compression test results

[jsw3644]

I done a compression test on my c20xe engine yesterday and I have varied results. Any suggestions as to what could be up?
results on cold test:
4: 16.5 BAR
3: 16.5 BAR
2: 15.0 BAR
1: 16.0 BAR
results on hot test:
4: 16.5 BAR
3: 17.0 BAR
2: 15.0 BAR
1: 17.0 BAR

[Stuart]

bent valve/duff rings on 2... could be a few things.

get a leakdown test done to comfirm

[jsw3644]

ok. thanks for such a quick reply.

[ck]

not bad results to be honest. id say leave it alone nothig to worry about, would be signs of an older engine but around a bar or so difference is no problem at all.

[Lee]

Stick some oil down number 2 and do another cold test. If the comp comes up then it will be the rings. if it doesnt, its something up with the valves / gasket. As CK says, its not a massive drop, but its a drop all the same so the engine will need attention at some point IMO

[Lee H]

Look rather high to be honest, thats about 240psi, would be expecting to see about 200 on a standard XE. Is the engine standard?

[turbo-boy]

valves need reseated?

[jsw3644]

not standard. Engine:
Fully rebuilt 20xej redtop, all new pistons, main bearings, big end bearings, crank reground, head skimmed 25 thou, all valves replaced and relapped, all seats and guides replaced, new hydraulic tappets, all new gaskets and seals, polished rocker cover and spark plug cover, bailey breather tank from series 1 rs turbo, brand new weber 45 dcoe carburetours, sbd inlet manifold, genuine weber linkage with twin cable, chrome trumpets, 38mm chokes, new facet red top fuel pump, h and h ignition solutions rebuilt distributor and reweighted for xe advance curve, new cambelt and tensioners and waterpump, bailey coolant header tank chrome, tas solid engine mounts, valvers.com rear engine mount spacer kit. Full mongoose stainless exhaust system,
Omex rev limter with launch control, limit set to 6800rpm, arp rod bolts, sbd lightened flywheel, regal autosport oversize exhaust manifold heatwrapped, Estimated power: 185 -190 hp @flywheel.
its done 21000 miles since rebuild

[Will F]

not standard. Engine:
Fully rebuilt 20xej redtop, all new pistons, main bearings, big end bearings, crank reground, head skimmed 25 thou, all valves replaced and relapped, all seats and guides replaced, new hydraulic tappets, all new gaskets and seals, polished rocker cover and spark plug cover, bailey breather tank from series 1 rs turbo, brand new weber 45 dcoe carburetours, sbd inlet manifold, genuine weber linkage with twin cable, chrome trumpets, 38mm chokes, new facet red top fuel pump, h and h ignition solutions rebuilt distributor and reweighted for xe advance curve, new cambelt and tensioners and waterpump, bailey coolant header tank chrome, tas solid engine mounts, valvers.com rear engine mount spacer kit. Full mongoose stainless exhaust system,
Omex rev limter with launch control, limit set to 6800rpm, arp rod bolts, sbd lightened flywheel, regal autosport oversize exhaust manifold heatwrapped, Estimated power: 185 -190 hp @flywheel.
its done 21000 miles since rebuild

That is almost exactly standard mate! :)

[meritlover]

yup pretty much a stock engine internals apart from the head skim and bolts.
since there is no mention of a cam, i'll assume its stock.
so apart from that the only thing that would influence the compression readings is the increased compression ratio due to the head skim.

[jsw3644]

That is almost exactly standard mate! :)
I know, but it hasn't obviously got the high mileage earlier mention due to the new parts and also it mentions the head skim. and coz im lazy just copied and pasted it from my spec sheet. :D

[Will F]

As long as it runs well and the tolerances in teh results are +/- 5% I wouldnt worry.