Hi,

My '98 P38 has the following symptoms:

Water loss
Some water exiting through drivers (RHD) exhaust tailpipe
Overheating
Pressurised top hose
Misfire and down on power
'chirp' sound from right bank, from cold - worsens with more throttle (not revs)

I've done a compression test, but the tester I bought was cheap & nasty and I'm not 100% sure it worked properly - these are the readings:

Left bank

1 - 70 psi
3 - 75
5 - 75
7 - 0 to 50 after several tries (duff readings?)


Right bank

2 - 50 psi
4 - 50
6 - 75
8 - 50


These all seem a bit low to me. I've obviously got an overheating issue, which I presume must be the H/gasket or a liner(s) issue. Either the compression is low (cam worn?) or possibly my tester is rubbish..... I'll beg/steal one and see what I get.

Any advice anybody?

As far as I see, I have 3 options:

1. Remove the head(s) and see if i can see a problem with the gasket/liners. I don't mind repairing a gasket(s), but don't want to bother if it might not fix the problem

2. Fit a 2nd hand engine - easy fix, as long as I'm not buying someome elses trouble.....

3. Rebuild my engine with top-hat liners etc. Bit more involved, but (as long as I don't make a hash of it, should last for ages.


I've never had anything to do with he inside of a v8 before, so am a bit daunted by any of my options.

Anyone got any pointers?

Cheers,

Nobby

well you have made all the right points. Its not much work to take the heads off and confirm yours is shot if its most likely going in the bon anyway (or to me to make a wine rack )

Then like you say fit a good used unit is the cheapest option if you can find a good one. some of the p38 boys may know where there is a a chance to find one.

I like the sound of a V8 wine rack - wouldn't be any good though......all the bottles would get too hot and then slip:lol:


I think I might re-test the compression with a different tester, then take the heads off. If there are signs of h/gasket failure (and no signs of cracked/slipped liners), I'll have the heads skimmed and fit composite gaskets and ARP studs.


If the liners are knacked, I'll take it out and rebuild - hopefully I can source a decent lump to put in whilst I'm rebuilding mine.

always seems to be the liners on the p38's, I would get a known good used one unless you can see where the gasket has failed before you get down the "a bit more cash, oh just a bit more cash" route

I am sure the p38 guys will differ on that view but I am on the outside looking in lol

fett said:

always seems to be the liners on the p38's, I would get a known good used one unless you can see where the gasket has failed before you get down the "a bit more cash, oh just a bit more cash" route

I am sure the p38 guys will differ on that view but I am on the outside looking in lol

Click to expand...

its the blocks that crack 200 thou thinner than 3.5 not liners

sure, block cracks and lets liner move no?

My understanding is tha it sometimes crack and sometimes doesn't. Either way, if the liner moves..... It's a bad thing......

Compression results are about 100psi lower than I would expect to see. Either you have a huge problem or you need to buy a better compression tester.

Did you do the test wet and dry?

classic kev said:

Compression results are about 100psi lower than I would expect to see. Either you have a huge problem or you need to buy a better compression tester.

Did you do the test wet and dry?

Click to expand...

agreed, comp test is way off! get a new tester imo

I thought the readings were unbelievable as I read them - that's why I didn't even bother squirting oil in the bores and retesting.

I have a 'known good' compression tester on its way and will take dry and wet readings and update.

Just while we're on the subject, people seem to recommend composite gaskets and ARP studs. I recall that somebody said the composite gasket was designed for use with stretch bolts - any opinions? Also, will any make of composite gasket be ok, or should I stick to OEM or is there an improved aftermarket one?

Cheers chaps,

Nobby

Nobby Nobson said:

I thought the readings were unbelievable as I read them - that's why I didn't even bother squirting oil in the bores and retesting.

I have a 'known good' compression tester on its way and will take dry and wet readings and update.

Just while we're on the subject, people seem to recommend composite gaskets and ARP studs. I recall that somebody said the composite gasket was designed for use with stretch bolts - any opinions? Also, will any make of composite gasket be ok, or should I stick to OEM or is there an improved aftermarket one?

Cheers chaps,

Nobby

Click to expand...

im prety sure the p38 v8 would have a comp gasket alrdy, if it has one dont put a tin on as you might get fouling problems with valves and pistons. realsteal is a great place to get bits for the v8

Water loss
Some water exiting through drivers (RHD) exhaust tailpipe
Overheating
Pressurised top hose
Misfire and down on power
'chirp' sound from right bank, from cold - worsens with more throttle (not revs)

I've re-done the compression test, here are the new readings:

Left bank

Dry ('Oiled')

1 - 130 psi. (150)
3 - 170. (200)
5 - 160. (200)
7 - 100. (130)


Right bank

Dry ('Oiled')

2 - 165 psi. (180)
4 - 150. (170)
6 - 150. (170)
8 - 130. (140)

I also discovered that no. 2 sparkplug is cross-threaded, which may account for the 'chirruping' noise as it didnt seem to be sealing.
The engine is overheating/pressurising hose and also 30-50%(ish) down on power
Now I am confident in the tester, and have a theory or two about what's going on, but would greatly value a second (and third etc.) opinion.
Anyone got any pointers?

Cheers,

Nobby

Nobby Nobson said:

Water loss
Some water exiting through drivers (RHD) exhaust tailpipe
Overheating
Pressurised top hose
Misfire and down on power
'chirp' sound from right bank, from cold - worsens with more throttle (not revs)

I've re-done the compression test, here are the new readings:

Left bank

Dry ('Oiled')

1 - 130 psi. (150)
3 - 170. (200)
5 - 160. (200)
7 - 100. (130)


Right bank

Dry ('Oiled')

2 - 165 psi. (180)
4 - 150. (170)
6 - 150. (170)
8 - 130. (140)

I also discovered that no. 2 sparkplug is cross-threaded, which may account for the 'chirruping' noise as it didnt seem to be sealing.
The engine is overheating/pressurising hose and also 30-50%(ish) down on power
Now I am confident in the tester, and have a theory or two about what's going on, but would greatly value a second (and third etc.) opinion.
Anyone got any pointers?

Cheers,

Nobby

Click to expand...

Comp test isnt terible.. could be better... 7 is allot lower than the rest wich may be leaking into a water way.. do a hg IMO... its not a masive job and dont cost to much.