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Posted by: motorvated Mar 10 2020, 11:02 AM

As I'm finishing up the top end rebuild of my 2.0 Liter Type IV engine, I'm starting to plan for test running it out of the car on the ground supported by the engine bar and a tranny on some sort of wooden blocks to keep it off the ground. My question is whether or not it is OK to leave the engine tin off for now so that I can easily see the source of any oil leaks. I already have installed the fan shroud and fan, but these also could be removed easily so I could see leaks coming from the new front main seal, oil pump housing, and oil pressure relief valve housing. No alternator yet installed. I wouldn't be running it very long in this condition, and certainly would not want to overheat it by doing this. Anyone have any experience doing this and/or have any opinions about this? The tin located behind the pushrod tubes is installed and will remain in place. It's the new pushrod tube seals that I'm most worried about leaking. I'll be able to see if the new rear main seal is leaking when I pull the tranny off of it after the test. Leaking valve covers would be obvious too. What do you think?

Posted by: ClayPerrine Mar 10 2020, 11:07 AM

Bad Idea. I would not do it.

It's like running a water cooled engine without a radiator. You get about 2 minutes before it overheats. You need to run the engine for longer than 2 minutes to initially seat the rings.

Clay

Posted by: mepstein Mar 10 2020, 11:39 AM

I don't see why not with a decent size electric fan in front of the engine. Just keep an eye on the oil temp. We run sixes all the time on the engine stand and on the dyno.

Posted by: porschetub Mar 10 2020, 12:49 PM

not worth risking a new build doing that,you risk the rings or pistons being damaged without air circulating around the barrels which the cylinder tin upper and lower is designed to do.
Spend the time and fit it all...end of story,good luck on the startup.

Posted by: mbseto Mar 10 2020, 02:11 PM

Wait, there are all kinds of threads about building engine stands and running T4's on stands. What am I missing here?

Posted by: mepstein Mar 10 2020, 02:30 PM

Nothing. Engines are run on engine dynos all the time. A decent fan is all you need. Wire up oil and head temp gauges if you want to monitor temps.

Posted by: SirAndy Mar 10 2020, 03:00 PM

You are missing the part where he wants to run the engine without any cooling ...

Posted by: 911GT2 Mar 10 2020, 03:20 PM

The tins provide serious distribution of airflow. Removing them is going to have a big impact. When it leaks you can find those leaks afterwards as well with some investigation.

Posted by: Chris914n6 Mar 10 2020, 03:41 PM

You have to get the engine up to operating temp anyways, at which point I would want to prevent hot spots.

What's another 10 minutes in the big picture...

Posted by: Al Meredith Mar 10 2020, 03:49 PM

I built and engine run up stand by mounting a bare transmission under a metal table . Note the 2x4s extending out the front to keep the weight of the engine from tipping the table. Works great for checking a new rebuild for leaks and for heat cycling and then adjusting the valves without having the engine in a car . [attachmentid=733957][attachmentid=733957]

Posted by: Al Meredith Mar 10 2020, 03:55 PM

I must add, I use ratty tin and blower housing on the test stand . I also use a single carb for run up , much easer if you don't have to sync carbs . Note behind the distributor is a direct reading oil pressure gauge. I also use a shorty exhaust header with old VW tips to quiet the exhaust . I learned the hard way that if the engine is running straight out of the heads you can't hear if something is not sounding correctly

Posted by: barefoot Mar 10 2020, 05:01 PM

Yes, keep the fan and the bottom, side & top tins on. I just set the mount bar up on blocks with another under the back of the tranny. don't need to bolt it down.
I re-torqued the cylinder heads and the exhaust H/E bolts and re-set valve lash after the cam beak-in cycle, some of them needed it.

Posted by: Mark Henry Mar 10 2020, 06:53 PM

A bit of trivia

I toured the North America VW engine rebuild plant line in Toronto when I was a young lad in high school. To test run the engine at the end of the line with no tin/fan the worker clamped on a propane intake, stuck in a dizzy and wires (all production quick connect kit) and test ran it for about 10-15 seconds twice. Took him no more then two minutes each engine. They did the type 1, type 4, rabbit/golf, Dodge Omni (rabbit) engines. The plant closed in the early 90's.

If your 914 (bug, bus, etc) had a dealer replacement engine before the 90's it came from the Toronto factory.

Posted by: Andyrew Mar 11 2020, 07:00 AM

Not going to take long to see leaks... I say leave the tin off and get a couple of fans plus a laser thermometer and just check for hot spots.

Posted by: rgalla9146 Mar 11 2020, 04:09 PM

A minute or two is not going to hurt anything.
No dyno pulls.