ISO: 3A-C engine for 1985 SR5

Need a car part and don't know where to get it or how to install it. Look here!
Post Reply
User avatar
MrWrench
Top Notch Member
Posts: 252
Joined: Sun Feb 03, 2019 9:10 pm
My tercel:: 1985 Tercel SR5. aka Spud
Location: Michigan
Contact:

ISO: 3A-C engine for 1985 SR5

Post by MrWrench »

*engine currently not needed*
Last edited by MrWrench on Tue May 28, 2019 7:43 pm, edited 4 times in total.
1984 SR5. Lifted offroader with a snorkel. Aka "Thunderbucket"
1985 SR5. Daily driver. Aka "Spud"
1986 SR5. Dakar Rally clone build.
User avatar
BaileySims
Highest Ranking Member
Posts: 626
Joined: Sat Aug 30, 2014 6:52 pm
My tercel:: 1983 Tercel SR5 4WD
Location: Texas
Contact:

Re: ISO: 3A-C engine for 1985 SR5

Post by BaileySims »

I was in the same boat awhile back. I spent a ton on trying to save the block. It was able to be bored .40 over to be salvageable, only to find out I couldn't find any .40 pistons. Threw away a lot of money on that block.

If it comes down to it. I do have a head I put together that's been sitting on the shelf. It's got the cam, new valve stem seals and new valves in it, if you ever need it.
WAGON MAFIA.
Blood, sweat and beers.
User avatar
Petros
Highest Ranking Member
Posts: 11930
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: ISO: 3A-C engine for 1985 SR5

Post by Petros »

Do not pull the engine just yet!

usually that kind of compression is not rings (most are very good numbers, expt #4), but a burned exhaust valves.

you only need to pull the head and take it to a machine shop. Have the valves seats reground, and intake valves reground, replace the exhaust vales with new ones (they do not cost much, not worth reusing the old ones), and install new valve stem seals. if any of the guides are out of tolerance, than have those replaced too.

While the head is off, carefully inspect the #4 cylinder walls and piston top. if there is anything suspect, than the engine has to come out and over bored with new oversized pistons. Chances are you only need a good valve job, but if the cylinder walls are badly buggered up, or the piston top is deformed or damaged, than the engine would have to come out anyway.

Good luck.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
User avatar
MrWrench
Top Notch Member
Posts: 252
Joined: Sun Feb 03, 2019 9:10 pm
My tercel:: 1985 Tercel SR5. aka Spud
Location: Michigan
Contact:

Re: ISO: 3A-C engine for 1985 SR5

Post by MrWrench »

Petros, thanks for your response! I will try pulling the head next weekend and bring it to a local trusted machine shop.
Before I go too in depth, is there any recommendations for an additive that might free up a sticky valve? I will attach some pictures of the cylinder wall I took with a cheap Amazon bore scope.
I can take some more

Image
http://imgur.com/tg1zOBs
Image
http://imgur.com/dlnumCw

Image
http://imgur.com/u8RHAPF
1984 SR5. Lifted offroader with a snorkel. Aka "Thunderbucket"
1985 SR5. Daily driver. Aka "Spud"
1986 SR5. Dakar Rally clone build.
User avatar
MrWrench
Top Notch Member
Posts: 252
Joined: Sun Feb 03, 2019 9:10 pm
My tercel:: 1985 Tercel SR5. aka Spud
Location: Michigan
Contact:

Re: ISO: 3A-C engine for 1985 SR5

Post by MrWrench »

BaileySims wrote: Mon Mar 18, 2019 6:18 pm I was in the same boat awhile back. I spent a ton on trying to save the block. It was able to be bored .40 over to be salvageable, only to find out I couldn't find any .40 pistons. Threw away a lot of money on that block.

If it comes down to it. I do have a head I put together that's been sitting on the shelf. It's got the cam, new valve stem seals and new valves in it, if you ever need it.
I'm struggling to find any oversized pistons as well.
I am hoping it's a stuck ring, but Petros said it's likely head related. I'm contemplating doing an atf soak or marvel mystery oil and seeing what happens.
I will definitely keep in touch with the head. Do you have a rough idea of what you would want for it?
1984 SR5. Lifted offroader with a snorkel. Aka "Thunderbucket"
1985 SR5. Daily driver. Aka "Spud"
1986 SR5. Dakar Rally clone build.
User avatar
slimdude85
Advanced Member
Posts: 83
Joined: Thu Jun 01, 2017 1:50 pm
My tercel:: 1981 Toyota Tercel
Location: Missouri, USA

Re: ISO: 3A-C engine for 1985 SR5

Post by slimdude85 »

If all else fails and you do need pistons, you may try out this site: https://partsology.com/amfinder?find=to ... ecRKSKTAB0 . I used their pistons for my rebuild and they seem to be doing well so far. Only have the pistons up to .20 over, though.
Do not be afraid of sudden fear nor of the onslaught of the wicked when it comes; For the LORD will be your confidence and will keep your foot from being caught.
‭‭Proverbs‬ ‭3:25-26

I have learned to kiss the wave that slams me into the Rock of Ages. -C.H. Spurgeon
User avatar
Petros
Highest Ranking Member
Posts: 11930
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: ISO: 3A-C engine for 1985 SR5

Post by Petros »

i purchased .020 oversized pistons last year, found them on Amazon I think.

the exhaust valves get pitted and burnt and cause the low compression. usually if it is rings, all are worn evenly, vales tend to lose their seal randomly. though I had the adjoining rings on @2 and #3 cylinder crack, making me think the head gasket between 2 and 3 failed. but I needed new pistons and rings.

do a leak down test on the low cylinder: you have the piston at TDC (both valves closed) and with the compression tester fitting and hose in place put compressed air into the cylinder. When pressurized (I turn the compressor off so I can hear), if the exhaust valve is bad you will hear hissing in the exhaust pipe, if intake, hissing in the carb (intake) and if rings/pistons bad you will hear hiss or gurgle from the oil filler cap. that is how I learned the two adjoining rings were bad.

it is rare that one ring would just fail, but it does happen occasionally. I saw one tercel 3ac engine where the piston wrist pin came loose (that should be an inheritance fit), and was rubbing against the cylinder walls. It gouged a deep groove in the cylinder wall. block could not be saved, it was scrap.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
User avatar
MrWrench
Top Notch Member
Posts: 252
Joined: Sun Feb 03, 2019 9:10 pm
My tercel:: 1985 Tercel SR5. aka Spud
Location: Michigan
Contact:

Re: ISO: 3A-C engine for 1985 SR5

Post by MrWrench »

Thanks Petros! I will run to my local harbor freight and pick up a leakdown test kit.
I'm really hoping it's just the head and nothing else. It would be significantly easier to just replace a head, especially with your write-up!

Thanks again for all of your help on this forum Petros!
1984 SR5. Lifted offroader with a snorkel. Aka "Thunderbucket"
1985 SR5. Daily driver. Aka "Spud"
1986 SR5. Dakar Rally clone build.
xirdneh
Highest Ranking Member
Posts: 2121
Joined: Thu Aug 04, 2005 11:38 am
My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Re: ISO: 3A-C engine for 1985 SR5

Post by xirdneh »

the old fashioned test is to squirt oil in cylinder
if compression does not go up then its a burnt valve
if it does go up its piston ring related
this should only be done after you have checked compression with all spark plugs out
because if you have a blown head gasket between cylinders you should get same reading on those two cylinders
Love those Tercell 4x4 wagons but they sure suffer from road noise.
User avatar
MrWrench
Top Notch Member
Posts: 252
Joined: Sun Feb 03, 2019 9:10 pm
My tercel:: 1985 Tercel SR5. aka Spud
Location: Michigan
Contact:

Re: ISO: 3A-C engine for 1985 SR5

Post by MrWrench »

xirdneh wrote: Thu Mar 21, 2019 4:49 pm the old fashioned test is to squirt oil in cylinder
if compression does not go up then its a burnt valve
if it does go up its piston ring related
How much oil should be added? I tried a hot soak with ATF. I put a few ounces in the plug hole which filled up past the top of the piston by a little bit. Turned the crank slightly and I left it for two days. When I came back it had drained down the cylinder and only had a small amount on top of the piston.

I planned on picking up a leakdown test kit, but I haven't had time
I will try the oil method, just don't wanna hydro lock it. Haha.

Thanks!
1984 SR5. Lifted offroader with a snorkel. Aka "Thunderbucket"
1985 SR5. Daily driver. Aka "Spud"
1986 SR5. Dakar Rally clone build.
User avatar
Petros
Highest Ranking Member
Posts: 11930
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: ISO: 3A-C engine for 1985 SR5

Post by Petros »

you just squirt in enough oil to wet down the walls. use motor oil, it is heavier htan ATF. usually worn rings will seal better and you get a higher compression reading. so it gives a gauge of the condition of the rings.

Usualy oil will not improve the seal of burned or badly pitted valve seats, so the compression only changes a bit. the problem is that if you have a damaged piston top, gouged cylinder walls or broken rings, you could get not raise the compression much with oil in the cycliner, and you would think it was valve related.

it is a simple and quick test, so worth doing, but the leak down test is more reliable way to isolate why the compression is low on one cylinder. BTW, most of the kits that included compression test gear will also have the ablit to use if or leak down test. they have a fitting for the spark plug hole with a length of fex hose with a normal air line connector. you have compression gauge on the air line fitting, and you pop it off and slip on the air hose with the same connector fitting to pressurize the cylinder.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
User avatar
MrWrench
Top Notch Member
Posts: 252
Joined: Sun Feb 03, 2019 9:10 pm
My tercel:: 1985 Tercel SR5. aka Spud
Location: Michigan
Contact:

Re: ISO: 3A-C engine for 1985 SR5

Post by MrWrench »

Bumping. On the search for a 3a or 4a engine.
Located in Michigan, but will travel.
1984 SR5. Lifted offroader with a snorkel. Aka "Thunderbucket"
1985 SR5. Daily driver. Aka "Spud"
1986 SR5. Dakar Rally clone build.
Post Reply