Engine Swap

#1

So I finally picked up a new (to me) engine to replace the one that I blew a while back at Summit. The new engine has 170k and good compression. Only stated issue is a possible oil pan leak.

I don’t want to do a full rebuild, but would like to refresh it before installation. Any recommendations on what I should do before installation? I’m sure this has been discussed before, but I didn’t see anything in the search.

Obviously I’ll do the timing belt, water pump, spark plugs, all fluids, rubber hoses and belts, motor mounts, oil pan gasket, adjust the valves and replace the rubber dog ears. Any recommendations on a baffle for the oil pan? Should I do the rear main seal? Anything else that I should do?

Thanks.

#2

I would do a head refresh. If you don’t, your teeth are going to grind at every event because you’re going to wonder if you pissed away 3-4hp because you didn’t refresh the head.

The engine\oiling subforum has a thread for each oil control system available to us. I would put in a baffle and also a scraper.

Might as well put in a rear main seal. Get an OEM one, not a cheap one.

#3

Thanks Ranger. Still doing HPDE’s so I can live with the loss of 3-4 hp. Would consider a head refresh if it really makes sense to do now vs having to do it down the road.

Also, is it worth replacing crank seals as preventative maintenance or is it best to just leave it alone?

#4

I can’t gauge how comfortable you are with these tasks so it’s hard to answer. This is a good time for the rear seal because once the engine is in that task gets a lot harder. A weepy front seal just means an oil drip, but a weepy rear seal can mean oil on the clutch. If both front and rear of the engine have no evidence of leaking seals, maybe leave them alone or maybe replace the rear seal. There’s no right answer. Flip a coin.

With a 170k motor, it’s time for a head refresh. Sure, it’s not a crisis, but it’d be a lot easier to do it now then do it next year with the engine in the car.

#5

To expand on Scott’s suggestions. Check main and rod bearings while you have the pan off…easy to replace. Look at doing the oiling modification of getting rid of the oil pressure relief valve which enables you to baffle the pan better.

A good junk yard motor will make 145hp…I said GOOD!!! Mill and freshen the head will add up to 15hp!!

#6

[quote=“Ranger” post=77099]I can’t gauge how comfortable you are with these tasks so it’s hard to answer. This is a good time for the rear seal because once the engine is in that task gets a lot harder. A weepy front seal just means an oil drip, but a weepy rear seal can mean oil on the clutch. If both front and rear of the engine have no evidence of leaking seals, maybe leave them alone or maybe replace the rear seal. There’s no right answer. Flip a coin.

With a 170k motor, it’s time for a head refresh. Sure, it’s not a crisis, but it’d be a lot easier to do it now then do it next year with the engine in the car.[/quote]

Yeah, I had to replace the rear main seal on my last engine a few times (major pain). It was a rebuilt engine that came with the car when I bought it and I believe that I may have had excess wear, which caused the seal to leak regardless of me using Curil and placing the new seal outside of the existing groove. I should probably do the seal now while the engine is out. I don’t want to do this job again from under the car.

Hmm. I guess I should look at refreshing the head now.

#7

Any idea how much I’m looking at to freshen the head? How much to have the engine installed? I’m in Northern Virginia so rates here are a little high. Thanks.

#8

If the shop disassembles and reassembles the head, I’d figure $400-$800 depending on how impressed with themselves the shop is.

Assumptions:

  • All valves are good.
  • You choose not to replace cam ($200) or rockers ($25-$40 ea).
  • Head’s cam journals are fine. If they are not fine the head is junk.

Replacing the rockers, rocker eccentrics, and cam, is not mandatory but if you’ve got the cash now is the time. You will get a bit more lift out of new rockers and eccentrics, and some of your old rockers might be stressed and therefore headed for failure. The cam might have wear on it’s leading lobe.

One way to approach this is to tell the machine shop to closely inspect rockers, rocker eccentrics and cam, and tell you if anything shows wear. Then you go buy replacements.

The idea that a valve adjustment compensates for rocker and eccentric wear is not 100% correct. Valve lash is set with the rocker horizontal touching cam and valve stem, but when the cam pushes it up a different place on the rocker (and eccentric) touches cam and valve stem. Therefore adjusting valve lash is only a rough adjustment once rocker and eccentric become worn.