knocking

[chadslawn]

I re-did the entire top end back in July. I drove today 100mile ata steady 80-85mph. I hit a 100mph once or twice, just to see if it had some good pickup. Awesome pickup. I got to my motel and noticed a knocking. Ahhh shit now what! So I lifted the hood and gave it some gas and for sure, sounds like a rod knocking in the front half.

My question is, does this engine have to be removed to do the bottom end?

91 z34 163k miles yes DOHC

[series8217]

Yes. You have to remove the front cover to take out the crank. This is not something you want to do in the car, if its even possible.

[chadslawn]

the knocking is real bad now.. 1 more question. Can the motor be lifted out from the top.. Ive heard it has to be taken out from the bottom. If so, I guess I have to jack it up real high.

Anyone live near pasco county florida?

[Husky]

You can lift from the top, and stop driving that thing before you throw the rod out of the engine block! It's rebuildable until that happens.

[chadslawn]

yeah I parked it today.. it got pretty bad driving back 100miles. But I was only going 60mph.

anyone have a dollar amount for redoing the bottom end..

[series8217]

Yeah, crank regrind including new bearings is $150 at most. You'll need the bottom end gasket set, $40. Thats the minimum that will be necessary. You may also want to replace your timing chain, tensioner, and sprockets while you're in there. Also check the intermediate shaft bearings for corrosion or wear. I rebuilt the the crank/bearings on my motor one time except I forgot to check the intermediate shaft bearings. Turns out they were in really bad shape; one failed and sent debris through my motor thus destroying my new bearings, and my cam carriers. Oops.

Its possible that the rod big end is damaged. If so you have to pretty much completely disassemble the motor because you have to have the rods resized; its not like you can pull 'em out the bottom. It then it becomes a big deal because of the nearly $200 in top end gaskets, head bolts, etc.

[Juglenaut]

You said it sounds 'like' a rod knocking, are you certain that it would be a rod especially just after rebuilding the top-end.

To me I would recheck the top-end first before ripping apart the engine, check everything from lifters, valves, seats, locks, springs. check each valve to make sure that they match each others length to stock. Make sure each lifter is primed, make sure each spring is to stock pounds. make sure the valve seats are ground to fit the respective valve, make sure the guides are good.

Sounds to me like cylinder slap, or an improperly timed engine. After rebuilding any part of an engine you should treat it like a new engine break in. If you ran some lifters dry then a lifter will fail fast, especially since you ran it above 55 at most likely revved it to.

Did you use new parts?? or reused lifters, valves, and such...
If you reused any part they should be matched to the cylinder removed. and new valves should be ground to the seat.

[chadslawn]

the car ran great since July. no noise what so ever.I beleive its a rod knock. Its a deep knock. Now it knocks at an idle(after 100mile trip)the more gas you give, the louder it gets..

91 3.4DOHC 73K miles.. $600 complete with warranty. Is it worth it?

[Jakemetz63]

The doogan I bought my car from didnt think to check the oil, and it developed a rod knock. I paid 1100 for a brand new engine, 97 style. Thats a pretty good price for an engine with a warrenty though.

[chadslawn]

bought the motor for $600, guess what had water in 1 of the cylinders. so i got my money back and decided to reduild it. took it all apart except I cant get the fake camshaft bolt off. Wont budge what so ever.

any ideas?

Chad

[Husky]

What I did for mine was use a longass breaker bar, and a rounded off bolt removal socket(Was rounded off). I used a C-clamp jammed in the teeth to hold it in place, but that's probably not reccommended.

[SappySE107]

There is a tool to put on the flexplate/flywheel to keep the crank from moving. THe intermediate shaft shouldn't move if the crank can't move. Impact should be nice as well. I hammer a smaller socket in place when the bolts round off and then spend a while getting the socket back off.

[Husky]

The rounded bolt removal set works very nicely, I definitely reccommend one.