The valve sizes mentioned in Bulletin M-118 are for an 1800 Type 4. Were 41mm inlet 34mm exhaust valves ever fitted to a 1600 type 1? I don’t think so but then I don’t know much about the type 1 engine.
Could do with some expert advice please. Have been following the Wilson book to inspect the pistons. They are all within the various dimensional tolerances, there’s no skirt wear, ring clearances are good. The only iffy thing is the light scuffing on the top side of piston 2; The scuffing isn’t at all deep, you don’t notice it with your finger. What would you do, scrap the lot or pop back in with new rings? The only other issue is just one of the circlips has a very little wobble on the top side, but I think I’d overlook this if I could also ignore the scuff. What do you think?
I'm by no means an expert but in my eyes the piston has seized at some point or at the very least sucked something in but not the end of the world as you say it was running well and the grooves have smoothed over meaning it's an 'old injury' - how does the barrel look ?? Oh , and hoping that's a typo and you're not reusing the circlips ...! Sent from my SM-G960F using Tapatalk
If the cylinder is in perfect condition you could clean up the scuff on the skirt with a fine diamond file, don’t use sandpaper or any abrasive that could be embedded in the aluminium. New rings and circlips of course. But 96mm pistons for 2056cc are cheap, flat top to increase the CR with a better cam and you’d have a decent engine.
The No2 barrel has a corresponding scuff too… Probably overheated when I was running for a while 20k ago with a dodgy dizzy that over-advanced. I’ll measure the barrel- piston gap tomorrow. Wasn’t planning on going for more umph tbh but if I end up replacing the P&Bs then will give it some thought. 2056 - that’ll will be with the KB pistons then. For a stock 1970cc engine, is there anything to choose between Mahle and AA P&B sets?
Personally, I wouldn’t reuse that cylinder or piston and I wouldn’t change just one B&P. You could get them all bored out for 96mm pistons, especially if they are original VW – they’d be better than anything you can buy today. I wouldn’t pay a premium for Mahle, AA usually supply pretty good stuff, but not always. They might say that their B&P kits are ready to install but you must check everything. Their iron cylinders might have very large scallops for the studs leaving very little of the sealing face. For what it’s worth I use AA Biral cylinders with KB Hypereutectic pistons – forged pistons are not required for a road engine.
Thanks Geoff, that’s just the concise response I was hoping for. Having slept on it I think I’ll go with a modern, like for like replacement with the AA 94mm set. Heritage have a Black Friday sale on, so time to get the plastic out. So, while I’m at it - could anyone direct me towards what’s best for a cam shaft and lifters that’s closest to stock? Heritage offer Brazilian lifters and an ‘American’ but otherwise unbadged stock cam but I’d be more more keen on a matched set where relative hardnesses have been thought about. Cheers…
Stop sleeping and buy: https://www.heritagepartscentre.com...kit-2056cc-96mm-x-71mm-for-2000cc-type-4.html + https://www.heritagepartscentre.com/eu/ac10920086-scat-c25-camshaft-1700-2000cc.html + https://www.heritagepartscentre.com...aft-follower-set-lube-a-lobe-1700-2000cc.html Job done.
Get thee behind me! Hadn’t looked at the prices for the warmed up kit - ouch..! If I bought that all that stuff you’d then be telling me to ditch the Solexes next and fit some Webers that don’t like the cold…. Given I mostly do long distances with mates’ vans that are 1600 I think I’d just be burning more fuel for the privilege. Nope, stock set up is the way. Just need a nice bassy cam….
If you can run to the extra cost the Scat cam and lifters are the way to go. If not I went with Heritage standard cam & lifters which have been fine. Whether they will last 70k plus ask me in about 15 years time
Interesting - what’s makes the Scat a good choice? …but some horses must be shot! First time I haven’t taken your advice Geoff, I’m feeling nervous!
At very low revs a C25 will make less torque than a standard cam but by say 1500 revs it will start to work well - and most of us drive in the 2000 to 4000 range – aircooled.net says ‘it will work great even with the stock carburetors or FI, but it also shines with dual 1bbl carbs, or a single 2bbl. This is a nice upgrade on stockish engines, it's an outstanding bus cam! HD Springs are required! This cam works best with Compression from 7.5-8:1. Power band is from off-idle to 4000.’ I know zed likes the standard cam but if you look at the power graph you’ll see torque drops off almost as soon as the revs increase from idle, there is still a lot of torque because the engine is 2.4l. I think a better compromise is to fit a cam with more duration to increase exhaust scavenging, improve efficiency and move maximum torque more into the rev range where we normally drive. But that does mean torque at very low revs is reduced, which is why I keep banging on about increasing capacity. A bigger engine makes more torque so what is lost at very low revs is offset by the capacity. IMO the standard cam was good in the 1700, not so good when VW increased the capacity to 1800 and decidedly mediocre when the engine grew to 2.0l.
Pay no attention to me, I have never built a completely standard engine of any type but VW sold many thousands that work adequately. I just think we can make them a bit better. It’s called fixing what’s not broke.
Comparing Cam & lifter prices on Heritage the Scat cam & lifters works out about the same as the standard cam & lifters. No brainer really
