#4 cylinder not combusting

[David Jones]

You are correct Martin. Old age does that to one, confusion reigns sometimes.

[Martin Benade]

Old age is a good thing, I'm trying to get as much of it as I can!

[Adam Willis]

Guys,

We have touchdown! all cylinders are firing! Lots of work and lots of patience's...looks like Peter may have been on the mark with the vacuum leak on the intake manifold gaskets...after much a-due, and a helical-coil in the head for the intake manifold bolt, we have vacuum on the passenger side carburetor...Yahoo!!!! Now for the hard part...tuning everything I just did and making it work like a normal car...Am I kidding myself? Another day!

Adam

[Adam Willis]

Hey Guy's,

Thought I would update this posting with the current status of the "issue"! Well, after a lot of work, pain and Bud light, I did get the old girl running...however, after even more pain and more bud light, it was simply not running very well...always felt like it was down a cylinder. So, this weekend, yesterday in fact, I got tired of another round of tuning and pulled the engine. Got the tin off, put the engine stand on her and started wrenching...it is always amazing what you find...I have had this car since 1995...drove it approximately 5 mile to my garage and have been restoring it ever since...the motor sat for a god awful time until last year when I was finally ready to put her back in and fire it up...you know the rest of the story on that one...so, on with the story as they say...

As we all have discussed, the "miss" and the lack of power continued to bug me...everything I did, all the tuning simply would not get rid of that nasty lack of power. I think I now know why...after removing the valve covers and taking off the rocker arms, the #3 exhaust rocker shaft was rather lose in the two "eyes" of the stand. The #4 exhaust rocker, which is where I believed my lack of power issue came from did not feel that bad. So, onward...off came the head for #3 and 4...(had one short head nut, the rest correct for an A engine). That told me that at least one time this had been opened up...anyways, the head came off and holy moly...the #4 looked really bad...very wet...after looking at the head a little longer, I noticed that the #4 exhaust valve guide looking thru the spring was charred and burnt. Again, onward, off came the cylinders, starting with #4 cylinder...which slipped off like it was butter....I mean just about fell of the piston and rings. That is when it got interesting, because as the cylinder came of and just about fell off, there was a noise of something hitting the ground...as I looked around on the floor for what possibly could have come out of the cylinder (my mind was catching up to the reality at that point), I found the culprit...a portion of the top ring land had broken of (looked like it had been broke for awhile) and fell out when I took off the cylinder. I must admit, that surprised me...hadn't seen that before. After removing the other head and the other two P&C's, I started to do some measurements. Looks like someone in the history of the car, put a Big Bore kit on it...85.89mm cylinders. No markings except a 44 in the middle of the piston and two of them had the number 2 on the top. Cast with iron barrels. As I looked over the general condition of the engine, I then noticed the rods...boy do they look bad...like a shot peening gone haywire...anyways, I am going to spit the case today...wonder what I will find in there. By the way, it has been awhile since I and a machine shop have been close...the 010 on the head is the flycut number, correct?

Thanks

Adam

[Chuck Allard]

Early stages of Harry's "Ring Eating Monster".

[Ron LaDow]

Those heads were cut for sealing and never re-cut for the bore diameter. You may well have had a very high localized CR (in the 'peripheral chamber' - "Y") leading to detonation and the failure of the ring land.

Can't seem to find the info, but 30* pistons in 22* chambers can do the same.

[Adam Willis]

Ron,

As I was looking at the piston...I remember reading you post before on that and thought the same thing...I checked the angle of the pistons and the heads and both are 22*..."Those heads were cut for sealing and never re-cut for the bore diameter"...not sure I am following...do you mean the flat surface was cut and not the inside of each chamber?

[Adam Willis]

Well,

Didn't get the case split...I could not get the front pull nut off...even broke a wrench with a 4 ft cheater bar attached to it...thought the engine stand was going to snap. I need to get an impact socket for the impact gun and give that a try. If not, got a diamond blade on the grinder if all else fails. Soooo, after much cursing, I decided to remove one of the rods...interesting. Looks like the bottom end was upgraded when the rebuild was accomplished. After looking at the crank and rods, this is what I found...

Crank.......616.102.015.01 and I thing the serial number??? D58509 don't know the journal size until I get it out...not sure if it has been resurfaced or not, but the rods were, so thinking the mains are too??
rods.........616.103.101.01 the bearings are stamped .25 on the underside of the rod bearing

Could use some help deciphering this setup...her is what I think I have (please, please, chime in if you see me going off the deep end or simply saying something stupid)...I'm not that proud...need all the help I can get

SC/912 Crank...from what I could gather on the Reg, the SC/912 came in counter weighted and non-counter weighted. It looks like I have a counterweighted crank? Not sure if you can see in the third photo...the journal weight between the two inner rod journals are full (span the wide of the other weights)...

SC/912 rods...It looks like they have had some heavy weight removal from the bottom ends...fully rounded. Is this for clearance? Thought most folks clearance the block? Not even sure that is what it is for...I need to get the halves separated and spin it see if this is for clearance or weight?

With the rod bearings installed in the rod, the measurement was on the big end is 52.8mm...without the bearing, 56.71mm. The pin end with bushing in it measured 22.02mm

Adam

[David Jones]

Adam, if it is the flywheel gland nut you cannot get off then you need to go borrow the 36mm torquemeister tool from one of the guys in the Drie staten group, or go take your case to Yuri at The Garaj and I am sure he will take it off for you and help with ID'ing stuff.
The torquemeister is an invaluable tool if you are going to do your own work.
http://www2.cip1.com/ProductDetails.asp ... C10%2D7036

[Ron LaDow]

Ron,not sure I am following...do you mean the flat surface was cut and not the inside of each chamber?

Yes:

The red area shows a peripheral chamber which would not be there if the conical part of the chamber had been cut to the blue line, matching the cylinder bore. As you can see, that 'chamber' is cut off from the main part of the chamber and can easily trap enough mixture to produce a CR high enough to cause detonation.

[Adam Willis]

Dave,

I haven't even gotten to the flywheel gland nut yet...the front pulley nut (bolt) is the one that appears to be welded in place( just kidding)...but boy is it on there. Good point on the gland nut...Yuri is literaly right around the corner. Went by there the other day...I have never used the torquemeister before...is this the same type of set used for the rear axle nuts? Torque multiplier?

[Adam Willis]

Ron,

OK...got it...yep, the top of the piston is definitely has the lip area which is flat...about 040" across which sits perfectly in the chamber as your diagram shows...which then begs the question, can you not just mill the piston at the 22* or 30* or whatever angle the combustion chamber is so that "flat" area is removed and you have a continual slop on the dome...ahhhh, what if the piston is a flat top piston...must do the chamber.

So to take that to the logical conclusion, is the correct "fix" or method when you buy new or different pistons to have the chamber cut? Or can you just have the chamber cut to the 22* or 30* irrespective of the piston?

Thanks Ron...more to add to my list of things to do on the build up side...still unfortunately on the tear down (or destruction phase as I like to call it)...

Adam

[David Jones]

Adam the torquemeister is the same tool for the axle nuts but has to be modified as the Porsche studs are a larger diameter than the VW. Go to Harbor freight and buy an electric impact. Works as well as a pneumatic and no compressor to run up to pressure.
It is not so much the torque that breaks it loose but the hammering, and you will save the time spent cutting the bolt off and the cost of a new bolt.

[Adam Willis]

Dave,

That is a great idea...electric impact! I think that is exactly what I am going to do...I love this place.

[Martin Benade]

As for the rods they are shaped like that originally, they were not attacked by a grinder.