Author Topic: Compression testing  (Read 2688 times)

December 12, 2008, 03:48:05 pm

rabbitman

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Compression testing
« on: December 12, 2008, 03:48:05 pm »
Ok so I bought a a ebay compression tester kit for $22. It seams ok at first but the gauge leaks soI had to watch it go up as I cranked, as soon as I stopped cranking the gauge started dropping. When I did the first cylinder the gauge lost maybe 10psi by the time I got out of the car and walked up to the front. All of the rest lost 50-100psi, perdy cheezy.
Here is the numbers tested hot:
(1) 420psi
(2) 410
(3) 400
(4) 420
I'm happy enough with that, it's better than I thought. Last check was 2 years ago and they were all in the 370 range, but that might have been checked cold, can't remember.

Then I had a problem, I disconnected the fuel solenoid but it still leaked fuel real bad. Nobody else was around and I couldn't crank and watch at the same time. It made a lake of diesel about one and a half feet wide and back to the middle of the car. :(
Anyone have this problem before? Also the IP is wet on the front but not by the outlets, and the engine block is wet straight below the IP.
It acts like the IP is pressurizing and forcing fuel out somewere but it's made to hold quite a bit of pressure......uh oh....I just looked at it again and now I feel really stupid.
Note the little fuel return line in this picture.

 :oops:
Problem solved, thanks guys :roll:
Nuther Q.
Does the black junk need to get cleaned out of the injector hole?


Also see the IP sprocket in the first pic, is the belt too far off center to be safe driving it? Thanks guys :)
'82 Rabbit, I put on a euro vnt-15, 2.25" DP, 2.5" exhaust, the result.....it whistled.

I removed the turbo, made a toilet bowl 2.5" DP, the result....it was deafening. Now it has a homemade muffler up front and a thrush in the rear, the result.....less loud.
Watch: AGENDA, GRINDING AMERICA DOWN

Reply #1December 12, 2008, 04:08:26 pm

burn_your_money

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Compression testing
« Reply #1 on: December 12, 2008, 04:08:26 pm »
You can take the release valve apart and clean it and then it should work properly if it's the kit I'm thinking of.

Yes, even with the stop solenoid disconnected, fuel will exit the return if you crank the engine.

I don't think I would worry about the carbon in the injector boses, but it's hard to say without seeing them in person. Yours doesn't look serious.

While you have the injectors out it's the perfect time to check the glowplugs. Just turn them on and watch the tips turn red.

Is the belt overhanging the pulley on the other side? If no then you are probably ok.

Nice compression numbers btw. I wish I had those
Tyler

Reply #2December 12, 2008, 04:33:49 pm

rabbitman

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Compression testing
« Reply #2 on: December 12, 2008, 04:33:49 pm »
Yeah, it's the harbor freight kit.
I should've just plugged the little fuel return line but I wasn't thinking. I even saw the fuel before I'd checked all the cylinders and I still didn't think of it. grr, waste of fuel.
Well the t-belt hangs over a dinky bit, like fingernil thickness, but it hangs over the int-shaft pulley almost a eighth inch. :x  It's perfect on the cam. The IP bushings are shot is the problem, I have new ones I just need to order reamers and then I'll stick 'em in.
I think the injector bosses would be cleaner if the injectors had been tighter, I put 'em in 2 years ago and torqued them to 52ft-lbs but I should've re torqued 'em 'cause they loosened super easy.
'82 Rabbit, I put on a euro vnt-15, 2.25" DP, 2.5" exhaust, the result.....it whistled.

I removed the turbo, made a toilet bowl 2.5" DP, the result....it was deafening. Now it has a homemade muffler up front and a thrush in the rear, the result.....less loud.
Watch: AGENDA, GRINDING AMERICA DOWN

Reply #3December 12, 2008, 05:38:19 pm

Dakotakid

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Compression testing
« Reply #3 on: December 12, 2008, 05:38:19 pm »
Pardon me, but....THAT is a top line head right there. How many miles you got on it and any problems?????
The mask and the shot(s) are actually an IQ test. If you are wearing or circulating, you just failed the test. I can't feel sorry for you.

Reply #4December 12, 2008, 06:10:33 pm

rabbitman

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Compression testing
« Reply #4 on: December 12, 2008, 06:10:33 pm »
haha, I wondered if anyone would notice.
I put the head on 43,000 miles ago if my odometer is accurate, it's not though so it's probably closer to 50,000. The only issue was the little bracket in the picture next to cyl 1 boss that bolts on for picking the engine up needed some grinding 'cause I couldn't line the bolt holes up w/o it hitting the head, not a big deal. No problems at all with running though. I took it off about 8,000 later for a ring job and there wasn't any cracks between the valves :shock: but I don't know how long it usually takes for 'em to crack.
Do you have a topline head?
Does this belt look normal? Kinda looks burnt on the side towards the block.
'82 Rabbit, I put on a euro vnt-15, 2.25" DP, 2.5" exhaust, the result.....it whistled.

I removed the turbo, made a toilet bowl 2.5" DP, the result....it was deafening. Now it has a homemade muffler up front and a thrush in the rear, the result.....less loud.
Watch: AGENDA, GRINDING AMERICA DOWN

Reply #5December 13, 2008, 08:38:29 am

Dakotakid

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Compression testing
« Reply #5 on: December 13, 2008, 08:38:29 am »
No, I do not have a topline head. Although, at some point in time, more of us will need to use aftermarket heads as the still-viable (rebuildable) heads are disappearing with each day that passes. I posed a question in another section last night regarding a comment made re: Topline head problems.

I do not think your belt appears "burned" or overheated. I think it is just normal appearance. Seems like most of my belts take on this colorization. Maybe someone else can elaborate.

I recently had a problem with belt alignment with installation of the latest engine rebuild. I overlooked the significance of the little 90 degree piece of metal that bridges the forward end of the plate which holds the IP body and the bottom pump bracket. If you tighten the bolt on the bottom pump bracket first (with reassembly) you can pull the plate (that the pump mounts to), or push the plate to one side of the car or the other. This results in a belt which does not track properly. This was on a Mk. II.

It is the kind of problem which you do not think about until it happens. I thought the side plate which holds the pump was very stiff and could not be distorted without doing something really drastic like using a pry bar or something. I am wondering if many of the questions related to belt alignment initially hinge on this same mistake.

I had slightly distorted the belt alignment and had a condition where the belt ran slightly to the fender side. The belt was running hard against the outer lip on the intermediate shaft pulley. It did not seem real bad, and I was kind of excited to get this new engine up and running....so I ran it like this for about 150 miles.

The next morning, the car had clearly lost prime and it appears as though I damaged the IP shaft bushings due to this alignment. Yes.....I was throughly pissed and had to literally walk away from the car for awhile until I cooled down. This pump was JUST FINE prior to my mistake. I then spent a lot of time installing a newer pump and inspected all components until I found the mistake.
The mask and the shot(s) are actually an IQ test. If you are wearing or circulating, you just failed the test. I can't feel sorry for you.

Reply #6December 13, 2008, 09:33:54 am

jtanguay

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« Reply #6 on: December 13, 2008, 09:33:54 am »
just looks like rust from one of the pulley's.  interesting how its only on one side though...


This is how we deal with porn spammers! You've been warned.

Reply #7December 13, 2008, 11:32:43 am

rabbitman

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« Reply #7 on: December 13, 2008, 11:32:43 am »
Quote
I recently had a problem with belt alignment with installation of the latest engine rebuild. I overlooked the significance of the little 90 degree piece of metal that bridges the forward end of the plate which holds the IP body and the bottom pump bracket. If you tighten the bolt on the bottom pump bracket first (with reassembly) you can pull the plate (that the pump mounts to), or push the plate to one side of the car or the other. This results in a belt which does not track properly. This was on a Mk. II.

I'll have to check that.
'82 Rabbit, I put on a euro vnt-15, 2.25" DP, 2.5" exhaust, the result.....it whistled.

I removed the turbo, made a toilet bowl 2.5" DP, the result....it was deafening. Now it has a homemade muffler up front and a thrush in the rear, the result.....less loud.
Watch: AGENDA, GRINDING AMERICA DOWN

Reply #8December 13, 2008, 01:22:54 pm

Green79

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Compression testing
« Reply #8 on: December 13, 2008, 01:22:54 pm »
Have a look in this thread as well:
http://vwdiesel.net/phpBB/viewtopic.php?t=17482&start=15

I thought maybe my IP was misaligned, or the bearings were bad, but when I put the new t-belt on, it now tracks perfectly, with no other adjustments. My old belt tracked to the very outside of the IP sprocket, and up against the intermediate shaft pulley lip, just like yours. The edge of the old belt was actually worn at a bit of an angle from running on the lip on the i-shaft pulley (kinda like a v-belt).

If you're gonna play with the alignment at all, might as well just drop $20 on a new belt and try that first... never hurts to throw a new belt on, for how cheap they are (unless the belt is already fairly new of course).
'79 1.5 Rabbit

Reply #9December 15, 2008, 01:32:24 pm

rabbitman

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Compression testing
« Reply #9 on: December 15, 2008, 01:32:24 pm »
My I-shaft pulley doesn't have the lip so it hangs off the edge there. My belt was new in '05.
'82 Rabbit, I put on a euro vnt-15, 2.25" DP, 2.5" exhaust, the result.....it whistled.

I removed the turbo, made a toilet bowl 2.5" DP, the result....it was deafening. Now it has a homemade muffler up front and a thrush in the rear, the result.....less loud.
Watch: AGENDA, GRINDING AMERICA DOWN

Reply #10December 15, 2008, 10:29:54 pm

rabbitman

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Compression testing
« Reply #10 on: December 15, 2008, 10:29:54 pm »
Just remembered my belt was actually new in July '06 :P 'bout 30,000 mile old I guess, I was kinda stupid and never kept track of any major work I did. :x  But I have a real good memory, haha :roll:  :lol:
'82 Rabbit, I put on a euro vnt-15, 2.25" DP, 2.5" exhaust, the result.....it whistled.

I removed the turbo, made a toilet bowl 2.5" DP, the result....it was deafening. Now it has a homemade muffler up front and a thrush in the rear, the result.....less loud.
Watch: AGENDA, GRINDING AMERICA DOWN