rob83ke70 Posted October 3, 2009 Report Posted October 3, 2009 (edited) Hey AE93 Seca with a 7A-FE engine fitted. Having never had the tappet cover off an A series engine, can anybody advise me on the (I'm)possibilities of changing the valve stem seals without removing the head off the engine? I've been told that you cannot physically do it as the valves are too constrained by the lack of space around the cylinder head. Anybody got around this? can you hold the valves in place with a leakdown tester, remove the camshaft and the shim/bucket assembly and then carefully push on the top valve retainer with a large screwdriver, remove the collets, remove valve spring and replace seal and then reassemble? reckon it would be possible? I put a flush through the engine oil and then put fresh 15w40 in it, and I think that it may have had a thickener type additive in it before I flushed it as now it blows lots more blue smoke than it previously did. I have added stuff that apparently softens oil seals (hopefully valve stem seals will soften) and it seems to have cleared it up a little bit. I can't see smoke most of the time driving it now provided I don't let it idle a long time or go down a hill under high vacuum conditions. This all being said, at 200,000km is it likely I have a worn guide causing my problem? Robert. Edited October 3, 2009 by rob83ke70 Quote
Hiro Protagonist Posted October 3, 2009 Report Posted October 3, 2009 HeyAE93 Seca with a 7A-FE engine fitted. Having never had the tappet cover off an A series engine, can anybody advise me on the (I'm)possibilities of changing the valve stem seals without removing the head off the engine? I've been told that you cannot physically do it as the valves are too constrained by the lack of space around the cylinder head. Anybody got around this? can you hold the valves in place with a leakdown tester, remove the camshaft and the shim/bucket assembly and then carefully push on the top valve retainer with a large screwdriver, remove the collets, remove valve spring and replace seal and then reassemble? reckon it would be possible? I put a flush through the engine oil and then put fresh 15w40 in it, and I think that it may have had a thickener type additive in it before I flushed it as now it blows lots more blue smoke than it previously did. I have added stuff that apparently softens oil seals (hopefully valve stem seals will soften) and it seems to have cleared it up a little bit. I can't see smoke most of the time driving it now provided I don't let it idle a long time or go down a hill under high vacuum conditions. This all being said, at 200,000km is it likely I have a worn guide causing my problem? Robert. At 200,000 it is quite common for 7As to start blowing oil smoke, as noted most likely valve stem seals if it is only really on startup. Can't be too much help on replacing them, as I have never bothered (my engine has never been opened, after 315,000km), but I would recommend stepping up to a 20W50 oil at least - 15w40 is too thin for an A-series engine that old that isn't built. Quote
altezzaclub Posted October 3, 2009 Report Posted October 3, 2009 I'm happy to have a look at it with you Rob- we used to do Datsun 1200s by putting a bit of bent wire in the spark plug hole at TDC to hold the valve up to re-assemble. The valves wouldn't fall down very far at TDC when we removed the seals, we just slipped the wire in to lift them to get them closed with the new seals on. The leakdown idea is a good one- Quote
rob83ke70 Posted October 3, 2009 Author Report Posted October 3, 2009 I've got a new rocker cover gasket sitting at work (the old one is leaking) and I was thinking I would get to have a look when I replace that. The way its burning oil I think the valve stem seals are really really bad or the rings are gone... hopefully just the valve stem seals. I'm headed down to work today to repair the clutch pedal (the hole for the pushrod assembly is flogged out) and maybe grease the caliper slides and replace that gasket. I'll probably find something interesting to do :) If you aren't doing anything, feel free to come down :( I've got 4 matching (near new) black steel rims off a kia rio jb to go on it, and 4 pirelli p6000's lined up from jax, all I need to do is pop the new steering rack bush in it (the rack was moving side to side about 50-60mm because a D clamp was loose and now the bush is flogged out) and get a wheel alignment and we are all set :) Robert. Quote
rob83ke70 Posted October 7, 2009 Author Report Posted October 7, 2009 anyone see any dramas with me running castrol edge sport 25w50 in the 7afe? put new valve stem seals on, and cleaned a lot of carbon off everything, and then took it for a good bed in procedure type drive.... and its still blowing some smoke (with the magnatec 15w40 in it) Robert. Quote
Hiro Protagonist Posted October 7, 2009 Report Posted October 7, 2009 anyone see any dramas with me running castrol edge sport 25w50 in the 7afe? Nope, no problems at all, I ran it for probably 2-3 years before I switched to the Penrite. Quote
rob83ke70 Posted October 8, 2009 Author Report Posted October 8, 2009 what flavour of penrite are you running? any particular reason for the switch? I'm having a guess here that dohc 16v 7afe needs an oil with higher shear resistance and possibly temp resistance than pushrod little 4k (or pushrod big lump of a holden 202 etc) so I should run something like the edge sport 25w50 as opposed to a gtx3 20w50 or similar.... Robert. Quote
Hiro Protagonist Posted October 8, 2009 Report Posted October 8, 2009 what flavour of penrite are you running? any particular reason for the switch? I'm having a guess here that dohc 16v 7afe needs an oil with higher shear resistance and possibly temp resistance than pushrod little 4k (or pushrod big lump of a holden 202 etc) so I should run something like the edge sport 25w50 as opposed to a gtx3 20w50 or similar.... Robert. HPR-30 (20W60), it's the same stuff the 4AGE guys run. Did the swap because it was a bit cheaper than the Edge Sport but had a good rap. And GTX2/GTX3 is what is recommended for the car from factory, or Magnatec, in reality if you're not tracking it then there isn't much difference between oils of the same weight as long as you don't buy the $5 recycled crap. Quote
rob83ke70 Posted October 9, 2009 Author Report Posted October 9, 2009 oil book said 15w40 of some flavour in castrol.... valvoline say 20w50 probably.... i think... anyway, I will look into it for the next oil change... in the mean time.... let the smoke flow freely! Robert. Quote
Hiro Protagonist Posted October 9, 2009 Report Posted October 9, 2009 oil book said 15w40 of some flavour in castrol.... valvoline say 20w50 probably.... i think... The Toyota manual (ie what comes with the car) recommended either 15W40 or 20W50 from factory (depending on what kind of temps you were expected to experience), seeing as how your engine is over 15 years old I would definitely go to the upper/thicker range to compensate for worn rings/seals. Quote
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