Rebuilt Engine - Recommendations

[lofoxx]

Hi all,

Got the car up and running, but it feels like the cylinders are missing... it's hiccuping. Discussed with some mechanics I know, and found that in their opinion rather than replacing the cylinders and head gaskets I'd be better just replacing the engine. Of course, these don't grow on trees. So I need some smarter people than I am, hence I am here.

Would you:
1. Replace cylinders and head gaskets, leaving the engine intact?
2. Find a replacement 411 engine?
3. Swap out the engine entirely, and if so, with what?

thanks in advance. I can provide more info, too.
Loren
_________________
1972 VW 411

[raygreenwood]

35 years ago I knew more than a handful of good mechanics qualified to work on type 4 engines in general and D-jet iniected 411/412 and 914 engines in specifc. I also knew there had to be many more I did not know.

Over the years......that number has dropped to about two or three....all retired. This is not because they aged out....but because as I learned how to work on it...and later got a factory certification .....I realized simply that ahout 98% of those I "thought" could work on D-jet injected type 4.......had no idea what they were doing.

So.....since you just got this running a couple of weeks ago...and its 45 years old....and you did not mention whether its still fuel injected and what condition the engine in in, the fuel injection harness is in, the vacuum system is in, the fuel feed system.....or what you have done with it so far......
.......and due to the fact that 99.9% of mechanics who lay hands on a D-jet injected type 4.....have no idea what they are looking at what it requires.......I would say with good confidence that these mechanics you "trust".......are probably wrong.

Questions:

1. How long was the car not running?

2. How many miles.....guess?

3. Is it still fuel injected?

4. What has been done to all of the systems?

5. What is the compression on the cylinders?

See......on these engines especially with D-jet injection.....you are not allowed to have one single tiny vacuum leak....none....nada...."0".

The EFI wiring harness is 100% suspect ....and known to be the cause of about 90% of all driveability issues.....partly due to age and partly due to poor design of the female terminals in the plugs.

The grounding system must be perfect along with voltage supply.
The fuel pressure must be rock solid stable.
The two temperature sensors are generally out of spec by this time if they have never been replaced.

And.....most importantly....and very telling.....if these "trusted mechanics".....looked you in the eye and said your engine needs to be REPLACED .....and yet did not immediately hand you an estimate to simply rebuild what you have........then they have no idea what to do with your engine.

Lastly......all US spec 411 and 412.....unless they came kn through Canada....came with fuel injection.
If they came in through Canada......they could have twin solex carburetors.

If your engine does not have D-jet injection or factory twin solexes.....and instead has a pair of some other carbs or a nasty, worthless center mounted two barrel carb........then at this point....unless you have a compression and leak down test that points to worn out rings, valves and pistons.........there is not yet any evidence to say your engine needs to be replaced.

What is the history and data here?
Ray

[Lars S]

Agree with Ray, there are lots of things that could cause a hiccup beside bad cylinders.
Take a compression test.
If good start checking other things.
If bad try to get a picture of the engine overall status (oil pressure, oil leaks, mileage etc) before deciding how to go further.

Lars s
_________________
Porsche 914 -72, Bahia Red daily driver
VW411 2-d -70, White, sold
VW412 4-d, -73, Gold Metallic, daily driver
Suzuki T500, -69, Candy Gold, sold
Suzuki K50, -77, Black, daily driver
BMW R69S -69, White, sold
Husqvarna 118cc, -47, Black, Sold

[raygreenwood]

Also...as far as the top end rebuild question...new cylinders, pistons, rings and rebuilt heads....

......I would not take the heads off at this late date without at least doing a valve job....and the head gaskets should be removed, left out and cylinders lapped to the heads. the factory started doing this on type 4 engines on the buses. DO NOT use the head gaskets.

Also.....unless the bottom end has an EXACT known number of miles and it is less the 50k miles on the ORIGINAL CAM and Lifters and bearings...and not rebuilt in the past......and is PRISTINE in every way....meaning no cam wear at all......there is no benefit to leaving the bottom end intact and replacing the top end.

If the bottom end has many miles, it will have the standard cam wear and will have a half life that will get even shorter when you put new cylinders pistons and rings.

Also....look very carefully at the original pistons and cylinders. If this is a 1.7L....with D-jet....and its not California version with low compression....it will have domed pistons.

Those are very hard to find new.

If yours have good skirts, little or no scoring and good ring grooves....put new rings on them and either lightly hone your old cylinders or replace just the cylinders...and put your old pistons in.

I would split the case and measure the crank. If its clean and not worn and the main bearings are not showing heavy wear...just get new rod bearings and have the rods resized and balanced.

Put back in the old mains, new rod bearings and rebuilt rods. Put in new bushings...cheap. Put in new cylinders with old pistons...have the heads properly rebuilt.

Never re-use type 4 heads at 45 years old without a basic rebuild. Replace all the valves....and you really should replace the seats.

I would never reuse the factory cam. It was not all that good and its days were numbered. It ran hot as well. Get a web #73 and new lifters to match.

A tightened up motor like that can get you another 100k miles.

DO NOT get rid of the domed pistons. That will drop your compression to 7.3:1...and you will lose about 10-11 hp and the injection will be hard to tune. Ray

[lofoxx]

Whoa.

Some of these questions I can answer, some not so much.

I know the car had sat for at least five years since it last ran. The odo says 69k miles, but it may be 169k (or 269k). My guess would be 169k...

Questions 3-5: still fuel injected, it looks like belts and hoses have been replaced but everything else is basically factory stock, and I am not sure what compression is on the cylinders.

Some of this stuff is super arcane, as you mentioned. My knowledge is crap on this thing, though i used to do random crap to my old one back in 1991... I just have no idea how to find someone who can be trusted to think intelligently about this stuff.

But the combined list of what to do helps. I just need to find someone intelligent to speak to up here, then bang some of this out.

Thanks again,
Loren
_________________
1972 VW 411

[raygreenwood]