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Discussion Starter · #1 ·
Figured people may want to know the results of a high mileage TT motor. These were while the engine was warm and everything.

Cyl 1 - 80%
Cyl 2 - 40%
Cyl 3 - 47%
Cyl 4 - 72%
Cyl 5 - 35%
Cyl 6 - 39%

If anyone currently has numbers worse than this, please post so I feel better. Thanks!
 

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Damn mark...that's pretty bad...and pretty wide ranged too.

There is someone I think selling a block you might wanna look into...


You engine must have a slight wobble when sitting there at idle??
 

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Mark, i would start saving money towards a new short block because those numbers are a little on the low side. I'd give ryan a ring to see what this rates are installatin a factory short block. Usually on a high mileage car like yours i wouldn't want to see any more than 15% leakdown. 80% is a little on the extreme side, i would do another leakdown test to verify because your numbers are quite high.
 
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Discussion Starter · #5 ·
I think they're really just that high because Mike and I are awesome at leakdown.

I'm not sure, honestly, about why they're high. Mike seemed to do everything by the book, with what seemed like a pretty good gauge, and we compared them to his numbers. His were low, relative to mine. Honestly, you're right in the sense that they SEEM high. My car still seems pretty fast to me, and some of those numbers would suggest I'm not making very much hp at all, whereas the car feels otherwise.

I was thinking about just riding it out. Do the rebuild and single at the same time. I mean, the car still runs just fine, and still has a great amount of pick-up. It's serving my purposes now. Would it not be logical to just wait it out and deal with having a slow TT for a year or so? Or is there more to it than that?
 

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Here is what you should do. Check the compression to verify the leakdown #s(low compression clylinders should be the ones with high leakdown). If they verify, i would add one quart of Rislone to the engine at the next oil change then recheck it. I have a feeling that the leakdown was done wrong. If not, ive seen Rislone bring a engine with leakdown numbers like yours back to accetable standards.
 

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Shawn Davis
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Hopefully you did something wrong. My engine with 200k miles had leakdown numbers ranging from 5-13%. If you have anything greater than 10% the rule of thumb says you should consider a rebuild.
 

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Mark and I used a proform gauge for the leakdown. To verify the reading on number one (since we were so shocked) I squirted some oil into the cylinder and sure enough the number went into the 30% range. I have a mac compression gauge but didn't have the hose to connect to his car with me. We took the readings at tdc with a warm engine and 100psi pressure. The following link will show you how we did it and also explain some numbers alittle better.

http://www.proformparts.com/v2/TECH/PDF/66839story.pdf
 

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Sooooooo JDM
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Hmmm.....looks like operator error, unless you loosened all the head bolts first ;) OK, first off, for the "Umpteenth" time....

VALVE STEM SEALS HAVE NO (READ: ZERO) EFFECT ON A COMPRESSION/LEAKDOWN TEST.

The valve stem seals are on top of the valve guides. I've "illustrated" their location in blue with an orange arrow. When a leakdown number is achieved, ideally all the valves are closed. The tool is screwed into the spark plug hole and compressed air is applied. I've illustrated the leakdown points with purple arrows. If air leaks by either of the intake/exhaust valves or the rings, the gauge will indicates by how much. Some air will leak, hence the ideal "10% or less". As you can see, the valve stem seals play no role in this. Their ONLY job is to prevent oil from running down the valve stem causing oil consumption. When they get old and start to fail, the rubber loses it's elasticity and can't "contract" properly when cold. This means, when your car sits, the oil runs down and pools on the exhaust valve. Hence the big momentary cloud of blue smoke on startup. WHEW!



I get frustrated when people give out armchair advice about something they really have no clue about. Not trying to directly attack the poster here, your not the only one.

Now, back to Mark's problem :D How did you verify that the valves were completely closed? Did you put each piston at TDC and just apply air? You could have inadvertently pushed the piston down (with air), which rotated the crank, which rotated the cams, which cracked a valve open. Those numbers are awfully high. If you need to, pull the valve covers off when you do the leakdown and look at the cam lobes for that respective cylinder. If the lobes are straight up, valves are closed. Make sure you don't have any crap build up in the head which is causing the valve to stick open. Saw that once with a JDM motor...(~80% leakdown on that cylinder, IIRC).

Hope this helps (everyone),

Ryan
 

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As I stated earlier we put oil into number one to verify the low readings since I heard the sepage was past the rings. Sure enough the numbers went way down to the 30 range. Therefore elimination of valve hanging open. Mark also held the crank bolt with a wrench to make sure engine didn't turn over. And yes it did apply pressure to the wrench and try to turn over. When the ratchet was set the wrong way it did turn the engine over also.

Also we used a proform gauge which has the precentage on the second gauge. People saying they have acheived 2% leakdown must calculate using either a single gauge tester or via a basis reading on the second gauge. On my second gauge it doesn't give the psi differnetial but rather a % with green/yellow/red zone to show amount of leakdown. Mark got between the yellow and green on most and only red on two cylinders.

 
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Discussion Starter · #11 ·
Damn, I didn't realize this was gonna cause such a huge dilemma. I'd chime in to tell you all how we did it and everything but basically I just did what Mike said. He really seemed to know what he was doing, though. Fact is, I'm not considering a rebuild right now, even though I know I need one. I don't race my car, and I won't be boosting over 16 psi on it. I also won't be throwing a single onto this engine until its' rebuilt. Once money comes around, I'll surely be looking at a rebuild and single at the same time.

Perhaps someone else that can do leakdown tests wants to run one with me?
 
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Discussion Starter · #12 · (Edited)
Welp, I pulled out all the stops this time.

Got a nice Craftsman compression gauge and got my best friend Billy from the special education academy at our school, and we performed a compression test. Results are as follows:

Cyl 1 - 97
Cyl 2 - 120
Cyl 3 - 114
Cyl 4 - 100
Cyl 5 - 140
Cyl 6 - 200

Kick ass. :drag:
 
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Discussion Starter · #13 ·
Btw, my last post was a joke. The car's fine, fellas. I don't burn much (if any) oil, doesn't seem like I have a blown head gasket, the car still pulls really well compared to most cars. I'll just hold off till it's time to go single, then do it all at once while the motor's out of the car.

I am thinking I'd get lower numbers if I used a single leakdown gauge, but this just gave me a decent idea of what is up. Thanks for the replies everyone.
 

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hmm, let's see how do we all do a leakdown? Well, bring engine to top dead center or atleast on the compression stroke or hell let's call it a power stroke. Either way your valves are closed and you'll get a "reading which should be close" Then we hook up our air and zero out the gauge... <<<that's hard..... then we put pressure to the cylinder (warmed engine mind you) to get an accurate reading.. From there we either do the math or if your lucky enough to have a dual gauge which has the percent on the second gauge there is your leakdown.

Only *uckups there can be either air pressure isn't enough (test done at tractor trailer shop that has two 30hp compressors) or the dumbass didn't zero the gauge using the regulator. Again verified gauge set to one hundred psi on left and zero'd on right.. Leakdown on number one cylinder conifirmed then to double check operator wasn't a complete dipshit he put oil into cylinder to verify sepage was at rings and again confirmed since oil sealed rings and leakdown went to green or less than 40%.

For all those who got 2% leakdown on a turbo motor again look at previous post regarding how to do it correctly and you'll find NA motor will be hard pressed to get that brand new! Don't forget Turbo motors have more ring gap and therefore more leakage than an NA even new!
 

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Shawn Davis
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Based on what's been said, I'd say you're engine is in some serious trouble.

On a side note, if you're truly at TDC the cylinder will not want to rotate. I applied 100 psi to each cylinder and when I was truly at TDC they held rock solid. In some cases I had to try to get to TDC two or three times, but each time it tried to rotate I just put it back until I got it right.
 

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Sooooooo JDM
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mike91t said:
hmm, let's see how do we all do a leakdown? Well, bring engine to top dead center or atleast on the compression stroke or hell let's call it a power stroke. Either way your valves are closed and you'll get a "reading which should be close" Then we hook up our air and zero out the gauge... <<<that's hard..... then we put pressure to the cylinder (warmed engine mind you) to get an accurate reading.. From there we either do the math or if your lucky enough to have a dual gauge which has the percent on the second gauge there is your leakdown.

Only *uckups there can be either air pressure isn't enough (test done at tractor trailer shop that has two 30hp compressors) or the dumbass didn't zero the gauge using the regulator. Again verified gauge set to one hundred psi on left and zero'd on right.. Leakdown on number one cylinder conifirmed then to double check operator wasn't a complete dipshit he put oil into cylinder to verify sepage was at rings and again confirmed since oil sealed rings and leakdown went to green or less than 40%.

For all those who got 2% leakdown on a turbo motor again look at previous post regarding how to do it correctly and you'll find NA motor will be hard pressed to get that brand new! Don't forget Turbo motors have more ring gap and therefore more leakage than an NA even new!
Mike -
I've never met you, so I'm not saying you are completely clueless. Don't take it so personal. I think the figures people are having a hard time swallowing is 80% leakdown on one cylinder and 72% on another. Meanwhile, Mark says his car pulls fine and apparently runs good. What do you think? Is the car blowing smoke? Does it pull like a normal TT should? I guess ultimately, that is the deciding factor. I don't know anything about 2% leakdown but 10%-25% is *normal* on these motors.

Ryan

P.S. Don't make assumptions based on what's "typical". FWIW, both of the 2J ring end gaps fall into the same service range.

#1 GTE- .012 - .016
GE - .012 - .0185
#2 GTE- .014 - .018
GE - .014 - .0205
 

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I did this for a favor to Mark. My gauge accepts 40% to still be considered Green or good engine. Therefore maybe we should look at what other gauges were used to yeild a lower leakdown number? I am just as curious to see why his numbers turned so low but then again with oil in the cylinder the numbers went so low. The information gathered would assume two low cylinders but his car does run well and only burns minimial oil. Ryan, I have the 2jz service manual and can compare piston dia's and ring grooves or whatever but I was basis my "turbo usually yield higher leakdowns than NA" motors on the overall consensus that they do usually allow more leakdown.

I work everyday on turbo diesel engines that have a hell of alot more blowby than any 2jz I've ever seen. But they run fine and don't burn oil and still put out great HP on our dyno.

If anyone else has any numbers from a leakdown using a proform gauge it would be interesting to see how they compare. Maybe my second gauge is not working correctly and I'll replace it.

I did do a leakdown on Josh's 44kmi supra yesterday also. Cold engine yielded the 30~45% range. But his engine just ingested about 1gal of water and meth and hydraulic'd so we were looking for cracked pistons.
 

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Shawn Davis
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For the sake of comparison here are my numbers with two different gauges:

First gauge was purchased through harborfrieght tools and was a dual gauge setup, but I found it to leak a little at one of the fittings: 9%, 15%, 15%, 10%, 16%, 17%, 17%

The leak concerned me so I build my own gauge using a high precision regulator (0.1 psi accuracy) and got the following results: 4%, 7%, 10%, 12%, 13%, 6%

A compression test of the same engine 50k miles prior showed:
165, 157, 161, 159, 160, 161.

This is a TT engine with 200k miles on it (leakdown) and 150k miles at the compression check. I burn 1/2 quart of oil over 5k miles. My oil analysis comes back looking very clean.

I hope those numbers will give you some perspective on the variability of the test and the values normally achieved.
 

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Cyl 1 - 80%
Cyl 2 - 40%
Cyl 3 - 47%
Cyl 4 - 72%
Cyl 5 - 35%
Cyl 6 - 39%

Cyl 1 - 97
Cyl 2 - 120
Cyl 3 - 114
Cyl 4 - 100
Cyl 5 - 140
Cyl 6 - 200

If you look at your leakdown and compression #s side by side you see you have a prob on 1 and 4. Number 6 though is pretty high.

I say drive her till she poops. I did that to mine and drove it at 30psi 700rwhp for over a year after i found out my compression in #4(95psi) was bad. Then rebuild it to whatever your hearts and moneys desire.
 
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