Engine pull, Stripdown and Rebuild

[Prof]

Thought I\'d put up a post - been working on this for several weeks on and off (mostly off - bloody weather )
 
I had water seal failure - basically the engine combusion gases were pressurizing the coolant system.  A rather too good repair of my radiator with chemical metal meant the pressure had nowhere to go - after only reaching 50 degrees C, there was a lot of pressure build up in the rad  (this also means my rad cap is probably not working properly - to be investigated).
 
Anyway - the engine was one I picked up from Ben Lewis in late summer last year - it had done about 6-7K miles on a rebuilt and made good power in his FC.  I got it fitted in the car in time for JAE last year, and it\'s given me a lot of trouble free miles and made some good power too.  Just before it let go on the coolant issue, it was running over a bar of boost and felt strong.  Compression was still pretty good despite the coolant blow by - which was odd I thought.
 
In any case - I had wanted to attempt an engine build so now was my chance.  I took the motor out of the car with help from Mitch one wet weekend, and then set about getting it all apert.   I had some issues getting the flywheel off - Mr Hayward\'s help on that job - very well received
 
Got the engine in pieces finally and set about listing the issues with the engine (some of these I fixed already, but just listing them for completeness)
 

• Missing Oil pan gasket - and wrong sealant used - white silicone (should have been the black RTV stuff
• Missing Front cover gasket - again wrong sealant used
• Missing O ring from front cover (the one inside the teflon ring
• Missing O ring from front stationary gear
• Oil Pan bolts on \'finger\' lose
• Some damage to the rear torrington bearing and the thrust plate
• Water seal lifted/twisted in one location on the inner surface - front iron
• Water seal leaked slightly on outer seal but resealed itself with crap on the rear iron

Now the good points:
 

• Rotor housings in generally excellent condition - no scoring / cracks around plugs - only one small amount of corosion near one of the spark plug seats where the metal is thickest.
• Irons in good condition - no cracks / damage on water seal areas
• Rotors had only a small amount of carbon build up - mostly on the combustion recess - very little elsewhere (seems my 2 stroke oiling mod was working well )
• Apex seals all good
• Side seals all good
• Corner seals - excellent
• No stuck springs
• Engine oil ways all unblocked
• Engine porting work looks good - well carried out

All in all it\'s been profitable to take it apart just to get an idea of what goes on inside these things !
 
I\'m not having a dig at the engine builder by the way - this car was making very good power and has been very reliable upto the coolant failure - the downside is that on a rotary this basically means pulling the engine apart to fix it.  There were a few issues around the front housing - the torrington bearing - that could have been me when I did the fix in this area - a tiny bit of grit/dirt is all it would have taken - but the o rings / gasket / sealant issues were down to the builder.
 
 
I\'ll post up some piccies later - when I dig out the camera and get snapping away - tis too cold to go in the garage at the mo.

[dubber91]

who did the rebuild originally?

[m1tch]

Awesome news

[Prof]

who did the rebuild originally?

I think it was Powergains - but BenLewisMav will be able to confirm that. I don\'t know if I just reached the spot where the was enough boost to blow out the water seal - it\'s not unheard of. The seals themselves looked in good condition - no splits or marks on them - which suggests the engine was assembled carefully.
 
I can understand not putting a sump gasket on - not everyone does, and I think Ben was going to put a baffle plate on in any case, so perhaps the gasket was left off knowing that was going to be done. I got the baffle off Ben so I might use it on this build - still thinking about that one - it might go to Mitch instead - as he is aiming at higher eventual power than myself.
 
I think the small O ring for the oil feed on the front cover plate may have ended up in the sump, the 2nd one I put it ended up in the filter pedestal - so I am replacing the teflon ring as well, as I suspect it\'s not quite right.
 
As for the front cover gasket and Front stationary gear O ring - not sure why they weren\'t on the engine - in any case - I suspect if you pull apart a lot of engines you can find something amiss if you looked hard enough. All in all thought - this was a good engine - and hopefully will be again !

[drtool]

Front stationary gear o-ring? Where does that go then?

[Prof]

Front stationary gear o-ring? Where does that go then?

My bad - I always assumed there would be one - but on checking service manual and speaking to a people in the know - it doesn\'t have one.
 
Actually - I should have noticed when looking at it - the rear one has a groove for it to sit in - the front one doesn\'t.
 
Seems I made an incorrect assumption :spank

[shaunwil]

I thought the sump gasket was only goo ? There are proper gaskets but its usually better just to seal them up with sealant.

Have you any pictures ?? Sounds like fun. Are you doing any porting ??

Shaun

[Prof]

Well typically - I didn\'t get any pictures of the dirty bits - pulling the engine apart and degreasing it - which takes a while - incidentally - tesco\'s do some big black plastic containers that are excellent for cleaning engine bits in.
 
I got some piccies today - front and rear irons, showing the black hammerite, and the rotor housings - resplendant in their pink primer.  They will eventually end up blue.
 
I\'ve also included a shot of the manifold I got from Alan at RS III - as mine is cracked quite badly - and alan\'s was mint apart from a rust coating - I gave it a good wire brushing, genolite and a coat of Halfrauds high temp paint.
 
Finally, there are shots of the bearing plate, and rear thrust plate showing signs of bearing damage, and a close up of the torrington bearing that\'s failed and caused it (grit got in somewhere and caused this).

[Prof]

OK - progress update.
 
On Saturday I built the rotors up - side seals / corner seals / oil control rings and their rubbers.  It  was such a messy job, I didn\'t get any pics till I finished - I will plonk them up later.  When I took the rotors off the engine - I put each one in a seperate place, and kept all the seals sorted.  When I was sorting out which springs were for front and which were for rear of each rotor, I found another issue with the old build - the inner springs were the same for front and back of each rotor - in other words - one of the springs was wrong on each rotor.  This has been rectified now
 
I used red rubber grease for the oil control ring rubbers, and good old petroleum jelly for the other seals.
 
 
Sunday was spend cleaning up the paint edges ready for assembly - put the oil pressure regulator, and rear stationary gear in and torqued up those bolts.  Also started cleaning the through bolts - all 18 of them.
 
 
Monday - Finished the cleanup of the through bolts, and put the new washer/o-rings on today.  Fitted rear oil seal to rear iron.
 
Then it was engine assembly time !
 
Some pics to follow when I get them off the camera - but working outside in the garage with no heating - I am chilled to the bone and velly velly cold.
 
Block is back together - but flywheel still needs to be torqued up.  Then it\'s setting e shaft clearance tomorrow hopefully - and getting the front cover back on.

[grinder]

looking good Dave , keep up the good work

how are you finding it so far , i know you are clued up on elecs etc.. but what about engine building - or have you entered this pretty much blind ?

[Prof]

looking good Dave , keep up the good work
 
how are you finding it so far , i know you are clued up on elecs etc.. but what about engine building - or have you entered this pretty much blind ?

One eyed I should think - :Giggle
 
I\'ve watched the rebuild vids several times, followed Aaron Cakes thread on his website - linked off of Rx7club - read the haynes guide and the FSM - but nothing prepares you for how fiddly this job is :3Confused
 
Apart from having to get a few special tools, and the engine stand - it hasn\'t been to bad - just the stupid flywheel.
 
I want to pressure test the engine before I put all the ancillaries and manifolds back on - just need to cut some ally bits to go over the water pump holes and the inlet manifold area - that should do the job - then blank off the heater hose on the rear iron and use the top water pipe to test it.

[TiddlesRX7]

Yeah well done Dave taking this on. It nice to see that your getting through it ok. It gives the rest of us hope!

[Prof]

These first 2 show the rotor assembled - you can make out the other one in the bag - building them ahead of time and having them ready to go really makes the job of doing the engine much quicker !
 
Did these on Saturday afternoon (indoors)
 
I used petroleum jelly to hold the side seals and corner seals in place, and red rubber grease was used to hold / lubricate the o rings that seal the oil control rings - this stuff stops them swelling and allows the rings to be pushed in easily without sticking.

[m1tch]

Rebuilt by Profsport

[Prof]

Again, apologies for not taking too many photos - it\'s hard to operate the camera when you\'re all greasy
 
Still I\'ve taken a shot showing the front housing on the front iron, then with the rotor in it ready for the eshaft to go in - then it\'s a fiddly job to get the apex seals into the rotor with their springs - used new springs for those - as the others looked a little discoloured - although I\'ve cleaned one up and they don\'t look to bad - so will most likely use them for the other engine.
 
Pic of the 2nd housing in, then it seemed to go quickly - so final shots show the block back together and all through bolts torqued up - in 3 stages - 13, 24, 36Nm - makes for a more even torquing up - and it\'s what the FSM and rebuilt vids recommended too.