First time engine removal questions

[930cabman]

Must be the German in my heritage, I would change the bearings, but yes, good discussion.

[earossi]

Originally Posted by 930cabman

Must be the German in my heritage, I would change the bearings, but yes, good discussion.

Agreed. I did change mine out.....but, it was not straight forward having to measure up and reject a new set of Glycols. Thank God for this forum and the mentors that I have to get me through the issues!

[keynsham1]

I have just rebuilt one of my cylinder heads. All was going well until I came to fit the valve stem seals. They are almost impossible to get on the stem. I ended up removing the small spring around the seal so as not to damage it, and drifting the seal on with a socket that sits over the seal and on the metal shoulder of the seal. I am sure this is not the way Porsche did it in 1978!

Has anyone tried this and is there a better method?

[keynsham1]

Has anyone on this forum actually rebuilt a cylinder head themselves, or is this a task that is always avoided? I cannot find any reference to anyone who hasn't just sent them of to be refurbished! It is actually one of the easier tasks to do when rebuilding the engine, but I never seem to get any answers to this type of question!

['78 SC]

RE: installing valve stem seals

My machinist gave me a thin plastic tube that slips over the valve stem to protect the seal from the sharp edges of the keeper grooves. It has rounded, bullet-shaped nose that makes it easy to slide the seal on. Can't find a picture, but it looks like a Bic pen cap made of very thin plastic, almost like a soda straw.

[yelcab1]

If you buy a set of Valve stem seals, they come with the "condom" that slips over the end of the stem so the lubricated seal can slide over, That is how they do it at the shop. If you have to drill something then you got the wrong part. Mercedes valve stem seals are sold in quantity of 1 each and they come with the condom, 1 each.

But, doing the valve work at home is a pain in the butt unless you have all the set up and special tools: stands, seal pliers, valve grinder, spring compressor, spring checker, mill, angle cutter, and parts cleaner. It is better just to farm it out.

[930cabman]

I will be pulling the engine soon for some minor work, included is a valve grind. I can recall the "three angle" approach US hot rod guys would use. I would assume our German heads would flow the same way?

Who are reputable shops for servicing the 911 heads?

[r-mm]

Mine just came back from Anchor Atlantic in NJ looking better than new. Bob Hirst is a gentleman. Doesn't hurt that his price was better than any other I was quoted. I believe it was $1000 with ALL new intervalve valves, viton seals and whatever the latest guides are. He also stamped my name and the cylinder number on them!

[keynsham1]

So I haven't posted any updates here for a while, but work has slowly been going on. Suffice to say all parts are now back with me except for three cylinder heads which are having valve guides replaced. (The other three have already been done). I spent today cleaning the two crank case halves as tomorrow I intend to reassemble them. I have all the seals, glues, spanners, fairy dust, that is required all ready laid out in my garage.

One case interior cleaned


The other one!


Crankshaft and Intermediate shaft/oil pump


I am not going to go mad cleaning the outside of the crank cases. They are degreased but do have some corrosion on them. As I will probably hopefully) never see them again once the engine has been refitted I can't really see much point.

After a lot of thought, inspection, and measuring, I have decided not to replace the main shells. I will replace the intermediate shaft ones though. The mains show absolutely no sign of wear and neither does the crankshaft. All dimensions I could measure were in tolerance, and although there have been some very interesting thread comments about replacing mains, the spending has to stop somewhere! My oil pressure is good, and I only started this to replace cylinder head studs in any case.

One interesting thing I noticed is that there is absolutely no sign of any gasket sealant on the main shell through bolt areas. I know that this engine has never been apart before as I know the cars history and owners. In Wayne's book it shows sealant in this area. Did the factory seal here or not?

Also, interestingly, the book talks of having spotlessly clean mating faces with absolutely no scratches or marks or an oil leak can occur. I can assure you mine never left the factory like that. There are loads of scratches and marks in the interface lines! Strangely this was one of the only areas that my engine didn't leak oil!

I will add more tomorrow hopefully if all goes well.

[keynsham1]

Today I reassembled the crank cases of my engine. Not so much a difficult task as a very time consuming and methodical one. Very satisfying to complete though. Now I am sitting here wondering what I have forgotten!

Picture of oil pump seals to remind myself I put them in. I did remember the one underneath as well!


I fitted my new cylinder head studs as well....the problem that kicked this all off.


Note nice bead of sealant around the case joint.


Loads to do still of course, but I feel I have the right to feel smug and drink beer this evening!

[keynsham1]

It has been a few weeks now, and my rebuild has been interfered with by Christmas but today I made some decent progress. Firstly, I have replaced my rear crankshaft seal and installed it so it is flush with the casing. The one I fitted when the cases were split was pushed in too far and needed to be replaced again. Sounds simple bit getting the old one out when the engine is on a stand does have its interesting moments. In the end I drilled a small hole in it and used a self tapping screw and a slide hammer. I put the new one in by making a puller from a piece of plywood, three pieces of threaded bar and the old seal.



The problem I have now is that when I try to fit the flywheel, it fouls on the engine stand frame seen in the lower left hand of the above picture by the mounting bolt. Flywheel installation is presently on hold. I haven't sealed the ends of the dowel pins with JB Weld yet so I will do that first as some are behind the flywheel.

Finally I managed to install all six barrels and pistons. I didn't use any Loctite on the base gaskets as recommended in the rebuild book. I have decided to stick to the factory assembly methods after the fun and games I had with the through bolt O-rings and silicon sealant.

Note the 'special tool' for holding the barrels in place. A piece of aluminium tube from a local hardware store (B&Q if you are in the UK!)


The engine cooling tinware was cleaned back to bare metal and sprayed with high temperature paint. I was going to go down the powder coating route, but there seems little point as no-one can see it and I can save a bit of cash!


The bottom cover (rusty) is temporarily fitted to stop me dropping anything inside the engine.


The cylinder heads are just in place at the moment and the nuts finger tight. I haven't got as far as fitting the camboxes today and so I didn't want to squash the head gasket rings until finally assembling the top end.


It is a good feeling when you can see this progress in your own garage. I feel more inspired to get on with it now! Hopefully I can get the camboxes fitted and all torqued up this weekend. Then it is rockers, cams and the fun of cam timing!!!!

[keynsham1]

A bit more progress yesterday. I got one side, head and cam box, bolted down.





Fitting oil return tubes with new O-rings is a challenge due to a tight fit. Loads of oil helped along with a few nuts to pull the cam box down onto the heads, forcing the oil return tubes into place.


I am on hold now pending getting some more Loctite 574 as I have just about run out. Because of this I turned my attention to another task.

My steering wheel stitching has perished over the years and is coming apart.





I have made a start restitching it with red thread and I am pleasantly surprised with the results.







If you have the same problem, give it a go. It is really not that difficult!

[Harvs11]

I'm at a similar stage to you. I've just got my motor sealed up after replacing broken head studs.
I had the same trouble with the oil tubes. Get a friend to put some weight on the cam carrier and tap it home with a soft hammer. It should seat down easily.

[keynsham1]

A bit more progress on my engine rebuild. Flywheel on, sump plate and intermediate end shaft on, A few exhaust studs helicoiled, and the heads and cam boxes now both fully fitted.









The oil return tubes seem to push a long way through the cam box when everything is done up. See pictures below.





The O-ring still sits against the bore so the seal will be OK but I was surprised how far through the cam box they go. They are seated at the other end correctly. Is this normal? I have had no skimming or machining work done so all dimensions are as they were when the engine was dismantled.

[keynsham1]

I have devised a sneaky way to measure the 1.0mm valve lift needed to set the valve timing:



Basically, it is a steel plate bolted onto two cam cover studs with a magnetic gauge block attached. The edge of this aligns perfectly with the edge of the inlet valve spring cap. I have used a set of digital callipers clamped to the side of this and use the depth gauge part to measure the valve lift. I have done some trials and it is very rigid and gives repeatable figures. All from stuff in my garage!



I have a DTI but no extension and I don't want to buy all the bits as they cost a fortune so this seems a good DIY solution!

I plan to fit a rubber band to the callipers so they stay in contact with the valve spring cap and don't just displace under upwards movement.

[keynsham1]

Tonight I set my cam timing. It is a bit fiddly, but can be done without too much trouble with the tools I used shown in the previous post. I clamped both chains tight but I am not sure how tight they should be. Waynes book says for the left hand side " clamp the top of the tensioner idler arm to the side of the timing chain housing". This must be further than it would ever go during use otherwise it would make contact and rattle/knock. Also, as there are plastic chain tensioners, there is always going to be a certain amount of extra movement, if you push hard enough, over and above what happens under normal operation due to the deflection of all the parts. I chose to clamp them to a sensible tension, both the same, not too tight but with no slack.

I plan to go through the checks again tomorrow as a sanity check just to make sure all is well. By the way, I gave up with the special tool feeler gauge I bought as it just doesn't fit. I bent the end of a .004" feeler gauge I had in my toolbox which has now become a "special tool"!

[keynsham1]

It has been a while since I posted anything here, but I have been busy. At last I have finished rebuilding my engine ...almost. My Targa is off on Friday for a bare metal respray, along weith a few areas of bodywork that need the attention of a specialist, and then hopefully it will be back for final assembly. I still hope to be on the road this summer!

[Flojo]

umh... did you "seal" this...

[keynsham1]

I did, and I sealed the area. There was no sign of a leak on my engine so after 36 years I guess it is OK, but I sealed it anyway!

[keynsham1]

As I have finished rebuilding my engine, and I have moved on to the rest of the car, I am going to start a new thread in the Porsche 911 Technical Forum. It will be called 'Engine Complete, Bodywork Next'.









Thanks for looking!