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spitfiremk16
11-23-2011, 01:19 AM
hey guys, i just bought a jdm st205 engine for my alltrac and i went to check the compression today, here are the numbers

1 120 psi
2 150 psi
3 150 psi
4 160 psi

i checked the bgb and the spec is 164 psi
128 psi minimum and
no more then 14 psi difference between cylinders

i rechecked the compression after the first round of testing and cyl 1 went up to 135 psi

i then put some oil in it and it jumped up to just over 150. now the engine is still within warranty as i just bought it yesterday, do you guys think this might be a case of a dry cylinder from sitting for a long time or it a bad piston/rings? im seriously thinking about driving it back down there and demanding they trade it for another because im thinking if its kinda not really within spec now whats it going to be like after i drive it 10k miles. any thoughts or opinions would be appreciated.

klapa
11-23-2011, 01:43 AM
It is difficult to measure with any accuracy unless the engine was at normal operating temp - these readings are with the engine up to temp (based on the numbers I would think they are)?

That being said - normally a jump when adding oil is indicative of bad rings - but maybe you are right - it being sitting awhile maybe skewed the results.

Bet to let it cool down stone cold - crank it up and run to temp again - and redo the test.

alltracman78
11-23-2011, 01:53 AM
When you add oil the pressure will always go up, even with a good engine. There is still some loss past the rings, and the oil will seal it.

Did you do the test right?
Engine hot
Plugs out
Pull ECU fuse
Throttle fully open
Crank ONLY 4 times per cyl. If you crank more than 4 times per cylinder you may be adding a second compression stroke to your test, giving you the wrong reading.

Carbon could also be effecting the readings.
Usually if there's a problem with these it's cyl 3 [as far as pistons/rings go]. They're pretty reliable otherwise.

spitfiremk16
11-23-2011, 01:56 AM
on the top of the intercooler it said, runs ok, 9-9-09 so im assuming that this thing has been sitting for over 2 years so thats a good deal of time. Also, the engine is not in the car yet, i have yet to run it, and you are right, i just rechecked the bgb and it says to check it when the engine is at operating temp. this will definitely make a difference in how well the rings seal, wasnt sure if im just overeacting or not, id hate to put this engine in and have to take it back out after 6 months because i do plan on beating the piss out of it!

spitfiremk16
11-23-2011, 01:59 AM
When you add oil the pressure will always go up, even with a good engine. There is still some loss past the rings, and the oil will seal it.

Did you do the test right?
Engine hot
Plugs out
Pull ECU fuse
Throttle fully open
Crank ONLY 4 times per cyl. If you crank more than 4 times per cylinder you may be adding a second compression stroke to your test, giving you the wrong reading.

Carbon could also be effecting the readings.
Usually if there's a problem with these it's cyl 3 [as far as pistons/rings go]. They're pretty reliable otherwise.

yup, i didnt have the tb open at all, thanks alltracman, major brain fart there on my part, i should know better! i dont plan on putting the engine in the car quite yet, is there a good way to get the oil out of that #1 cyl? blow it out with some compressed air? im thinking i should do my best to blow the oil out of there and redo the test with the tb OPEN

alltracman78
11-23-2011, 02:07 AM
The oil should come out as you crank. Plus it will [slowly] run down past the rings if you give it time. You'll still have to crank it some to get rid of the pool sitting in the middle of the piston dish.

And you really can't trust the readings if it's a cold engine.
Obviously if you got some crazy reading you'd know, but low readings go up when the parts are all hot, and that's the reading that really matters.

Also, did you use the 185 manual or the 205 one?
185 has higher compression [8.8:1 vs 8.5:1], so it would list higher readings.

spitfiremk16
11-23-2011, 02:19 AM
The oil should come out as you crank. Plus it will [slowly] run down past the rings if you give it time. You'll still have to crank it some to get rid of the pool sitting in the middle of the piston dish.

And you really can't trust the readings if it's a cold engine.
Obviously if you got some crazy reading you'd know, but low readings go up when the parts are all hot, and that's the reading that really matters.

Also, did you use the 185 manual or the 205 one?
185 has higher compression [8.8:1 vs 8.5:1], so it would list higher readings.

ok, i will have to wait till tomorrow to try it again anyways so im sure some of it will have run down past the rings. and i will try it with the tb open! yeah, they all looked good as i stated in my first post except for #1 which was just out of spec. im probably just being paranoid, i just want everything to be spot on as i did pay a good deal of money for this engine and i want it to check out good. i checked using the st205 bgb on this website, thats where i got the specs in the first post from,

klapa
11-23-2011, 02:41 AM
Truth - The thing has to be hot to get a reliable reading and you must insure the same number of pumps between each cylinder to make any comparison.

All these engine sellers give these 7 day warranties knowing full well that you will never get the thing in your car and properly run it enough to determine if it is any good or not in that much time.

The only TRUE test is to install it - takes a reading after first hot - then run it to blow out the gunk after such a long period of inactivity and then re-check it again.

Based on what you have cold - I would not think you have any big problem with the rings or pistons - but you really won't know about that - or the head gasket - until you run it up hot driving it and then re-check at temp.

spitfiremk16
11-23-2011, 02:46 AM
Truth - The thing has to be hot to get a reliable reading and you must insure the same number of pumps between each cylinder to make any comparison.

All these engine sellers give these 7 day warranties knowing full well that you will never get the thing in your car and properly run it enough to determine if it is any good or not in that much time.

The only TRUE test is to install it - takes a reading after first hot - then run it to blow out the gunk after such a long period of inactivity and then re-check it again.

Based on what you have cold - I would not think you have any big problem with the rings or pistons - but you really won't know about that - or the head gasket - until you run it up hot driving it and then re-check at temp.

i agree, i think i just kinda went nuts when i saw that kinda low #. im still going to recheck it properly tomorrow just to make myself feel better, like you said, its probabaly ok, the engine looks like it was well taken care of by its previous owner. the next step will be to get it in there and running, drive it and see how it feels and then check the compression when its hot to get an accurate reading. ill let you guys know how i make out with it, and thank you for the help.

temperacerguy
11-23-2011, 06:49 AM
Regardless of temp, or number of cycles, or if your throttle body is open or closed, those are low numbers... One slug is not going to expand more than the rest by a discernible difference by warming the engine. If the throttle body is closed, it's going to be even because the throttle body is closed for all the cylinders. So regardless of cold/hot, throttle body open/closed, the numbers should be close or similar

Just for a point of reference. My JDM import, on a full cold engine, testing by jumping the starter while the thing was strapped to a pallet the cylinders were 158, 160, 160, 162.

Call up the importer, tell them your findings. Tell them you are concerned about the health with the engine. If they are a large volume supplier, they will just give you another one and drop that engine off on the next poor fool. If not, tell them that you are willing to install the engine (within a reasonable timeframe), and test the engine while warm, but that if it falls outside of factory test specifications, that you want it replaced. GET IT ALL IN WRITING.

klapa
11-23-2011, 08:42 AM
^Good advice.

Like I said - a 7-day warranty that is standard among these engine guys is impossible - no way could you tell if an engine/trans combo is good in 7 days.

temperacerguy
11-23-2011, 12:13 PM
^Good advice.

Like I said - a 7-day warranty that is standard among these engine guys is impossible - no way could you tell if an engine/trans combo is good in 7 days.

You got to look at it from the suppliers point of view...

They don't want to have "risk" on their books for any longer than they need to. Their bread and butter is not Jimmy and his "mechanic" friends... In fact, they pose the most risk, fucking shit up during the install, damaging the engine then blaming the engine supplier. Then returning a now junk engine and demanding their money back. (This happened to me when someone crushed an oil pan flattening the pan against the pickup... then ran the engine for a few hours wondering why their oil pressure light was on). The short warranty period reduces the time period available where Jimmy can fuck it up with it being the suppliers responsibility.

The majority of their business is other businesses and real mechanics. Any time I put a used engine in a car (against all my recommendations to the customer), I would pull the oil pan off, check the bearings, pull the plugs and do a compression check before we even considered installing it. Then we would have the engine in and running typically the same day it was delivered, at the most 24 hours later. As for Toyotas, SW20s posed the biggest problem, but we got engine swaps down to 6 hours with two mechanics and a gopher boy.

spitfiremk16
11-23-2011, 12:19 PM
^Good advice.

Like I said - a 7-day warranty that is standard among these engine guys is impossible - no way could you tell if an engine/trans combo is good in 7 days.

agreed. luckily this engine has a 30 day warranty, i bought it from this website, www.jdmenginezone.com they have a good ebay trader rating and seem like nice guys. a friend of mine has bought several engines from them and had a similar situation and they sent him another engine that tested excellent for compression. i think i am going to give them a call today and let them know my findings, luckily i took pictures of my compression results with my girlfriends iphone so it will be hard for them to dispute,

klapa
11-23-2011, 06:17 PM
Yea - well if they are giving you a 30-day warranty and have a high percentage of satisfaction among previous customers, that is a real good indicator that they do in fact carefully screen the motors they sell. 30 days should be enough time to get the engine in the car if you prepared in advance.

Luni
11-23-2011, 07:23 PM
With these engines they can develop rust on the cylinder walls from lack of running. Ive personally also experienced LOW compression and collapsed rings from an engine sitting so long. It was so bad it filled my catch can up in a day. After a few days of running it, the compression was at a steady 150-160psi and no oil consumption. The rust on the walls can negatively effect a compression test initially, but once you run it a bit and the rust gets taken off by operating the engine and the walls smooth out a bit, and get oil back on them, the numbers can/will change.

If your engine is installed, go drive the hell out of it for a bit, put some miles on it and see how it is after a few.

spitfiremk16
11-24-2011, 01:51 AM
problem is my car is no where near ready to have the engine in it! when i went down to new jersey to buy the engine(i live in rhode island) i went to both jdmenginedepot and this place and neither of them had any st185 engines which is what i was planning on buying, i figured i would buy it and install it as a long block and run it, then when neither place had a st185 motor i figured screw it, ill buy an st205 engine seems as it has most of the upgrades i plan on doing from the factory(better turbo bigger injectors etc.) im going to send them an email tomorrow along with the pics i took of the compression gauge and see what they have to say. im hoping that they will just allow me to come down and do a straight up exchange for another engine. like most of you guys have said, there is a good chance it is ok, but there is part of me telling me to not take the chance seems as i am known to have terrible luck.

temperacerguy
11-24-2011, 03:00 AM
I agree on just swapping it with another engine. if there is "rust" in the cylinders, the rust came from somewhere... Rust doesn't come from water, rust comes from iron oxidizing in the water (which should not have gotten in the engine in the first place)... therefore the rust is remnants of either your cylinder walls, or your rings. (or your valves/valve seats) In any case, not something I would want in my engine (pitted valves/seats/cylinder walls/rings)

spitfiremk16
12-02-2011, 01:04 AM
update: went back to return the engine a few days ago. i ended up trading it for a 2nd gen mr2 turbo engine and transmission(all i need is a good long block/turbo). i hand picked the engine this time. found a really nice looking one. it had toyota oil filter, belts and ignition wires. it also had no major signs of oil leaks and the oil in it was pretty clean when i pulled the dipstick and there was no aftermarket modifications done to it. when i got home i did a compression test and the numbers are as follows

cyl 1: 165 psi
cyl 2: 167 psi
cyl 3: 164 psi
cyl 4: 165 psi

factory spec on a gen 2 is 164 psi so im a pretty happy camper at the moment! now i just need to sell the mr2 trans and ecu and all the stuff thats attached to the engine!
heres a few pics of me down at jdm engine zone's warehouse. yes that is me climbing on the shelves. something tells me they wouldnt let everybody do that for liability reasons but for some reason those guys really liked me.

http://i21.photobucket.com/albums/b260/themeesh2004/th_IMG_2168.jpg (http://s21.photobucket.com/albums/b260/themeesh2004/?action=view&current=IMG_2168.jpg)

http://i21.photobucket.com/albums/b260/themeesh2004/th_IMG_2166.jpg (http://s21.photobucket.com/albums/b260/themeesh2004/?action=view&current=IMG_2166.jpg)

Luni
12-03-2011, 12:35 AM
Is the trans an LSD unit? Look inside the differential. Is there a bar in there?

spitfiremk16
12-03-2011, 01:51 AM
there is a bar in it! it is a lsd transmission!

Luni
12-03-2011, 07:24 PM
Nice. Makes it worth a bit more.

spitfiremk16
12-04-2011, 12:21 AM
Nice. Makes it worth a bit more.

yes, i was quite happy to see that, fortunately the folks at the engine place werent to well versed in toyotas and didnt realize it was a lsd transmission, they didnt even know if it was a 2nd or 3rd gen engine at first! lol

klapa
12-04-2011, 10:38 PM
Nice to be close enough to actually go see the engine you are buying - it looks like you got a good one now.

spitfiremk16
12-05-2011, 12:43 AM
Nice to be close enough to actually go see the engine you are buying - it looks like you got a good one now.

yeah, its nice to look before you buy! i took the valve cover and timing covers off today, looked very clean under the valve cover! no sludge, and it has a toyota timing belt as well.

New Guy
12-22-2011, 10:53 PM
I've purchased from JDMEngineZone before as well. Got a smokin' deal on a practically new (200psi compression) engine for my Tracker. Good company and willing to deal.

They did, however, sell me the wrong transmission... Claimed it was a 3-speed automatic but it was actually a 4-speed. They fixed their listings and I do have a use for it, so no biggie... But it was $800 spent on the wrong thing.

Sounds like you did good on your second engine!