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Based on advice gleaned both here and elsewhere, I've decided to replace both heads on the 1776 which some previous owner installed in my speedster. One of the original heads had an intake valve seat hammer loose from its bore and lodge behind the valve. Fortunately, there was no damage to the piston, just a little nick, and nothing hard broke off, so no scoring in the cylinder. Talk about luck!

The original heads are Brazilian VW 043 castings with 40mm intake valves, 35.5mm exhausts, and dual valve springs. I measured 59cc combustion chamber volume. They were ported and polished. I liked the engine's performance, so I wanted something similar. 

I settled on a set of CB's Panchito 044s with dual valve springs. They have a slightly larger 61cc combustion chamber, but my original heads had .040" gaskets in addition to an 0.065 deck height, for a calculated static compression ratio of 6.828. I guess they did this so it would run on regular (87 R/M octane) pump gas. The added 2cc of chamber volume with the Panchitos, coupled with deleting the head gaskets actually increases the static CR to 7.197. This should be still be acceptable with regular pump gas, but if it knocks I can always step up to 89. So I'm leaving the Panchitos as-is, no flycutting required. 

I measured my camshaft's duration, lift, and lobe centers, since the oil pump was glued in solid. From the numbers, it's an Engle W-110, which works with 1.25:1 rockers, so I'm upgrading to CB's super stock complete kit and elephant feet for better contact with the valve stem. A little extra lift should help the engine breathe better, that's what I'm thinking. 

Other parts on my list are a set of the matched Panchito intake manifolds, a set of CB's aluminum super duty pushrods, the straight ones, not tapered, and racing pushrod tubes, which are required for clearance with the 1.25:1 rockers. Lastly, I'm getting a set of NGK DP8EA-9 12mm, 3/4" reach spark plugs. 

I'm about to pull the trigger on this order. Can anyone think of something I forgot, or find flaws with my thinking? I'm always open to constructive criticism. 

Eric

57 CMC widebody, 1776, Dell 40s, IRS, 4 wheel discs, 18" Boyds, 225/35/18

Last edited by Eric (McGruff)
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Those heads are pretty messed up!

 @Eric (McGruff) said-"I'm guessing whoever ported and polished the head took out too much material behind the valve seat."

Or the press fit was wrong. How high does the engine rev with power? I'm guessing that with the added effective duration the 1.25's provide it must peak up around 6,000 rpm?

 If you want a big kick in power- up the compression to 8 3/4 - 9:1. You'll have to run premium, but it's a toy, right? And you'll be amazed at the difference in throttle response! If you're insistent on running regular you can still raise the compression 1/2-3/4 of a point safely. Again, you'll find an improvement in throttle response and should feel an increase in low end and lower mid range torque, which will translate into slightly better mileage (if you can keep your foot out of it).

Hope this helps. Al

I take it you're going for the Panchitos with the cnc'd combustion chambers?

Last edited by ALB
ALB posted:

If you're insistent on running regular you can still raise the compression 1/2-3/4 of a point safely. Again, you'll find an improvement in throttle response and should feel an increase in low end and lower mid range torque, which will translate into slightly better mileage (if you can keep your foot out of it).

I take it you're going for the Panchitos with the cnc'd combustion chambers?

Originally, yes. But after reading your advice, I'm considering switching to the 54cc chambers. Losing 7cc pushes static CR to 7.87:1. If it knocks on regular, I can always buy mid-grade. and a little extra mileage never hurt anyone. Who am I kidding? I've never been able to keep my foot out of it!

Super low compression is a dinosaur thing. Those Panchitos not only flow better, but will mix the fuel and air better. You'll have so much speed on the intake that the swirl will be better too. I'd up the compression to 9:1 minimum. FYI, I run 9.8:1 on 93 Octane Ultra(with 10% ethanol) in Headflow Masters 44 x 37 heads in a Raby 2165cc.

Gene Berg has been gone a while, and the low compression motors of old should go away these days. Alcohol in the fuel actually deters knock/detonation. All you have to do is pull back the timing a couple degrees at a time until the knock goes away. Try 32, then 30, then 28. I seriously doubt a high compression 1776 with Panchitos is going to knock. But talk to Pat Downs, he knows what to do.

Oh, and REALLY good choice on the heads, they are exactly what they are cracked-up to be.

Last edited by DannyP

Good choice on the heads.

    My recommendation;  Use the swivel ball adjuster instead of the elephant foot when using a 1.25 rocket. The reason being, you will run out of travel on the elephant foot and damage it with the increased valve lift.

   Second, I also recommend running a little more compression. The combustion chamber of the panchito is well designed and the head runs cool. You should be able to run 9-1 compression with mid grade fuel, Although I recommend premium on any engine I build.

   If you wanted to take it a step further, get the chambers CNC machined to 61cc and then fly cut to 9-1. You will see even more power due to the unshrouding effect of the intake valve. When I designed the panchito chamber, I had to make it fit a standard 85.5mm bore. Unshrouding it increases intake flow 7-8 cfm, about 7 horsepower.

Last edited by Pat Downs
Pat Downs posted:

Good choice on the heads.

    My recommendation;  Use the swivel ball adjuster instead of the elephant foot when using a 1.25 rocket. The reason being, you will run out of travel on the elephant foot and damage it with the increased valve lift.

   Second, I also recommend running a little more compression. The combustion chamber of the panchito is well designed and the head runs cool. You should be able to run 9-1 compression with mid grade fuel, Although I recommend premium on any engine I build.

   If you wanted to take it a step further, get the chambers CNC machined to 61cc and then fly cut to 9-1. You will see even more power due to the unshrouding effect of the intake valve. When I designed the panchito chamber, I had to make it fit a standard 85.5mm bore. Unshrouding it increases intake flow 7-8 cfm, about 7 horsepower.

Pat,

Thanks for the advice. I recalculated the static CR. My engine has an 0.65" deck height, so if I start with the 61cc chambers, flycutting to 45cc yields an 8.98:1 CR. Adding the price for the shop work brings the cost to around $1225 plus shipping. Not that I'm complaining, good components are worth the price.

The mor I think about it, my engine was built by someone unknown to me and  I have no idea what issues are hiding in the bottom end. Rather than throw $1200+ into a questionable build, it makes more sense to put that money towards a new one with a known pedigree. Surprisingly, my better half concurs. So I'll be starting a new thread about a new engine as soon as I wrap my head around my goals for the build and the other changes involved, like a bigger exhaust and carburetors, or possibly fuel injection.  

Good move on the new power plant.  It is amazing how one thing leads to another.  A top end issue soon tuns into a bottom end inspection which may as well be. Full rebuild whic turns not machine work and case welding and then you say, “screw it, may a wel order one new!”  

I can vouch for the quality, advice, communication and delivery of CB Performance.  Good luck with your project!

McGruff posted:
Pat Downs posted:

Good choice on the heads.

    My recommendation;  Use the swivel ball adjuster instead of the elephant foot when using a 1.25 rocket. The reason being, you will run out of travel on the elephant foot and damage it with the increased valve lift.

   Second, I also recommend running a little more compression. The combustion chamber of the panchito is well designed and the head runs cool. You should be able to run 9-1 compression with mid grade fuel, Although I recommend premium on any engine I build.

   If you wanted to take it a step further, get the chambers CNC machined to 61cc and then fly cut to 9-1. You will see even more power due to the unshrouding effect of the intake valve. When I designed the panchito chamber, I had to make it fit a standard 85.5mm bore. Unshrouding it increases intake flow 7-8 cfm, about 7 horsepower.

Pat,

Thanks for the advice. I recalculated the static CR. My engine has an 0.65" deck height, so if I start with the 61cc chambers, flycutting to 45cc yields an 8.98:1 CR. Adding the price for the shop work brings the cost to around $1225 plus shipping. Not that I'm complaining, good components are worth the price.

The mor I think about it, my engine was built by someone unknown to me and  I have no idea what issues are hiding in the bottom end. Rather than throw $1200+ into a questionable build, it makes more sense to put that money towards a new one with a known pedigree. Surprisingly, my better half concurs. So I'll be starting a new thread about a new engine as soon as I wrap my head around my goals for the build and the other changes involved, like a bigger exhaust and carburetors, or possibly fuel injection.  

PM Pat Downs and have him build you a new motor. You won't regret it.

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