3AC Head Bolts all the same length?

[Scout23]

Hey All,

I was reading Petros head gasket replacement for the 3AC and noticed that there are suppose to be 5 long and 5 short head bolts for the 3AC motor. After looking at mine (pulled the head off a few days ago) all are the same length which is approximately3 7/8 inches long without the washer. With the washer they are approximately 3 3/4 long. Does anyone know if this will cause problems and what the proper length should be for I'm assuming the 5 longer bolts? Can I go to the Toyota dealer and buy the correct bolts?

I'm thinking this may be the cause for my head gasket leaking exhaust back through the system and flushing the coolant out the radiator. Guessing the individual I purchased the vehicle from didn't realize there were suppose to be two different lengths. He supposedly did have the head redone and new gasket installed.

Any thoughts are welcome. Thanks for all the help I've gotten so far.

Aaron

[john]

Hi Aaron,

It has been several years since I pulled one of my 3ac engines apart, however I do not remember the head bolts being of different lengths. As I remember, they were all the same. It is possible I am wrong. I always put the bolts back into the same hole they come out of. I glanced at my Chilton manuel and it does not mention different lengths.
john

[xirdneh]

pretty sure they are all same length
i have had quite a few of those engines apart and never noticed a difference in length

[smokerx]

You should have 10 head bolts and steel washer, 5 longer bolts and 5 shorter ones.

Yes, this is correct. You either have all shorts or all longs. I'm not going to bother to measure which, by Googling 3AC head bolt sizes. If they're all shorts I could imagine them yielding proper torque. If I remember Right, the longs go on the driver side while the shorts are passenger holes. Check to see if any of your piston or cylinders are steam cleaned. This is a sure sign of head gasket failure on that cylinder. Also make sure to measure the flatness with a feeler gauge like the FSM describes on the block and head surfaces to check for warpage and follow the Petros Method. also pull the intake valves and clean the crud. Get the loaner tool from autozone, it's easy.

I'm convinced you have a blown head gasket or you overheated and warped(unlikely). Change the bolts to Factory spec. if you want. I'd hate to see still leaking over the cash for the bolts when you got it back up and have to take it apart again. I'd try to find them from a junkyard if the time and cash equate since sreel quality has only gone down and they are not TTY. Like I said I don't see why all smalls wouldn't yield torque but they made them different lengths for a reason I guess. Good Luck.

[Scout23]

Thanks everyone for the responses. smokerx. The motor doesn't have any cylinders or pistons that were clean at all. No breaks in the gasket. Just couldn't keep coolant in the system so I stopped driving it (I did peg the temp gauge twice). When I drained the radiator it didn't have much. I just used a water heater pan to catch the antifreeze and it didn't hardly fill it.

[Petros]

actually I think all of the head bolts are the same length on the 3a engine, they are at two different heights in the head, but I think the row of holes on the right side (as you face it) are just deeper. There are some engines that use different length headbolts, but not the 3a head.

[smokerx]

OK, I'm pretty sure my engine is a 1983 3AC based on Full service manual Vac. Line diagrams I've looked up. The 1983 3AC diagram shows only two vac lines running to the diaphragm mounted under the Distributor(forgot the name ). Where as other models have three vac lines porting directly to the diaphragm. The 3 AC uses a plastic 3 way to unite 2 vac lines.

SO, 2 lines connecting here is 3AC. 3 is not. You might not have a 3AC..

I am pretty sure I remember seperating two different sized head bolts and making mental note of which side they went on (also noting the long ones probably wouldn't screw down into the short holes anyway, if I forgot). I think I would have remembered noting this if there was a discrepency with the Petros write up here in regards to same sized bolts not being in the Petros Method.

My thoughts are you have an engine other than 3AC. Or I'm mistaken about my own engine.

Also maybe exhaust gas is leaking into the coolant system through the head gasket but coolant is not leaking into the cylinders. Or you have a coolant leak that only leaks when the coolant is at operating temp and rolling.

[dlb]

SO, 2 lines connecting here is 3AC. 3 is not. You might not have a 3AC..

the federal emissions version of the T4 has 3 ports on the vacuum advance. 3A and 3AC are the same engine, the C just indicates a specific emissions package.

if you're unsure about what engine you have you can check the block for the engine serial #. i have a 4A in my terc and its # is 4A6881453 so i presume the serial # for a 3A will start with that.

[Lil Beast]

3AC the C means is catalityc and needs a cat. to pass emission and the 3A does not have one! I know cause in the rally regulation, I can have a cat. Exemption on my car cause it was manufacture without it meaning 3A!

[Scout23]

Yes after cleaning out the head bolt holes the ones on the right side or drivers side are just deeper. This leads to the conclusion all the head bolts are the same length. I'm sure I have a 3AC engine. It's on the plate on the car and the head cover has big markings and matches what's in the book. We will see if it was the head gasket in the next few days. Just finished putting it head back on. Just need to add coolant and change the oil and will be all done! Thanks all for all your help.