Jump to content

Looks like it is engine rebuild time!


Recommended Posts

Ok so head gasket has gone for the second time in a month!

Head is newly reconned

Correct gasket used

Correct torque sequence

Newly calibrated torque wrench

Was concerned about the surface of the block which shows some corrosion where there were blind holes in the head gasket (interestingly the same holes didn't existing the Payen ones I have been using recently).

Anyhow, the engine block is the only part of the car (and the heater core, see other thread) that hasn't been gone over. I did a refresh a few years ago (timing chain, cam, followers and bearings) but guess O should bite the bullet. There is a clear wear ridge at the top of the bores.

 

Soooo any suggestions of places to go to get it rebuilt and things to get done?

Was thinking:

Decking the block, need to be careful of CR as am running a supercharger, so perhaps mill the pistons to get desired CR

Line bore and Cam bearings

Rebore

Check and regrind crank if needed

Balance rotating components

Wondered about lightening the flywheel, but is it really worth it?

Get the block cleaned, acid dipped etc and new plugs fitted all round..

 

What else?

Want an engine that is reliable, don't care too much about high rpm as supercharger provides low end grunt and that is the fun for me..

 

Cheers

Tim

Link to post
Share on other sites

Pity you are so far down there, J@E Engines in Rossendale.

 

Massive TR experience, and gentleman too.

 

Try a phone call to John at 01706 222662

 

you only want to do the job once.

Link to post
Share on other sites

Shouldn't be an issue with the supercharger, only running 4psi which is pretty soft as far as superchargers go.. The CR of the engine is also pretty low around 9:1.

Last head gasket blew after a year of driving including some fairly spirited driving..

Latest head gasket blew after 10-20 miles of driving.

Have successfully fitted head gaskets to the a number of cars including to this one (albeit with a different head).

There are some signs of corrosion on the head from where there were openings in a previously fitted head gaskets but no corresponding openings in the block. Looks like the coolant that sat in contact with the block slowly corroded the surface and now it sits a little proud. Obviously not a problem with the original HG as there was a corresponding hole. but the new payen HGs don't seem to have the same holes so it becomes an issue.. whatever, I suspect the block isn't as flat as it should be.

Also have clear wear ridges on all the cylinders so time for a refresh..

managed to strip all the ancilaries yesterday in 2 hours.. going to attempt to remove the top bell housing bolts today.. have heard it is possible if you support the engine on a crane and remove the engine mounts, then drop the engine a little..

we'll see..

Cheers

Tim

Link to post
Share on other sites

Hi Tim.

Yes it's possible to remove the engine how you've described, I did it 2 years ago as I'd recently revamped the cabin and didn't want to disturb it.

Good luck, Mark.

Link to post
Share on other sites

Hi Tim.

Don't know how far you're willing to travel but try having a look at Frank Anderson racing engines. Not the cheapest in the world but the overall job is fantastic.

Mark.

Link to post
Share on other sites

Hi Tim,

 

You are near to Dave's Engines in Studley. I have used them twice in the last 3 years. Excellent service and very fast - 2 week turnaround! If you want head work, you could use Cylinder Head Developments in Bromsgrove. They'll port and polish if you want to go down that route. They did a super job on my head and turnaround was around 4 weeks.

 

Both recommended by me.

 

Colin

Link to post
Share on other sites

Tim,

You have several recommendations on where, how about some on what?

 

Decking the block, need to be careful of CR as am running a supercharger, so perhaps mill the pistons to get desired CR Last resort of the obsessive racer with deep pockets, IMHO, as it includes work on all the pistons to equalise their height at TDC, but if your block face is damaged by corrosion, then a very light skim will be easiest

 

Line bore and Cam bearings Again, only if you really need to.

 

Rebore How high is the ridge?

 

Check and regrind crank if needed Certainly
Balance rotating components Indubitably!

 

Wondered about lightening the flywheel, but is it really worth it? The really, really last resort etc. and if carried to a properly effective degree, makes road driving less easy. I don't know the weight of a TR6 'wheel, but 2.5 Saloons' weigh 12kgs. Can be reduced to 7, without much problem. The 5kg alloy ones might be less tractable.

 

Get the block cleaned, acid dipped etc and new plugs fitted all round. Good idea!

 

Some others, while the engine's out and in pieces.

Steel exhaust valve seats.

Flowing of head ducts

Tubular exhaust manifold - 6-3-1

 

JOhn

Edited by john.r.davies
Link to post
Share on other sites

Make certain that they magnaflux the block- to check for cracks.

Hi Sapphire,

this brings us back to the Dyson Hoover thread where everybody calls a vacuum cleaner a Hoover.

 

Magnaflux, within the auto trade, is synonymous with fluorescent Mag Particle inspection.

However the founder of Magnaflux started life in the 30's working for Dr. Foester in Germany developing the EddyCurrent method of testing https://en.wikipedia.org/wiki/Eddy-current_testing.

After the war he went off to the USA and used his German knowledge to start his own company.

MPI had been around for quite some time so was easy to get started.

His Magnaflux eddycurrent systems were pretty poor compared to the German machines.

 

However the MPI systems were good and have stayed with us.

 

Sometimes I'm not sure that the various workshops and garages actually know what they are doing.

 

Roger

Link to post
Share on other sites

Interesting, Roger. Thank you for pointing this out. You are right in your analogy with the Hoover.

 

My concern was that Tim have the block checked for cracks- and the cylinder head, as well.

Head gasket failure can be an indication of excessive heat, which can be related to a cracked head or block.

 

Sorry that you are having expensive problems, Tim.

 

Walt

Link to post
Share on other sites

Yes, definitely getting it all crack tested. a number of the places I have used to do machining in the past will not do any work until this has happened.

Has anyone else used dave's engines in studley?

Cheers

Tim

Link to post
Share on other sites

You Brittish TR people are lucky with such a big choice of companies who have experience with TR engines!

Regards,

Waldi (poor Dutch guy)

Link to post
Share on other sites

Hi Tim, you probably already know this, but just in case - you will need bigger ring gaps on a supercharged engine. I am just doing mine now, I'm aiming for 18 to 20 thou, not the 5 thou that the rings come as standard (County pistons and rings, +030).

Btw, the North Wales Group have a resident supercharger expert - Peter Cobbold. He really is a mine of information, and a thoroughly nice bloke, too!

Stay in touch.

Austin

Link to post
Share on other sites

Hi Austin

Thanks for the advice.. have been talking to Peter for the past couple of years. We not only have a shared unhealthy interest in forced induction, but we share a professional interest in biology..

Cheers

Tim

Link to post
Share on other sites

Ok, I'll admit I'm no expert on superchargers on the 2.5L Tr motors but have followed the threads of owners who have them with interest over the years. Your comment about "my compression is low at around 9.0 to 1" is a direct contradiction to any comments I've read on how to properly set up these motors. Most advice from the guys who have built and run the 2.5 L with a supercharger is that the motors should have a compression ratio that starts with a 7...with warnings for those who's compression is in the low 8's. Here in North America, a 9.0 to 1 compression ratio is higher than any stock ratio ever offered by Triumph, just to give you some perspective. From our point of view, you've got a high compression motor already. Thrown on a supercharger and well, I'm guessing, the weakest link becomes the headgasket.

JMHO.....Dan

Link to post
Share on other sites

Shouldn't be an issue with the supercharger, only running 4psi which is pretty soft as far as superchargers go.. The CR of the engine is also pretty low around 9:1.

Last head gasket blew after a year of driving including some fairly spirited driving..

Latest head gasket blew after 10-20 miles of driving.

Have successfully fitted head gaskets to the a number of cars including to this one (albeit with a different head).

There are some signs of corrosion on the head from where there were openings in a previously fitted head gaskets but no corresponding openings in the block. Looks like the coolant that sat in contact with the block slowly corroded the surface and now it sits a little proud. Obviously not a problem with the original HG as there was a corresponding hole. but the new payen HGs don't seem to have the same holes so it becomes an issue.. whatever, I suspect the block isn't as flat as it should be.

Also have clear wear ridges on all the cylinders so time for a refresh..

managed to strip all the ancilaries yesterday in 2 hours.. going to attempt to remove the top bell housing bolts today.. have heard it is possible if you support the engine on a crane and remove the engine mounts, then drop the engine a little..

we'll see..

Cheers

Tim

Hi Tim! Which head Gasket did you fit? As your car looks to be a 1972 car, this is when the head gasket was changed to suit the counter bored/ reinforced block block? Is your block counter bored? if it is, it requires the later Payen head gasket with the increased fire rings and tab that sticks out from the cylinder head.

 

Bruce.

Link to post
Share on other sites

Yes used the recessed block payen gasket.

Link to post
Share on other sites

Regarding the extra boost and gasket failure. Absolutely true that if there is an issue with the fitment of the gasket a forced induction motor will find it. But it should be entirely solvable as there are people running twice my boost very successfully. I suspect the block surface as it didn't look too special and finding corrosion on the block surface is never a good thing I guess. There are other factors that also point to rebuild. Worn bores, stepped threads in the front alloy sealing block. Excessive oil leaks. Silted up water jacket etc. So think it is time to get it check and reconned. Real question is what to do and what not to do?

Cheers

Tim

Link to post
Share on other sites

Interestingly I noticed differences in the water passages in different heads when I had them reconditioned in 2015

http://72tr6.blogspot.co.uk/2015/01/the-cylinder-heads-return.html?m=1

And it is under the extra water passages (in yellow on the figure half way down) that the block shows corrosion. The current payen gaskets do not have holes to match these meaning that water from the head doesn't touch the block here. I wonder however whether a previous gasket did leaving water in contact with the block causing corrosion and a less than flat area?

Just a thought..

Tim

Edited by Tim D.
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.