1981 Poo brown two door restore.

Many thanks DL,I checked that one out on your advice,seems I can blow bubbles in the fuel tank,with a hose onto the carb overflow pipes which joins to return line,so think we’re ok there,good call tho.

Both carbs have fuel drip at overflows after a hot run,possibly vapour build up from engine heat.

Tapping top end source found..
Did a compression test,even at 125 on drivers bank as suspected a valve sticking.
Took a photo before ,note the stem seal on cylinder #4.

Attachment 178047

You can see how high the valve stem seals are, right at top near retainer.
Ran across the top of valves with a Gentle hammer tap, and a closer look gave me the answer.

Now the valve seals are bottomed out as the guide has dropped back down..

Attachment 178048

The valve guides are moving with the valve causing the clatter which sounds like tappet noise.

I had noticed this earlier but assumed the guy who built up the engine hadn’t levelled them in the guide holes.
Now it makes sense as in the pics the valve guide dropped on cyl #4 but had seen similar on that bank at exhaust valve cyl#1 also.bugger!

I would hazard a guess that these heads had some overheating in the past.

So it seems all my efforts over the last few days need to be repeated,at least down to heads off..
I have a matching set of original 14 bolt heads from my old 3.9.
The date code stamp both show 48/93 so they must be one of the last 14 bolt heads ever made.

They measure up as having had no work on the surfaces.
Of a mind to merely clean them up with valves and seals in place,straight edge the surfaces and if all good,install them as they are a good known entity, and let sleeping dogs lie so to speak;)

Thoughts on best solution for a quick cleanup without destroying the valve stem seals?

Are you saying that the valve guides are moving with the valve, or just the valve stem seals?
If it’s the valve guide, it would make a mess of the head very quickly.

Phil

True,definitely the valve guides,could have been holding up or seizing valves.
Pulled the head and seems ok at first glance..

Attachment 178046

Quote:

---

Originally Posted by westy1

True,definitely the valve guides,could have been holding up or seizing valves.
Pulled the head and seems ok at first glance..

Attachment 178046

---

In that pic why does the piston crown second from the left look different?

DL

That’s a reflection off the cylinder wall,slight halo there.
Crap phone pic,any scratches there are from me scraping at the carbon .
Surface is fine,did notice #8 (far left) has slight cleansed look on lower piston ,but that could be from the coolant sitting a while before I got to clean it away.

In the interim,I’ve cleaned up the 3.9 heads in a diluted simply green potion,and grabbing a head gasket tomorrow ready to go.
This engine builder used composite gaskets, so will match,and with the engine at 8:13:1 it sure won’t matter,may explain my compression figures all at 125 psi tho.
Must say it pulls ok for a 3.5 once tuned in,and I’ve noticed I can run higher advance without any pinking on this low comp engine,always run 95 octane anyway.

Checked the lifters surface on the suspect cylinders,and all looks consistent.
Seems even with moving guides,it doesn’t appear to have sustained any fatal damage,touch wood;)
Will do a forensic on the loose guide head after buttoning up:)

Next day.

Installed the new heads,took most of the day quietly.
Used a composite gasket,new stretch bolts done at 20Nm,then 90 deg/ 90 deg.
Always scary,but no issues as cleaned out threads and lightly oiled bolts.

Attachment 178084

Rockers back on,ancillaries,coolant topped up, resealed valley & intake manifold.
Wound it over dry to get some oil up to the rocker shaft ,then started in anger.
After nearly a week of being craned over an engine bay ,all is now quiet and smooth..

Quick test drive,and walk away..hands wrecked;)

Good result.
All that shiny aluminium looks great. What is the Simple Green potion you use, or is it just Simple Green.
I have a lot of aluminium parts to clean and I’ve always struggled to find something effective.

Regards
Phil

Howdy Phil,Yes a diluted (approx 30%) simple green all purpose does wonders,doesn’t seem to stain or darken the alloy,but cautionary note not to leave in the solution long term.
I soaked the heads in a bath for an hour,enough to loosen the hardened Black Death with a small wire brush :)

Quote:

---

Originally Posted by westy1

Howdy Phil,Yes a diluted (approx 30%) simple green all purpose does wonders,doesn’t seem to stain or darken the alloy,but cautionary note not to leave in the solution long term.
I soaked the heads in a bath for an hour,enough to loosen the hardened Black Death with a small wire brush :)

---

Could you let us know which version of their product you used?

I have to ask as it seems to be remarkably similar to the good old ct-18 / CT-14 which are both quite aggressive alkaline surfactants.

leaving this stuff on alloy undiluted will make it 'white spot' in a short space of time, and the only way I've found to stop that is to do a 1-2 clean, with a diluted base then a diluted acid.

I just pulled this info from their site:

"▶ Aluminum — Is it safe to use Simple Green All-Purpose Cleaner on aluminum?
When used with caution and according to the instructions, Simple Green All-Purpose Cleaner has been safely and successfully used to clean aluminum. Simple Green All-Purpose Cleaner, Crystal Simple Green Industrial Cleaner & Degreaser, and Simple Green Pressure Washer Concentrates have been used on aircraft, automotive, industrial and consumer aluminum items for over 20 years. However, caution and common sense must be used: aluminum is a soft metal that easily corrodes with unprotected exposure to water. The aqueous-base and alkalinity of Simple Green All-Purpose Cleaner can accelerate the corrosion process.

Therefore, contact times for unprotected or unpainted aluminum surfaces should be kept as brief as the job will allow - never for more than 10 minutes. Large cleaning jobs should be conducted in smaller-area stages to achieve lower contact time. Rinsing after cleaning should always be extremely thorough - paying special attention to flush out cracks and crevices to remove all Simple Green product residues. Unfinished, uncoated or unpainted aluminum cleaned with Simple Green products should receive some sort of protectant after cleaning to prevent oxidation.

Simple Green has also developed break-through water based cleaners that are safe for use on metals, plastics, rubber and high tech alloys. Extreme Simple Green Aircraft & Precision Cleaner, Pro Series Simple Green Automotive Cleaner, and Simple Green Pro HD are available on both the industrial and retail markets, respectively. These products were initially developed for the aircraft industry and extensive testing shows that they are safe and effective on a variety of metals and other sensitive surfaces even in the most extreme circumstances.

Simple Green Stainless Steel One Step Cleaner & Polish is another option for cleaning polished aluminum. This product is designed for light duty metal cleaning and polishing.

So naturally I'm wondering if you used the general purpose stuff or if you found a more specialized product to use like the product mentioned in their marketing blurb.

I recently had an om606 intake manifold wet blasted (Al02 1600grit) and it's properly clean and has not oxidised in the last several weeks with all this rain and salt-laden coastal wind. Conversely I have a hot-water pressure washer and steam cleaner and I'd argue that any chemical stronger than say, morning fresh is a guaranteed oxidation rejuvenator - and I've not had much success in preventing the white oxidation returning despite extreme rinsing and post-treatment with HD lanotec (it does keep it away for a while, but the return is a "guarantee") I find the lanotec to be far more effective on body/chassis stuff and not on engine parts that have been cleaned in diluted alkaline salts.

It would appear that once the aluminium gets any of that stuff on it, despite any amount of rinsing post-cleaning, it will always come back.

Yes,did read all that,and shared your concerns,did some google research of those that had used it on blocks and heads.
With that ,used the all purpose,purely as local shops didn’t have the aircraft version.
For the duration and dilution I used, saw no pitting or metal deterioration,nor oxidation at all,even left the valve stem seals on,merely loosened the carbon nicely,minty fresh:)

Sounds like it's a lot less aggressive than the chemtech stuff.

what ratio did you dilute to? - or an approximation if you measure by eye....