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Resident Idiot
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Discussion Starter · #1 ·
After my dyno session last week, I left wondering why the car wouldn't build more than 19psi. I even use a HD actuator and a bleeder valve. With the actuator rod as tight as I could get it, and the bleeder open full tilt, I was left scratching my head as to what the problem was.

Well, today I made a contraption that pumps up the entire air path starting at the MAF pipe. It effectivly tests the I/C for leaks and everything between the turbo and the back of the intake valves. Removed the rocker arms and then I connected a standard leak down tester to it, regulated at 30psi. Boy was I surprised:


Picture shows 30psi is entering the MAF pipe and the circuit is only holding 10psi. There is air whistling from everywhere.


IAC is leaking pretty bad, eventhough it's tight.


My AFPR is leaking air out the threads.


I always knew this mess of hoses would leak. These are fairly new pieces of hose too. Time for some saftey wire--everywhere.....


Most of the intake bolts are leaking as well. I know I put sealant on the threads. I will have to investigate this when I pull it apart.



And here is the problem that's not getting fixed anytime soon.. The intake is leaking horribly on both sides. The air is just shooting out from between the head and the intake. I used a ROL intake gasket when I put the motor together and that was a hard lesson learned. I didn't like the way it fit, but I was in a rush and put it together.

So all these air leaks mean what? It means that the turbo has to make that much more air to compensate for the air that's being lost. More boost means more heat. Just taking an educated guess here.. If I am losing roughly 50% of the boost the turbo was making Sunday on the dyno, it means the turbo was putting out _a lot_ yet I only saw 19psi on the gauge. The temperature of the compressor housing and intercooler were very hot. I have never seen it that hot, and in conjunction with the rod being fully tighened and the bleeder all the way open, I knew something was up.

What does all this mean? It probably explains why some cars run better than others. Also it probably has something to do with why some people can get away with murder on things like boost vs. timing vs. octane. A car that is sealed up tight is going to use most all of the boost that the turbo is creating. This means his inlet temps will be less than a car like mine that is wasting all kinds of air.
 

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Mike, I wonder if your leak-down test would fare any better with a warmed up motor due to expansion? Sure is an eye opener though!

[This message has been edited by KENNE-BILL (edited December 16, 2001).]
 

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Resident Idiot
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Discussion Starter · #5 ·
Correction. I meant to say I am now going to use the Felpro replacement intake gasket # MS96033

I have a used one out in the garage. Hopefully the number is stamped on it.

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Stock Block, Stock Cam, PTE-52, Champion Heads, V4, MSD50's, TH DP, JayJackson 62mm TB, 16position MaxEffort Chip. 3680# with Driver
12.0 @ 116.5mph w/20psi using 17.9* timing

mailto:[email protected][email protected]</A>

[This message has been edited by Orlando_87GN (edited December 19, 2001).]
 

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And nobody ever believes me about those adjustable FPR's.Jeez.

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Give em' hell!
 

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Actually the intake bolts should not need any sealant. They do not penetrate anything that would have air or coolant. The only reaon you're seeing them leak is because the intake gasket is leaking so badly.

The only bolts that actually require sealant are the headbolts/studs.



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TurboDave & Kathy Huinker, mailto:[email protected][email protected]</A>
TurboD Racing,Turbo Buick Web Ring
San Diego CA http://home.san.rr.com/buickv6/
86 GN[email protected](MM/MAF Xlator/Extender,MM BstC Boost Command,THDP,PTE44,CAS V2FM,MSD50's,9.5"vigilante 3500)
87 GN [email protected](Stock)
84 Z28 L69
01 Excursion LTD TTS"race" chip 7.3L PSD(power stroke diesel) Turbo 4X2
Pictures of my toys
 

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That's a cool idea you have there for checking things out but its not as bad as you stated. The restriction and air flow through the tester are not the same as from the turbo through to the throttle body. I am not saying you shouldn't fix the leaking but your turbo is not pumpin out 50 psi while the engine only gets 19 psi.

Think of it this way if there was only a pinhole for the air to pass through in the tester between the gauges then you would have 50-100 psi at the tester inlet and 0 on the car side.

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87 Turbo T, CAS V4 and Cold Air
 

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that's what I figured on the intake bolts. while were on the topic of intake gaskets . What has to be done to the Fel-Pro 1200 intakes before installing ? is the only thing that has to be done is cut out the EGR port on the drivers side ? Do you cut out that odd shape ? or do you just need the small rectangular shape cut out , like the one found on the manifold ? thanks.
 

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Smart man that Pete.
Nothing like loosing dynamic range on your F/P regulator.One nylon washer[Home Depot-7 cents],and one polylock,1/4" fine nut.Problem solved.

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Give em' hell!
 

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I wonder how much leakage is passing through the combustion chamber? Boost connections etc? I've seen a smoke machine used to check for vacuum leaks and look for the leaking smoke with a light source! Interesting procedure for sure! Gene
 

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Hi Mike,

Good idea... sorry your results were disappointing! I'm curious... did it exhibit poor idle characteristics? I'm having problems with my "new" rebuild, but I used the "magic" GTE1200 silicone around the ports on the same intake gasket you used. I had ported the gasket so much to match the ported heads/intake that I used the silicone "just in case". Anyway, I am wondering if my car may have similar probs which are leading to my idle probs. Thanks,

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Jay Jackson
(the 62MM TB guy!)
http://hometown.aol.com/ygettv8/myhomepageindex.html

"YGETV8" '86 gray T-Type 94K... high tens...?? (Finally together and running for the first time in 5 years... but more work needed!) Girdled stock block, Stealth turbo, 62-65mm TB, PI 9.5" 7-disc, Jimmy's Trans, P&P heads, 218/218, Hooker Headers, 3" D.P., HKS w.g., thumbwheel chip, and more... (previously ran [email protected] with the stock long block, DOTs, thru the muff, & on pump gas!)

'86 GN "Beater"... 144K driver w/ P&P stock turbo, 21.5 psi boost, K&N, 3" DP and ported elbow, Z93 chip, 30# inj., Walbro 307, AFPR, new valve springs, alum. drums, 2.5" IC neck, 62mm TB/upper, and that's about it! Best ET: 12.61 (on 215/65 all season radials!); best MPH: 111.97! Now: pump gas, alky and GNX wheels w/ Radial TAs = 12.60 @ 110.87!

'87 WE4 60K ... "stock appearing": TA61, MJ 17 row IC, Blue tops, Alky and 93 octane, 62mm TB, P&P stock elbow w/ 3" DP, and even the "stock" airbox! [email protected] w/ a lousy 1.967 60' full weight and through the muffs!
 

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I've had bad luck with felpro gaskets, well not myself cause my engine never been opened but I'm a mechanic and I've seen a lot of people install felpro gaskets in their TR's and within a year there bringing the car to me to get the aftermarket gaskets removed and the factory ones put back in.
I used to work in the aftermarket but since I've been at a Buick dealer for the last 7 years I've seen how poor quality the aftermarket venders gaskets are in these cars.


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Craig Winters
President
Manitoba Grand National Association
(204) 771-1127
www.mgna.ca

'87 GN, all stock [email protected]
 

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My stock engine came with the metal intake gasket, the factory sprays High Tack on both sides and installs them that way. This engine leaked no oil at all and saw high boost several times! Even the combustion leak down was very little with the stock rings and pistons, all stock. I use "Rol" metal gaskets on my intake, cork oil pan gasket, and stock GM head gaskets with the O ringed heads. Gene
 

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Mike! I owe you some thanks! I used your above idea and am pretty sure I found my MAJOR problem with my T-Type! HUGE vacuum/boost leak from the backing plate of the turbo! Thanks a bunch!

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Jay Jackson
(the 62MM TB guy!)
http://hometown.aol.com/ygettv8/myhomepageindex.html

"YGETV8" '86 gray T-Type 94K... high tens...?? (Finally together and running for the first time in 5 years... but more work needed!) Girdled stock block, Stealth turbo, 62-65mm TB, PI 9.5" 7-disc, Jimmy's Trans, P&P heads, 218/218, Hooker Headers, 3" D.P., HKS w.g., thumbwheel chip, and more... (previously ran [email protected] with the stock long block, DOTs, thru the muff, & on pump gas!)

'86 GN "Beater"... 144K driver w/ P&P stock turbo, 21.5 psi boost, K&N, 3" DP and ported elbow, Z93 chip, 30# inj., Walbro 307, AFPR, new valve springs, alum. drums, 2.5" IC neck, 62mm TB/upper, and that's about it! Best ET: 12.61 (on 215/65 all season radials!); best MPH: 111.97! Now: pump gas, alky and GNX wheels w/ Radial TAs = 12.60 @ 110.87!

'87 WE4 60K ... "stock appearing": TA61, MJ 17 row IC, Blue tops, Alky and 93 octane, 62mm TB, P&P stock elbow w/ 3" DP, and even the "stock" airbox! [email protected] w/ a lousy 1.967 60' full weight and through the muffs!
 

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Smart man that Pete. Nothing like loosing dynamic range on your F/P regulator.One nylon washer[Home Depot-7 cents],and one polylock,1/4" fine nut.Problem solved.

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Give em' hell!

..... make me a believer!!... what does this mean???
TIA!
 

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Where do you guys get ROL gaskets?Mainly the cork oil pan autozone show it as discontinued on there site. I am stuck with a crappy silicone oil pan gasket,how about a rubber one?Sorry to hijack the thread.:D
 
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