4.2 Liners

4.2 Liners

Author
Discussion

notaping

Original Poster:

405 posts

85 months

Tuesday 30th March 2021
quotequote all
Anyone know a source for 4.2 cylinder liners? I've tried Powers and Westwood, but none in stock and too costly for a one off set.

Options are to migrate up to a 4.5. Bearing in mind that I've still got a small journal crank and 4.2 top end.

Looking for a reasonable solution.

Ta.

Gordon

spitfire4v8

4,018 posts

195 months

Tuesday 30th March 2021
quotequote all
can you go to 4.7 .. i went from 4.2 to 4.5 on my cerb and totally regret not going to 4.7 instead, chat to andy at apm

Jhonno

6,036 posts

155 months

Tuesday 30th March 2021
quotequote all
notaping said:
Anyone know a source for 4.2 cylinder liners? I've tried Powers and Westwood, but none in stock and too costly for a one off set.

Options are to migrate up to a 4.5. Bearing in mind that I've still got a small journal crank and 4.2 top end.

Looking for a reasonable solution.

Ta.

Gordon
Speak to Andy @APM as Joolz suggested. He may have some options for you.

plasticman

907 posts

265 months

Tuesday 30th March 2021
quotequote all
How many do you need ?

notaping

Original Poster:

405 posts

85 months

Tuesday 30th March 2021
quotequote all
I really would like a full set, but minimum of 6.

3 are badly damaged with corrosion, another 3 have bad vertical scoring, 1 with very minor vertical scoring - which I could get away with, and one good one :-)

I've had a word with Andy at APM and he advised NOT going to a 4.7 with the small journal crank. It would mean a lot of additional outlay for the upgrade whereas going to a 4.5 is just liners pistons and a chip for the ecu.

It's early days, but it kind of feels like 4.5 is the way to go.

G.

Jhonno

6,036 posts

155 months

Tuesday 30th March 2021
quotequote all
notaping said:
I really would like a full set, but minimum of 6.

3 are badly damaged with corrosion, another 3 have bad vertical scoring, 1 with very minor vertical scoring - which I could get away with, and one good one :-)

I've had a word with Andy at APM and he advised NOT going to a 4.7 with the small journal crank. It would mean a lot of additional outlay for the upgrade whereas going to a 4.5 is just liners pistons and a chip for the ecu.

It's early days, but it kind of feels like 4.5 is the way to go.

G.
4.5 would possibly not even be liners depending what ones you have.. Just a bore and hone.

notaping

Original Poster:

405 posts

85 months

Tuesday 30th March 2021
quotequote all
Bore the existing liners. Interesting. 4.2 = 88mm, 4.5 = 91mm

Anyone know if this has been done? Successfully :-)

Bogsye

406 posts

166 months

Tuesday 30th March 2021
quotequote all
Would Performance Unlimited be able to help? I got my Superseal piston rings from there.

Byker28i

74,623 posts

231 months

Wednesday 31st March 2021
quotequote all

notaping

Original Poster:

405 posts

85 months

Wednesday 31st March 2021
quotequote all
Thanks. If they were new I'd go for them, but having stripped the engine down to it's last nut 'n' bolt, I think the sensible policy is to replace with new parts.

It could be they were replaced for the same reason I'm replacing mine, and photos aren't good enough for liners. The photos I've taken of mine make them look nice and shiny, but they're far from it.

Looking into reboring the liners to 4.5 - seems the max recommended oversize for liners is 40 thou. Taking them from 88mm up to 91mm is 60 thou, so doesn't look like an option.

I'm going to get in touch with a local workshop to see if they can fit new liners for me (Pistons & Components - Glasgow). If they can do the work - all good, I'll move up to 4.5. Otherwise it'll mean boxing up the block and sending it down south to Powers?

Thanks all for the input.

Gordon

RUSSELLM

6,001 posts

261 months

Wednesday 31st March 2021
quotequote all
Mine had a refresh some years back, and TVR Power put 4.5 pistons and liners in it.


ukkid35

6,341 posts

187 months

Wednesday 31st March 2021
quotequote all
If you check this thread you'll seem there seems to be quite some variation in the 4.2 liners, some are perfectly round, some are siamesed like the 4.5 (and the German eBay liners)

https://www.pistonheads.com/gassing/topic.asp?h=0&...

notaping

Original Poster:

405 posts

85 months

Wednesday 31st March 2021
quotequote all
Mine are round. Here you can see the damage on the worst one . . .


Jhonno

6,036 posts

155 months

Wednesday 31st March 2021
quotequote all
Byker28i said:
These would work perfectly to bore to 91mm..

Jhonno

6,036 posts

155 months

Wednesday 31st March 2021
quotequote all
notaping said:
Thanks. If they were new I'd go for them, but having stripped the engine down to it's last nut 'n' bolt, I think the sensible policy is to replace with new parts.

It could be they were replaced for the same reason I'm replacing mine, and photos aren't good enough for liners. The photos I've taken of mine make them look nice and shiny, but they're far from it.

Looking into reboring the liners to 4.5 - seems the max recommended oversize for liners is 40 thou. Taking them from 88mm up to 91mm is 60 thou, so doesn't look like an option.

I'm going to get in touch with a local workshop to see if they can fit new liners for me (Pistons & Components - Glasgow). If they can do the work - all good, I'll move up to 4.5. Otherwise it'll mean boxing up the block and sending it down south to Powers?

Thanks all for the input.

Gordon
You can't bore your round liners. You can bore the eBay ones, so if they have a bit of marking it doesn't matter. They would work perfectly to bore out to 4.5 at a considerable cost saving. If I was building your engine I'd use them. (I have built my own 4.2-4.5).

notaping

Original Poster:

405 posts

85 months

Wednesday 31st March 2021
quotequote all
Problem is - there are only 6 liners on ebay, and if mine can't be bored out that leaves me 2 short. I think I'll be going with new 4.5 liners etc.

Ta.

G.

Jhonno

6,036 posts

155 months

Wednesday 31st March 2021
quotequote all
notaping said:
Problem is - there are only 6 liners on ebay, and if mine can't be bored out that leaves me 2 short. I think I'll be going with new 4.5 liners etc.

Ta.

G.
Depends if you can buy 2 or not.. They will be the same as the ones on eBay.

ukkid35

6,341 posts

187 months

Wednesday 31st March 2021
quotequote all
notaping said:
Mine are round. Here you can see the damage on the worst one . . .

Most of the liners in my engine have similar tide marks from coolant that has sat in the cylinders



It has not significantly affected the compression or the output, both are very reasonable

I'm not saying don't replace them, I am suggesting it won't make as much difference as you might hope

ukkid35

6,341 posts

187 months

Wednesday 31st March 2021
quotequote all
Actually the most interesting thing is that we haven't suffered bent con rods from hydrolocking

notaping

Original Poster:

405 posts

85 months

Wednesday 31st March 2021
quotequote all
Although it looks like tide marks, it's really rough and the surface further down is badly pitted. Three of them were like this, but not quite as bad.

Compression checks returned a significant drop in most cylinders - which is why I pulled the engine. 59k - it was time for a rebuild ;-)