1990 740T compression

[5ft24]

ok, 90 740 turbo, 253K miles, runs rough on startup, but clears up in a minute or so. lots of piston slap when cold, also lessens as it warms up.
decided to do a compression check. checked each cylinder 3 times, had just driven about 10 miles 15 minutes before I checked to make sure the engine was fully warm.

#1 - 140PSI
#2 - 120PSI
#3 - 150PSI
#4 - 170PSI

going to pull the valve cover tomorrow and make sure valve clearances are correct, head was replaced before I purchased it.

Time for a rebuild/short block?

[93Regina]

ok, 90 740 turbo, 253K piston slap when cold

Use 10W-40 QUAKER STATE® DEFY

or

Shell Rotella T Triple Protection 15W-40


"Piston slap is nothing new to piston driven internal combustion engines and compressors. It is the secondary (sideways or perpendicular) movement of a piston against the side of a cylinder bore where the primary movement of a piston is intended to be parallel (up and down) to the cylinder bore. All piston driven internal combustion engines and compressors have a certain amount of piston slap.

Excessive piston slap occurs when the clearance between the piston and the cylinder bore is too great. The piston to cylinder bore clearance becomes too great either through wear, mismatched pistons and cylinder bores at manufacturing or, a combination of both. The audible noise associated with excessive piston slap is due to the perpendicular impact of the piston against the wall of the cylinder bore. Audible piston slap is typically loudest when the engine is first started up. The pistons then expand with heat reducing the piston to cylinder bore clearance thus, reducing the perpendicular impact of the piston against the cylinder wall and its resulting noise."

[5ft24]

I run the Chevron RPM Delo 15W40. Piston slap I figure was normal. My concern is the compression numbers
Thanks

[93Regina]

My concern is the compression numbers
#1 - 140PSI
#2 - 120PSI
#3 - 150PSI
#4 - 170PSI

The B230FT has a deeper dish in the piston, giving a lower compression ratio (8.7:1 for the turbo...

So, pulling up a table, for 9:1 ratio, it should be around and less than "139 psi gauge reading."

TESTING (DRY)

The engine must be warm, the ignition disabled, and all sparkplugs removed. Caution: Wear protective clothing and gloves while working around a hot engine. While doing the test, the throttle and choke plates must be fully open for an accurate test. Have your helper fully depress the accelerator while he is cranking the engine.
====================================

My concern is how you got such high values? Engine appears to be "normal," except for those high values.

[5ft24]

Car was driven about 10 miles to make sure it was warm, pulled all the plugs, disconnected fuel and ignition ECU's.
Held throttle open, gave each cylinder 8 compression strokes. Gauge topped out after 4. Went over them 3 times. Brand new craftsman compression gauge. I thought the 150 was high, but 170 caught me off guard. That's why I went thru them 3 times.
This thing runs better than I thought it would... It's an auto trans, and on dry pavement I can punch it, and about half way across the intersection it will break the tires loose

[93Regina]

Chevron RPM Delo 15W40...but 170 caught me off guard....

Delo 400 LE SAE 15W-40 is the engine oil being used, and it was designed for vehicles using " low sulfur diesel (ULSD)," and is "CAT ECF-2 approved and the new formulation adds CAT ECF-3 approval."

I don't know relative cost, but Chevron has a product called Delo 400 SD SAE 15W-30, which is "intended for engines that have duty cycles which qualify as "severe duty." These include reducing idling time by turning the engine off at stops or deliveries, stop and go in heavy traffic or city delivery, or situations where engine cooling may be stressed like when towing heavy loads or when cycling between fully loaded and unloaded in off road applications."

Delo 400 LE SAE 15W-40 is a little bit thicker than Shell Rotella T 15W-40, via Kinematic Viscosity, but if using 15W-40, Shell might be a better oil. Otherwise, if Delo 400 SD SAE 15W-30 is available in your area, at a reasonable cost, I would consider using it.

Compression Test - The higher results could be due to valve stem seals: see replacing valve guide seals thread. But, I would consider doing an engine leakdown test.

[5ft24]

So it appears to be a valve adjustment issue...
supposed to be .016-.018" hot.
Cyl Int. Exh
1 .011 .014
2 .004 .012
3 .008 .008
4 .012 .012

so thats the next project...

any way to do it myself without special tools?

[93Regina]

do it myself without special tools?

Well the Copyright "Office granted several of the exemptions, which gave consumers the ability to diagnose, repair, and tinker with their cars, unlock and jailbreak their mobile devices and smart TVs (but not e-readers), preserve and continue playing video games no longer supported by the game makers, use alternative feedstock in 3D printers, and retrieve personal health information from their own medical devices."

First, make sure those measurements were good; I'd use room temperature value also.

There are two ways of doing this:

1. Valve clearance adjustment only - Valve tappet depressor tool (Volvo tool 5022 or equivalent) to push down the tappet sufficiently to remove the adjusting disc. A special designed pair of pliers (Volvo tool 5026 or equivalent) to actually remove and install the valve adjusting disc.

2. Installing new Hushers - How To Info

Quickest way is item one, but item two requires removing cam. You have to have specialty tools in both procedures, and you will need a micrometer to measure the new/old discs; keep your metric/english measurement straight.

I don't think there are relevant tools here, Volvo Special Tool Designs, but IPD and FCP have rented tools in the past. IIRC, one or both of them had a complete tool/disc they rented...like $300.00 deposit...forgot how much for usage.

I've only done it when rebuilding an engine, so I used different tools since head was off engine. Again, quickest way is item one...item two requires removing timing belt, so a day or two will be required.

[93Regina]

IPD: 101496 - Valve Shim Kit
Valve Adjustment on B21/B23/B230 "Red Block" Motors

[5ft24]

cold readings are .003 less than hot all the way across the board.
I verified hot again and got the same as the previous measurements

.008 .011
less than .002 .009
.005 .005
.009 .009