JP3 HEAD REMOVAL AHHHRRR

[sinkingbarge]

hi all,

 

after much running of my new jp3, i found a diesel injector dripping so all 3 off for replacement, but i also discovered a trickile of water coming out of heads 1 and 2 joints where the head meets the block, so i presumed it would be okay to pull heads off pretty quickly and swap the gaskets whilst also grinding valves and checking piston rings etc. I was also motivated to do this as the oil had been previously full of water so i figured history of water letting by into oil.

 

Regarding ease of head removal . . .how wrong was i .

 

- wobbled heads with a bar at the top, about a 16th of movement at the bottoms but no lift of head.

- turned engine over on electric start several times to the point where each cylinder squealed like a balloon as the air squeezed through, but still not falling off.

- not sure if this is just a tough three, or if the things rusted to the studs or something ?

- after 3 hours of getting no where wrestling, i am suspecting it probably wasnt that bad with just a minor water leak ! Im actually hoping to find dodgy valves to justify this ball ache !

 

will athis work ?

 

- I am considering trying to fire the enine with easy start to try and blow the heads off, any advice.

- loads of wd40 down the studs.

- can anyone advise where i can by a long stud from (the one from the flywheel end that has the extra thick mounting for the pulley)

- how much do head gaskets cost.

- when i finally get them out is there a way to check condition of rings WITHOUT lifting the pistons out. e.g. timing the oil dropped in there etc.

- what other methods of getting the heads off exist ? What can you tie into to lever or jack ? Can you shove a bar in the ports and hope to lever up, with out cracking heads - tried screwdrivering into the corners without success.

 

I am certain others have been stuck here ! please advise.

 

 

thanks

 

dave

 

"after much running of my new jp3, i found a diesel injector dripping so all 3 off for replacement", i meant off for servicing

[RLWP]

Well, having had this same problem recently on a different engine, I'll pass on the most useful piece of information I got - the one that made all the difference

 

Are you sure you have all the nuts and bolts out?

 

Richard

 

I had missed one

[Timleech]

Well, having had this same problem recently on a different engine, I'll pass on the most useful piece of information I got - the one that made all the difference

 

Are you sure you have all the nuts and bolts out?

 

Richard

 

I had missed one

 

There's a good chance you're right, because the classic 'beginners mistake' with a JP is not to realise that the pushrod tubes also serve as cylinder head studs.

 

Tim

[frangar]

Marine Engine Services in Uxbridge have newly made studs that have ben fine in my JP2 if that helps

 

Agree with Tim about the pushrod tubes...

 

I would fit new studs when you rebuild as I have had one snap flush to the block which was a bit of a pain to say the least!!

 

Let us know how it goes

 

Cheers

 

Gareth

[sinkingbarge]

There's a good chance you're right, because the classic 'beginners mistake' with a JP is not to realise that the pushrod tubes also serve as cylinder head studs.

 

Tim

 

 

oooh ouch that hurt .. i definigtely did not renmove any push rod tubes on the jp3. bugger wish id known. if i havent already warped the head during this process then they should come off next weekend without half the efforts wasted. so thanks for this info.,

 

thanks

 

dave

[RLWP]

Welcome to the club Dave

 

Richard

[frangar]

oooh ouch that hurt .. i definigtely did not renmove any push rod tubes on the jp3. bugger wish id known. if i havent already warped the head during this process then they should come off next weekend without half the efforts wasted. so thanks for this info.,

 

thanks

 

dave

 

 

The tubes themselves stay attached to the block but the nuts round the tubes need to be removed...to get to them you need to remove the rockers, rocker shaft and push rods...making sure you know which ones fit which head/port.....if you have a water cooled silencer you will need to take this off to get the rear head rockers out which is a pain....the rocker shaft is held on with a small bolt. The nuts round the push rod tubes are 3/4" Whit btw....there are/should be washers under the nuts as well.

 

HTH

 

Gareth

[Timleech]

The tubes themselves stay attached to the block but the nuts round the tubes need to be removed...to get to them you need to remove the rockers, rocker shaft and push rods...making sure you know which ones fit which head/port.....if you have a water cooled silencer you will need to take this off to get the rear head rockers out which is a pain....the rocker shaft is held on with a small bolt. The nuts round the push rod tubes are 3/4" Whit btw....there are/should be washers under the nuts as well.

 

HTH

 

Gareth

 

All true and helpful, except to be pedantic although the nuts take a 3/4" Whit (7/8" BSW) spanner, the threads are actually something like 3/4" BSP if I remember correctly.

 

Tim

[mykaskin]

Yes - I had the same problem - why, oh why, doesn't this thing come off!? Oh you mean I have to have a huge big socket just to get them funny large nuts off....

 

Once they were off however, I still had problems as the gasket had been blowing for sometime into the recess around the tube and that was carboned up. In the end I used three ratchet straps along with various other techniques to free it off.

 

Yes - welcome to the club!

 

Cheers,

 

Mike

[frangar]

All true and helpful, except to be pedantic although the nuts take a 3/4" Whit (7/8" BSW) spanner, the threads are actually something like 3/4" BSP if I remember correctly.

 

Tim

 

I hadnt thought that the threads might not be whit but now you mention it they do look more like BSP!....I do know that the price of new tubes was a lot....I changed the studs but left the tubes and said a little prayer as I tightened the heads down.......All was OK though!

 

 

Cheers Gareth

[flatplane8]

I managed to remove the heads without removing the exhaust, by extracting the studs (two nuts locked together on the end of each one). Some info here.

Edited November 8, 2011 by flatplane8

[Timleech]

I managed to remove the heads without removing the exhaust, by extracting the studs (two nuts locked together on the end of each one). Some info here.

 

How did you extract the rocker shaft from the rear head? Usually these have a greaser on an elbow screwed into the rear end of the shaft, so the greaser comes up between head & expansion box.

 

Tim

[flatplane8]

How did you extract the rocker shaft from the rear head? Usually these have a greaser on an elbow screwed into the rear end of the shaft, so the greaser comes up between head & expansion box.

 

Tim

 

 

Ah, mine is missing all the greasers, perhaps thats why it worked? I oil the rockers manually every few hours of running, not sure if thats the best way, but better than nothing I guess.

[Hairy-Neil]

Welcome to the club Dave

 

Richard

 

Paddington Bear was having similar issues with Chertsey's PD2 timing cover a couple of weeks back, and I'm a paid up member too having once destroyed an inlet manifold from a 70's Vauxhall before finding that last bolt hidden under the thermostat/housing....

[sinkingbarge]

hi all thanks , after getting the pushrod tubes free, the heads more or less fell off. probably after all the whacking they got before.

 

latest is 2 of the heads are cracked. one very historic water damage, but the other one may be new. im trying to convince my self that its not due to my mauling efforts prior to taking the pushrod tubes off.

 

Does anyone know where i can aquire tow heads? already i am dreading the potential cost.

 

also does anyone know if you can fix the cracks ? on my old vw aircooled engines you could get the head cracks welded and reconditioned.

 

thanks

 

dave

[David Mack]

Does anyone know where i can aquire tow heads? already i am dreading the potential cost.

 

One here.

 

David