1776cc Engine Build Help

Engle says dual valve springs are required if 1.25:1 ratio rocker arms are used.  Believe those heads are dual valve.

You'll get better bottom end and through midrange power (where you do 99% of your driving) with some properly ported 35x32mm heads- a 1776 doesn't rev high enough with an Engle W110 (even with 1.25 rockers it'll top out at about 6,000 rpm) to make good use of the larger valve heads.  If you're insistent on using the bigger heads it will run well enough; the combo just won't be optimal.  Lots of people use them on smaller engines and report them running just fine, but a dyno comparison would only show the bigger volume heads to be a benefit in the very highest part of the powerband (last 1,000 or so rpm?).  I think the 34 mm vents may be a little on the large side as well; again, for better power and driveability throughout the rpm range 32's might be the better choice.

Hope this helps.  Al

I’m a newbie to VW engine building. My research on the heads are saying that the combustion chamber is 64cc. Sounds big for a 1776cc. Because of that will I have a low compression ratio? Will it run ok? Just don’t want to have a engine that is hard to set up or runs poorly. 

If you're going this way, you "may" want to sell the 69mm crank. IMHO, those heads are too big and will fall on their face with a near-stock displacement.

I'd get a case already clearanced(and don't forget the camshaft itself!) for a stroker crank.

A 78mm or better(82, 84, or even 86) crank will help you use those heads for proper breathing.

64cc heads are old-school low-compression. Some milling machine work to make the chambers smaller is most likely in order. Mine are 52cc, my static CR is 10.2:1. But admittedly I'm at the sharp end of the stick.

The important thing to remember is that EVERY part of the engine has to be sized to work together. Dynamic compression is also a big factor. Cam/ports/rocker are all related and important.

@DannyP posted:

If you're going this way, you "may" want to sell the 69mm crank. IMHO, those heads are too big and will fall on their face with a near-stock displacement.

I'd get a case already clearanced(and don't forget the camshaft itself!) for a stroker crank.

A 78mm or better(82, 84, or even 86) crank will help you use those heads for proper breathing.

64cc heads are old-school low-compression. Some milling machine work to make the chambers smaller is most likely in order. Mine are 52cc, my static CR is 10.2:1. But admittedly I'm at the sharp end of the stick.

The important thing to remember is that EVERY part of the engine has to be sized to work together. Dynamic compression is also a big factor. Cam/ports/rocker are all related and important.

Would I be better off just selling the heads and getting smaller ones and use the rest of my parts? Is there a cylinder head that you could recommend  that will work with the parts that I have. 

I have to admit, I am totally NOT an engine builder. If it was me, I'd either spend a lot of time researching(and look HARD at CB's engine builder kits) or call a couple builders and ask questions. But don't waste their time if you're building it yourself.

The main point is, be honest with yourself NOW as to your needs, desires, and expectations of a new motor. And for safety's sake, please upgrade the handling and braking of your car before you add gobs of power. As Peter Parker's Uncle Ben said, "with great power comes great responsibility"!

@JB356SR posted:

Would I be better off just selling the heads and getting smaller ones and use the rest of my parts? Is there a cylinder head that you could recommend  that will work with the parts that I have. 

None of us are engine builders, but lots of us have built engines. I'd look at ACN's L3 heads for your engine.

@ALB posted:

You'll get better bottom end and through midrange power (where you do 99% of your driving) with some properly ported 35x32mm heads- a 1776 doesn't rev high enough with an Engle W110 (even with 1.25 rockers it'll top out at about 6,000 rpm) to make good use of the larger valve heads.  If you're insistent on using the bigger heads it will run well enough; the combo just won't be optimal.  Lots of people use them on smaller engines and report them running just fine, but a dyno comparison would only show the bigger volume heads to be a benefit in the very highest part of the powerband (last 1,000 or so rpm?).  I think the 34 mm vents may be a little on the large side as well; again, for better power and driveability throughout the rpm range 32's might be the better choice.

Hope this helps.  Al

If I fly cut the head to get a smaller combustion chamber will these heads work better?

@JB356SR posted:

If I fly cut the head to get a smaller combustion chamber will these heads work better?

You're better off to cc them first and figure out what you really have. There are kits for sale for this, or you can build your own. Check YouTube for how-to videos.  

Here's some info on my 1776 which might help you.

I had a valve seat come loose a couple of years back, so I bought a new set of Empi heads with 40/35.5 mm valves and single HD springs. Off the top of my head, the chambers measured 56 cc. Once I accounted for deck height and ran the math, my static CR worked out around 9:1, which is right where I want it.

I'm using stock VW rockers on Gene Berg shafts and chrome moly pushrods. Not really sure what the cam is because someone else built the engine and I've never cracked open the case. I tried pulling the oil pump to examine the end of the camshaft, but it's glued in solid with aviation Permatex. The new heads aren't ported. The old ones were, pretty radically, along with the manifolds, so I bought a new set of Empi manifolds to match the new heads. It's running dual Dellorto 40s. Not sure of venturi or jet sizes because I've never needed to dig into it. My Pertronix SVDA distributor is timed at 30 degrees, I pull vacuum from ports above the throttle plates on both carbs, teed together, with a restrictor inline to smooth out the pulses. 

I like the way my engine runs with the new heads. It's driveable anywhere above 2000 RPM, but the power really builds by 3000. It pulls strong to 5400 RPM, my self-imposed red line. I pushed it to 5800 once and power was still strong. I'm guessing it has a performance cam, probably a W110 or similar. I won't rev any higher because the valve springs are only good to 6000. I also don't fully trust the bottom end because I didn't build it. But I have put about 9000 smiles on it. (-:  

When I first bought the car, with the old ported heads, matched manifolds and a Magnaspark II mechanical advance distributor, it had an awful dead spot off idle and no power at the low end. It was high strung, and no fun for just putting around. I blame that on both the porting, which reduces the velocity of air entering the cylinders under part-throttle conditions, and the distributor, which had an RPM based curve only. To be streetable, ignition timing needs to account for throttle position, especially at low RPM. 

I hope this helps,

Eric

Looks like a nice list of parts; I would go with a 78 mm 4340 chromoly crank instead of 4140.  It would make the motor a 2007 cc.

I really thought about changing the crankshaft but I decided to use most of the parts I have except the camshaft. I’m going to a Engle 120.

Again, it will run well enough, but it will be much more responsive and happier with ported stock valve heads (the intake ports of the big valve heads will be too large to keep airspeed up at lower rpm's with the smaller displacement, which will reduce low rpm power).  Take Stan's suggestion- ACN's L3 heads are what this engine needs, even with the W120 cam. A simple flycut to raise the compression (which makes the combustion chamber smaller but does nothing to the intake port volume) is not the fix here.  If you're insistent on using the bigger valve heads, Impala's suggestion of increasing the displacement with a 78 mm crank is a much better solution.

And while none of us are engine builders per se, a lot of us have been around long enough to know what works and what doesn't. You're getting good advice here.  Al

@ALB posted:

Again, it will run well enough, but it will be much more responsive and happier with ported stock valve heads (the intake ports of the big valve heads will be too large to keep airspeed up at lower rpm's with the smaller displacement, which will reduce low rpm power).  Take Stan's suggestion- ACN's L3 heads are what this engine needs, even with the W120 cam. A simple flycut to raise the compression (which makes the combustion chamber smaller but does nothing to the intake port volume) is not the fix here.  If you're insistent on using the bigger valve heads, Impala's suggestion of increasing the displacement with a 78 mm crank is a much better solution.

And while none of us are engine builders per se, a lot of us have been around long enough to know what works and what doesn't. You're getting good advice here.  Al

If I go to a 78mm crankshaft do I have to change the rods and pistons?

@JB356SR posted:

If I go to a 78mm crankshaft do I have to change the rods and pistons?

I believe you can stay with the same rods but might be on the fence on the pistons.

You'll need B pistons if your stroke is above 74mm. Rod length has to be calculated, but what you have may work.

B pistons have the pin closer to the piston top.

AA makes very reasonably priced piston and cylinder sets if on a budget. Even Cima/Mahle aren't expensive in the smaller sizes. My 94s with forged pistons were $400, I think that's the highest price on the Cima/Mahle brand.

@JB356SR posted:

If I go to a 78mm crankshaft do I have to change the rods and pistons?

No, you don't need to go to longer rods- the rod ratio in a 1600 (1.98:1) is very conservative. Stock length rods (5.394 or 5.400") are used with success even in 82 and 84mm engines all the time.  With VW rods a 78mm stroke engine gets a little wider (just over ¼"?) with stock stroke pistons- not a really big deal.  You could use 356 length rods (2mm shorter from center to center) and it would be just a little wider than stock.  Using stroker pistons you would end up with an engine a little narrower than stock.

@ALB posted:

No, you don't need to go to longer rods- the rod ratio in a 1600 (1.98:1) is very conservative. Stock length rods (5.394 or 5.400") are used with success even in 82 and 84mm engines all the time.  With VW rods a 78mm stroke engine gets a little wider (just over ¼"?) with stock stroke pistons- not a really big deal.  You could use 356 length rods (2mm shorter from center to center) and it would be just a little wider than stock.  Using stroker pistons you would end up with an engine a little narrower than

Thanks for all the great advice. I appreciate it.