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Discussion Starter #1
I did a compression test on my recently purchased 86 Sammy and all 4 cylinders were at about 90PSI. I thought that was strange because the specs call for compression between 170 and 199 PSI. It doesn't smoke and power seems pretty decent so I was wondering how it could be so low. It will do 72MPH on the freeway which I hear is pretty good for a Sammy. Today I stumbled across this information:

How to do compression test?

It says that if your belt has slipped some teeth it can result in a low compression reading. Has this happened to any other Samurai owners? I'm going to buy a leak-down tester to get a better idea on the condition of the engine. But I found the information about the low compression due to the belt slipping interesting considering the example of 90, 91, 93, 90 was almost identical to my readings.
 

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Discussion Starter #2
Just checked the cam and crank alignment marks on my Sammy. When the cam marks are aligned, the crank mark on the pulley is one notch off to the left of the mark on the block. Wonder if that is enough to cause that much of a drop in compression? I do plan to replace the timing belt this weekend, along with the transmission, and a few other things I'm doing. Hoping that is the cause of low compression reading vs a worn out motor.
 

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Did you do a wet compression test or just a dry one?

That would probably have given you the answer to your question - low numbers in a dry compression test coupled with a significant increase on a wet test points to leakage past the rings.

The engine on my Swift (which is very similar to the one in your Samurai) gives just over 90 on all four bores dry, jumping to around 190 wet - so I know it's time for a rebuild.

For what it's worth - although that engine does use oil, there is very little smoke - if you drive behind the car and watch for it, you'll see the slightest "puff" on a gear change - and it has decent power.

I've just bought the gaskets & seals - so now I have to make the time to pull the engine and see how badly worn it is.
 

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I did a compression test on my recently purchased 86 Sammy and all 4 cylinders were at about 90PSI. I thought that was strange because the specs call for compression between 170 and 199 PSI. It doesn't smoke and power seems pretty decent so I was wondering how it could be so low. It will do 72MPH on the freeway which I hear is pretty good for a Sammy. Today I stumbled across this information:

How to do compression test?

It says that if your belt has slipped some teeth it can result in a low compression reading. Has this happened to any other Samurai owners? I'm going to buy a leak-down tester to get a better idea on the condition of the engine. But I found the information about the low compression due to the belt slipping interesting considering the example of 90, 91, 93, 90 was almost identical to my readings.
While having the timing off a bit is not a good thing, I don't think that small amount of difference will affect your compression.

Fordem's suggestion of a "wet compression test" as described in kick-fix's webpage in your first link (a teaspoon of oil in the cylinder before the test) is a good idea.

Pardon me while I wax philosopical:
I don't trust the accuracy of anyone who can't (or is too lazy to ) put together an intelligible sentence in a post or a web article.

All the good intent behind a post or webpage is wasted if what you write makes no sense or is very hard to read!

my 2 cents.
 

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I did a compression test on my recently purchased 86 Sammy and all 4 cylinders were at about 90PSI. I thought that was strange because the specs call for compression between 170 and 199 PSI. It doesn't smoke and power seems pretty decent so I was wondering how it could be so low. It will do 72MPH on the freeway which I hear is pretty good for a Sammy. Today I stumbled across this information:

How to do compression test?

It says that if your belt has slipped some teeth it can result in a low compression reading. Has this happened to any other Samurai owners? I'm going to buy a leak-down tester to get a better idea on the condition of the engine. But I found the information about the low compression due to the belt slipping interesting considering the example of 90, 91, 93, 90 was almost identical to my readings.
My Samurai has the same compression as your, plus a broken crankshaft, yes thats right a broken crank! It has been running just fine for years. Some how the crank cranked down the center, saw that when I pulled the motor to change the oil pan gasket. Just makes a click sound when its running, I always wondering what that sound was, I alway though it was in the valvetrain. I beat the crap out of my samurai red line, powershift up hills all day in the derest with my pertrowork cv carb kit and custom exhuast system! Bottom line Suzuki engines are reliable.

My verdict, you probably need a rebuild kit, i.e., seals, bearings, rings. Check the bores when you pull the head, to check if you need oversized pistons depending on the cylinder wear.
 

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Discussion Starter #6 (Edited)
If yours is running fine with 90PSI I'll probably use mine as-is for as long as it holds up.

Do you need to hone/ream the cylinders when you put in new rings?

I'm getting burned out working on it. Tranny was bad so today I picked up a used one and put that in, along with a new clutch, and new starter. Man, it was a lot easier taking the tranny out than putting it back in. For some reason took forever for it to line up and slide in. I still need to do the timing belt and I am wondering if I should do the water pump while I have the timing belt cover off. Sammy has about 85K miles (or maybe 185K miles, who knows...) Also need to install a steering damper as mine is missing. The transfer box was leaking so I changed the oil seals on it. Hoping that by Saturday it is all finished and ready to test off road.
 

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I'd say with 90psi - it's getting to where you need to rebuild (or replace it), it'll definitely be down on power, and it'll run kind of ragged when it's cold.

If you don't want to do the rebuild yourself - and I see no reason why you shouldn't, this is a very simple engine - you can get one from G13b.com
 

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If yours is running fine with 90PSI I'll probably use mine as-is for as long as it holds up.

Do you need to hone/ream the cylinders when you put in new rings?

I'm getting burned out working on it. Tranny was bad so today I picked up a used one and put that in, along with a new clutch, and new starter. Man, it was a lot easier taking the tranny out than putting it back in. For some reason took forever for it to line up and slide in. I still need to do the timing belt and I am wondering if I should do the water pump while I have the timing belt cover off. Sammy has about 85K miles (or maybe 185K miles, who knows...) Also need to install a steering damper as mine is missing. The transfer box was leaking so I changed the oil seals on it. Hoping that by Saturday it is all finished and ready to test off road.
Mine actually has about 110 in #1-3, and 90 in #4.

Typically not, so long as the cylinder walls arent scored, you'll be good to go!

I have a hard time taking these trannies out, and putting them back in ;)

Unless your vehicle is overheating, I wouldnt waste money on a waterpump, I know everyone recomends doing it while your in there, but I ask them, are you going to pay for the pump? If the pump goes out someday, its not hard to change it out on a Samurai, lol!

Sounds like your getting it in good running condition! Good luck!
 

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Discussion Starter #9
I have a hard time taking these trannies out, and putting them back in ;)....
Replacement tranny has noise so I will need to pull it out. :mad: On th eplus side it should go faster now that I have done it once before.
It does not have the loud whine that mine had in 1st, 2nd, and 3rd gear. It sounds kind of rattly. 4th and 5th has a bit of noise. Since I still have the original tranny I will pull the parts from 4th and 5th gear from that one (4th and 5th were nice and quiet on the original tranny) and use that on the replacement tranny. Man, I don't want to pull that out and put it back in again. Massaging that tranny under the car to get it back in took forever and my arms feel like I had a hard gym workout. This time around I am going to grind off about 1/8" from the rear tranny mount support. I think maybe my replacement clutch cover is a little thicker than the stock one because it was an incredibly tight fit to get tranny case past the bottom part of the clutch cover. Grinding off some of the mount support will not hurt anything and should make it a lot faster to slide the tranny back in.
 

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Discussion Starter #10
I'd say with 90psi - it's getting to where you need to rebuild (or replace it), it'll definitely be down on power, and it'll run kind of ragged when it's cold.

If you don't want to do the rebuild yourself - and I see no reason why you shouldn't, this is a very simple engine - you can get one from G13b.com
You are probably right. It does run rather rough until it warms up and I think when I get it on a steep hill I may regret not having the extra power. Not like these engines had an abundance of excess power when new.

I there a good tutorial / guide for doing the Samurai engine rebuild?

Where I picked up the used tranny the guy at that lot said I should keep an eye out for an 8 valve tracker motor. He said they are about $300 if you pull it yourself from the salvage yard and they often have a 50% weekend discount making the cost of a complete used engine $150. He said it is a drop in replacement but has quite a bit more power. I guess finding a used one is the hard part.

Maybe I'll just use the tired motor a while longer. I'm tired myself of messing with it for now.
 
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