How to remove main bearing caps
Does anyone know how to remove the 4 main bearing caps in order to remove the crank?
NEED 4 SPEED
Undo the boltsOriginally Posted by maldotcom2
I knew some smart arse would say that. Aside from that, they're jammed on. Even a knock from a hammer wont dislodge them.
In the Gregorys workshop manual they say to use a slide hammer to remove the main bearing caps.They attach it to the caps with expanding masonry bolts(dynabolts)in the bolt holes.Do not try to use a normal hammer to loosen them or hit them with anything.These caps take huge loads and stresses and have very fine tolerences.
Last edited by Brett_jjj; 08-12-2009 at 08:29 PM.
Ok i've tried this and fails horribly. The slide catches on the dyna bolts and i cant get enough force. The engine is bouncing around on the stand and im getting redder in the face and swearing at it and eventually the dyna bolts pull out. I've tried WD40, hitting both sides of the cap with a hammer, it shifts but will not come off!
Someone who's done this help!
We have used this method lots of times and the caps come off no worries.I dont know what you are doing wrong.We use a piece of steel plate 1 cm thick,about 15 -20 cm long and about 5 cm wide.Drill a hole at each end then put the dyna bolts through it, then connect the slide hammer to the centre of the plate.Usually only takes a few hits to get em off.
Last edited by Brett_jjj; 15-12-2009 at 01:19 AM.
Ok i bought a block of steel 15mm thick, 20cm long and 5cm wide. Two holes, 12mm dyna bolts. The dyna bolts simply pull out after about 8 hits.
Let me just confirm, the idea is that the momentum of the steel block as it comes up and hits the nut on the dyna bolts is supposed to pull off the caps? A slide hammer is a fancy name for a handle right? I just used a peice of threaded rod welded to the centre of the block. I'm very close to welding the bloody bolts into the holes and ordering new caps upon reassembly.
The steel block doesnt move ,it just bolts to the dyna bolts. The slide hammer screws into the middle of the steel block where you welded the threaded rod.It has a heavy steel weighted handle that slides up and down,the momentum from this pulls the caps off.Its very similar to a dent puller.
Oh shit so i have been doing it wrong. Here's a diagram of how i was doing it. The block and handle (black) slide up the dyna bolts (brown).
This pic is where we first got the idea from.Have you undone the cap side bolts,the caps won't come off with them still in it.
Last edited by Brett_jjj; 22-12-2009 at 09:54 PM.
Yes i have that book. I guess i mis understood the picture. So the block of metal is held against the nuts with one hand and the other hand moves that handle up and down the shaft? (lol)
Yeah.And have you removed the side bolts from the caps as well as the main bolts.
Well now i feel stupid.Didn't even realise there was side bolts. Lol. I bet they're bent by now. Cheers mate i'll get back to ya.
The manual says to replace them anyway.With these bolts they use a sealant to stop oil coming out through the threads and leaking.
If you re-use old/second hand ones,give them a good clean with a wire brush then use a non hardening sealer like permatex or loc-tite.I'm not sure if the new ones come with sealant already applied,sometimes they do,sometimes they dont.Also take note of the picture of the plastigage on the scan,it measures the main bearing oil clearances.Its a must do/must have when re-assembling any engine just about.Its cheap and you can get it at most car parts places etc.Your workshop manual will explain how to use it .Just thought Id mention that.Its cheap insurance.
Last edited by Brett_jjj; 23-12-2009 at 11:44 AM.
Got it off in 3 goes. Ok i'll get some plastigauge. Are the side bolts torque-to-yield or is it just because they have a seal? Can i use RTV sealant?
Im not sure if they are torque to yield or not.The Gregorys manual says "The manufacturer recommends the renewing of the side bearing cap bolts to ensure an oil tight fitting.If new bolts are not available,clean the thread of the bolts and apply permatex auto gasket or equivalent before installation of the old side cap bolts". So it sounds like they can be re used as long as sealant is used on em.
Ok just one more related question. I bought a dial gauge to measure the runout of the main bearings. Gregories is a little unclear, it says "maximum crankshaft runout: 0.008mm" is this the maximum runout at any given place along the axial?
Yeah, but taken from the two centre main bearing journals.
Last edited by Brett_jjj; 24-12-2009 at 08:17 PM.
Donating Member
maldotcom2 - see this post as it refers to the bearing shells:
vn - vs main bearing caps
Cool, they're only about 0.003mm out so that's ok.
Hako, i didn't see that coming. I would expect all the buick engines would use the same bearings. I'm going to be buying a full ACL bearing set for the VS from supercheap, the fact that there's numerous suggests those stooges will stuff it up.
Ok i've got an issue. Apparently the bearing caps are plated with another metal. Consequently this was stripped off in the acid bath i was using to clean the parts. Now the caps are black instead of silver. Is this going to be an issue for the health of the engine?
Its probably some type of case hardening,I'd be getting some other ones from a wreckers,it would be there for a reason,unless someone else on here can confirm that it won't matter,but as I said ,its obviously there for a reason.Id be seeing a wreckers,and use petrol ,then hot soapy water to clean stuff like that.Then smear it with clean engine oil afterwards to stop it rusting etc. I think the only things that get acid cleaned/dipped is bare heads and blocks.And even then they are only dipped in,not soaked.
Last edited by Brett_jjj; 26-12-2009 at 07:40 PM.
Ok no worries. It's probably carbon left over. I got held up over night with christmas stuff so the crank and caps were sitting in phosphoric acid for a while. I just hope it was weak enough to not have damaged the journals.
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