MR2 Roadster Owners Club

The Workshop => Maintenance, Problems & Troubleshooting => Topic started by: MartinF on October 25, 2021, 09:10

Title: 1ZZ engine refresh - not what I expected!
Post by: MartinF on October 25, 2021, 09:10
Hi guys

Got a winter 1ZZ engine refresh on the go - valve stem seals and piston rings and anything else that looks worn. Have been really surprised at how clean the engine is inside with no crud anywhere and oil rings and drain holes as clean as a whistle at 100k miles.

It ran great but burnt oil so I am thinking it was mostly down to the piston rings just letting it past. A puff of smoke at startup suggests to me the valve seals were also past it, but I am not whipping them out until tonight.

Quick question though as this is the bit that makes me nervous on a modern block - anybody got a recommendation of a decent, well priced hone tool that didn't wreck their bores? (The last block I did was a '76 Triumph Dolomite, so it's been a while...)

Cheers guys
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: Carolyn on October 25, 2021, 11:04
I use a basic 3 stone tool with a very light lubricant.. The trick is to run it as slow as your drill will go and get the up and down motion to the point it's giving a 45 degree hone pattern.  It takes a while to really get through the glaze.

Getting the inlet valve seals out can be a bugger.  I used an angled pair of seal pliers. (Cheapo ones as they rarely get used.)  Depending on the replacement seals, you may have green and black rubbers, in which case the green ones go on the inlet, or you may have all black rubbers, in which case (on close inspection) you'll find the metal part of the inlets is slightly brown coloured compared to the exhausts, which are more silver.  It matters, as they use a different 'rubber' compound.
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: MartinF on October 25, 2021, 18:04
Many thanks for the advice. I was fully expecting to find gummed up oil rings so as they were clear I am naturally wondering just how much the valve seals were letting through. If I had my time again I guess I would have changed the valve seals in-situ before pulling the head, but no worries - I'm committed now! I find it pleasing that even my 2001 car with original pistons had all the oil drain holes nice and clear, it must have been pretty well serviced.

Big end bearings are showing a little wear (nothing drastic) so I am thinking some new shells and a Plastigauge session are in order. Carolyn (or any other friendly contributer) - would you advise starting with the same numbered shells it came with and checking clearances with these or could I save a few quid by getting standard size bearings by someone like King?

As usual, really grateful for your tips!
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: Call the midlife! on October 25, 2021, 18:11
Changing the seals with the head in place is quite a challenge as you need the valves out of the way so I wouldn't lose any sleep over the route you've taken.
Depending on what you class as "wear" on the shells I'd be inclined to gauge the current ones to see where you're starting from and if needed replace them with new for old. You would only really need to go bigger if you had the crank reground due to damage etc.
But you'll soon know once you gauge it.
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: Carolyn on October 25, 2021, 18:24
Quote from: MartinF on October 25, 2021, 18:04Many thanks for the advice. I was fully expecting to find gummed up oil rings so as they were clear I am naturally wondering just how much the valve seals were letting through. If I had my time again I guess I would have changed the valve seals in-situ before pulling the head, but no worries - I'm committed now! I find it pleasing that even my 2001 car with original pistons had all the oil drain holes nice and clear, it must have been pretty well serviced.

Big end bearings are showing a little wear (nothing drastic) so I am thinking some new shells and a Plastigauge session are in order. Carolyn (or any other friendly contributer) - would you advise starting with the same numbered shells it came with and checking clearances with these or could I save a few quid by getting standard size bearings by someone like King?

As usual, really grateful for your tips!

I've done well with standard bearings.  You might struggle if one of your rods and cap is marked as a '4'.  But if you look up the specs for oil clearance, they quite generous.
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: MartinF on October 25, 2021, 19:13
Thanks guys. Hoping for some quality garage time later to check the old shell sizes and make a decision on their reuse. Then it's back on the computer to start ordering bits.

I'm not sure whether a head gasket kit will include all the other stuff a person might want to change (stuff life tensioner, water pump and injector o-rings, oil strainer gaskets, etc, etc) or if I should just bite the bullet and get the whole engine gasket set. Aside from that, a set of head bolts, manifold nuts and piston rings and I'm getting there...
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: Call the midlife! on October 25, 2021, 19:19
I'd give Paul Pridham a call at TCB and get a price for a full kit, think I paid £150 ish for the last one. Carries everything you need for a rebuild/refresh, gasket and seal wise, including stem seals and injector seals.
I fitted a set of ARP head studs rather than the single use stretch bolts.
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: MartinF on October 25, 2021, 19:28
TCB are in my part of the world and have been great before, so they are my first port of call. I managed to get a set of rings (TPR) on Ebay for a great price so I'm on my way.
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: jonbill on October 25, 2021, 21:27
might also be a good idea to check the bores for wear, given the oil rings are free.
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: Call the midlife! on October 25, 2021, 21:51
Quote from: jonbill on October 25, 2021, 21:27might also be a good idea to check the bores for wear, given the oil rings are free.
That's a very good point, I was surprised how much scoring was showing on mine, no doubt adding to the oil use.
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: MartinF on October 25, 2021, 23:07
Bores look pretty good at a glance. Might try and get a pic up tomorrow. Can see some horizontal dashes that I am guessing is part of the laser etching process? Looks a bit like morse code dashes and definitely not scratches.

Last question for tonight - any recommendations of a bore gauge that works and won't break the bank?

Cheers!
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: jonbill on October 26, 2021, 14:25
you can get quite a long way checking the bores with just your new rings and feeler gauges - is the end gap consistent through the bore?
can you get your thinnest feeler gauge between the ring and bore anywhere?
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: MartinF on October 26, 2021, 20:57
Good tip - thanks Jonbill. As usual I've been sidetracked - life getting in the way. Hope to return to car tomorrow.
Title: Re: 1ZZ engine refresh - not what I expected!
Post by: thetyrant on November 23, 2021, 16:55
If you havent started on the head yet ive got a nice freshly rebuilt pre-FL one here, i stripped it down had it lightly skimmed then lapped in the decoked valves and fitted new stem seals, its all ready for cams to go back and in fit on engine, save you a lot of work let me know if of interest :D