I’ve had a friend do a compression check on my engine and im getting low compression in cylinders 2&3. Other symptoms are difficult starting and lumpy tick over once warm.
Please can I have your thoughts on what to look for.
Many thanks in advance.
Jon
Probably nothing to look for if the cylinder head gasket has gone unless it has failed near a water way and you would get gunge in the oil or steam out the exhaust.
Engine size? Year of manufacture {if known)? Mileage? I’m no specialist, but sounds like you need a good engine specialist, the condition of The head gasket first, Cylinder head (is it warped?) then each cylinder and pistons are the obvious things to look at, which means stripping the engine down. That will determine whether it’s a simple question of replacing the head gasket, or compression and wiper rings on each piston, or a total rebore and re-equipping the pistons to match the new bore size.
Easier with a 1.6 than a 1.8 IMHO. (The 1.6 has more room for expansion)
Other alternative? New engine, or at least a second hand one in good condition. (cost you more in the end I reckon.)
Others may have other suggestions, these are just the ones that occur to me, for what it’s worth.
It is a 1998 1.8 with 80k miles. The car had a new head gasket and skimmed head about 12 months ago but hasn’t really been driven since the work had been done. Someone has mentioned that it could be worn piston rings or sticky rings.
Thank you for your help so far.
Jon
We have good used engines if you need one.
Hi Robert,
what at are your contact details should I need a replacement.
Jon
'98 with 80K miles - have you had it from new, or bought S/H? Either way , has the car ever been fitted with forced induction? If not, then it’s strange to say the least, plenty of cars around with 150 - 200K miles on same engine, so this ones either been pushed or badly used, and FI would do it.
Just a thought?
We used to joke a car with over 40K miles was just run in, so you’ll see where I’m coming from. Which county are you in? Maybe we can help to point you to someone to help.
I would firstly suspect the head gasket, particularly since it was replaced only last year and the car not driven much. Possibly not correctly torqued down.
Hopefully it has only blown the gasket and not damaged the head.
How low are they, did he give you the figures?
There is a simple way to check whether it’s bore wear/piston rings or if it’s more likely to be valves or cylinder head.
You first take a reading with the compression gauge, then take another reading with a small squirt of oil into the cylinder. If the reading improves there is a problem with the bore or piston/rings. The oil acts as a seal.
If it’s the same reading it’s likely to be valves or cylinder head.
It may be worth having a cylinder leakage check done if your friend has the equipment.
Is there any sign of oil in coolant or water in the oil?
The car is second hand but I don’t believe it to have ever been modified, i had heard that the engines were pretty bulletproof one of the reasons I chose to go for one.
I will check with him now what the figures are and I’ll update you, I’ll also see if he has time to redo the test with some oil above the piston.
Im in Plymouth Devon and would be very grateful of any assistance. Tea, coffee and biscuits will be provided.
Jon
Jon -
Only place near you is Andy at Autolink, Though not sure he’ll want the work, but ring him and ask. Don’t know anyone else in your neck of the woods I’m afraid, unless a SW member sees this thread.
http://www.autolinkuk.co.uk/ 01489 877770
Jon -
Only place near you is Andy at Autolink, Though not sure he’ll want the work, but ring him and ask. Don’t know anyone else in your neck of the woods I’m afraid, unless a SW member sees this thread.
http://www.autolinkuk.co.uk/ 01489 877770
Hi All,
sorry for for the late reply, the compression figures are around 95/100 on 1 and 4 and down at about 50 on 2 and 3.
we also did an air leakage test and it seemed to be leaking between the cylinders. So thoughts are lifters pumped up or valve seats moved, what do you think to this?
cheers,
Jon
Cylinde rhead gasket replace and have the block top and head checked for flatness.
Head gasket blown between cyls 2and 3.
GM engines used to do it for fun.
Looks like a straightforward blown head gasket. As it blew soon after being replaced I still think that it was incorrectly torqued down.
It would be worthwhile checking the tightening torque on each head bolt prior to removing the head. Don’t check the undoing torque but set the torque wrench to the correct tightening torque and see if any bolts move before the wrench clicks off. Alternatively it could be that the bolts were tightened in the wrong order and the head hasn’t pulled down completely flat.
Thank you for all of your help I will keep you posted on how I get on with it.
Is the Bosch S5 a good replacement battery?
Just to add to PR yorkshires comments.
Before you fit the head blow out the head bolt tapped holes and run the bolts down to make sure they are clear and not bottoming out too soon and there isn’t any water or oil in them, which could cause hydraulic lock.
Compression 95/100 on the good cylinders is quite low?? Though around 150 for good engine?