Turbo unknown build question on compression test

Turbo unknown build question on compression test

Author
Discussion

scoobydo123

Original Poster:

76 posts

18 months

Wednesday 24th June
quotequote all
Hi,

Have a ka24de (turbo) that has been plagued with build issues from previous owner. Recently been reading my plugs and noticed that cylinder 3 and 4 has slight fouling. When testing an engine like this with custom pistons would you expect such an increase with 16ml of engine oil added to the pot? The pistons are deep dished (not sure if this has an impact on getting the oil into the rings but readings went up so guess ok) previous owner claims engine suffered from DET, i think poor map. Cylinder 3 and 4 had leaky valves when I done the headgasket that was causing pressure in coolant this is fixed but not the leaky valves (was a bit of a rush job as had a warranty claim on the transmission). Unfortunately cannot find my leakdown tester (anyone local to Romford Essex who could lend me one) :-)?

cold wet hot
150 178 165
142 177 155
139 162 150
130 152 142

below prior to headgasket change cold and hot only

147 170
157 170
142 156
148 170

Appreciate we are not looking for absolute figures more so even figures but wonder about impact of ring gap on a boosted motor.

Tks

scoobydo123

Original Poster:

76 posts

18 months

Thursday 25th June
quotequote all
Here is a picture of the plugs

Boosted LS1

19,115 posts

216 months

Thursday 25th June
quotequote all
Plugs are a bit rich but not a big issue. You have a problem with compression on one of the cylinders though and another is borderline imo. Have you bought a vacuum guage? That can be a helpful tool. I would say it's got low compression pistons in there as all the readings are low.

scoobydo123

Original Poster:

76 posts

18 months

Thursday 25th June
quotequote all
Yes they are low CR pistons very deep dished. Havent got a Vac gauge, have got boost gauge and can log it via the ECU. Have seen guides that mention using the vac gauge but this reads low obviously due to the low CR pistons.

scoobydo123

Original Poster:

76 posts

18 months

Thursday 25th June
quotequote all
Getting some wavering at idle. Had the ign locked and idle control motor disconnected. Note when the video was took I am on top of the engine as the engine is under the drivers seat.

https://drive.google.com/file/d/1evFyXl2n3spIbQRuo...

stevieturbo

14,879 posts

203 months

Thursday 25th June
quotequote all
And you're doing all this because ?

Is there an actual problem ?

scoobydo123

Original Poster:

76 posts

18 months

Thursday 25th June
quotequote all
plugs 3 and 4 are not looking that happy. Found my leak down tester (neighbour had it). Results are in from a hot engine.

1 inlet minor leak 100psi in 4psi drop
2 ex leak 100psi in 5psi drop
3 ex leak 100psi in 7 psi drop
4 inlet and ex leak 100psi in 8psi drop

To confirm compression test carried out with the following results cold /wet / hot

1 150 179 165
2 142 177 155
3 139 162 150
4 130 152 142

I seem to be getting some leak between adjacent cylinders is it worth noting. Dont seem to be getting much down the dipstick tube. Trying to work out if just a valve grind required? Help much appreciated as want to do it right this time as have time on my hands :-)Bottom end was rebuilt around 3000 miles ago with new low CR piston (dont know ring gap) and new bearings as previous owner melted the electrodes 1 day after having it mapped. Exhaust manifold also had cracks had them welded and timing seems retarded maybe burnt valves EGT too high? Have been working thru all the issues on this so called perfect built engine :-)

stevieturbo

14,879 posts

203 months

Friday 26th June
quotequote all
stevieturbo said:
And you're doing all this because ?

Is there an actual problem ?
And I repeat again....

You're talking about a lot of previous problems, but why exactly are you doing this now ?

If you're trying to justify something "because plugs 3/4 don't look happy"......are you on another planet ?

scoobydo123

Original Poster:

76 posts

18 months

Friday 26th June
quotequote all
Would you leave it then? 3 cylinders have leaky exhaust valves I thought differential load on the crank is a bad thing? Thought that maybe if I nip it in the bud then might stop things getting nasty.


stevieturbo

14,879 posts

203 months

Friday 26th June
quotequote all
"differential load on the crank"

What in the name of fk are you talking about ?

So far you've stated no actual problems, no actual symptoms of a problem, yet are doing some random tests trying to find....what ?

The leakdown tests show very low leakdown, assuming even conducted correctly and with engine up to temperature..

You say plugs 3/4 are unhappy, yet show plugs with nothing wrong and that clearly have thousands of miles on them, which makes them relatively useless to indicate much.

Your compression tests shows little difference between cylinders....even if overall numbers appear rather low. But that could be test procedure, your gauge, or maybe your engine is very low compression...although you havent stated what CR it is.

So back to the same thing...

Is there some sort of actual problem you're trying to find ? Is it not running properly or somethin ?

scoobydo123

Original Poster:

76 posts

18 months

Monday 29th June
quotequote all
The engine is low CR calculated between around 7.3 (didnt know the crush thickness of the gasket I used). I here what you are saying reference is there an actual problem. The vehicle has been riddled with issues that I wont muddy this thread with if you would like to know the details feel free to contact me by PM and I will speak with you there, put it this way there are some very unscruplous people out there.

Due to the leaky valves highlighted during my leakdown test I found 3 banks leaking on the exhaust side and 1 on the inlet I decided to take the head off again. It had previously been skimmed twice I believe by the previous owner with no success in stopping coolant being pressurised. I think this was due to poor prep for the MLS gasket. My attempt resulted in finally not having to top up the water every 300 miles or so. On taking the head off I noticed that it appears that the warp has travelled through to the cam caps (my mistake on reassembly to not have checked that) as the exhaust cam is rocking in its carrier. So hopefully not a wasted tear down as found something out of tolerance here. Hopefully this can be recovered as there is a lot of time gone into the head by someone before. Standard bhp for the engine is 150bhp this engine made 420bhp at some stage in its life, previous owner had low CR pistons put in to "cure" a det issue which I think was just plain stupid as the CR had already been dropped with the previous pistons he had. Not even running that much boost (22psi).

stevieturbo

14,879 posts

203 months

Monday 29th June
quotequote all
scoobydo123 said:
The engine is low CR calculated between around 7.3 (didnt know the crush thickness of the gasket I used). I here what you are saying reference is there an actual problem. The vehicle has been riddled with issues that I wont muddy this thread with if you would like to know the details feel free to contact me by PM and I will speak with you there, put it this way there are some very unscruplous people out there.

Due to the leaky valves highlighted during my leakdown test I found 3 banks leaking on the exhaust side and 1 on the inlet I decided to take the head off again. It had previously been skimmed twice I believe by the previous owner with no success in stopping coolant being pressurised. I think this was due to poor prep for the MLS gasket. My attempt resulted in finally not having to top up the water every 300 miles or so. On taking the head off I noticed that it appears that the warp has travelled through to the cam caps (my mistake on reassembly to not have checked that) as the exhaust cam is rocking in its carrier. So hopefully not a wasted tear down as found something out of tolerance here. Hopefully this can be recovered as there is a lot of time gone into the head by someone before. Standard bhp for the engine is 150bhp this engine made 420bhp at some stage in its life, previous owner had low CR pistons put in to "cure" a det issue which I think was just plain stupid as the CR had already been dropped with the previous pistons he had. Not even running that much boost (22psi).
Well if your CR is 7.3:1, there is your first problem !1 Unless you're running about 90psi boost.

And if the cam is rocking on the head....that head is scrap.

Really...by the sounds of things, find another engine.

Stan Weiss

251 posts

104 months

Thursday 2nd July
quotequote all
scoobydo123 said:
Hi,

Have a ka24de (turbo) that has been plagued with build issues from previous owner. Recently been reading my plugs and noticed that cylinder 3 and 4 has slight fouling. When testing an engine like this with custom pistons would you expect such an increase with 16ml of engine oil added to the pot? The pistons are deep dished (not sure if this has an impact on getting the oil into the rings but readings went up so guess ok) previous owner claims engine suffered from DET, i think poor map. Cylinder 3 and 4 had leaky valves when I done the headgasket that was causing pressure in coolant this is fixed but not the leaky valves (was a bit of a rush job as had a warranty claim on the transmission). Unfortunately cannot find my leakdown tester (anyone local to Romford Essex who could lend me one) :-)?

cold wet hot
150 178 165
142 177 155
139 162 150
130 152 142

below prior to headgasket change cold and hot only

147 170
157 170
142 156
148 170

Appreciate we are not looking for absolute figures more so even figures but wonder about impact of ring gap on a boosted motor.

Tks
Not sure if you typed in the above numbers wrong or not. If they are correct Than I need to ask if you know what you are doing? Before head gasket change all cylinders cranking PSI was higher hot than after head gasket change hot. That would make me thing the intake cam timing is off (retarded).

Stan

scoobydo123

Original Poster:

76 posts

18 months

Saturday 18th July
quotequote all
Hi Stan no not a typo, the previous owner hadnt degreed the cams so during the head gasket change I set the cams up as per the cam card specification. The cams previously were just on the default factory slot so it appears like how it was set the engine was making more compression at the 300 or so cranking rpm. The adjustable cams are via offset holes in the sprockets so can only advance or retard 2.5 degrees to a maximum of 10. Thanks

Edited by scoobydo123 on Sunday 19th July 08:21