Timing Chain Do you need to remove cylinder head to change the timing chain on 1994 Toyota Previa?

There is no cabin air filter on that vehicle.
RPM gages are an option and may or may not be present.
The engine is a 4 cylinder and most 4 cylinder engines have BELTS,

Did you grind the cylinder head so your timing chain is longer, You need to change the cylinder head.

Impossible. This is a dual cam engine. There is a camshaft in each cylinder head. The head cannot be removed without removing the timing chain.

May be its problem with timing chain and it has to be inspected and replaced.Or its possible that timing chain is got misaligned.

There are few help,links provided related to timing chain assembly and dis-assembly. Go through it and confirm proper inspecting of timing chain.

Click the required help link below:----How to Replace Timing Chain Cover & Seal on Audi A4 ? http://repairhelpcenter.blogspot.com/2011/11/how-to-replace-timing-chain-cover-seal.html
----------1982 Toyota Pickup: Set ignition timing, engine overheating, timing chain issue, dist off? http://whatisbyme.blogspot.in/2012/05/1982-toyota-pickup-set-ignition.html
----------How to Remove Timing Chain Cover and Seal on Toyota Previa?

http://technoanswers.blogspot.com/2011/12/how-to-remove-timing-chain-cover-and.html

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How to Remove Timing Chain and Gears on Toyota Previa?

http://technoanswers.blogspot.com/2011/12/how-to-remove-timing-chain-and-gears-on.html

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Ford Mondeo ST220 camshaft Timing specifications? http://technoanswers.blogspot.in/2012/02/ford-mondeo-st220-camshaft-timing.html
------------Replacing Timing Chain Cover For 2009 Ford?

http://repairhelpcenter.blogspot.in/2012/03/replacing-timing-chain-cover-ford-2009.html

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Timing Chains & Front Cover Removal on 2008 Ford Taurus? http://repairhelpcenter.blogspot.in/2012/03/timing-chains-front-cover-removal-on.html
----------How to Replace Timing Chain Cover, Chain, Sprockets, & Seal On Ford Taurus? http://repairhelpcenter.blogspot.in/2012/03/how-to-replace-timing-chain-cover-chain.html
---------How to Replace Timing Chain & Sprockets on Ford Windstar? http://repairhelpcenter.blogspot.in/2012/03/how-to-replace-timing-chain-sprockets.html
---------Timing Chain & Sprockets Replacing on Ford, Mercury and Lincoln? http://fordrepairhelp.blogspot.in/2012/03/timing-chain-sprockets-replacing-on.html
----------How to Replace Timing Chain & Sprockets on Ford Edge and Lincoln MKX? http://howtobyme.blogspot.in/2012/03/how-to-replace-timing-chain-sprockets.html
------How To Replace Timing Chain, Sprockets & Front Cover on Ford Expedition and Lincoln Navigator? http://repairhelpcenter.blogspot.in/2012/03/how-to-replace-timing-chain-sprockets_356.html
---------Timing Chain, Sprockets, Front Cover & Seal removal for Ford Mustang? http://schematicsdiagram.blogspot.in/2012/03/timing-chain-sprockets-front-cover-seal.html
---------How to Replace Timing Chain on Buick LaCrosse? http://howtobyme.blogspot.in/2012/03/how-to-replace-timing-chain-on-buick.html
---------These details will help.For more help keep updated.Thanks.

Timing Chain and Gears Removal & Installation To Remove:


Except XRS

XRS

1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
2. Drain cooling system.
3. Remove the upper front fender apron insulator.
4. Remove the upper radiator support insulator.
5. Remove the right front wheel and tire assembly.
6. Remove the right lower splash shield.
7. Remove the drive belt and alternator.
8. Remove the air switching valve (XRS)
9. Remove the power steering oil pressure switch connector.
10. Remove the 2 power steering mounting nuts and through bolts. Remove the steering pump from the engine. Secure the steering pump to the cowl
    
    
11. Raise and support the engine with floor a jack.
    
    
12. Remove the right engine mount.
    
    
13. Remove the 2 nuts, 2 clips and the cylinder head shield (except XRS).
14. Remove the 4 ignition coils.
15. Remove the 2 ventilation hoses from the cylinder head valve cover.
16. Remove the 9 bolts, 2 seal washers, 2 nuts, cylinder head cover and gasket (except XRS). XRS
    
    
17. Remove the 4 bolts and the cylinder head shield (XRS).
18. Remove the 2 nuts, bolt and remove the ventilation hose from the ventilation pipe (XRS). XRS
    
    
19. Remove the Ventilation pipe and gasket (XRS).
20. Remove the 9 bolts, wire harness protector. Remove the cylinder head cover and gasket (XRS).
21. Remove the O-ring from the cylinder head cover (XRS)
22. Turn the crankshaft pulley and align its groove with timing mark "0" on the timing chain cover.
    
    
23. Ensure that the marks on the camshaft timing sprockets are in straight line on the timing chain cover surface as shown.
    
    
24. If not turn the crankshaft 1 revolution (360°) and align the marks as above.
25. Remove the crankshaft pulley
    
    
26. Remove the 2 mounting bolts and remove the crankshaft position sensor.
27. Remove the mounting bolt, nut and the drive belt tensioner.
28. Remove the right engine mount bracket.
29. Remove the front exhaust pipe (XRS).
30. Remove the Exhaust manifold brace (XRS).
31. Remove the Exhaust manifold (XRS)
    
    
32. Remove the 2 mounting nuts and remove the chain tensioner.
33. Remove the water pump. Except XRS
    
    XRS
    
    
34. Remove the 11 mounting bolts and nut (except XRS).
35. Remove the 12 bolts (XRS).
36. Remove the stud bolt.
37. Remove the timing chain cover and 2 gaskets.
38. Remove the crank sensor plate.
39. Remove the timing chain tensioner slipper mounting bolt. Remove the tensioner slipper.
    
    Note: If the crankshaft timing sprocket cannot be removed by hand, use 2 screwdrivers. Position shop rags as shown to prevent damage.
    
40. Remove the timing chain and crankshaft timing sprocket.
41. Remove the 2 chain vibration damper mounting bolts. Remove the vibration damper
    
    
42. Hold the camshaft hexagonal section with a wrench. Remove the sprocket mounting bolt.
43. Remove the valve timing controller assembly and timing sprocket.

Note: Be careful not to damage the cylinder head and valve lifter with the wrench.
Do not disassemble the valve timing controller assembly.

ALL MOTORS ONE TIME OR ANOTHER NEED TO BE CHANGE SOME CARS MANY TIME YOUR ANSWER YES IT DOES

4 cyl engine 2.7L , has t / chain.
V6 3.0L , has timing belt.

If you have the sound of no compression you either have a timing chain that has jumped time, or valve seats that have dropped out of the cylinder head. Check the timing, and, it it is correct, the head has to come off. The cyl head removal is an incredibly difficult undertaking in a Previa. I drop the whole engine out of the vehicle to work on them.

you need to pull the timeing chain sprockets off with the chain their is no master link in the chain...make shure u line up the timing marks before u pull it off so it will make instlation easyer

Be sure to replace all the gears, tensioners, guides and seals if your going to replace the chain. Perhaps the water pump as well if it hasnt been replaced in a while. Sounds like alot of work with that many miles unless the engine has good compression on all cylinders and the head is in good shape as well. You might consider finding another engine if you plan on keeping this truck for a while. By the time you do all the work and pay for all the parts to do the timing chain, you could find a low mileage engine for a few bucks more as long as its tested for compression and has documented miles on it.