you most of the way. You could run it like that with no headwork at all, it would be interesting if someone tried that.
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Post by Zed on Jul 16, 2017 21:22:47 GMT
A type-1 has to be stroked or the capacity is limited to 1835 (I think) cc's, but essentially the same converstion on a type 4 gets you to 2413cc.
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