Just got a call from my mechanic to say I need to replace my exhaust valves, guides and seals. Head was pressure tested and they're leaking! Where do I go for everything? Engine dynamics are on my call list first thing in the morning but is there any watch outs? Some uncertainty by the machine shop that tested the head. Apparently the supplier lists the valves at 5.5mm but they've been measured at 6mm in 5je machine shop. Also the intake valves are listed as triple collet but ones on the engine are single collet. I'm way above my head with this, don't understand the jargon or what's needed but I need my engine back and in the car asap so trying to help research the topic. Not helped by being in Ireland and not having much knowledge of these engines. Help please :-)
I have bought my valves from Pure motorsport, i bought Supertec valves, very quick delivery, next day. I also bought new valve springs as the Renault ones are a bit weak, he also does the valve guides. The 250/265 and 275 all have 6mm valve stems, its the 225 and R26 that have the 5.5mm stems. You have to get new keepers for the 250 Supertec valves as the 250 exhaust valves are single groove, the intake valves are three grove, Pure motorsport threw the keepers in for me. If i were you fit the new valve guides, Supertec valves (intake and exhaust) and new springs, while its apart then the job is done. I have changed valve guides on a few engines now, as they seam to wear quite a lot.
Just to add, as i have read it again. Pressure testing the head is normally done to check for cracks in the head and not for seeing if the valves are leaking. A leak down test would be for piston blow by, there is no real way of checking the valves with the head on the engine. We used to take the head off and put it on its side, then pour petrol down the exhaust or intake ports and see if it ran out around the valve heads to see if they were leaking.
Head is off the engine and the mechanic thought they looked bad so took them to a machine shop. I dont know exactly what was done but they felt the intakes were ok
I was not expecting to spend this money, I'm beyond what I expected to spend on this engine, feeling more than deflated with it all now to be honest! Pure Motorsport only appear to have the oversized valves in stock. This is a pretty mild original rebuild rather than an forged high power rebuild. What would oversized valves be like on a standard cam, standard 250 turbo engine
Might be a little late but the ship has sailed if the mechanic is already racking up bills for you. Give cooksport a call they might be able to help
Ah it's not that to be fair, it's a used engine I bought to put into my R26. Needed to have some work done and we agreed to strip and do a few jobs and this was a surprise when the head was off. This conversion is proving a little more costly than initially expected. No one's fault, such is life unfortunately!
I'm running oversized valves, they are fine on standard cams and turbo, he only had the larger ones in stock when i wanted some, same price so why not I'm sure that if you went to Renault you would pay that sort of money for stock valves if not a bit more.
I think i still have the valves from my 265 if that helps you, will see if i can find them over the weekend.
Cheers. Looking at Pure Motorsports.site,.they have Supertech uprated valve springs which are.double springs £444 and catcam uprated single valve springs for £140! Was it the catcams you went for? A double spring and original cam would be overkill
Yes i only went for the single Catcam springs, but went for the gold version as there supposed to be more durable. Double springs are an overkill unless you are running high lift cams and really high revs.
Are they reusable and you selling them? I'm not well versed on head work. Need to replace guides etc too so not sure what the mechanic will say about used valves! Possibly a false economy, if the head is off prob worth replacing them with new
Its your call, they were taken out for the only reason that i was forging the engine, personally i would fit new Supertec valves, catcam or Supertec valve springs, but its the cost. As i can do the work myself it saves on labour so i can spend that money on extra parts.
I'm with you. It's all cost and ramping up quickly as I've taken this approach to a few things now like new rad and air con condenser so starting to bite. Am I right in saying, valves, collets, guides, springs and seals is everything?
You only need collets for the inlet valves i think, the original ones only have one groove the rest and the Supertec valve have 3 grooves. The rest of your list looks good, some rebuild lube and cam cover sealer will also be needed, the valve stem seals should be in your head gasket kit, but that kit doesn't come with the cam caps, but if your replacing cambelt as a kit they should be in there. This is the stuff i have used For the cam cover https://www.ebay.co.uk/itm/303707698375?epid=249614517&hash=item46b663b4c7:g:j24AAOSwoddaa0Un assembly lube https://www.ebay.co.uk/itm/193293049945?epid=8035053388&hash=item2d0129e059:g:ujUAAOSwXIheFd95
Perfect. I've loctite 518 for the rocker. This all started because I wanted to get the rocker resealed, oil leaking into the plugs. Then decided to do headgasket and now valves!!! FML! I must check the headgasket kit I got, don't recall valve stem oil seals but I didn't open the pack either so could be. Have the cam caps ordered separate and TB kit obviously
Hey Ian more questions. Had you do add any shims to the springs? I've read on one forum that they felt that position of the collet etc was different and used a 1.2mm shim I think. Not sure what valve spring they used though! I've been struggling to find a full set of valves, think I may have a set tracked down. One supplied mentioned reusing the collets off the original valves, I would have assumed the new valves come with them in the box
I didn't add shims, the seals i used had a rim that the springs sat on. The standard springs are about 4mm shorter than the Supertec ones when i measured them and the aftermarket springs are a lot stronger. Use the collets you already have, there not a stress item, you only need replacement collets for the intake valves as the 250 engine only has one groove, the 225 and R26 have 3 grooves on the in and out valves. The new valves do not come with new collets.
Looks like my engine has been tampered with previously as the valves that have come out are triple collets. Got Supertech valves and no got no collets. FML.
@ianplymouth , by any chance do you have valve spring retainers off the old springs that you might part with? As above, the exhaust valves that came out of my RS250 engine are 3 groove but the new Supertech valves are single grove collet. Have sourced some new collets but the mechanic that has the engine expects the valve retainer cap to be different between a 3 groove collet and a 1 groove collet valve so I now need retainers. Not a clue what the story is with the valve springs, really assuming for now that I can reuse whatever is there!!
