13 replies to this topic

[wildcard_mike]

Hi all. I recently purchased a 1985, 998 Mayfair, verto. I was told the engine itself was free, but that it hadn't likely been run since the early 90's. It certainly moved when I turned it by the crankshaft bolt on arrival, but I wouldn't have turned it far.

 

The last hard info I have, was a diagnostic report in 1992, which details the compression levels were all good, but power balance was poor. Cyl1 74% / Cyl2 94% / Cyl3 100% / Cyl4 64%.

 

I wanted to check and run the engine before progressing too far along the ever growing repair list, so I changed all the radiator pipes, heater matrix (obviously an historic leak), water pump, oil and filter. Fitted new alternator (old had seized solid), battery and oil pressure switch (old one not working) and new fan belt.

 

I jacked the car up, removed the sparks, squirted some oil around each cylinder and left overnight. Cracked off the banjo, squirted some oil down, selected 4th gear and attempted to prime the oil pump by turning the road wheel. This is when I ran into my problem.

 

I can rotate the road wheel by hand, with relative ease (brakes maybe binding slightly), around half a turn or so, in both clockwise & anti-clockwise, but it will then lock solid at the end of each half turn. (wheel turns freely when in neutral) I can see all the pistons moving, and it appears I can reach TDC - by feeling air on cylinder 1 and the crank mark on the timing cover. Just purchased a boroscope for a closer look, this shows some crud (guessing mixed old oil leakage & soot, and new oil?) on the top of some of the pistons, but not so much on #4. There are some run/stain marks from the top of the cylinder #1 & #2, but not all the way down the sides. There is also some scoring to the sides, in particular to cylinder 1.

 

I have checked, as best as I can, the tappets for movement and gap, which seem to be ok.

 

Before I pull the head, is there something that I could have done by changing the earlier parts? Or something else I can/should check first?

 

Thanks for any help you can provide,

Mike

[Ethel]

Something obstructing the flywheel?

 

Where is it when it stops? Approaching TDC on any cylinders?

 

Have you had the rocker cover off any valves held down & not moving when it's turned?

[wildcard_mike]

Flywheel - hadn't considered that.

 

It stops at/near TDC on #1 & #4, (and #2 & #3. edited) goes through TDC #2 & #3 OK

 

Rocker cover is off, we can see numbers 1,3,4,5,6,7 moving when being turned. But numbers 2 & 8 we couldn't see any movement.

Edited by wildcard_mike, 03 October 2022 - 08:21 AM.

[MiniMadRacer]

Unless I misunderstood which is highly likely, take all the plugs out, you may have a hydraulic lock going on... how much oil did you put down each cylinder...and can you turn the engine by hand negating any gearbox issues

[wildcard_mike]

I already have all the spark plugs removed. When I say squirted oil, it was a very small amount - probably a couple of teaspoons at the most into each.

 

Can't turn the engine more than half a rotation of a road wheel, regardless if a gear is engaged or not.

[nicklouse]

Then it sounds like gearbox.

 

take it out of gear remove the rad and turn the big bolt in the pulley. Can you rotate the engine?

[wildcard_mike]

Then it sounds like gearbox.

 

take it out of gear remove the rad and turn the big bolt in the pulley. Can you rotate the engine?

I haven't removed the rad, but if I take it out of gear, I still can't rotate it fully using the pulley bolt.

[KTS]

possibly worth taking the flywheel cover off to check whether anything fouling at that end;  clutch slave bolts, engine mount bolts etc

[GraemeC]

Rocker cover is off, we can see numbers 1,3,4,5,6,7 moving when being turned. But numbers 2 & 8 we couldn't see any movement.

 

Do the springs on 2 & 8 look compressed?  I suspect these are seized open and the pistons are coming up and hitting them

[Ethel]

 

Then it sounds like gearbox.

 

take it out of gear remove the rad and turn the big bolt in the pulley. Can you rotate the engine?

I haven't removed the rad, but if I take it out of gear, I still can't rotate it fully using the pulley bolt.

 

Just to confirm, try turning the gearbox only.

 

In neutral

 

With the clutch depressed

 

With one wheel 0n the ground it'll take 2 turns of the raised wheel to turn the crownwheel once. So, in 4th, that'll be (give or take) 1.5 turns of the engine.

 

Half a tyre turn will be 3/8 of an engine rev, or 135degrees, again give or take the final drive ratio not actually being 3 to 1.

 

 

It should turn about double in 2nd gear if it's engine/flywheel related.

[nicklouse]

 

Then it sounds like gearbox.

 

take it out of gear remove the rad and turn the big bolt in the pulley. Can you rotate the engine?

I haven't removed the rad, but if I take it out of gear, I still can't rotate it fully using the pulley bolt.

 

Then it is time to start removing one thing at a time and rotate the engine each time to see when it moves freely. 
 

into neutral.

clutch slave and any mounting brackets off. And anything bolted the the transfer case. Then starter motor. I would then back  the wok side mounting bolts for the engine mount. As if they are too long they can stop things. The rocker cover off and check the rockers are not binding.

 

then it is engine out time.

[BaronVonchesto]

if I were you, I would just take out the engine and strip it down completely. an engine that has been sitting that long could certainly use a rebuild. Perhaps theres even rust on the crankshaft or flywheel causing it to be seized up.

[wildcard_mike]

Thanks for all the advice. I don't have much freetime, so any update will likely be weeks if not months away! I'm now caught up In the middle of looking at a potential head gasket failure on my daughters first car. After dumping coolant, I've refilled and now have bubbling in coolant. It's back with the garage who sold it...she's only driven 23 miles in it. Not a happy bunny!

[Ethel]

That can happen, even with an honest garage. Asking for a refund would be safest.