Engine drop or do the work in it?

[syngen smythe]

This most likely will be a bit of subjective answer, but looking for quick opinions or tips. I have a 1977 630csi that has at least a blown head gasket, I am hoping for the end of it there but kind of doubt it. I don't know the car history as it is a Craigslist buy a couple years ago. Symptoms: runs like crap, and I can see sparks occasionally shooting out above exhaust manifold along with a lot of burnt oil smoke from same area. No water in the oil.

So I will be pulling the head, and if it the engine appears salvageable I will delete all the thermal reactor stuff, throw some headers on to replace current exhaust manifold, address anything else I might find. I am wondering... should I drop the engine (out the bottom, I have a lift) or try to do this with the block in the car? How much work am I adding by dropping the engine? Or- how much work will I save with the good access to everything compared to trying to do this (at least the head and ex manifold) in the car? Seems like I should drop it, but not having been in there before other than just looking at I may be adding work rather than saving it.

Any other insights appreciated...

Thanks!

[88m53453]

ABOUT 2x the work. I would do a leak down test. It won't tell you anything on the cylinder where the gasket is blown, but it will tell you if you have ring problems on the other cylinders ( and valve problems as well)... If you can leave it in, if not , pull it..and find a nice b34 set up

[syngen smythe]

ABOUT 2x the work. I would do a leak down test. It won't tell you anything on the cylinder where the gasket is blown, but it will tell you if you have ring problems on the other cylinders ( and valve problems as well)... If you can leave it in, if not , pull it..and find a nice b34 set up

I use a lightweight oil in the cylinders and see if it stays there. If so, I would rebuild the head- if it isn't toast- and bolt it back on. I suppose I could do the leak down though, its not like it will hurt anything. Thanks for the input- I will leave the block in for now and do the leak down test as a start.

[Dash01]

Ditto on twice the work if you pull the whole engine out. OTOH, it may be possible to use a hoist and lift the head off the block about 4-6" without needing to disconnect much of the wiring harness--just don't put stress or tension on the wiring harness. By hoisting it 4-6" there may be enough room to check trueness of the head while it hangs over the block by using a mechanic's straightedge, and if true, clean the surfaces of the head and block with acetone and simply insert a new headgasket. Clean and dry the bolt holes of any oil or crud with acetone and long Q-tips, use 14 new head bolts, clean threads of bolts and holes with tap and die kit, use anti-seize applied with a clean toothbrush, and lower the head back onto the block and button it up. While in there, replace timing chain guide rail and tensioner.

This only works if the head is true. If not, disconnect wiring harness, etc. and take the head to a machine shop for cure of any warpage, per normal procedure. Set it at TDC and triple-check that it's at TDC, then unbolt and ziptie the timing chain and sprocket together so there's no way to misalign the crankshaft and camshaft sprockets. If you need a new chain, get a closed one unless you have the chain rivet tool from Harbor Freight and so can install an open chain without needing to remove the front cover, but that gets fiddly.

If you don't have an engine hoist, check local Craigslist or maybe Autozone, etc. for borrowing one, or use a come-along hoist hung off the rafters of your garage. Otherwise, a couple of tall saw horses and a stepladder can be rigged into a crude hoist by making a bridge over the engine bay.

Don't forget to first drain the engine coolant via that bolt plug on the passenger side of the block, lest coolant dump into the cylinders and pan while removing the head.

[Sansouci]

I'm no expert, but everything I've read about torque specs says to lube the head bolts with motor oil. Using antiseize stuff (aluminum or copper based) changes the pre-load on the bolts due to the lubricating characteristics of the anti-seize. This may result in overtorqueing the head. Do some research on this topic.'

[88m53453]

you'll never get a good reading on the cylinder head flatness while hanging by a chain as I see it. It's not rocket science to pull the head and lay it on the nearby bench and get a good read on it.(Now dissassembling it completely as old as it is might be a different story.) In addition, it will be extremely difficult to get the surfaces clean before buttoning it back up.

[DaHose]

I did a top end rebuild on my M6 in-bay. I would only pull if I KNEW the bottom end is roasted. Pulling it without a head would be easier anyway.

Jose