14 replies to this topic

[josh_S70GLT]

it is possible to change the connecting rods without removing the engine/transmission from the car?

also, what needs to be changed when changing the rods besides screws? do the bearings need to be renewed too?

[TheMan5952]

I would get new bearings as well since your in there. I honestly haven't been under my volvo enough to see if you can get to everything under the car.

[JoshV70]

You can change rods by removing the head and oil pan from the engine.

[tenn850]

It is possible to remove the lower part of the rod and remove the main bearings from the oil pan area with engine in the car. Remove the lower part by undoing the bolts and remove the lower journal, then introduce a small screw driver and turn the upper journal to turn 180 deg. to come to lower side and remove them too.

But the upper part of the con. rod is connected to the piston by the pin. And I do not think you can lower the piston to the point that you can remove the pin out! The crankshaft is connected to the flywheel and to the tranny so it can't be removed this way.

In all you can replace the bearings and the lower part of the con. rod only. If the rod is bent or the crank surface is damaged the new bearings will be damaged soon too.

You can replace the rods, pistons, rings etc by removing the head cylinder and the oil pan. But if I had to do this job I would just remove the engine and tranny out for a complete overhaul. It is too hard on the back to do it with engine in the car.

Edited by tenn850, 18 March 2006 - 04:14 AM.

[josh_S70GLT]

i'll have to see how far I get this summer

[850-Turbo]

it is possible to change the connecting rods without removing the engine/transmission from the car?

also, what needs to be changed when changing the rods besides screws? do the bearings need to be renewed too?

I gotts ta know, why do you need to change the connecting rods? Is it making noises?

[josh_S70GLT]

yeah, it's got a knock to it on the bottom end, this was after I refitted my MBC that I thought was still adjusted correctly...apparently not

I am not driving the car, just using my jeep until I get to taking everything apart

[850-Turbo]

yeah, it's got a knock to it on the bottom end, this was after I refitted my MBC that I thought was still adjusted correctly...apparently not

I am not driving the car, just using my jeep until I get to taking everything apart

Well, that is unfortunate. But I don't think you need to replace the whole connecting rod. Just the bearings. And as a rule of thumb, never replace connecting rod caps and not the rod. I don't think you can buy them separately, though, anyway.

Another important point is not to mix up the caps. Unless I'm wrong, they're matched pairs, (rods and caps).

One more thing to note (bad news) is that, when rod bearings go out, the crank journal, corresponding to the bad rod, tend to get damaged. So most likely you'll need to remove the crankshaft and have the journals turned and you'll need to get oversize rod bearings.

That means, you'll also be doing the timing belt R&R and at the least, separate the transaxle and remove the flywheel/flexplate. You probably can't do this without actually removing the trans completely.

If you do find that you need to do the crank job, I would just pull the motor/trans together and work outside, or even do a rebuild or replace the motor.

Another possiblity for the knocking noise. I had an old Ford 6-cyl in the 80's and it developed knocking sounds on the bottom end. Somehow, I figured out that it was a crack in the flexplate at one of the mounting bolt holes. This is probably rare, though.

Did you use a stethoscope to determine that it's the con rods?

By the way, what is MBC?

[jross]

By the way, what is MBC?

MBC = manual boost controller


I second checking that noise with a stethoscope.

If you bent a rod, you're probably looking at some damage either on the cylinder walls or the crank - that's the lovely knock noise you're hearing. I'd definitely just plan to remove the engine for an overhaul at that point. You can do it all in-car, but you're talking about a serious pain in the ass doing it that way. If you have cylinder wall or crank damage, you'll have to pull the block anyways.

[BlackT5]

The noise from my bent rods came from the top of the rod hitting the crank counterweight. You could drop the pan and look for any visible signs of damage. Even pull off the rod caps and check the bearings.

Like the others have said, it will be a serious pain in the ass to replace the rods with the motor in the car. What would really suck is if you missed something, put it all back together only to find that it's not fixed properly.

Some pics of what to look for..







and here is where my rods were hitting..



you've probably seen this one before, i've posted it many times



good luck man. are you thinking of upgrading the rods?

[josh_S70GLT]

yes, I'll get the forged rods from VMS

if I cannot change them with the engine in then I will plan on getting the pistons and rod set, bore the engine and grind the crank.

[Swedish Mike]

Normally the crank handles rod bending well, if you turn off the engine in time you only need new rods and bearings.

/Mike

[SIAMBLUE]

Hi pal, I did my rods today too at Avon Park raceway, finally had the car back up and running well, and for some stupid moment i took the MBC off and fitted the standard BCS, 3K revs and that was it, slight stutter and a very loud noise,
Car is at the garage now waiting to be stripped down, and will be fitted with H rods,

fastest time of the day was Stuart of SW Auto's put in a 13.02 quarter mile,

Gary

[jross]

yes, I'll get the forged rods from VMS

if I cannot change them with the engine in then I will plan on getting the pistons and rod set, bore the engine and grind the crank.

I've got drop-in forged setups, no machining required. Let me know if you're interested. SPM H-beam rods and custom Venolia pistons - we can even match it to your existing cylinder bore if you want.

[ms007]

The noise from my bent rods came from the top of the rod hitting the crank counterweight. You could drop the pan and look for any visible signs of damage. Even pull off the rod caps and check the bearings.

Like the others have said, it will be a serious pain in the jerk to replace the rods with the motor in the car. What would really suck is if you missed something, put it all back together only to find that it's not fixed properly.

Some pics of what to look for..Was the compression lower the cyl with the bent rod???







and here is where my rods were hitting..



you've probably seen this one before, i've posted it many times



good luck man. are you thinking of upgrading the rods?