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engine noise at higher rpms


trtturbo
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Just bought an '88 for $500.00. Seller said engine was knocking. Got it home and it was 3+ qts low on oil. Put oil in and jumped it off. Rattled for about 2 seconds and cleared up. At idle it sounds normal. If you rev it a little it rattles/ knocks, but only as the rpms go up, not down. Went and drove it and as it gets above 1800 rpms or so, the engine sounds terrible.

It did seem low on power too. I am prepared to put a motor in, but here is my question.

Is there a chance it jumped time? It starts a little different than my '89, sort of like its out of time, but when you rev it a little; off idle to 1500 or so, it seems very responsive. Wish it had an oil pressure gauge so I could see what its running.

Also, when you start it cold, the noise is there for about 2 seconds, then goes away. If I kill it and start it again, there is no noise. That makes me think it is bearing/motor related.

Opinions and advise welcome.

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Also, when you start it cold, the noise is there for about 2 seconds, then goes away. If I kill it and start it again, there is no noise. That makes me think it is bearing/motor related.

Opinions and advise welcome.

sounds like the valve ticking noise that a lot of these trucks have on cold starts. IIRC

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this is not valve ticking. The same noise that goes away after a few seconds happens as you drive and get above 1800 rpms or so. The noise is very loud.

Dont think there is any issue with rings. Absolutely no smoke, no missing, motor is responsive off idle doing little revs.

Do these motors ever jump a tooth and if so, what is the result? Will one tooth off cause the pistons to hit the valves?

I'm not a novice, but dont have any experience with this motor. All mine is with LSx based g.m. motors.

Motor has 227k on it and the guy I bought it from acted like "whats that" when I asked him about the timing belt.

I kindof leaning toward just putting a motor in. I can do the timing belt before the install and it will have lower miles hopefully.

Also, if I do a motor, can I buy a '94 or '95 motor and just put my intake on? Is everything the same?

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this is not valve ticking. The same noise that goes away after a few seconds happens as you drive and get above 1800 rpms or so. The noise is very loud.

Dont think there is any issue with rings. Absolutely no smoke, no missing, motor is responsive off idle doing little revs.

Do these motors ever jump a tooth and if so, what is the result? Will one tooth off cause the pistons to hit the valves?

I'm not a novice, but dont have any experience with this motor. All mine is with LSx based g.m. motors.

Motor has 227k on it and the guy I bought it from acted like "whats that" when I asked him about the timing belt.

I kindof leaning toward just putting a motor in. I can do the timing belt before the install and it will have lower miles hopefully.

Also, if I do a motor, can I buy a '94 or '95 motor and just put my intake on? Is everything the same?

I've read on here that if the timing belt jumps one tooth, that it will have serious power issues, and will have trouble gaining speed up hills and keeping it on the highway. I KNOW if it jumps 3 or more teeth will cause the pistons to hit the valves.

 

The timing belt interval for an 88 is 60k miles, so.....its wayyy over due if it hasn't been done.

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I think I'm going to just go with another motor. I found one with 108k on it. I can put a T-belt on before the install and I should be good for a long while. $550.00 is what they want. Seems about average and its local in the Dallas area.

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