head gasket set.

[Phil Read]

I have a TR250 which has had a new block (no engine number) and has been rebuilt to TR5 spec with the lucas fuel injection system. I wish to buy a head set but notice there are variations, recess and no recess, whatever that means. could any one explain the difference and which would be suitable for my engine.

Thanks in advance.

[john.r.davies]

When you have the head off, Phil, look around the tops of the bores.   A small recess may have been machined where the bore meets the block face.     Later (others must say how much later, or even if this applies to TR250s) engines had this. The seam where the metal of the gasket face is returned is left thicker than the gasket and compressed in the groove as a "fire ring" to improve gasket sealing.

A non-recess gasket where there is one would leak, badly!

John

[Phil Read]

Hi thanks for that. I intend to do some touring so want to buy a gasket set just in case. the engine itself has only done 2500 miles and runs well.

[stuart]

You should just need a non recessed set if its a correct early engine block to suit a TR250

Stuart.

[Kenrow]

Have you thought about going with triple Webers or SU's?  You would be able to use your current TR 250 head/block and get similar performance to the PI. You're going to upgrade the cam in either case.

** Sorry misread your 1st post and didn't realize you already had the PI system with the wide spaced inlet port head. I would recheck you head numbers as it probably is 219015/313248.

Edited February 26, 2022 by Kenrow
added info

[BlueTR3A-5EKT]

Look down the back of the cylinder head, between engine and head where the head gasket is located.  

Is there a 1/2” x 1” bit/tab of gasket sticking out?

If so it is fitted with a later gasket which suits the recessed type cylinder block.   (TR6 from (e) CC/CP75001 all CF and CR)

 

If there is no tab, the gasket fitted is the early type used with the flat topped cylinder block.  (TR5, TR6 to (e) CC/CP75000)

 

 

Edited February 21, 2022 by BlueTR3A-5EKT

[Phil Read]

16 hours ago, BlueTR3A-5EKT said:

Is there a 1/2” x 1” bit/tab of gasket sticking out?

If so it is fitted with a later gasket which suits the recessed type cylinder block.   (TR6 from (e) CC/CP75001 all CF and CR)

Thanks for that, there is no tab so I assum its the non recess type. I have been given a gasket set which has a tab and on the set it clearly says for recessed blocks, which is why I made the enquiry. Looks like I need to buy another gasket set.

[john.r.davies]

I think I may have one, Phil, let me look.   I only use recessed blocks.

John

[BlueTR3A-5EKT]

You will only need the head gasket as all the other gaskets in the set are the same for a PI engine.

gasket pt no. GUG702597HG. Or 213776 or AJM346

one from Chris Witor.  £12.50.  213776RM. https://www.chriswitor.com/search.php

[Dave McDonald]

Phil,

You say that your new block has no engine number. This could mean that it has been skimmed, for whatever reason. Even if it started off as a recessed block, skimming approx 0.7mm would have removed the recess so, as others have said, a flat block head gasket would be appropriate.

You also said in your first post that the TR250 engine had been built to TR5 spec., including Lucas PI. If the original TR250 cylinder head, built for twin Strombergs was used, then the PI throttle bodies won't line up correctly with the ports in the head. They will bolt on without any problems because all the stud layouts are common to both types of inlet and exhaust manifolds. However, the spacing between each pair of Carb head inlet ports is 17mm, while that on the PI head ports is 22mm. So fitting PI throttle bodies to a carb head results in a thin moon shaped crescent of misalignment, meaning you will only be getting partial inlet areas.

Your cylinder head type number is stamped on the right side near the front. A TR250 head would be 516323. See attached head identification table from Chris Witor website. Could be worth checking to see what you've got.

Dave McD

 

 

head_applications_chart.pdf

[Phil Read]

On 2/24/2022 at 7:56 PM, Dave McDonald said:

Phil,

You say that your new block has no engine number. This could mean that it has been skimmed, for whatever reason. Even if it started off as a recessed block, skimming approx 0.7mm would have removed the recess so, as others have said, a flat block head gasket would be appropriate.

You also said in your first post that the TR250 engine had been built to TR5 spec., including Lucas PI. If the original TR250 cylinder head, built for twin Strombergs was used, then the PI throttle bodies won't line up correctly with the ports in the head. They will bolt on without any problems because all the stud layouts are common to both types of inlet and exhaust manifolds. However, the spacing between each pair of Carb head inlet ports is 17mm, while that on the PI head ports is 22mm. So fitting PI throttle bodies to a carb head results in a thin moon shaped crescent of misalignment, meaning you will only be getting partial inlet areas.

Your cylinder head type number is stamped on the right side near the front. A TR250 head would be 516323. See attached head identification table from Chris Witor website. Could be worth checking to see what you've got.

Dave McD

 

 

head_applications_chart.pdf 151.78 kB · 5 downloads

Thanks for that, its interesting. The stamped number is 219018 which is not on the list, however the raised casting nuber is 313248. accoring to the application list it looks as though it could be from a number of engines so I am no wiser..

[Dave McDonald]

Phil,

I can't comment on the absence of 219018 from the chart. However, the casting No 313248 is common with head No 219015 - used on TR6 PI, CR series, and 219016 - used on the Triumph 2500S saloon. Both of these definitely had the wider 22mm port spacing, so it would seem that you have a head which is appropriate for PI.

Regards

Dave McD  

[Andy Moltu]

If you look at the block and cannot see a groove machined around each bore you woill need a head gasket for a non-recessd block. The recesses were found on the later 6s (CR) to accomodate thicker fire rings.

I recall there were some TR250s with heads that had different spacing to the head ports which may need different manifold gaskets and may limit after market manifolds.  However theses heads can be swapped for one of the regular ones.

I recall Cris Witor has the differnt head casting numbers somewhere on his web site. The 25s heads were sead to be the best in out of the box form compared to the others but all can be gas flowed.

[Kenrow]

On 3/8/2022 at 3:56 AM, Andy Moltu said:

I recall there were some TR250s with heads that had different spacing to the head ports which may need different manifold gaskets and may limit after market manifolds.  However theses heads can be swapped for one of the regular ones.

This is true for the TR 250 and up to 72 US market TR 6’s. As noted previously the difference is only the inlet spacing, exhaust is the same.