How do these compression readings look? (208 GT4)

Give us the actual numbers - its hard to read the gauges - general rule of thumb is +/- 10 % for all -

 

Too much variation for me... I'd repeat the test, insuring that: the throttle is fully open, each cylinder gets the same number of "strokes"- 6 is a good number that will ensure a max reading. Also, the engine should be at operating temp when comp check is done because ring sealing when an engine is at normal temp is far more important than ring sealing when cold.

Admittedly, cold compression checks are common but they are often not accurate when checking for normal variation. I have seen cases where the amount of variation in your example would essentially disappear when the engine is warm...or get worse. Cylinder walls do not necessarily expand uniformly. A cylinder that is round when hot may not be when cold and visas versa. What matter is how the engine seals when at normal operating temp.

 

Seems a little low to me but it depends on atmospheric conditions.

 

How many miles on the car? Also mike996 is right, do it at normal operating temp if you can and have the throttle wide open (WOT)

 

It doesn't look bad, but it's very likely a never rebuilt engine. 208 GT4 are more or less all in this conditions.

ciao

 

When we "released" an engine after rebuild, the max allowable variation from high to low cylinders was 5PSI. Admittedly, these were performance/competition engines, not a rebuild of a "grocery-getter" motor. If I saw the readings per the original post, and they were rechecked/verified, I wouldn't like it but for practical purposes/normal driving the variation shown is not worth worrying excessively about.

FWIW the compression check on my 328 when I purchased it in '08 showed 8PSI max difference between the high and low cylinder. That comp check was done as I recommended earlier - engine hot, 6 cycles on each cylinder, throttle body full open.

 

Wouldn't a leak down test be more useful?

kc

 

Similar but different
Start with a compression test to determine if there's an issue to be investigated, if so then a leak down can help point to where that problem is coming from.

 

What's the elevation (feet above sea level) where the compression test was performed? For sea level, those numbers are on the low end. For 5,000 feet ASL, eg Denver, they're OK.

Gordon

 

Well...again, the variation is the important thing. As noted, the specific numbers will change based on several different factors but the variation percentage between cylinders will not. As I said earlier, the variation in the OP's test is outside my personal comfort zone but that's based on my past work on performance/competition engines and probably not totally relevant. As far as an engine for driving down the road/having any problem, it's fine.

 

Agree. It looks like a normally worn engine. Keep looking for other clues of a problem. For example, what are the spark plugs saying?

 

I think that an head service would reduce much of this variations: in my opinion the problems are valves more than the liners. Maybe even a valve adjustment service could help. Pay attention that disassembly the 208 engine is not easy, as rods are wider than the bore: to remove the pistons you have to remove the cranckshaft.

ciao

 

"Cost to ship a car is now over $10k btw, eye watering!"

WOW!

 

Generally, due to variations between tooling, you want to see less than 10% difference between all cylinders (with the same tool, at same engine temp, etc).

 

The 2 litre motor will cost at least as much as the 3 litre version, perhaps more - since they were produced in smaller numbers, the costs of specific unique items could well be higher - for example, the 2 litre engine had the same 71mm stroke as the 3 litre, but the 2 litre bore is 66.8mm, versus the 3 litre bore of 81mm. That means pistons, rings, cylinder liners are different and possibly more expensive for the 2 litre version (and you'll need at least a set of rings for a rebuild). Bearings are likely the same, but as smg2 has noted several times recently in different threads, finding rebuild parts is getting difficult and expensive lately. Some estimates say the cost of a proper rebuild (all bearings, rings, seals, valve work, etc etc) will be $15K USD or more - and the smaller displacement motor would possibly have a higher price tag. It would all depend on your engine builder, their experience, and parts availability.

Gordon

 

If you want 308 capacity I could sell you a set of used 81mm pistons, new rings and honed sleeves but suspect many on here in the US have them lying around. Not sure if any block mods are needed, I'm assuming 308 sleeves fit. The 208 heads are preferred by people wanting the most out of a 2V (more porting options) so you might find someone who will swap you your heads for refurbished 308 heads

 

I just had 2 cars shipped from EU (one was a friends 308 btw). You're getting hosed on shipping charges, I just paid 4800 EUR for a 20ft container. The 308 was RoRo and 1200 GBP.