VW engine mods - Cam's - Compression ratio - Valve size - Timing

cams, compression, valve size, engine size, and timing how to sort this sort of thing out

[@Mikefngarage]

ON Chevys We used to do that with the weights and springs. Plus they had a vacuum advance. we would put stops on them and use vacuum delays from smog equipment to bring it on slower to get more advance at higher RPM....IF your going to play with advance MAKE SURE TO DRIVE IT LUGGING IT AND SEE IF IT PINGs.....If your engine pings it will damage the engine quickly. Even just a small tinkle of a ping......Nothing.

[@tonypachanga9636]

Hi Mike how much will you charge built me a2000 cc engine ?

[@Mikefngarage]

@@tonypachanga9636 I dont build engines for anyone but myself. but you can check with brothers vw machine shop.

[@Mikefngarage]

When I refer to Barrel fire. I am talking about more than .060in Deck height. Too much cylinder shims and not enough combustion chamber caused the piston to need to be too low in the cylinder. This is a cause of detonation. On the stock heads to prevent this We used to step cut the heads to make a larger combustion chamber. Now with the CB Panchito's or the AA big valve performance they are made with a larger combustion chamber to solve the problem especially on stroker engines.

[@Hi_Tec]

The problem with the bigger cams at low RPM is that the mixture is not mixed very well due to the low gas speed. The more advanced ignition gives the flame front a bit more time to make its way. A higher compression leads to better ignition and to a faster flame front. As a coincidence just this morning I read about this in a book which is nearly 100 years old, written by Harry Recardo.

[@danielneuenschwander7381]

Mike: Great video on explaining the relationships between Compression Ratio (theoretical & actual), Cylinder Pressure, Cam Lift, Valve Size, and I'd like to throw in one more, Volumetric Efficiency of the heads/intake. Thanks for sharing this.

[@Mikefngarage]

yea good one. important.

[@johnreinburg859]

Perfect timing for me. My 2000cc Volkswagen Bus is having compression problems.

[@Mikefngarage]

Try advancing it if you have a big cam and low compression. Might come alive. just be sure to test drive it after and see if it is pinging....If it is back it off till it doesnt then see what you end up with.

[@clintonwilloughby7606]

The CB Magnaspark comes with 3 or 4 sets of weights and springs. I can't remember exactly as it's been a while since I installed mine. It allows you to set when the advance begins. Have a great day!

[@rscruiser3533]

Thanks -- Mike for the video -- For me -- it's fuel for thought for when I start to build my engine. ----- Rodney

[@Sellmyowngranmother]

Your videos are a joy to watch 👍

[@Paulman50]

My engine is 1600 twin port, 7.2:1 compression, big valve head, hot cam 😠👎 Just the problems that you are talking about. My fix is shimming the distributor stop posts to give me 13° idle 30° full advance. Set the accelerator pump to full Here's the good one-- set the valve gap to 8 thousandths. This was told to me by a friend that builds motors for racing. The idea is to eliminate some of the valve overlap .

[@eugenwulff9838]

Look at 123ignition, its fully programmable in a standard housing.

[@Mikefngarage]

$$$$$$$$$

[@jimmywilkinson9190]

Hey Mike ! On Rambus when I was putting the motor together using a new autolina mag. case I put some -040 shims on the barrels and it probably has what you call barrel fire . With a new case I shouldn't used shims . Now once again I am going to save up some money each month to get some new B,V. Heads . They seem to have them at Carcraft . Last time I had the $ we all caught COVID and the wife took my $ for the bills ?

[@Mikefngarage]

just make sure the deck height is between 50 and 60 max. those heads have about 60cc. depending on what engine size your building you want around 8 to 9 to 1. with those heads. check CB performance calculator and see what you end up with. all the info is on their website

[@jimmywilkinson9190]

@@Mikefngarage When I put it together with the stock heads it had at least 1/10 to a 1/8 of a inch piston to top of barrel . I should had stopped and took those shims off . A couple of hours ago I went to town and the first light the van stalled . I didn't let it warm up its was 35 degrees and the choke was still on ..........

[@daalhoffarm]

Performance cam, hmm have build some engines now and tuned/driven them. And a new stock cam with ratio rockets works te best for me.

[@Mikefngarage]

I like the web 86 because you can go stock rockers for small engine or 1.25 or 1.4 depending on what size you go. and the curve is better than the stock one.

[@vintage76vipergreenBeetle]

👍

[@TexarkanaPrepper]

Love the vdubs Mike, I’m trying to get up on a different subject. It’s about the Mustang that you painted for your friend with Parkinson’s. I have one that I’m restoring and that is the color I’m looking for. You Said it was British racing green. Do you have any idea what the paint code is or how that color was mixed? Do you know what car the color was taken from?

[@Mikefngarage]

no i dont remember the code it is the dark one. most of the places know the dark British racing green. they had a lighter one that was out later.

[@TN-oc3cw]

Do you have any thoughts on how a Mexicool/ACD 1600i engine may need altered timing when converted from fuel injection to carb? I have an ACD case w/hyd lifters and I assume stock cam (with old pistons and barrels). I have new heads on it (std 35.5 x32), SVDA distributor and 34 Pict 3 carb and it runs rich and will only run if the timing is very advanced. Thinking about replacing pistons and cylinders to address any compression issues, but not sure if the ACD cam/hyd lifters will affect how the stock valves/rockers work, and if that ultimately affects the timing.

[@Mikefngarage]

head cc, cam and valve sizes plus compression. use the CB calculator. IDK what that cam is. it all depends on what that is. I had a mexican case AS I think it ran great. wanted to be at 28 max though. never took it apart. ran pretty good. also make sure the jets are right in the carb. could be too lean.

[@goldentrunnell7450]

Do you have any thoughts or info on compression ratio at higher altitudes? I'm at 5700 feet so I'm trying to understand if I should run higher compression compared to sea level. I have a 2110, w110 cam, slightly better than stock heads, and dual 40 carbs. This combo seems to be fine since my Baja is geared low, especially 3rd and 4th. I'm wanting to build more of a street version for another bug (bigger cam, heads, and carbs) and compression ratio is something I'm trying to understand better. Thanks for your videos.

[@thestove2407]

#1 You must use a svda distributor. #2 Set the timing to 7.5 btdc Do you have pre-heat to the breather ? And do you have heat to the intake manifold ? You need all three or you will run rich

[@brunomahle1618]

Why do you have that weber on backwards? blended two vids? With the 009.....bend the stops in to limit total and get 12-14* at idle What exhaust? bore a 1.5" hole in your fan shroud freeze plugs.

[@Mikefngarage]

1.5 on that.....exhaust

[@brunomahle1618]

@@Mikefngarage It is really important to have proper manifold heat with a centered carb. You should connect one side of your heat riser to the collector of your exhaust,...the way VW did it on the stock exhaust. Backwards carb? The hole in the freeze plugs mimics the bleed through the heater boxes when off,and doesn't disrupt the airflow in the shroud.

[@tonypachanga9636]

Hi Mike is that cam web 86 has a rough idler because that's what I want and do you have a email or shop that I could go to. Hope you could get back to me.

[@Mikefngarage]

Yea it has a slightly rough idle but not terrible. I dont know any shops that would do a cam change right now.

[@coltsimpson]

70 1600 sp likes being at 10° will not run at 7.5

[@martinharris5017]

68 1600 sp has factory spec at "0" degrees. I thought it was the same for 69 and 70 models. At 10 degrees my 1600 would have way too much static advance! With a mild cam and worked heads I run about 3 degrees but factory spec is 0. See here: www.volksconversions.com.au/VC_TimingFigures.pdf

[@Mikefngarage]

all depends on what distributor is in there. compression and cam. most have been rebuilt. and lots have been modified. hard to know when they are all original anymore.