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My '91 744 B204GT project

Not yet, few days ago I bought the complete cruise control kit from 960 plus the steering column switch but it is not installed yet.
I guess the pulley was always the same and not connected if the car was not equipped with cruise control...
 
Not yet, few days ago I bought the complete cruise control kit from 960 plus the steering column switch but it is not installed yet.
I guess the pulley was always the same and not connected if the car was not equipped with cruise control...

Good luck, but probably you will have problems with console of vacuum cell, anyway make photo if possible.
 
Good luck, but probably you will have problems with console of vacuum cell, anyway make photo if possible.
Not the first not the last problem on this car :) I've already checked the console in the pedal box, there is a mounting holder for the brake pedal vacuum valve but not for the clutch pedal valve. I'll have to fabricate something.
You’re doing some amazing work brining life back to this one, love what you’re doing!
Thanks! Now with corona it's plenty of time...and while many friends are bored at home I keep myself busy every day ;-)
 
Some cosmetic fixes lately...working on the front grill and some other small imperfections.

The plastic tabs were missing so the fibre bondo and repainting took place.

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I enjoy the thread!

Please document the cruise install. I wanna do this on my 1991 740 T. I think I have the bits from an 89 740 GLE
 
Please document the cruise install. I wanna do this on my 1991 740 T. I think I have the bits from an 89 740 GLE
I will ;-)
During one of the trial warmups, the old tired radiator gave up and started leaking badly, so next week new Valeo unit is to be fitted. Also I have replaced the two-piece air guides behind the front grill with the updated one-piece version from 940 (better design). The corner lamps has been replaced, trims under headlamps has no holes for the wipers anymore and are repainted, and I started playing with idea of fitting the 2din black face SC805 radio that I coincidentally bought.
The >plastic radio frame from 780< is NLA, but fortunately there is a >guy< in Norway that makes a 3D printed equivalent. I just need to check how the SC805 fits the universal 2din metal frame, if it does I am going that route (and combine it with the Yatour to have the convenient support of the mp3/usb/bluetooth).

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Take out the frame weights next time the bumper's off. The weight is probably 5 Kg each side.
I was checking with the endoscope today and I can't find it. If I understood correctly, these weights are not present on the engines equipped with balance shafts (b234f and b204ft/gt).
 
Oh, and in the meantime...based on some my suspicions and long talk with a friend of mine who is a mechanic, I've decided to do a dry and wet compression test on the cold engine again.

The dry measurements were similar to what I've got last time:

#1 135psi (9.5bar)
#2 130psi (9bar)
#3 138psi (9.6bar)
#4 119psi (8.2bar)

then I injected teaspoon of oil and measured the same thing again per cylinder:

#1 148psi (10.2bar)
#2 148psi (10.2bar)
#3 144psi (9.9bar)
#4 126psi (8.7bar) :grrr::grrr::grrr:

So while the #1, #2 and #3 responded to the wet test by increasing the compression as expected, the #4 stayed almost the same. Seems I have a leaky or burnt valve :roll:
I have already started disassembling it again, and I need to find a shop that is open for head resurfacing these days :poo:
 
Alright, head is removed.

The good news...head looks good from the other side, no cracks or damaged valves on the first sight. Some carbon build up but nothing serious.

The bad one - and correct me if I am wrong - all the pistons have quite some play in the bores :grrr:
According to the greenbook the allowed used piston clearance is up to 0.08mm. The worst piston in my engine has around 1.1mm play, the other ones around 0.9mm. When I push on it with my thumbs (see the video below) it makes the clicking noise that I would swear is the same that I've heard when the engine was idling.

Other than that the walls are smooth without any scoring. The engine officially has 220tkm by the way.

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That's normal.
Normal for what? For a good engine? Or for a worn redblock? The excessive play is by the way almost the same at the TDC and BDC.
The point is that I am building this car for fun, so although I believe it could still run for some time, I don't want to assemble it back if there is already an apparent issue. And the knocking I've posted in one of the youtube videos I didn't like at all...

What are my options here, sorted from $ to $$$?

- resurface the head, grind the valves and put it all back together
- get a known good b200f/ft 8v bottom end and cut the valve reliefs? Not sure if this is possible
- get a good known b230 8v bottom end and b234f head and make it b234gt
- rebore it and get custom pistons & rings (Volvo doesn't supply them anymore)

I am almost certainly not going the fourth way. How much work it would be to have the second/third option working? Different crossmember? Different engine mounts? And then of course the timing belt changes...

Oh, by the way...>Volvo< webpage shows the same number for the B204gt/B234f head...is that correct? As these engines have different bore, I doubt the head is the same, or am I wrong?
 
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I'm not sure piston slap would cause uneven compression. Have you checked for valve leakiness?
Yes I have checked that. The valves are all sealing perfectly.
My theory is that the worst cylinder reacted so poorly to the oil during the wet compression test because the gap between the piston and bore is already so large that the oil just went through giving barely any resistance...not sure if that makes sense.
 
That's a lot of movement. I had a worn engine (0.1mm measured bore wear) that had less movement than that.

I would see if you could get a good b230 turbo block and cut the recesses in the pistons.
 
Some more pics...the worst one is on the last picture, the scoring of the cylinder wall by the wiggling piston is already visible at the top...

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You are going deep down the rabbit hole.

You could pour some ATF in the holes and see if any is left overnight.

A leakdown test while it was all together would've been a good place to start.

Maybe put new rings, do the valves and then continue on with boosting.
 
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