engine tapping/knocking 89 2.9l auto

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Mar 19, 2001 | 04:55 PM

mentalvavcuum

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engine tapping/knocking 89 2.9l auto

For awhile my trusty old BII has been sounding like a tuckboat after a cold start. the tapping will disappear after about 5min of driving and then return and stay after about 15min of +2500rpm. The tapping will then get really bad and the engine sound will deepen and loose power until parked for about 30min.

I'm mechanically challeged but my mechanic says its the lifters and that I need a new engine, but other people say it can be rockers, intake/exhaust manifold probs etc. STP additive helps a bit but not a lot. the compression is low, fuel economy is less than 15MPG and it wont maintain 65mph on even a moderate slope. if rpm hits 4K (only by accident these days) a metallic scurring comes from the engine.

Money is a factor, and I hope to avoid rebuilding the engine, so any help will be greatly appreciated.

THANX

Mar 19, 2001 | 07:44 PM

Avanti

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engine tapping/knocking 89 2.9l auto

How many miles on the engine? What is the oil pressure reading after engine is hot & idling? Need to answer these questions.

89 Bronco II XLT, I rebuilt engine in 98
92 F150 XLT EXT cab Mint, with all goodies
93 Aerostar AWD

Mar 20, 2001 | 06:13 PM

mentalvavcuum

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engine tapping/knocking 89 2.9l auto

the engine has about 140K on it.

I'm not sure what you mean by oil pressure reading (I'm a foreigner) - do you mean from a compression test?

Mar 22, 2001 | 08:17 AM

Avanti

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engine tapping/knocking 89 2.9l auto

What does your oil pressure instrument gauage read? When hot it should read in the NORMAL range when the engine is idling. Also even this may not show the true oil prssure as a good mechanical gauage should be used.

Mar 25, 2001 | 12:45 PM

mentalvavcuum

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engine tapping/knocking 89 2.9l auto

oil pressure rating is in the normal range, but my roommate who drove it for the past year had an compression test done and it showed low compression. I'm considering to do the 4.0 v6 conversion mentioned here and on the Duff site, but I need to get more info from people who have done it. The motor shop people I have talked to say it's too much hazzle.

Mar 25, 2001 | 09:02 PM

rcriverclub

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engine tapping/knocking 89 2.9l auto

rockers wont change with temp/time, at least not enough to make the diff. you discribe. Exaust manifold is the same, no real power rober here, if its got a prob you will hear it loud and stong. intake manifold is possible but unlikely. it would have to leak bad enough to effect fuel/air mix to drop power and mileage but this would not account for lifter nosie you describe (it would lean it out and make it tend to run hot). The lifters do get noisy on 2.9's after awhile (140-180k). the other noise you describe at higher rpm is scary, so is the complete lack of power. if she is so sick it cant make 65mph any more i'd check that compresion one more time. and if it is as bad as i think, shoot it. put it out of its misery, its served you well, rebuild or replace it.

the only other major power robber is a lack of being able to breath. intake or exaust blockage ie: catalytic conver blocked or air filter blockage (these can make it sound throtey like you discrbed). these dont make a lifter noise but the can rob power. maybe you have a combination of more than a lifter problem.

Mar 26, 2001 | 11:16 AM

mentalvavcuum

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engine tapping/knocking 89 2.9l auto

THanks for the feedback, I appreciate it.

would you happen to know if the switch to a 4.0 V6 is doable, and still passing the CA SMOG check? It seems the switch is not too much hazzle, execpt for possibly having to change the axle and the Tranny.

alternatively, would a 2.9L with performance headers/chip and K&N filter be substantially more powerful than stock?