'89 107 fears, woes & questions

[rjk]

And another...
Can/should the heads be torqued down BEFORE the cam towers are installed & torqued?
Or should they all be torqued at the same time.
Are all the (main) head bolts torqued the same?
I have found specs that say the regular bolts are a 3-stage torque up to 60 nm but the cam tower bolts only go to 50 nm. Is this correct?

[rjk]

OK
Found most of my answers on STARTEK

[rjk]

CRAP!
Finally see the end of the tunnel and it all falls apart.
I'm torquing the heads down and one of the bolts strips out at about 50 nm.
Did all the proper prep work but...

I found a few small tell-tales as I was disassembling the beastie and am now convinced someone had the heads off before I got the car and did something to weaken the threads. The blown head gaskets I found might also point to that conclusion.

Bottom line, I am screwed (or should I say bolted).

So here's my question...Does anyone have the drill plate for the head bolts I can rent, buy, borrow or steal?

In the meantime, I'm going to go cry in my beer.

[97 SL320]

You could make one with a block of steel and some transfer punches. Hardened drill bushings can be purchased from a machine shop supply company ( KBC tools , MSC and others )

The drill will mostly follow the hole freehand given the threads are pulled. Heli coils are more or less designed to use a hole the size of a pulled thread.

[rjk]

I'm fabbing up a drill jig for the block.
A 7/16" brass tube is perfect as a guide for the 13/32" bit needed to drill out the old threads.
I'll drill some holes in a hardwood block at the appropriate angles, epoxy tubes in and voile!

I found some 30mm thread depth helical coils online, 304 stainless.
I almost choked when I saw what Grainger wanted for them
Almost $3 a coil and the minimum order was 100 units

Found some online with a minimum of 50 units for about $100 with expedited shipping ($76 for the 50, claims to be USA made).
I'll have some left over if anyone is interested.
Lots of cheaper stuff from China with a month's shipping wait, no thanks.
I decided to do all 36 holes since 4 stripped out on one head and on the third bolt in the other head it stripped out before I reached stage 1 (30nm).
That was the decision point.
So I have lots of drilling & tapping to do before the coils get here.

[97 SL320]

The brass tube won't last, order a hardened drill bushing. ( See KBC Tools, they should have them. )

Grainger lives off govt contracts. The advertised pricing is high so they can negotiate a somewhat lower price. They also won't sell to a end user customer that does not have a account ( RE resale tax ID number ). As a result I won't use them when ordering stuff even at work.

Mcmaster-Carr is the go to place for _ everything _ and will sell to non account holders.

KBC is a good place.

Enco used to be good however MSC bought them up and shut them down.

MSC is huge and OK ish on pricing ( they reduce pricing to commercial accounts ), just don't try to order replacement parts from them, they make a huge markup.

[rjk]

Grainger sells to the public here in Atlanta (I've purchased from them before when I was desperate) so it may be a regional thing with them.

Thanks, I had forgotten about McMaster-Carr, I'll look into it.

The brass tube is only going to get things started with alignment, suggestion from a long-time MZB indy. He claims once the hole is started there isn't much to worry about. I trust his judgement. If it looks like he is off base I'll go the hardened steel route

[rjk]

So the drilling/helicoil project went without a hitch.
My oak wood block/brass tube jig worked just fine, were I going into business rebuilding these beasts I would have gone the hardened steel route but I was only drilling out 26+10 holes (yes, I chose to do all of them) and the brass held up just fine, I wouldn't use it again but for a one-off project, it works.
I made the oak blocks large enough so I could set up a clamping system using the other holes to dial in and solidify the alignment.

Amazing how much stronger the threads feel with the helicoils in. I feared (with good reason) for the threads before I helicoiled them, no fear once they were in. The feel was solid.

Things are going back together nicely now as I find time to work on the beastie.
School has started back up and my time is limited. Will update when I can.

[rjk]

The rebuild resulted with a start-up on the second try.
Wonderful!
Over time I am noticing some nagging issues.
Tell me if I am on/off base on my thinking.
Engine fires right up when cold but has a very high idle (1500 rpm) for awhile, even after it reaches operating temp.
Gas use seems higher than I remember.
Engine runs rough & then stalls as I put it in gear when starting warm but after a few tries, begins to catch.

Could these be symptoms of a cold start injector being stuck open?
I cleaned the Idle Air Control Valve so that is lower down on my list.
Anything else I should be looking at?
It also feels like I have a miss at times, not always but often.
Will be checking wires first.

[97 SL320]

Is this D jet or cis? For the high idle I'd be looking towards the throttle stop being open too far / vacuum leak. This might even have an air bypass bolt in the throttle body that adjusts base idle speed.

The cold start injector sprays lots of fuel so it probably isn't stuck open.

[rjk]

Thanks for the suggs SL320
It is CIS
Issues seem to have settled to these
#2 cyl does not seem to produce power: I went old school and pulled each SP wire and got a measurable drop in idle with every wire pull except with #2 cyl, no drop in idle speed.
I swapped injectors with #3 cyl (there was fuel present at both injectors): no joy, #2 still acts dead.
Wires seem OK and spark is present at #2: wires are properly routed.
Cap & rotor are new.
Next step is to swap wires to see if that's the problem but,
Ran a compression check on #2 and got 150 psi.
I had feared a collapsed or stuck lifter but not at this point with that compression level.
I can do a leakage test if it is appropriate at this point but I'm thinking fuel not compression nor spark.

Car sat for a year before I rebuilt the engine, could the fuel delivery system have developed a clog?
I ran a few tanks worth of fuel through the engine with Regane cleaner additive. There did seem to be smoother running after the additive addition but that might be wishful thinking. #2 is still dead.

The spark plug is a bit wet and looks a bit dirty.

Car is still stalling with low idle when started warm and a high (1500 rpm) idle when a cold start.
Idle will run high and suddenly drop to 500 rpm then return to a high idle then repeat.

[Diseasel300]

If the plug is wet and you have good compression, you have an ignition issue. Either a bad plug or a bad wire. You can test for fuel being present by cracking the fuel line to the injector with the car running. If it spurts fuel, it's an ignition issue.

The idling issues can be related to the idle control box in the dash behind the glove box. It has a transistor in it that controls the idle air solenoid. My SL had issues with seemingly erratic idle speeds, randomly raising and lowering. The idle control box had poor solder joints and resoldering it has repaired it successfully.

[rjk]

Thanks for pointing me to the idle control box.
Did Bosch source the box?
They have a history of breaking solder joints across manufacturers (my Volvos suffer from it).
I'll check it out.

[Diseasel300]

Not sure who made it. Any time I have an electronic issue in either of my cars, one of the first things I do is replace capacitors and resolder most of the connections. Amazing how many things can be repaired that way for little money.

[rjk]

Well, I've had a LOT of items to attend to over the past few months so have not had time to play with the idle issues. #2 cylinder seems to be producing power so that either was never an issue or has resolved itself.
The idle still is all over the place.
Once it gets past idle into higher range rpms it runs strong and steady so it still points to the idle circuit.
I pulled the control module and reflowed the solder joints but no joy. I pulled the IACV and applied power to it. It clicks and acts as if it is functioning properly.
I really don't want to drop $700 on a new IACV or $500 on a control box without it being a certainty.
Any other tests I can perform to isolate the problem unit?
Any other items in the idle circuit to check out?
Carburetors are so much simpler