Changing a Midget Engine

[kawazar]

I recently purchased a 78 Midget for the engine and interior. I will be putting the engine in my 76 Midget. The engine has 50000 miles and runs great. I have not pulled it yet but from what I can see through the oil fill the head and valve train are very clean. My question is what if anything should I do prior to putting it in the other car? A clutch, oil pump? Also, the head on the 78 has no air injection ports or rails. It did have a smog pump at one time. Is this correct?

 

[Bugeye58]

Rob, the first thing I would check would be the crank end float. If it's over .008" put in new thrust washers. 1500's are notorious for eating them. Any idea what kind of oil pressure the new engine has? If it's decent you could still have a look at the pump, and replace it if you think you should. It probably wouldnt hurt to take a look at at least one rod bearing, and one main bearing,while you're there.
A new clutch (all three pieces) would be a good idea as well, as long as it''s out. Easier to do it now as a precautionary measure, than to have to yank it later.
Only the California spec cars had the air distribution rails to the head. The Federal cars had an air pump, but it ran to the exhaust manifold.
Good luck.
Jeff

 

[kawazar]

I am not sure what the oil pressure is. I will probably get a gauge on it before I pull it. What am I looking for on the bearings? The internal engine stuff is something I have never dealt with before. How ever I am not scared to try it.

 

[Andre the Giant]

I'm a strong proponent of doing internal work whenever you have the engine out. New rings and bearings, timing chain, water pump, push rods and oil pump are all worth the money if you can spare it. Definitely replace the clutch!

Hopefully you won't have the engine out of the car again... but lets be realistic... I pulled the engine out of my Midget three times in the same year trying to fix a clutch problem. If you don't get around to an engine rebuild, you will probably get another chance somewhere down the road.

 

[ThomP]

For the bearings, you are looking for any obvious wear. Scoring or ridges on the crank, copper showing through the bearings.

I would suggest you purchase some "Plastigauge" from your local auto supplier and measure the clearances of the bearings you choose to remove. It's a bit more fiddling, but you will know scientifically that the clearances are up to snuff.


Plastigauge

Here's their site.

 

[StevenA]

I agree with Andre... If you have the engine out... rebuild everything you can afford and take it down as far as you are comfortable. If you don't do that at this opportunity, It is guaranteed that you will HAVE TO in the near future. Get a manual for that year of engine and follow step by step a full engine rebuild... don't rush it and do as much as you can afford to do before you put it back in place. Put in new motor mounts and tranny mounts while you are at that end of the car too. Do it right and do it complete. You will be much happier in the long run.

 

[kawazar]

If you guys would not mind helping me out here, can I replace the bearings by just removing the old ones and putting in new standard size ones?

 

[aeronca65t]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by kawazar:
If you guys would not mind helping me out here, can I replace the bearings by just removing the old ones and putting in new standard size ones?<hr></blockquote>

Maybe.
It depends on whether the crankshaft has been cut down in the past. You would need to see if the bearings are marked "0.010" or "0.020" or "0.030" (the amount of undersize). Not all bearings are marked, so you might have to measure the crankshaft with a micrometer to see the actual size.
If the cranks measures stock (or very, very close) you could slip in a new set of bearings with good results. If you were to put standard bearings in an engine that had a cut-down crank, you'd have a disaster in short order.
In my experience, rod bearing and thrust washers are the weakest link in these engines.

 

[TommyMG]

Not to steal this thread but I am currently pulling my engine out of a 75 Midget. (1500)
Is there a rebuild kit out there that includes all the gaskets, bearings, rings etc? Thanks!

 

[Matthew E. Herd]

You can find gasket kits from moss or (probably) a number of other places. However, bearings and rings are determined by overbore and grind of crank, which needs to be done first, so they pretty much need to be bought separately

 

[tony barnhill]

There's a difference in 'rebuild' & 'refresh'.....'rebuild' - to me - means new pistons, turn crank, replace cam, etc...'refresh' - to me - means just replacing the rings, bearings, etc....if you've got decent oil pressure, I vote for 'refresh'

 

[TommyMG]

I am looking into the "refresh".
Only 43K on the engine but has been sitting and run only once or twice a year.I cant seem to find a complete kit...Its all bit by bit. I have all new parts for the outside...its the inside I want to take care of since the engine will be out of the car.

 

[Matthew E. Herd]

Alrighty then, in that case, like i said before, check out moss or their distributors for the gasket kits (which are pretty much all encompassing in that department). Victoria british is also good. For bearings and rings, perhaps you could contact your local engine builder and find out where he orders them from. In that department, once you've determined the correct sizes (measure!) you can order bearings and rings from a variety of locations. VB and Moss offer rings, i know for sure, I don't recall about the bearings. However, a common type is "Federal Mogul." These are probably adequate for all intents and purposes. There is a bit of a debate about different types, but for a street engine, I don't believe that its terribly critical.

 

[aeronca65t]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by TommyMG:
....I cant seem to find a complete kit...Its all bit by bit....<hr></blockquote>

There is no such thing as a complete kit. Parts are purchased as required.
And Matthew is correct....measure! (especially bores and bearing journals).

 

[TommyMG]

Thanks for the input! Just thought there would be one out there. Looks like we have a few people with 1500 experience. Are you still running Strombergs or did you modify? What was your best findings here. Also thinking about a cam upgrade...Bad idea? Thanks again!!!

 

[kawazar]

The engine I am using has a Weber downdraft that I will probably remove and sell because I previously purchased a dual SU set up that is used on the UK cars. I do feel that my engine ran better with the Weber than the Strom. unit.

 

[TommyMG]

The Strombergs are a funny animal thats for sure.
That will be probably last on the list I have for now. I have been eyeing up those aluminium fly wheels but they sure are pricey but the weight differnce seems to be impressive. I need to complete the body work first. I am getting way ahead of myself here....again!

 

[Matthew E. Herd]

I wouldn't bother with the flywheel for a street engine. It makes the engine spin less smoothly. I did the Kent Cams TH5 kit (this is designed to be a street racer for autocross, hill climb and time trail) and dual 2 barrel 40mm sidedraft Webers (not the downdraft). The downdraft was on it when i got it, and ran alright, but if you do work to the engine, i suggest a single 2bbl weber 45 ... my dual 40's really roar!

 

[TommyMG]

Thanks for the info on the flywheel...does not sound like its worth it. The dual webers sound great though! I have been looking at the Kent cams in the VB catalog and they only list a "road" cam for the 1500 but they do have the bearing kit I was looking for. Hopefully all will be done by this fall.

 

[aeronca65t]

Source of various Kent cams and lots of other neat 1500 stuff:

https://www.aptfast.com/Main_Index_Page.htm

This site is a bit clumsy: easiest way to find Kent cams is to type "kent" into their search box.
Remember that most parts for 1500 Spitfire are the same so you can look at the Rimmer Brothers site for more stuff.

https://www.rimmerbros.co.uk/cgi-bin/rimmer?spitfire/spitfireindx

[ 04-16-2004: Message edited by: aeronca65t ]</p>