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Guest bones774

Is 4a-fe Engine Non-inter?

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Guest bones774

Have 96 corolla I believe it is callled the 4A-FE engine is this non interference? Timing belt or chain? not changed in 220k miles. Need to know before winter sets in, no owners manual with car. Thanks

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trap

Non-interference engine and uses a timing belt.

 

Sure it is 220K without a change - if it is I believe that is the highest mileage without a change that I've ever seen. Needless to say - that belt is on borrowed time.

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That has to be some sort of a record :P

 

Change it before you find yourself stuck on the side of the road. Towing your car long distance can cost a lot of cash. A good chunk of paying for a t-belt change.

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Guest bones774

Yup, I got this car from my neighbor who was original owner and he knows the maintenance history. I guess I better start looking into replacement before I get stuck. Anything else needs to be done with this job, like water pump, tensioner pulleys?Keep trying to go to search function, but it's not working, any help from anybody , I would like to do this job myself.

Edited by bones774

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Yes, you would want to replace the water pump and pullys while you are in there. You can change it yourself. I change the timming belt on my Mitsu 4G63T engine. You do need tools and floor jacks and a jack stand a weekend and some cold beer might smooth things out too.

 

*EDIT* the stock crank pully probably needs to be changed too. If it's a dampener, then it is probably two piece and can come apart.

Edited by gvr4ever

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The 4A-FE is definitely a non-interference engine. You don't necessarily need an impact wrench to remove the pulley. I went to Autozone and they wanted to rent a pulley puller, but I bought it for only $10.00. The pulley is also known as a harmonic balancer or a timing belt pulley. The puller is a plate that has two bolts that go thru it and into the pulley. It holds the crankshaft from rotating so that you can loosen and remove the center bolt. I have a lot of experience with it, since I bought a car from e-bay for $500 that was supposed to need a new crankshaft, but just needed another pulley and bolt. I got them from the junkyard for $30 and the car has been running great ever since (check my other thread). Hope this helps, feel free to e-mail me if you have specific question.

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The 7A-FE is also non-interference. They have been designed that way. The 4A-FE is 1.6L and the 7A-FE is 1.8L. Both use the same block, but the 7A-FE has a little larger cubic displacement. The design is the same.

Edited by Bikeman982

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You can take a non-interference engine and drive its valves into the tops of the pistons by hand (I've done it with the other "non-interference" engines from Toyota) - but in the event of a belt letting go - the probablity of crashing the valve into the piston is remote.

 

There is no 100% guarantee that a non-interference engine will survive a timing belt break - but the odds that the timing sync is such that the valve will be bent by the piston is too remote to be much of a concern. If that belt lets go - the engine will stop immediately. You could actually bend a valve and still be OK - bepends on the extent of the damage. On interference engines - bent valves would be the least of your worries. Could be holed pistons, scored cylinder walls, broken rods, cracked block, etc. All boils down to valve/piston sync.

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That's very true fish...the engine stops right when the belt brakes because the camshafts no longer turn. I never heard of any valve damage from a non-inteference engine malfunction, but I guess it is possible. How did that happen for you?

I believe the 1996 still has a belt and not a chain in it for the timing.

Edited by Bikeman982

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all the A blocks use belts. i know what the 7afe is, but like i said having looked at how closely the pistons mate to the combustion chamber and the valve releifs in the pistons, maybe the releifs are just deep enough?

 

http://cgi.ebay.com/ebaymotors/Toyota-7AFE...sspagenameZWDVW

 

thats the only image of the pistons i could find, that "ring" around the top of the piston looks like it fits right upto the heads combustion chambers and the chamber itself where the burn takes place is infact in the dish of the piston primarily.

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all the A blocks use belts. i know what the 7afe is, but like i said having looked at how closely the pistons mate to the combustion chamber and the valve releifs in the pistons, maybe the releifs are just deep enough?

 

http://cgi.ebay.com/ebaymotors/Toyota-7AFE...sspagenameZWDVW

 

thats the only image of the pistons i could find, that "ring" around the top of the piston looks like it fits right upto the heads combustion chambers and the chamber itself where the burn takes place is infact in the dish of the piston primarily.

From what I know the interference would come from the pistons coming in contact with the valves as they open and close during their cycle. The "Ring" probably does come up to the combustion chamber, but where do the valves go (and how far into the chamber do they go)? Do the valves extend into the combustion chamber far enough to come in contact (interfere) with the pistons stroke, if they were out of time?? Someday soon I am going to completely dissasemble both a 4A-FE and a 7A-FE engine to see for myself and to answer these questions for certain.

Edited by Bikeman982

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That's very true fish...the engine stops right when the belt brakes because the camshafts no longer turn. I never heard of any valve damage from a non-inteference engine malfunction, but I guess it is possible. How did that happen for you?

 

Didn't happen to me - but I did see it on a 4AGE engine. Kind of surprising - since the 4AFE and 4AGE are very close (4AGE has valve angle wider than 4AFE for enhanced breathing) - but still a non interference design). Seen Nissan engiens that have literally holes punched in them from the belt letting go at high RPMs.

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I have heard of cars that have had serious engine problems like broken connecting rods and pistons that have cracked and broken, as well as valves that have warped or become bent or broken. What is the differences between the 4A-FE and the 4A-GE engines? I guess if the belt did break suddenly and the engine was rotating that the momentum of the motion could continue it until the valves were opening at the same time that the pistons were at the top of their stroke, but I thought that there was still enough clearance for them not to hit each other??

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