Does anyone on this list know whether the 1993 1.8L DOHC engine has the tappet and shim-type valve adjustment or hydraulic lash adjusters?
The Haynes manual says that 1995 and later 1.5L DOHC engines, 1.6L, and
1.8L DOHC engines have the tappet and shim adjustment. Does that mean all 1.8L DOHC engines have the tappet and shim or just 1995 and later? I also understand that the tappet and shim adjustment is a dealer service since it requires a large assortment of shims?jc
Your '93 DOHC has hydraulic adjusters (followers) that ride over the valves in the same bores. You would have to remove the cams to really see them. No adjustment is necessary.
Toyota MDT in MO
I can't speak for the 1.5, but I do know that the 1.6 and 1.8l DOHC engines have hydraulic valve actuators. I hesitate to call them 'lifters' since they sit on top of the valve and the cam sits on top of the actuators. Mazda calls them "HLA's"
Chris
"Comboverfish" wrote in news: snipped-for-privacy@h48g2000cwc.googlegroups.com:
I have to ask: What are the benefits of hydraulic followers other than a reduction in owner maintenance?
Quieter. No valve adjustment necessary on the production line or in the field.
Don
Your answer begs another question:
There's quite a bit of clacking going on from underneath the valve cover on this Protege'. If I do have hydraulic followers, then how do I fix the clacking?
jc
Comboverfish wrote:
If the noise *is* from the followers, then the noisy ones most likely need replacement. Mazda had a TSB regarding an improved HLA (follower) design and a procedure to test the old ones. They wanted you to check for a very small clearance between the cam lobe and the HLA. Basically, any clearance would indicate a collapsed or stuck HLA. If the HLAs are good, you could have restricted oil flow to the HLA feed ports, low oil level, wrong viscosity or contaminated oil.
Toyota MDT in MO
Check the oil? We have cars come in all the for all kinds of reasons, Tony starts the car to drive it in and check the brakes or whatever
-- Damn, that motor's kind of noisy! Pulls out the dipstick and its dry. Owner says "But I get the oil changed every 4000 miles." Who lied to all these folks and told them the dipstick is obsolete?
Sometimes an oil and filter change will shut up noisy valve hydraulics, sometimes not. Replacing parts will get expensive.
Don
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