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1/2 Na-T Project
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987 Posts
Discussion Starter #1
Well I was having excessive blowby from my PCV system and some other problems with the oil draining from my turbo oil return so I decided to do a compression test. Before the compression test I did a block test for combustion gases in the coolant system and it came up Negative so no BHG. These are the results
Cyl 1: 180
Cyl 2: 180
Cyl 3: 60
Cyl 4:180
Cyl 5: 180
Cyl 6: 155

After the first test I tested all cylinders again and came up with the same results.
I tested cylinders 3 and 6 again after pouring a teaspoon of oil in the cylinder. The results were
Cyl 3: 65
Cyl 6: 175

So my question now is where to go from here. I am thinking something has to be wrong with the valves on Cylinder 3 for compression to be so low. Cylinder 6 is most likely the piston rings. I know at the very least I have to pull the head and inpect the valves that coincide with cylinder 3 but what should I do about the 6th cylinder? Also when I do pull the head do I have to resurface both the block and head? I already have an hks 1.2mm mhg and arps.
 

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1/2 Na-T Project
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987 Posts
Discussion Starter #2
Anyone have any advice?
 

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when this baby hits 88mph
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2,198 Posts
ouch!
did you have your tbody open when you did the test?
my next step would be a leak down test. excessive blowby id look right at the rings.

for the mhg yes you will need to resurface both for a good seal. lapping is the best method.

dave
 

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1/2 Na-T Project
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987 Posts
Discussion Starter #4
dbsupra said:
ouch!
did you have your tbody open when you did the test?
my next step would be a leak down test. excessive blowby id look right at the rings.

for the mhg yes you will need to resurface both for a good seal. lapping is the best method.

dave
My throttle body was taken off completely so I could get to the spark plugs. BTW I did the 1/2 NA-T conversion so the pcv system probably doesn't function as well as the turbos. Thanks for the info db. When you say lapping is the best method, how much would this cost? A leakdown test should tell me where my problem is correct?
 

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1/2 Na-T Project
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987 Posts
Discussion Starter #5
I just purchased a leakdown tester so I guess I will use that and try to figure out where the engine is leaking(ie valves, rings). The 7M is so damn frustrating. If I were to find out that the piston rings in cylinder 3 and 6 are the problem could I just replace the rings and pistons in those cylinders if needed? Any other advice is appreciated.
 

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5,728 Posts
I'm sorry about your troubles, JT. I think I'm going to just tap out my oil drain hole to the 12mm, use the ghetto return kit that I have, and see how it goes. I'm using the GTE PCV system anyway, so it might just work for me.
 

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1/2 Na-T Project
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987 Posts
Discussion Starter #7
Thermactor said:
I'm sorry about your troubles, JT. I think I'm going to just tap out my oil drain hole to the 12mm, use the ghetto return kit that I have, and see how it goes. I'm using the GTE PCV system anyway, so it might just work for me.
Mine might not of worked because I was getting excessive blowby and the pressure was not allowing the oil to drain correctly. So who knows maybe it will work after all. Later.
 

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Yea man It might work for you. I just started up my 1/2 na-t last night. I haven't driven it yet but I let it run for quite some time. It ran very good and didn't have much blow by at all. I think the oil hole you used is fine. I think you clearly have something wrong with your motor itself. BTW, what did u boost at? I reved my car to 3grand and hit 6psi..just wondering what you were boosting at. Good Luck

-Dave
 

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1/2 Na-T Project
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987 Posts
Discussion Starter #9
86SUPRA7mgte said:
Yea man It might work for you. I just started up my 1/2 na-t last night. I haven't driven it yet but I let it run for quite some time. It ran very good and didn't have much blow by at all. I think the oil hole you used is fine. I think you clearly have something wrong with your motor itself. BTW, what did u boost at? I reved my car to 3grand and hit 6psi..just wondering what you were boosting at. Good Luck

-Dave
I was boosting at 8psi with the stock ct-26 without any washers, probably because a free flowing exhaust.
 

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Can't wait for Spring!
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2,364 Posts
DAMN!

that sucks dude, i'm sorry.

You compression tested the engine before the 1/2na-t correct? I thought you did and your numbers were fine.

well.. we now know where all taht blow-by is coming from.
 

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1/2 Na-T Project
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987 Posts
Discussion Starter #11
jong said:
DAMN!

that sucks dude, i'm sorry.

You compression tested the engine before the 1/2na-t correct? I thought you did and your numbers were fine.

well.. we now know where all taht blow-by is coming from.
It's life and cars, it can be fixed, I am taking it in stride, not anything I can do now except rebuild...I am thinking I will just rebuild this engine as long as everything is within specs and not at its service limit. Hopefully ATK will pick up some of the cost involved although I am not counting on them. Has anyone purchased a short block or rebuild kit from www.rpmmachine.com/enginetoptoy.html ? Prices don't look bad, just wondering about their work. Well I should have my leakdown tester by this weekend so I should be able to pinpoint where the engine is leaking from. Luckily I have pulled the engine before so it shouldn't take me long to pull it out and inspect it. Later.
 

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HKS T51R
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2,732 Posts
tha sucks its just cyl. 3 and 6 are going, all your others are good though, that sucks but its life. good luck on the rebuild
 

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Premium Member
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4,409 Posts
i say you buy yourself a nice jdm 7mgte, theyre so cheap nowadays and as long as you personally inspect it, you can get yourself a gem.

86SUPRA7mgte said:
I reved my car to 3grand and hit 6psi..just wondering what you were boosting at. Good Luck
as for revving and hitting 6psi at 3k... thats impossible, car doesnt have enough load to boost, unless you have a two step rev limiter.

Ang
 

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1/2 Na-T Project
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987 Posts
Discussion Starter #16
NegativeGeForce said:
dam didnt you rebuild that current engine a little while ago? That seriously blows :(
around 20k ago, it is still under warranty from ATK the place I purchased the engine, so they might chip in a little, but I doubt it. I always get screwed on warranties.
 

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Can't wait for Spring!
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Nothing you did to the engine should cause that much blowby and that low of compression.. That is completely thier fault!

^ based off of what i already know

I would bitch and moan in thier managers face until you get a COMPLETE rebuild for no charge! that is absolutely rediculous! What kind of place are they running if the engine breaks down after 20k! What is the coverage on the engine? What are the terms/conditions? you might be screwed if it says anything about engine modification, cause that may void the warranty.
 

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1/2 Na-T Project
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987 Posts
Discussion Starter #18
jong said:
Nothing you did to the engine should cause that much blowby and that low of compression.. That is completely thier fault!

^ based off of what i already know

I would bitch and moan in thier managers face until you get a COMPLETE rebuild for no charge! that is absolutely rediculous! What kind of place are they running if the engine breaks down after 20k! What is the coverage on the engine? What are the terms/conditions? you might be screwed if it says anything about engine modification, cause that may void the warranty.
Well they aren't going to know about any modifications because they are in Cali so I can remove anything before they want pics or if they want me to send the engine back it will just be the long block without any accessories. So far I haven't heard anything from them. I am gladd I did a compression check before the warranty period was up.

This is the warranty 3 years 100,000 miles:

ATK Remanufactured Engine Limited Warranty

ATK warrants to the original purchaser that each engine sold by ATK shall be free of defects in material and workmanship under normal use and with periodical maintenance as set forth by the original manufacturer subject to the following terms and conditions.
DEFINITIONS:
Engine: As used in this warranty refers to the remanufactured assembly (basic block, cylinder head and internal components) as supplied by ATK. Cylinder Head: As used in the warranty refers to the remanufactured cylinder head including those parts and accessories as supplied by ATK.

TERM:

STANDARD WARRANTY: 3-Years/Unlimited Miles on most engines
Please refer to the label affixed to the last page of this Owner's Manual for the standard warranty term of this engine. The information on the label applies only to the term of the warranty; all other terms and limitations of the warranty are as follows. Warranty term begins on date of installation. The standard warranty applies to all ATK products with the following exceptions:

EUROPEAN and DIESEL ENGINES carry a warranty term of 12 months or 12,000 miles whichever occurs first.

CYLINDER HEADS supplied separately carry a warranty term of 3-months or 4,000 miles whichever occurs first.

VEHICLES Over 11,000 GVW (Gross Vehicle Weight) carry a warranty term of 12 months or 12,000 miles whichever occurs first.

COMMERCIAL VEHICLES such as police cars, taxi cabs and other vehicles used for commercial purposes carry a 3-Year/75,000 mile warranty.

MOTORHOMES: Class A or Motorhomes over 11,000 GVW are NOT COVERED by the ATK warranty. ATK expressly does not offer engines for these applications. Please be aware that only engines designed expressly for large motorhomes should ever be used in such an application. ATK does not catalog nor prepare engines for these applications and therefore takes no responsibility when an ATK engine is used in this manner.

MARINE: Engines cataloged and sold as Marine Engines are specially prepared for this use and carry a warranty term of 12 months with a maximum labor liability of $350.00. Engines used in marine applications that are not cataloged carry a warranty term of 30 days with no provision for labor claims. ATK does not recommend engines be used as marine engines unless cataloged as such.

FARM, LIFT TRUCK and INDUSTRIAL applications carry a warranty term of 12 months with a maximum labor liability of $350.00.

PRODUCT REPLACED UNDER WARRANTY: Product replaced under warranty carries the remainder of the original product's warranty term.

STANDARDS: Subject to limitations listed herein. ATK, at its option, shall repair or replace a product within the warranty term after determination by ATK that the product is defective. All products are to be returned to ATK for inspection. Products not returned to ATK will not be warranted. All repairs and/or replacements covered by this warranty must be authorized by ATK. Unauthorized repairs will not be paid.

LIMITATIONS: This warranty applies to products originally supplied by ATK. This warranty does not apply to or include any of the following:

* Damage as a result of OVERHEATING, LACK OF LUBRICATION or CONTAMINATION.
* Damage resulting from PRE IGNITION or DETONATION. This includes but is limited to melted or broken pistons, broken piston rings, damaged cylinder heads, leaking head gaskets, etc. For more information regarding pre ignition and detonation please contact our Customer Service Department at 1-800-421-3746.
* Repair or replacement required as a result of any accident or misuse.
* Repair or replacement of any accessory or service item, including specifically but not limited to: all components of the cooling, fuel, electrical and ignition systems in addition to all belts, hoses, and filters.
* Any product used for competition, racing or related purposes.
* Any product to which a device or accessory not conforming to original manufacturer's specifications has been installed.
* Damage as a result of electrolysis, including but not limited to, deterioration of engine components as a result of excessive electrical current or improperly maintained coolant, and/or any product on which periodic maintenance services required by the original manufacturer have not been performed.


ON APPROVED CLAIMS:


LIMITED LIABILITY:
ATK's liability under this warranty is limited solely to the repair or replacement of defective product. ATK shall not be liable for any incidental, special, consequential or exemplary damages, including but not limited to rental cars, towing fees or for any service not expressly provided for herein, relating to or arising from the ATK product. LIMITED WARRANTY: This warranty is given in lieu of all other warranties, expressed or implied, including any warranty of merchantability, or fitness for a particular purpose, on the part of ATK or the dealer installing the engine. No dealer nor any agent or employee thereof, is authorized to extend or modify this warranty.

LABOR PAYMENTS:
ATK authorized repairs will be compensated at a rate not to exceed the Mitchell Repair Manual's published applicable flat rate schedule. Hourly rates for all authorized labor claims will be paid in accordance with the original installation rate, not to exceed $50.00 per flat rate hour. Do it yourself repairs, and repairs performed by unlicensed repair facilities do not qualify for labor reimbursement. Some do it yourself installers do qualify for labor reimbursement at $15 per flat rate hour. Please call for details.

PARTS PAYMENTS:
ATK authorized repairs will have parts reimbursed at the original purchase price. Proof of purchase may be required. Fluid and filter costs will be reimbursed for the first 2,000 miles of service.

Additional Owner/User Obligations:
Initial startup: Valves must be readjusted to manufacturer's specifications. Due to various component designs, cylinder head retorque may or may not be required in your particular application. Refer to your factory shop manual for the proper procedure for your engine type. If for any reason you are unsure what action to take please contact our customer service department via our toll free telephone number. First service between 600-1,000 miles after installation: Oil and oil filter must be changed, valves readjusted and cylinder heads retorqued (refer to initial startup instructions).

GOLD SEAL SERVICE AGREEMENT:
An optional Gold Seal Service Agreement is available for purchase that will cover Labor Payments up to a maximum of $85 per flat rate hour, as well as Rental Car Coverage up to $150, Towing expenses up to $100 and extra fluid reimbursement. Limitations do apply so please call for details.

VIP, Valued Installer Protection Plan:
A VIP, Valued Installer Protection Program applies in many cases. Please read the Plan for details.

Some engines sold by ATK/Bay Area Inc. are not built or warranted by ATK North America and a different warranty may apply.
Please make sure that you have the warranty that pertains to the particular engine that you are purchasing.


Effective 5/1/2004
Modified 4/1/2005
 

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Certified Supra Nut :P
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JT87NA said:
Anyone have any advice?

do a leak down test to see where youi're loosing the compression. cyl 3 is your biggest concern. You could have a cracked piston or broken rings. Or you could have a sticking valve or a seat that droped. Based on the leak down you'll know of you've got top end/bottom end or HG issues and can go from there.


you said you had issues with your PCV system, is it hooked up like stock?
 

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1/2 Na-T Project
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987 Posts
Discussion Starter #20
sammydafish said:
do a leak down test to see where youi're loosing the compression. cyl 3 is your biggest concern. You could have a cracked piston or broken rings. Or you could have a sticking valve or a seat that droped. Based on the leak down you'll know of you've got top end/bottom end or HG issues and can go from there.


you said you had issues with your PCV system, is it hooked up like stock?
Since I am na-t the pcv is hooked up to the valve covers and then run to a catch can then from the catch can to my intake charge pipe that connects to the front of the turbo. The port on the tb is blocked off. Here is a pic:

 
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