My engine in my 1988 4Runner, post HG replacement, is back together and doing great.

One small oddity. Upon final assembly I came upon a situation where the valve cover would not seat against the head towards the front of the engine. Basically, there is a ridge that is just to the front of the front two valve cover holes, and this hits the second row of cylinder head studs. I just took a Dremel and knocked down the ridge to clear the studs, but it kinda threw me as I don't remember anyone else mentioning this in their HG postings in the forum.

I was able to search and find mention of it on the Celica-GTS website, though, so I know I'm not crazy. I'm fairly certain that the studs screwed in as far as they could, as I spent a lot of time chasing the threads/cleaning out the holes.

Anyway, thought I'd post so if others searched for this it would come up in their results.

Anyone else experience this?

Mine fit w/o an grinding. I did seat the studs down very far, double-nutting them and tightening them down into the block pretty snug.

What Roger said, although my understanding is that the studs should be only finger tight when you actually begin assembly. Did you make sure you didn't trap any liquid/crud in the bottom of the head bolt holes? I've found it's good to chase these holes with a liberal amount of brake cleaner -- the potent, fast evaporating type. Having liquid trapped at the bottom of these would truly suck. Once you believe you have all studs bottomed out, use a straight edge across all five studs and make sure there aren't any that are obviously higher/lower.

-Jeff

I think I've got them seated all the way down w/o crud in there. Some of the headbolts came out clean, but some were nasty, so I knew I'd have to do some work on them. Brake clean, compressed air, grooved headbolt, tap were all used. They all seated to the same height, finger tight per instructions.

.009" was removed from the cylinder head surface, and any amount removed from the head could decrease the clearance to that ridge on the inside of the valve cover. So maybe that's part of it.

The Celica GTS thread is here, maybe it's just a valve cover design difference. The thread indicates an issue w/ the later valve covers, but I don't know what that date range would be. I'd say 85-95, but since you/4Crawler didn't encounter this, I'm not sure what to say...

Huh, sure seems like a problem I would have run into, but yet I didn't. Are you running a new valve cover gasket? In any event, it sounds like you've addressed the things that would cause this to be a problem. If everything else checks out I guess you'll need to grind a bit off the inside of the valve cover.

The older valve covers are a touch lower in height than the later ones; the baffles are a little bit different too; I have one of each; you can tell by the long profile the difference, without regard to the front being sloped as compared to vertical.

Seemed to me there was a tower difference; maybe EB mentioned it a few moons ago.

Just for reference, I hit this problem also. It's not obvious (at least not to me) - it looks like it seals, but I get leaks at RPM and when I'm up to temperature (thinner oil) - I'll pull the cover and grind tomorrow. Torquing down the valve cover does not increase the pressure on the seal, so I know something is out of wack. I've used ARPs before and this is the first time I've had an issue. Block was cleaned (tanked), threads were tapped, and the bolt holes sprayed out while upside down.

>>>*Yep, it's been many moons since we even ran into this one.

*Part of the reason is as time goes on we see less and less of the older engines. Without being 100% sure, it appears that the earlier 20R and 22R engines had a lot of "fitting" work done by the factories, so we were running into a few sets of rocker shaft stands that were actually taller than later ones. Not by much, but I have measured up to .030" difference.

That was embarrassing when we would rebuild a rocker shaft assembly and have it rock on the top of the casting. It was either that or someone beat us to them and had a setup milled to correct rocker arm angles when running reground camshafts.

The later ones seem to be much more consistant so differences like this correct themselves over time as we see less and less of those early engines.

Surfacing of course affects how high the stud sets too.

It is important to remember to not use a tap, those can remove metal. We cut a groove in the threads of an old head bolt to chase the threads, that works very well. Then we use brushes and with the block upside down we blow out the thread holes completely.

If it is going to interfere we will then cut a notch for clearence, this works fine too.

There was a concern regards oiling and cam lobe failures, the ARP stud being fatter. I read it on another board I think. But at this point I don't think that is a problem, still, something to check for....*EB

EB, what do you mean by cut a notch?

>>>*In the baffle, or just cut the stud back a little.

My son is fussy, he set up and machined the holdown nut seat back on the rocker stands, then he shortened the stud.

I was always lazy and used my die grinder.. <img src="/forums/images/graemlins/lol.gif" alt="" />..*EB