Triumph Sports Cars

engine swaps and other performance upgrades, plus "factory" V8s (Stag and TR8)

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Charles Frink

(7 posts)

02/08/2010 09:36AM

Main British Car:

Tophat liners for 3.5 Triumph
Posted by: wedgehead
Date: December 03, 2014 12:55PM

The 3.5 in my TR8 has been taken out 5.0. I just found I have at least 1 slipped liner and 2 or 3 others that look like they have moved. The worst one has moved 1/16" both top and bottom with the others 1/32 or less. It looks as if the engine builder had bored the block too far down and gave the liner no "shelf".

Are Top Hat liners the answer to keeping the liners from slipping again. Block has original bore of near 3.5 and it is now 3.75. Thuis motor was built in the late 80's and has all the "go fast" stuff popular back then and had run flawlessly for 9 of the 11 years I have had the car. It has never overheated in my time of ownership.

Any ideas ?



Ivor Duarte
Gloucestershire UK
(804 posts)

02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: Tophat liners for 3.5 Triumph
Posted by: 88v8
Date: December 03, 2014 03:14PM

You could try pinning it.
There was a thread on here a while ago.
Here's how


Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5965 posts)

10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Tophat liners for 3.5 Triumph
Posted by: BlownMGB-V8
Date: December 03, 2014 07:24PM

Or go to a 300 block and intake.


Clark Bruce Strock

(4 posts)

11/26/2013 03:57PM

Main British Car:

Re: Tophat liners for 3.5 Triumph
Posted by: trgrrr8
Date: December 17, 2014 01:59PM

Wildcat Engineering found that the aluminum thickness surrounding the liners varied greatly. The factory made three categories of the various cast blocks, some of which were scrapped completely. GM cast the liners in the block, Rover installed the liners after the aluminum block was cast. Variances and core shifts make it very difficult to install large bore liners. Wildcat devised the top hat liners to help with this problem when using large bore liners. // In your case I would get a used late 4.0 or 4.6 liter block, bore it 0.010 over to make sure that the oval often found is removed. These blocks have a 3.70 inch bore and cross bolted / 4 bolt main caps and are stronger than earlier blocks. With the 3.40 inch stroke Buick 300 crankshaft you would have a 294 cu. inch engine that is very strong [3.710 bore X 3.40 inch stroke] and a light weight engine. The 1964 300
Buick heads are the best bang for the dollar and performance. // D & D, and an article in HOT ROD magazine both built a 300 block with the 340 / 350 crankshaft [3.85 in stroke]. This produces a relative light weight engine with 349 cu. inches and the HOT ROD one got 390.6 HP and 422.4 lb./ft. on Joe Sherman's dyno. C. Bruce Strock 267 999 1179 trgrrr8

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