Questioncar overheated - oil in coolant removed head to replace gasket so doing timing belt, accessory belt, etc
1. what about water pump? remove clean and reinstall with a new seal or get a new one?
2. can I clean and reuse head bolts or is that asking for trouble?
3. I lost the cylinder head locating devices - have one, but that's it. how many are there and where can I order them?
4. timing belt alignment is scaring me, but have keith tanner book - guess I need someone to hold the camshaft rim marks at 12 oclock with I and E marks pointing towards head marks. any other tips? I put main crank at TDC before I removed head.
5. crank seal - I want to replace but am afraid of shearing off the crank pulley bolt...should I be concerned?
I have done head gaskets on my daughter's OHC chryslers before so I'm not a complete idiot. Sorry for all the questions but you are the first qualified person I have run across....hope you can help since I would like to get her back together before winter sets in. Do you take phone calls? I could pay you some for consulting on this....
regards,
ralph
AnswerYou'll need more than just a head gasket for an overheat. You'll need to locate a good machine shop familiar with the Mazda OHC 4 valve to overhaul it, check clearances and machine as needed. As part of it the valves will be removed cleaned and re-cut to the seats and new valve seals installed. During an overheat the heads suffer significantly. Cams expand, valves expand and these steel components can damage the aluminum. Only a shop experienced with the OHC head can insure that your putting back on a usable head. Otherwise you run the risk of going through the install only to discover other issues.
As for your other questions;
New water pump and use Mazda for another 125k of use.
The head bolts should be fine
Before you remove the cam gears snap a digital picture of the placement and be sure to put the dowel and cam gear slots exactly the same upon reassembly.
Upon reassembly, either remove the tensioner bearing or lock it all the way open this will help you slip the belt on. The crank and the exhaust side gear should remain constant for you have a 14mm socket on the intake gear so you can hold it in place as you slip the belt on. Put the tensioner on and allow it to spring seat loosely on the belt. Hand rotate the engine 2 times clockwise (do not turn it counter clockwise) and check your marks if off repeat. Once your right, rotate to 1 and 5/6 clockwise to the tensioner mark, lock down the tensioner the rotate to TDC and again, check your marks.
No concern with the crank pulley bolt but you must set the keyway properly upon reassembly. Seal replacement for the cams and crank are due at 125k. Also change the crank angle O-Ring and inspect the heater hoses for oil impregnation, specifically the #2 hose (behind the engine).
If you can't find a shop to machine the head you can ship it to us, Miatas are what we do.
service@miatashop.com
