compression and fuel pressure

[berttv]

Hi

thankyou for help with my last post. could someone please tell what a good compression is on the tr6.It has done 64000 miles. Also does anyone know of a diy pressure tester for the fuel injection sytem or a shop that sells them.thankyou

[john.r.davies]

Bert,

"Good" compression is readings across the block that are consistent, without one cylinder being lower that the others or a wide variation. Compression testers are not precision tools, and the readings are not calibrated. So you cannot compare the absolute readings of someone else with yours.

 

Have a search here for fuel pressure guages - several people will make up a batch from time to time and offer them for sale.

OR,

you can make your own! A cheap oil pressure gauge is fine, but lacks the damping that a proper fuel gauge has, so will "the oscillate itself to death" or to the point of losing the needle from the shaft, and reading it will be difficult!

'Proper' gauges are damped by being oil filled, and are correspondingly pricey, but there are otjher ways of damping it. I made a small copper disc from a piece of piping, and drilled a VERY small hole in the middle. This as sandwiched into the connection between the gauge and the fuel system, and works well.

OR,

if you don't mind a digital read out, you can buy a gauge and sender unit from the USA, for about £50: http://cgi.ebay.co.uk/NEW-52mm-GLOWSHIFT-D...A1%7C240%3A1318

This one has the advantage of being safe to fit inside your car, as the only connection to the fuel system is down a wire.

 

John

Edited April 2, 2009 by john.r.davies

[Crownwheel]

Hi Bert,

Loads of damped guages at reasonable prices (well less than a tenner) at harrierfluidpower - accessable (of course) via e-bay. I have bought guages from harrier and am pleased with value.

Agree with John on no absolutes on compression good / compression bad. Just look for variances then decide if you can live with them. If significant then lots of threads in this forum to help you decide whether rings or valves as culprits.

Have fun

john

[JOHN'S TR6]

Looking at old documentation from the 80's my car was tested on the compression by a specialist and the readings where about 170 psi per cylinder.

 

When I test it 20 odd years later my readings are about 145-155 psi. It still runs well and pulls well with no smoke and still sounds great. Of course tested with a different gauge. I also got the feeling that when i was testing the compression, my baterry was struggling towards the last cylinder

 

John

Edited April 3, 2009 by JOHN'S TR6

[smizgals]

Hi

thankyou for help with my last post. could someone please tell what a good compression is on the tr6.It has done 64000 miles. Also does anyone know of a diy pressure tester for the fuel injection sytem or a shop that sells them.thankyou

 

Hyrotechnik, http://www.hydrotechnik.co.uk/, provide a permanently installable test point for adhoc attachment of their gauge with their hose at around 50 Pounds net of VAT plus admin an shipment charges. My order for fuel pressure consists of:

 

Gauge, part number 9807-160,

with the Microbore hose, part number S103-AC-FA-00.80: 80cm long standard pipe to connect the above gauge,

and the 3/8" BSP test point/adapter, part number SNA02.

 

Thanks to Ivor on a previous post.

[Lockley210]

Thanks to Ivor, I fitted one and have found it very convienient to attach the guage. The valve seals instantly when removed so no fuel spillage !

 

 

Mark

[88V8]

Thanks to Ivor on a previous post.

 

Thanks to Ivor, I fitted one

To be quite fair, I think I cribbed this wisdom from TIMS, possibly without attribution or because I'd simply forgotten. So thanks to Tim

 

Ivor