Can it be done in car, without pulling the engine? Specifically, any issues with the front timing cover & chain. Thanks
You probably can do it but it is very difficult. There are studs that attach the timing cover that have to be removed. Cylinder head studs can be stubborn as well. Corrosion can make removal difficult even out of the car. Your biggest challenge may be getting it back together without a bunch of leaks. The timing cover is meant to go on AFTER the heads. I don't recommend trying this unless your life is devoid of stress and you like doing things "half-a ssed".
Sounds like a challenge if it can be done. I'll try it with the engine in the car, if it gets too hard, i can always remove the engine and continue. Thanks Michael
it takes just a couple of hours to pull the engine. The engine has been designed to worked on out of the car. remove the engine before starting to try and pull the heads. Words of wisdom learned from experience.
thanks for info. i have two heads that need valve jobs. any suggestion on source and cost of head gasket set
Just got a copy of the 400i service manual (applicable to the 412) in which they specifcally state heads can be pulled without removing the engine... So I will give this a go. However, replacing the bearings behind the water pump is a completely seperate story... engine out for that. Michael
What a mess! Indeed it is possible, you get a medal for it. good luck making anything presentable out of that.
I can confirm it's no problem removing the RH side cylinder head "in car" . There are quite a few things that need to be removed to get at it, the worst part of the job is lifing the head because it is quite heavy and you have to reach over the side of the car. Also, removing the dipstick tube is a pain, I made up a special spanner to reach the nut to loosen it off where it joins the sump. Regards Mike
Hi Mike, I have replaced head gaskets on both sides (84 400i). It is perfectly possible to do it in the car if the heads comes off easily, but if they don't! The main problems I had were the heads were corroded to the studs, and almost impossible to shift. I wonder if they would have been easier to work loose with the engine out of the car? Reassembly is a two man job in the car as the heads need to be lowered slowly onto the block by one person, while the other helper holds the special tool required to keep the 'o' rings in place in the timing chain chest casting. The replacement head gaskets can be troublesome as they do not always seal all the waterways at first, see previous threads. I would not remove the head studs from the block, unless absolutely neccessary, it can be extremely difficult. If you are doing this job due to head gasket failure on one bank do both banks as usually they are both in similar condition, and one will shortly be followed by the other. Regards, Tim. P.s. Change your timing chain while you have got it apart. Image Unavailable, Please Login
Tim Thanks for your advice, The head came of easily, no corrosion or anything, studs perfectly clean. I made up a pushing plate anyway, but it was unneccssary in the end. The reason for removing the head is that one intake valve seat had come loose, luckily the valve or the seat didnt break, so the damage is limited to the area around the valve seat, which will be easy to repair. The heads had been off the car before I owned it, about 5 years ago, but it's done maybe 1500 ks since then, so the chain, valves etc are all perfect. However, I'm changing the exhaust valves to S/S while it is apart, but I have no intention of pulling the other side unless I have to. I am concerned the valve seat "fell out" particulary on the inlet side, this is a very uncommon failure, and the valve seats are the originals, so if there was a defect, it was from new. The studs are staying on the motor, but i did have to remove all the 6mm studs on head for the camshaft bearing caps the valve cover studs so the head can be mounted in the mill, from memory over 70 of them. Snap -On make a great stud puller, you buy the tool and the matching thread adaptor, then tighten the tool around the stud to grip it and then just reverse it out. No damage to the studs at all. Only downside is that you need to buy the adaptor for each diameter stud / thread pitch and they arent cheap, but good tools never are. The other job is to change the water pump seal, IMHO this is the most common source of oil/water mixing in these engines, (i'm going to do it while I have good access to front of the motor ) Regards Michael
Dropped valve seats were a painfully common problem on Jag 12 cylinder motors. Typically would occur after the motor had been overheated. If one came loose all the others are suspect. The test is to heat the bare head to 300F in an oven and see if any fall out. Looks like you've been lucky so far. The water pump is a tricky SOB.
"Typically would occur after the motor had been overheated" Interesting, because I'm told by the previous owner that's the reason the the heads came off - he overheated the motor leading to head gasket failure. Had it rebuilt by a well reputed shop in Brisbane ( Australia ) at enormous cost - I have the receipts. Maybe I just just fit and LS2/Tremec combo to it ? : More power, less weight, better access, lower fuel consumption - anything i have forgotten ? Michael
If you want the free-15 cent version of a stud puller, go to the hardware store and buy 2 nuts (if you don't have 2), thread them on and tighten against eachother, then back the stud out using the bottom nut. You won't leave a mark on the studs. If it's really stuck warning the alum with a torch ususally does the trick, you can use 3 or 4 nuts too if they are slipping and you are afraid to tighhten any more. To put them back in, do the same thing, but use the top nut. It they are coming out and then going right back in, I usually buy a bag of nuts and just leave them on the studs until the job is finished to save time. Mark
Mike, You are the a very lucky man. I just pulled the heads from my 85' 400i. I took me 2 hours per side to pry them off of the munged up studs. It would have been impossible if the motor was in the car. Would you be interested in buying me a few lottery tickets?
Mark, Hang in there, I know a lot of us want pictures of your progress and wish you well. You will forget all the pain when you drive it again.
I've just finished the disassembly and check. Now comes the fun part. I have most of my pieces and have worked out many of the technical CIS conversion issues. I'm take pics and post them as it comes along.
