Tryke

[Carl]

Need to vent. Not related to mowers but still related to small engines. VWs are small engines? Went for a ride the other day on my tryke finally got the brake problem fixed. Just needed the plunger on the master cylinder adjusted. It seems that the old adjustment was holding the piston in the master too far in and not allowing both calipers to bleed back. Go figure.
On the way home engine began popping back through the exhaust, darn one thing fixed then another pops up. Running 70 75 mph, running down the road and bang, a loud bang heard. Pulled over and thing running real rough, decided to continue on home. Thought it was loading up on fuel in one cylinder. Pulled the plugs, all look good, burning as they should. Changed plugs anyway, no change.
Pulled a compression check on the engine this morning and found two cylinders dead, no compression on either. Other two 120 plus compression. The bad cylinders are directly across from one another, number one and three. Engine running on two cylinders. Now that is a good engine. Well back to work. Carl

[bobodu]

Sounds like you lost a cam. Pretty sure the cam only has four lobes....but has been 35 years...

[roym]

Are the rods still hooked to the crank?

[Franz]

VW = Farfigfixin

[jdm]

Carl.

Does the Tryke have disc brakes?

If it does, it may possible the master cylinder is for drum brakes. Drum brake master cylinder often have a low pressure check valve in the ports.

This slows down the fluid return and keeps a little pressure in the slaves. (the drum springs pull the pads off the drum surface).
The idea is to stop air being sucked past the cups when returning.


If it a drum master and disc brakes, you need to remove the check valves.

jd.

[Carl]

Sounds like you lost a cam. Pretty sure the cam only has four lobes....but has been 35 years...

Might be, but I really don't know how old the cam is. Will know in a couple of days when I get to her to tear into it. Yes the rods are still connected to the crank, if they weren't I would have big troubles. As for the brake master, I replaced the drum brakes with disc because of inadequate braking power. After adjusting the brake rod on the master closer I now have real good brakes. I have a friend who works for a heavy equipment company, one excellent mechanic and he stopped by to take a look. What was happening was the brake rod on the master was adjusted so far back that it was holding the piston in and not allowing it to come back far enough to allow both calipers to bleed back. I thought about pulling the check valve or going to a two stage master, but before doing it I Talked to the people I bought the disc brake kit from and they said they only have one master cyl for both. This may be hard to believe, but I have owned and played around with many VWs in my 70 years of life and this is the first one I have ever had engine problems with. Of course I am dealing with a home made tryke and really have no idea what was built for this engine. The engine numbers tell me it is a 1966 block but how or what has been done to build it, who knows. Once I get done, I will know what I have. Looking at the good side, I have another project that might just keep me alive alonger, or kill me? Carl

[bobodu]

Pop off a valve cover before doing too much Carl....but you knew that.
Pop the bale off and have a look.

[Carl]

Pop off a valve cover before doing too much Carl....but you knew that.
Pop the bale off and have a look.

Good news. Decided to do as you noted above before you gave the answer. All good in there, just for kicks I adjusted the valves on that side. Took another compression reading and it was the same. Decided to tear into it and was taking the belt off the alternator and put my hand on the breather to the carb. Dang thing moved in under my hand. You won't believe this but found the intake manifold loose, all four bolts holding it. Tightened them down, took another compression reading and all four good to go. Over 120 on all cylinders. I thought it was kind of funny to have both no one and no three go bad at the same time. Now I know what to look for in the future. Before taking a compression reading test to see that the intake manifold is tight. Now it is time for a couple cold beers, will test drive it Tuesday, I have to work on a mower tomorrow. Carl

[bobodu]

Don't quite see how that would matter...but I also don't see how I didn't realize that 1 and 3 were on the same side of the box either...
But....I was 19 the last time I had my hands on one of those engines.

[Mek-a-nik]

I'm a little confused,too. If the compression reading is taken at the cylinder, how would a loose intake affect readings?
I had a few VW's in the late 70's- early 60's to about 1970 models. Did a little hot rodding to them, but the factory crankshaft has no counterweights and was limited to 4000 rpm. Good cranks were available, but not to my budget!
I'll bet that trike is fast, even if the motor is stock. A couple friends and I used to take the body off of the Bugs to run them around in the woods. That body weight slows them down! We beat my 350 4bbl '69 Impala and a '77 318 4spd Dodge Aspen with it. (On a back road.) The Aspen was pretty new, and the owner was a "little" upset that he couldn't beat us. Those were the days, our $35 Bug chassis gave me more fun than many "real" cars I've owned.