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Engine very stiff after rebuild

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M. Personne John T
Champagne, Dordogne, France   FRA
Help! After a full rebuild, I struggle to turn over the engine of my 4.2 OTS. It's not very scientific, I know, but with a long bar and my biggest torque wrench it reads around 95 ft lbs before there is any movement, and this is with spark plugs removed.

The high-torque starter I have fitted can just about turn it, but not fast enough in my opinion to start the engine when the installation is complete. Am I unduly worried, or should I have investigated the reason for this before installing the engine and gearbox in the car?

I'm confident that the ring gaps were correct, and that each conrod would turn freely on the crank, and I'm guessing (I re-assembled the engine about 2 years ago and my memory doesn't last that long nowadays) that the crank turned reasonably freely as I fitted each conrod otherwise I would have noticed, but it was only when the sump was fitted that I noticed that it was almost impossible to turn.

I know it's a big engine, and that I'm trying to move 6 new pistons in their "new" bores, but should it be that tight? Is it possible that the rear rope seal could be gripping the crankshaft to that extent as a friend has suggested? Surely not?

Comments/ideas/suggestions welcomed.

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DAWTRIJAG Avatar
DAWTRIJAG David Warr
St. George's, Newfoundland, Canada   CAN
Hi!
I have heard of tight engine rebuilds before. Sometimes you may have to tow the car to get it to turn fast enough to get it to start. I have never seen that however. Perhaps it is just a story. Was the engine stored dry or was there oil in it? When the engine was rebuilt there should have been rebuild oil on all the bearings and that should have kept everything slippery. It is strange for this engine to be so tight. If you can take the sump off again recheck the main bearings and the big ends for clearances. If everything checks out you try the towing option if you are sure the engine was rebuilt properly. It is unlikely the rope seal would make the engine hard to turn. If that isn't installed properly you'll have a massive leak pretty quickly. Try some engine oil down the plug hole then turn the engine over with the plugs out. Put in just enough to wet the top of the pistons. It will cause a bit of smoke when the engine does start but that will clear up. Keep us informed on your progress
David

M. Personne John T
Champagne, Dordogne, France   FRA
Hi David. Thanks for that.

Yes, I was very careful to oil all the moving parts during reassembly, which was about 3-4 years ago (the rebuild went on the back burner when we moved to a new house that needed a rebuild even more badly!).

Although I can't swear to it, I'm reasonably confident that the crank would have turned freely or I'd have investigated it at the time, and similarly the big ends. I do remember that I gapped the rings, but that the pistons were a tight fit. I'm confident that the machining was done correctly, as it was all done by Oselli in the UK. They skimmed the head and block, re-bored the block, reground the crank, and balanced crank, conrods, pistons, flywheel and clutch pressure plate. It was only during re-assembly that I found that I had Iskendarian fast-road cams.

Perhaps I am worrying unduly, but it does seem very tight indeed. As for a tow start, I'm worried about pulling the frames off the bulkhead!

So, I have to decide whether to carry on fitting distributor, fuel lines, tank, carbs, exhaust etc and trying to start the engine on the starter, or take the engine and gearbox out yet again and have yet another look. Decisions, decisions ....

John

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DAWTRIJAG Avatar
DAWTRIJAG David Warr
St. George's, Newfoundland, Canada   CAN
Hi John!
It certainly is a dilemma. It is hard to know what to do. Hopefully someone with a similar experience will contact you on this forum.
I wonder how tight the cam sprockets and chains are. Try to do as much checking as possible before taking the engine out. That is no small task.
David

DAWTRIJAG Avatar
DAWTRIJAG David Warr
St. George's, Newfoundland, Canada   CAN
Hi again!
I decided to check Google. If you put in "tight engine after rebuild" you will get a lot of info. Consensus is that you have a problem somewhere that needs to be corrected.
David

clarsson Christer Larsson
Örebro, n/a, Sweden   SWE
Unless you are "made of money" and don´t mind scrapping an engine, ther's no alternative to opening the engine and checking clearances
Remove the sump, loosen the main bearing caps and try turning the engine again.
You can suffer from any one of the following problems:
Wrong dimension bearings
A "non straight" main shaft
Swtiched bearing caps (not matching numbering)

Stil sticking?
Check clearance on rod bearings
check piston ring gap
Good luck!
/Christer

M. Personne John T
Champagne, Dordogne, France   FRA
Thanks David and Christer.

Well, yesterday, with the help of a friend, we took jump leads from my Jeep, with its engine running, and activated the new high-torque starter, with the plugs removed, and oil in each cylinder.

The engine turned over steadily, though not all that fast. Then we tried again with the plugs re-fitted. This time the starter could just about turn over the engine, one compression after another, if you know what I mean, In my opinion not fast enough to start it, though I won't know for sure until we have a spark and fuel.

I'm beginning to think that I may have to do what I read in one of the articles on the 'net when I googled "tight engine after rebuild" as suggested by David, and that is to tow her with the spark plugs removed and let the clutch out gently in 3rd gear, and run her like that for a few minutes (it's very quiet around this part of France and doing this will not present a problem).

After having done that, replace the plugs and try and tow-start the car. If successful run it very gently for a while and then see if the engine has freed up sufficiently for it to be started on the starter motor. This seems like the only alternative to removing the engine and gearbox yet again and doing a partial strip down of the bottom end.

So, two more questions; where should I attach a tow rope, and is there any danger of pulling the space-frame off the bulkhead? Incidentally this will be without the bonnet in place. Having only recently refurbished and re-fitted the frames, and having seen how little actually holds them on, I'd hate to see them part company with the car!

John

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DAWTRIJAG Avatar
DAWTRIJAG David Warr
St. George's, Newfoundland, Canada   CAN
Hello John,
It looks like you are making progress. Before towing the car I would check the main and big end bearings with plastigage. According to my workshop manual you can take the sump off with the engine in place. With the bonnet off you should be able to raise the engine easily enough to clear anything in the way. If your bulkhead is in good shape you shouldn't have any trouble towing the car. If you can separate the frame from the body then I think your car wasn't safe. I would use fourth gear though to make it a little easier to pull. Also with the bonnet off you can attach a rope to the picture frame part of the front end.
David

nlneilson Avatar
nlneilson Neil Neilson
Mojave & Oxnard CA, USA   USA
1962 Jaguar E-Type Convertible "Chevy SB"
1974 MG MGB "MG"
1979 Porsche 928
1979 Unknown Unknown    & more
The space frame is brazed and not welded. Hook your tow strap to something a little stronger like the torsion bars that adjust the front suspension height, or the transmission mount.

Whoever does the towing make sure they do not jerk it. Been there just to move it and not to try and start it.

As others have mentioned check why the engine is tight even if you have to remove the engine.

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jagboy69 Avatar
jagboy69 Jason A
US, Planet Earth, USA   USA
Personally, I wouldn't risk towing this car in gear. Tight is TIGHT. It's not THAT big of a job to pull the camshafts out and remove the chain. Then see how the bottom end spins over without the timing chain and cams turning. This is way safer and will tell you if you need to go up or down in that engine to loosen it up. (Maybe, just MAYBE you've got the chain setup wrong) If it still spins too tight, pull the sump and then disconnect the rods and try it again. IF it frees up, It's rings. If it's still tight, it's Crank. EASY and much safer than dragging it into submission. Chances are, nothing will happen and it won't free up without causing SOME damage somewhere. Or wont free up at all unless you drag it to italy.

As a side note, have you tried marvel mystery oil? I know you said you used engine oil when you built it. Thats not the same as assembly lube and I dont think it lasts that long, but this is just my opinion. I think i saw something about france. If you cant find marvel mystery oil there. You can use automatic tranny fluid and get the same job done.

This is how I would approach the problem. Whatever road you choose, let us know what happens and if it really goes bad, TAKE PICTURES.
No pictures, It never happened!

Jason

SNIEDLEYWHIPLASH James Taylor
Jamestown, USA   USA
You might check the valve gaps. Series 2 E s had two different gap settings and with isky cams that setting might be different too. 69 E s were set at .04 and .06 intake and exhaust. 70 E s were set at .12 both sides. Check that the isky cams were set to Isky settings for 70 E head. Jaguar had a tendency to make changes on the fly or when they ran out of older parts. It's necessary to reference the numbers when buying parts. I'm not sure how an incorrect gap could cause tight engine but I've been surprised more than once with British car differences. Good luck! Jim

DAWTRIJAG Avatar
DAWTRIJAG David Warr
St. George's, Newfoundland, Canada   CAN
Hi John

How is it going with your engine? It has been awhile.
David

jdrubin David Rubin
Rochester, NY, USA   USA
After checking the bottom end and pistons, I believe the cams and head should also be checked. If the head was warped and shaved, the cam bearings may no longer be aligned. Line boring the cam bearing area may be necessary. Generally, I like to install and rotate the cams before installing the valves. Cams can be very hard to turn in a warped head. If necessary to line bore the cam bearing area, the surfaces where the cam covers set should also be shaved to prevent leaks.

erlewis Avatar
erlewis Eric Lewis
Madison, USA   USA
I have always used a special oil with suspended graphite when reassembling an engine, including my 4.2. This oil is intended for engine rebuilds that might not be completed immediately. The oil will drain out leaving the graphite behind so the bearings can spin easily until the oil pump builds up oil pressure. Otherwise you will get metal on metal contact during the first few crucial revolutions until oil pressure builds up. the cylinders walls are sprayed with oil and this works better when the oil is hot and thin. For this reason a thin SAE 5 or 10 would be a good choice for the first few minutes of engine break-in as would spinning the engine without spark plugs to pump the oil through the engine before trying to get it to fire up. (pre-spinning the engine after this much time sitting is a must, I believe.)

As for trying to start an engine that is as stiff as you say, I would not.

Your starter motor is expensive and it is real pain to replace the ring gear on the flywheel. n.b. there is no "ring" gear on the flywheel. If the starter gear teeth on the flywheel need replacement then a machine shop with a large lathe is required to remove the old gears and make the flywheel ready to accept a new ring gear. And this would be done after you locate a replacement ring gear.

On the optimistic side, you might consider pre-lubing the cylinder walls via the spark plug holes and note if this affects the torque required to rotate the engine. After a revolution or two the well-lubed pistons should move more easily and the required torque should drop significantly. If this does occur then it is a clue that the friction is with the rings perhaps aggravated by dry cylinder walls. Friction from any other source is not going to be addressed by a break-in but more likely by a break (as in broken part).

jagboy69 Avatar
jagboy69 Jason A
US, Planet Earth, USA   USA
They must still be towing this thing back from Italy trying to free it up!smiling bouncing smiley

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